Document 5RQQwKga1RjZ2dxO8LnG9weD

API RP*752 RSTB 0732jffibflSKW81% 130 Management of Hazards Associated With Location of Process Plant Buildings API RECOMMENDED PRACTICE 752 CMA MANAGER'S GUIDE, FIRST EDITION, MAY 1995 Responsible Care* A Public Commitment A CHEMICAL MANUFACTURERS ASSOCIATION 2501 M Street, Northwest Washington, D.C. 20037 Strategiesfor Today's Environmental Partnership American Petroleum Institute 1220 L Street, Northwest Washington, D.C. 20005 Copyfi<|lil by Ihc AMERICAN PEIR01CUM INSWUIE(API) I'li Ocl 04 11:11:4 j 19% API RP*7Sa H5 674 Date of Issue: October 1995 Affected Publication: API Recommended Prxtice 752, Management ofHazards Associated WithLocation of Process Plant Buildings, CMA Manager's Guide, First Edition, May 1995 (first printing) ERRATA On Page 5, in Figure 2, the paragraph references have been added to the Stage 3 box._The Stage 3 box should appear asfollows: OnPage21,ItemdinCJJ should read asfollows: d. B4: Steel or concrete framed with nnreinforced masonry infill or cladding. On Page 21, thefirst line ofItem d in C.12 should read asfollows: d. Steel or concreteframed with unrtinforced masonry infill or cladding, B4:... CopytMfhl by the AMERICAN PETROLEUM INSIITUTE(API) I'ti Oct 01 11:11:43 1996 API RP*752 'JS Q73&SnDWB)Q&iW fi77 Responsible Care* A Public Commitment In 1988, the Chemical Manufacturers Association (CMA) launched Responsible Care* to respond to public concerns about the manufacture and use of chemicals. Through Responsible Care*, member companies are committed to supporting a continuing effort to improve the industry's responsible management of chemicals. Responsible Care* has ten key elements: The Guiding Principles--the philosophy of Responsible Care*--outline each member company's commitment to environmental, health, and safety responsibility in managing chemicals. Six Codes of Management Practices, which are the heart of Responsible Care*, outline practices that cover virtually every aspect ofchemical manufacturing, transporting, and handling. CMA's National Public Advisory Panel, a group of environmental, health, and safety thought leaders, provides the public perspective on Responsible Care* and its activities. Member Self Evaluations provide a measure of member company progress in fully implementing Responsible Care* and are a valuable management tool. Performance Measures are being developed or exist already to show, through external measures, the progress CMA member companies are making in carrying out Respon sible Care*. Management Systems Verification will assist in member company improvement by including appropriate third-party involvement Executive Leadership Groups, in which the key executives from member companies meet regularly to share experiences and review progress in Responsible Care*. Mutual Assistance Network, which focuses on direct networking between companies at different levels to assist in implementation of all the elements of Responsible Care*. The Partnership Program provides an opportunity for those who otherwise might not be eligible for member in CMA itself to still be involved ia the Responsible Care* initia tive. Responsible Care* is an Obligation of Membership in CMA. Copyriqht by the AMERICAN PETROLEUM INSIIUJlF.(APl) hi Oct (M 1996 API RP*7S2 S STEP One of the most significant long-term trends affecting the future vitality of the petroleum industry is the public's concerns about the environment Recognizing this trend. API member companies have developed a positive, forward looking strategy called STEP: Strategies for Today's Environmental Partnership. This program aims to address public concerns by improving industry's environmental, health, and safety performance; docu menting performance improvements; and communicating them to the public. The founda tion of STEP is the API Environmental Mission and Guiding Environmental Principles. API standards, by promoting the use of sound engineering and operational practices, are an important means of implementing API's STEP program. API ENVIRONMENTAL MISSION AND GUIDING ENVIRONMENTAL PRINCIPLES The members of the American Petroleum Institute are dedicated to continuous efforts to improve the compatibility of our operations with the environment while economically developing energy resources and supplying high-quality products and services to consumers. The members recognize the importance of efficiently meeting society's needs and our responsibility to work with the public, the government, and others to develop and to use natural resources in an environmentally sound manner while protecting the health and safety of our employees and the public. To meet these responsibilities, API members pledge to manage our businesses according to these principles: To recognize and to respond to community concerns about our raw materials, products, and operations. To operate our plants and facilities, and to handle our raw materials and products in a manner that protects the environment and the safety and health of our employees and the public. To make safety, health, and environmental considerations a priority in our planning and our development of new products and processes. To advise promptly the appropriate officials, employees, customers, and the public of information on significant industry-related safety, health, and environmental hazards, and to recommend protective measures. To counsel customers, transporters, and others in the safe use, transportation, and disposal of our raw materials, products, and waste materials. To economically develop and produce natural resources and to conserve those resources by using energy efficiently. To extend knowledge by conducting or supporting research on the safety, health, and environmental effects of our raw materials, products, processes, and waste materials. To commit to reduce overall emissions and waste generation. To work with others to resolve problems created by handling and disposal of hazardous substances from our operations. To participate with government and others in creating responsible laws, regulations, and standards to safeguard the community, workplace, and environment. To promote these principles and practices by sharing experiences and offering assistance to others who produce, handle, use, transport, or dispose of similar raw materials, petroleum products, and wastes. \ Cosyiicjhl by the AMERICAN PETROLEUM INSIITUIE(API) 1 ri Oct 04 11:11:4j 1996 API RP*752 IS QAiaB5ai(B69`1Sl 425 Management of Hazards Associated With Location of Process Plant Buildings API Health and Environmental Affairs Department CMA Regulatory Affairs Department API RECOMMENDED PRACTICE 752 CMA MANAGER'S GUIDE, FIRST EDITION, MAY 1995 CHEMICAL MANUFACTURERS ASSOCIATION 2501 M Street, Northwest Washington, D.C. 20037 Copyriijht by the AMERICAN PETROLEUM INStlTUIE(API) fri Oct 04 11.1 l:4J 1996 American Petroleum institute API RP*7S2 SS Q7^^0tftWfe2 3bl SPECIAL NOTES 1. API AND CMA PUBLICATIONS NECESSARILY ADDRESS PROBLEMS OF A GENERAL NATURE. WITH RESPECT TO PARTICULAR CIRCUMSTANCES, LOCAL, STATE, AND FEDERAL LAWS AND REGULATIONS SHOULD BE REVIEWED. 2. API AND CMA ARE NOT UNDERTAKING TO MEET THE DUTIES OF EMPLOYERS, MANUFACTURERS. OR SUPPLIERS TO WARN AND PROPERLY TRAIN AND EQUIP THEIR EMPLOYEES, AND OTHERS EXPOSED. CONCERNING HEALTH AND SAFETY RISKS AND PRECAUTIONS, NOR UNDER TAKING THEIR OBLIGATIONS UNDER LOCAL, STATE, OR FEDERAL LAWS. 3. INFORMATION CONCERNING SAFETY AND HEALTH RISKS AND PROPER PRECAUTIONS WITH RESPECT TO PARTICULAR MATERIALS AND CONDI TIONS SHOULD BE OBTAINED FROM THE EMPLOYER, THE MANUFACTURER OR SUPPLIER OF THAT MATERIAL, OR THE MATERIAL SAFETY DATA SHEET. 4. NOTHING CONTAINED IN ANY API OR CMA PUBLICATION IS TO BE CONSTRUED AS GRANTING ANY RIGHT, BY IMPLICATION OR OTHERWISE, FOR THE MANUFACTURE, SALE, OR USE OF ANY METHOD, APPARATUS, OR PRODUCT COVERED BY LETTERS PATENT. NEITHER SHOULD ANYTHING CONTAINED IN THE PUBLICATION BE CONSTRUED AS INSURING ANYONE AGAINST LIABILITY FOR INFRINGEMENT OF LETTERS PATENT. 5. NEITHER API NOR CMA, NOR ANY OF THEIR EMPLOYEES, SUBCONTRAC TORS, CONSULTANTS. OR OTHER ASSIGNS MAKE ANY WARRANTY OR REPRESENTATION, EITHER EXPRESS OR IMPLIED, WITH RESPECT TO THE ACCURACY, COMPLETENESS, OR UTILITY OF THE INFORMATION CONTAINED HEREIN, OR ASSUME ANY LIABILITY OR RESPONSIBILITY FOR ANY USE, OR THE RESULTS OF SUCH USE, OF ANY INFORMATION OR PROCESS DISCLOSED IN THIS PUBLICATION, OR REPRESENT THAT ITS USE WOULD NOT INFRINGE UPON PRIVATELY OWNED RIGHTS. 6. GENERALLY, API RECOMMENDED PRACTICES ARE REVIEWED AND REVISED, REAFFIRMED, OR WITHDRAWN AT LEAST EVERY FIVE YEARS. SOMETIMES A ONE-TIME EXTENSION OF UP TO TWO YEARS WILL BE ADDED TO THIS REVIEW CYCLE. THIS PUBLICATION WILL NO LONGER BE IN EFFECT FIVE YEARS AFTER ITS PUBLICATION DATE AS AN OPERATIVE API STAN DARD OR, WHERE AN EXTENSION HAS BEEN GRANTED, UPON REPUBLICA TION. STATUS OF THE PUBLICATION CAN BE ASCERTAINED FROM THE API AUTHORING DEPARTMENT [TELEPHONE (202) 682-8000}. A CATALOG OF API PUBLICATIONS AND MATERIALS IS PUBLISHED ANNUALLY AND UPDATED QUARTERLY BY API, 1220 L STREET. N.W., WASHINGTON, D.C. 20005. Copyright O 1995 American Petroleum Institute :opyii(||il by the AMCRICAN PETROLEUM INSIITU![(AP1} ti Ocl 0-1 11:11:0 1996 API RP*7S2 =15 Q73^RP%WWi3 2Tfl FOREWORD This publication is intended to assist management in identifying process plant buildings of concern, understanding the associated hazards, and managing the risk. The hazards that normally can affect the occupants of buildings include fire, explosion, and toxic releases. This publication provides a methodology for assessing and evaluating the hazards associ ated with location of process plant buildings. This publication is based on the fact that serious accidental releases of toxic material or an explosion that impacts occupied process plant buildings are not frequent events. Addi tionally, preventing incidents in process plants is generally a better investment in safety than providing mitigation systems or redesigning process plant buildings. The implementation of process safety management, as described in API Recommended Practice 750 and the Chemical Manufacturers Association's (CMA) Process Safety Code, is intended to improve industry's safety performance. Risk management involves cost-effective applications of risk-reduction alternatives. Because this publication affects many existing buildings within processing facilities, a substantia] effort may be required for full implementation of the recommended practice. This could include identifying buildings of concern, conducting building evaluations, and, if appropriate, performing building upgrades or modifications. It is recognized that a substantial period of time may be required for complete application of the recommended practice, due to the scope and magnitude of the endeavor. API publications and CMA guides may be used by anyone desiring to do so. Every effort has been made by the Institute and CMA to assure the accuracy and reliability of the data contained in them; however, the API/CMA makes no representation, warranty, or guarantee in connection with this publication and hereby expressly disclaims any liability or respon sibility for loss or damage resulting from its use or for the violation of any federal, state, or municipal regulation with which this publication/guide may conflict Suggested revisions are invited and should be submitted to the Director, Health and Envi ronmental Affairs Department American Petroleum Institute, 1220 L Street N.W., Wash ington, DC 20005 or Process Safety Task Group, Chemical Manufacturers Association, 2501 M Street N.W., Washington, DC 20037. Copyrujtit by the AMI.RlCAN POROLLUM INSlUUIFfAM) hi Oct 04 11:11:4 j 1996 v API RP*7SS 073feWll3$%4 134 i CONTENTS i SECTION 1--GENERAL 1.1 Purpose.............................. 1.2 Scope.................................. 1.3 Definitions......................... 1.4 Referenced Publications.... Page ... 1 ... 1 ... 1 ... 2 SECTION 2--MANAGEMENT OVERVIEW 2.1 Hazards to Occupants of Process Plant Buildings..................................................... 2 2.2 Process Plant Building Issues of Concern................................................................. 3 2.3 Overview of Analysis Process.................................................................................... 3 2.4 Using This Recommended Practice............................................................................4 2.5 Occupancy and Emergency Role Criteria................................................................... 4 SECTION 3--EXPLOSION ANALYSIS 3.1 Stage 1--Building and Hazard Identification............................................................ 7 3.2 Stage 2--Building Evaluation................................................................................... 8 3.3 Stage 3--Risk Management..................................................................................... 11 SECTION 4--FIRES 4.1 Materials of Concern.......... -................................................................... ................. 13 4.2 Building Occupancy................ 13 4.3 Spacing........................................................................................................................ 13 4.4 Mitigation and Emergency Response....................................................................... 14 4.5 Risk Reduction for Fire.............................................................................................. 14 SECTION 5--TOXIC MATERIALS 5.1 Toxic Material of Concern..................... ................................................... . 5.2 Building Occupancy................................................................................... 5.3 Site Conditions............................ ............... ............. ................................. 5.4 Mitigation and Emergency Response..... -...... ........................................ 5.5 Risk Reduction for Tbxic Release............................................................. 15 15 15 15 16 SECTION 6--BUILDING CHECKLIST............................................ 16 SECTION 7--PROCESS SAFETY MANAGEMENT DILIGENCE... 16 APPENDIX A--BIBLIOGRAPHY OF ADDITIONAL READING............................ 17 APPENDIX B--EXPLOSION, FIRE, AND TOXIC RELEASE PHENOMENA, AND HAZARDS TO THE OCCUPANTS OF PROCESS PLANT BUILDINGS............................................................................. 19 APPENDIX C--DAMAGE CATEGORIZATION FOR BUILDINGS AND VULNERABILITY OF OCCUPANTS TO EXPLOSION OVERPRESSURE.................................................................................. 21 APPENDDCD--PROCESS PLANT BUILDING CHECKLIST................................... 25 APPENDIX E--EXAMPLES............................................................................................ 27 Figures 1--Stages for Explosion Risk Analysis........................................................................... 4 2--An Analysis Process for an Explosion....................................................................... 5 3--Sample Risk Matrix.................................................................................................. 12 vii Copyriqlil by tltc AMCRICAN I'tTROIlUM INSIIIUIC(API) IriOcl 01 11 11:43 I9`J6 API RP*7S2 RS 07AK3Dfl6ft^SS"Q7Q P*B 4--An Analysis Process for a Fire................................................................................. 14 5--An Analysis Process for a Toxic Release................................................................ 15 C-l--Overpressure Versus Vulnerability.......................................................................22 Tables 1--Examples of Process Safety Information Needs by Stage...... 2--Summary of Possible Explosion Effects on Buildings............ 3--Overpressure Effects oo Various Building Components.......... 4--Overpressure Effects on Various Building Types.................... 5--Typical Overpressure Effects on Unprotected People.............. 6--Sample Risk Ranking Categories.............................................. C-1--Generic Frequencies of Major Explosions............................ Copyriqhl by the MlRICAN PETROLEUM INSIHUTE(API) I,, ()cl 04 11:11:43 IMG viii API RP*7S2 1S (ASSWflOiSVnSb T07 Management Of Hazards Associated With Location Of Process Plant Buldings SECTION 1--GENERAL 1.1 Purpose This publication (RP 752) provides guidance for identi fying hazards that may affect process plant buildings and for managing risks related to those hazards. An analysis process set forth in this Recommended Practice provides a structured approach that can maximize worker safety by the following: a. Continuing to improve the understanding of identified hflTflnk. b. Continuing to focus on accident prevention and addressing identified hazards. c. Managing risk. The methodology recommended in this document will help provide the user with an understanding of the relative risk of each building studied. This relative.risk should be considered in long-range planning and projects that involve building changes (such as control building consolidation, office building replacements, and so forth). 1.2 Scope 1.2.1 APPLICABILITY This publication was developed for refineries, petrochem ical and chemical operations, natural gas liquids extraction plants, and other facilities covered by API RP 750 or the Chemical Manufacturer Association's Process Safety Code. This publication does not apply to production facilities surrounded by navigable waters, such as offshore platforms. Such facilities have unique siting issues which are addressed by other recommended practices, such as RP 14J. Additionally, this publication is not intended for use in designing and locating safe refuge from the effects of fires, explosions, and toxic releases.1 1 J2.2 RELATIONSHIP OF THIS RECOMMENDED PRACTICE TO OSHA 29 CFR 1910.119 OSHA 29 Code ofFederal Regulations (CFR) 1910.119, "Process Safety Management of Highly Hazardous Chemi cals (PSM)," includes requirements for addressing facility siting as part of a process hazards analysis (PHA). This publication is intended to assist in identifying the siting issues for process plant buildings, understanding the associated hazards, and managing the risk. Hence, this publi cation provides a framework that can be used to address facility siting within the PHA requirements of OSHA 29 CFR 1910.119 as applied to buildings. The PHA as required by OSHA 29 CFR 1910.119 is intended to identify scenarios that could lead to serious release of toxic or flammable materials or an explosion. Those parts of this publication intended to assist in the PHA process are identified on the flowcharts (see Figures 2,4, and 5) by a dashed-line box labeled "PHA." The remaining parts are intended to serve as management aids in resolving issues that arise when evaluating the location of process plant buildings. 1.3 Definitions For the purpose of this publication, the following deflntions apply: 1.3.1 Aggregate risk is a measure of the total risk to all personnel within a building(s) or within a facility, depending upon the risks being evaluated, who are impacted by a common event, taking into account the total time spent in the building(s) or facility. 1.3.2. Assessment describes a detailed qualitative or quan titative analysis to estimate the potential likelihood and consequences of site-specific events, and to then compare the results with acceptance criteria. 1.3.3 Confinement is a qualitative or quantitative measure of the enclosure or partial enclosure areas where a vapor cloud may be contained. 1.3.4 Congestion is a qualitative or quantitative measure of the physical layout, spacing, and obstructions within a facility that promote development of a vapor cloud explosion. 1.3.5 An evaluation-case event is the scenario with the most severe consequences, considering all incidents and their outcome, that is considered plausible or reasonably believable. 1.3.6 Evaluation describes the application of analytical tools to aid in making decisions about buildings. 1.3.7 A hazard is an inherent physical or chemical charac teristic that has the potential for causing harm to people, property, or the environment 1.3.8 Individual risk is the risk to a single person inside a particular building. Maximum individual risk is the risk to the most-exposed person and assumes that the person is exposed. 1.3.9 A process plant building (also referred to in this recommended practice as a building) is any temporary or permanent building within a facility that could be impacted by a serious release from a process covered by OSHA 29 CFR 1910.119. i Copyriqhl by the AMERICAN PETROLEUM INSTITUTED) hi Ocl 04 11:11:43 1996 API RP*752 SS 07^290103^57 *143 2 API Recommended Practice 782 1.3.10 Risk is a measure of potential economic loss or human injuiy in terms of both the incident likelihood and the magnitude of the loss or injury. 1.3.11 Screening describes a process of comparing the site-specific materials and process conditions, and building occupancy with pre-established criteria of concern. 1.4 Referenced Publications The following guidelines, standards, codes, and specifica tions are cited in this publication: AIChE1 Dow Chemical, Fire and Explosion Index Hazard Classi fication Guide, 7th ed. Guidelines for Chemical Process Quantitative Risk Analysis, Center for Chemical Process Safety of AIChE Guidelinesfor Evaluating Process-Plant Buildingsfor External Explosion and Fire, Center for Chemical Process Safety of AIChE, Work-in-progress Guidelinesfor Evaluating the Characteristics of Vapor Cloud Explosions, Flash Fires, and BLEVEs, Center for Chemical Process Safety Guidelinesfor Hazard Evaluation Procedures, 2nd ed,. Center for Chemical Process Safety of AIChE Guidelinesfor Technical Management ofChemical Process Safety, Center for Chemical Process Safety of AIChE 'American Institute of Chemical Engineers. 34$ East 47th Street. New York, New York 10017. Guidelines for Use of Vapor Cloud Dispersion Models, Steven R. Hanna and Peter 3. Drivas, Center for Chemical Process Safety of AIChE Plant Guidelinesfor the Technical Management ofChem ical Process Safety, Center for Chemical Process Safety of AIChE API RP 14J Recommended Practice for Design and Hazard Analysisfor Offshore Production Facilities RP 750 Management ofProcess Hazards CMA2 A Resource Guide for the Process Safety Code Manage ment Practice ICI3 The Mond Index, 2nd ed. OSHA4 29 Code ofFederal Regulations, Section 1910.119 The Effects ofNuclear Weapons, rev. ed., Samuel Gladstone, Editor, Prepared by the U.S. Department ofDefense, published by U.S. Atomic Energy Commission JQiemical Mxnofacmrers Association. 2501 L Street. NW, Washington. DC 20037. ^Imperial Chemical Industries PLC, Explosion Hazards Section. Technical Department, Winnington, Nortbwich, Cheshire CW8 4DJ, U.K. ^Oocnpatioaal Safety and Health Admifligradco. US. Deputmem ofLabot The Code Of Federal Regulations Is available from the U.S. Government Printing Office, Washington. D.C 20402. SECTION 2--MAN4 ;MENT OVERVIEW 2.1 Hazards to Occupants of Process Plant Buildings 2.1.1 FLAMMABLE MATERIALS Flammable materials, if ignited, can expose buildings to radiant heat from either a flash, jet, pool fire, or fireballs. Additionally, some flammable materials can form vapor cloud mixtures in air, and if delayed ignition occurs and certain site conditions (discussed below) are present, a vapor cloud explosion (VCE) can occur. Depending on the magni tude of the explosion, and the location and specific construc tion details of the building, the explosion can cause varying degrees of risk to building occupants. 2.1.2 TOXIC MATERIALS Occupants of process plant buildings can be exposed to toxic materials if such material enters the building. The dispersion properties of the toxic material involved, the release conditions, and the toxicity of the substance are some of the factors that should be considered when evaluating the potential for toxic effects on building occupants from intru sion of toxic materials. The building's ability to resist toxic materials ingress should also be considered. 2.1.3 OTHER PROCESS MATERIALS Some process materials pose potential risk from runaway reactions or chemically or thermally induced decomposition. Events involving these materials may produce explosion effects, toxic releases, fire, and projectile hazards to process plant building occupants. 2.1.4 EXTREME PROCESS CONDITIONS Extreme process conditions, such as high temperature or pressure, can pose hazards even when the process materials, at ambient conditions, might otherwise be innocuous. For example note the following: opyrujtit by the AMERICAN PUROICUM INSHTUTE(APl) i Oct 04 11:11:43 19% API RP*7S2 7A1BEHHD1036361SA fl&T Management of Hazards Associate) With Location of Process Plant Buhdcnqs 3 a. Compressed gases--Failure of vessels containing high pressure gases can result in the explosive expansion of the gases, producing damaging blast waves. b. Boiling liquid expanding vapor explosions (BLEVES)-- Liquids stored well above their atmospheric boiling points can evaporate at explosive rates if depressurized by the failure of the containment vessel. As with compressed gases, expansion of the resultant vapor can produce blast waves. Additionally, flammable materials, if ignited, can produce fireballs. c. Hot materials--Rapid combination of a hot material and a cold material can lead to the explosive vaporization of the colder material. Damaging explosions have resulted, for example, from the addition ofwater to vessels containing hot oil and from the addition of molten metals to water. 2.1.5 FACTORS INFLUENCING EVENTS Some factors that can determine the type of, or affect an event that may occur include the following: a. Inherent properties of the process material--These include variations in flammability ranges, dispersion proper ties, flame propagation properties (refer to Appendix B for a discussion of the characteristics of explosions, toxicity, and chemical and thermal stability). b. Release conditions--These include process conditions such as pressures and temperatures, as well as the release rate and location of the release. For example, a pressurized release of a gas or vapor, if ignited immediately, can lead to ajet fire. A release of material at cryogenic conditions might produce a heavier-than-air vapor cloud, even if the substance is lighter than air at ambient conditions. c. Other site-specific conditions--For releases that form vapor clouds with subsequent ignition, a key factor influ encing the development of overpressure is the degree of premixing with air and the acceleration of the flame front that results from turbulence generated during combustion. Turbulence can be caused by the release conditions, meteo rological conditions, or the physical layout of the release area. A flame front passing through congested areas containing obstacles, such as process plant equipment and structures, can generate turbulence in the unbumed portion of the vapor cloud, leading to significant increases in flame speed and resulting overpressure. Confinement is another site-specific condition that affects the development ofover pressure. Releases occurring in open areas, with no conges tion or obstructions, generally do not develop significant overpressure upon ignition. d. Process design and control--These factors indude inven tory reduction, process controls, process alarms and interlocks, shutdown systems, redundancies, and mitigation systems. e. Emergency response--The response in an emergency, such as operator intervendon, evacuation, emergency team response, and so forth, can impact the event outcomes. f. Process safety management system--Includes policies, programs, procedures, training, audits, and other elements intended to assure that processing plants are designed, constructed, operated, and maintained in a manner that reduces the potential for serious accidents. Examples include equipment and piping inspection programs, personnel training, safe work practices (for example, lockout/tagout and hot work permit), management of change, and operating procedures. 2.2 Process-Plant Building Issues of Concern Process conditions vary from facility to facility. The factors indicated in Section 2.1 may influence the likelihood or severity of an event depending on the facility being eval uated. At the same time, there are wide variations in building design, construction, function, occupancy, and location. Therefore, evaluating the risks to building occupants may require assessing a wide range of situations. Some buildings may be identified as having minimal risk for occupants and will require no further action. However, some evaluations may indicate that risk-reduction measures should be taken. Depending upon the results of the evaluation, a variety of options may be available, including the following: a. Process changes to reduce inventories or eliminate mate rials of concern. b. Preventive measures that reduce the likelihood of possible releases. c. Installation of mitigation systems. d. Building structural upgrades to withstand the predicted effects of fire, explosion, or toxic releases. 2.3 Overview of Analysis Process 2^.1 EXPLOSIONS Section 3 of (his publication outlines a three-stage analysis process for identifying hazards and managing risk to building occupants from explosions, as shown in Figures 1 and 2. The staged approach is used to systematically identify and evaluate buildings in which occupants may be at risk. As the user progresses through the stages, the analysis becomes more complex because the site-specific information is devel oped in more detail. If the user determines during any stage of the analysis that there are no significant risks to the building occupants, then the analysis process can be ended at that point Also, the user is not constrained to successively follow the stages of the evaluation process, but may proceed directly to Stage 2 or 3--after considering the implications of Stage 1. Stage 1, "Building and Hazard Identification," (Section 3.1) outlines an initial identification process for select build ings for further investigation due to their proximity, to processes which have the potential for explosions and their Gipyii(|hl by the AMERICAN PETROLEUM INSTITUIE(API) hi Oct 04 11:11:43 1996 API RP*7SE 5S Q7ATODl(l)SfeS^SR 71b 4 API Recommended Practice 752 be used in evaluating the possible effects of serious releases of highly hazardous materials. d. Risk acceptance criteria: These are the criteria, either qualitative or quantitative, that a company uses in making decisions about acceptable risk. 2.4.2 RISK REDUCTION At any time during the evaluation process, it may become obvious that a potential hazard needs to be mitigated and the effort may proceed to risk reduction. Figure 1--Stages for Explosion Risk Analysis occupancy level. Stage 2, "Building Evaluation," (Section 3.2) outlines three approaches that can be used to evaluate potential hazards to building occupants. Any or all of the approaches may be used. Stage 3, "Risk Management," (Section 3.3) outlines the use of qualitative and quantitative risk* assessment tools to perform a more complex evaluation for buildings, coupled with proposals for reducing and controlling risk, where warranted. 2.3.2 FIRES AND TOXIC RELEASES Sections 4 and 5 of this publication outline an approach for identifying risks to building occupants from fires and toxic releases. As discussed in Section 2.1, these risks depend upon various factors, inducting building design and emergency response plans. The analysis process for fire and toxic releases is considerably less complex than that for explosions. 2.4 Using This Recommended Practice 2.4.1 COMPANY-SPECIFIC ISSUES This publication has been developed to allow companies flexibility in choosing their preferred analysts techniques. However, to use sections of this publication, a company may need to develop the following: a. Occupancy and emergency role ofpersonnel criteria: These are company-specific criteria that define occupancy levels within a building and the personnel role of building occupants in an emergency. b. Evaluation-case events: These include the fire, explosion, and toxic release events that a company believes are plau* sible and realistic and may impact process plant buildings. c. Consequence modeling/analysis programs: These are the programs and techniques that a company determines are to 2.4.3 SCREENING, EVALUATION, AND ASSESSMENT Throughout this publication, the terms screening, evalua tion, and assessment are used. For the purpose of this publi cation, the following definitions apply: a. Assessment describes a detailed qualitative or quantitative analysis to estimate the potential likelihood and conse quences of site-specific events and to then compare that esti mated result with acceptance criteria. b. Evaluation describes the application of analytical tools to aid in making decisions about building. c. Screening describes a process of comparing the sitespecific materials and process conditions and building occu pancy with pre-established criteria of concern. 2.5 Occupancy and Emergency Role Criteria This section discusses occupancy and emergency role criteria that should be determined by each company. 2.5.1 OCCUPANCY STRATEGY Each company should define occupancy criteria according to its individual work environment and operating philosophy. When defining these criteria, a company should consider the following: a. The number ofpeople housed in buildings located in or adjacent to process units: Direct suppoit personnel, such as operators, field supervisors, board operators, engineers, and maintenance personal, may have to be located in immediate areas for logistical and response purposes. b. Congregations ofpeople in buitdings located in close proximity to process areas: Activities that result in an inter mittent congregation of people should be considered. These may include activities involving several people whose duty station is not at the process unit, training activities for personnel who do not need access to process equipment, and activities centered around dining facilities. c. Personnel assigned outside the process area: These personnel (for example, analyzer technicians, process oper ators. and maintenance personnel) normally havejob respon sibilities that must be performed primarily on unit equipment Copyright by ll>c AMERICAN PF1R01EUM INSIITUTE(APl) l ii Oct 04 11:11.43 19% AH1 Hb Management of Hazaros Associated With Location of Process Riant Buuxnqs 5 Figure 2--An Analysis Process for an Explosion CopY!|hl by the AMERICAN PEIROlEUM INSIIIUIE(APl) Eii Od O'! 11:11:43 1996 *PT Hi UX^P|(ft^^bjr-TFf 6 API Recommended Practice 752 i located outside the process area. These personnel may consider in determining the occupancy load are as follows: temporarily enter buildings near process areas (for example, 1. The routine presence of additional personnel, such as operator shelters) to write reports, use the phone, or seek visitors, contractors, and trainees. refuge from inclement weather. 2. Activities performed by personnel on a routine basis, d. Ability to evacuate: Buildings may provide adequate means such as calibration and maintenance of instruments. ofegress to permit evacuation. The potential events that result The occupancy load criteria used by some companies in fires, BLEVEs, and in some circumstances VCEs develop ranges from 200 to 400 personnel hours per week. over a period of time. In these situations detection, alarm, and c. Individual occupancy may be defined in terms of the evacuation may be available, and consideration should be percentage of an individual's total time spent in a building. given to the ability to evacuate. Process materials that have the An occupied building may be defined as one in which one potential for runaway reactions or chemically or thermally person does a significant portion of his or her work. The induced decomposition may produce toxic, fire, or explosion individual occupancy criteria used by some companies effects with little or no warning. These circumstances will ranges from 25 percent to 75 percent normally be discovered during a PHA, and if proper early d. Peak occupancy may be defined as the number of people warning cannot be provided, building evacuation may not be potentially exposed for a given period (for example, a safety a viable option to mitigate the hazards. or toolbox meeting where operators/crafts people meet for a short period). The peak occupancy criteria used by some 2.5.2 OCCUPANCY CRITERIA companies range from 5 to 40 persons. There are a number of alternative methods available for defining occupancy criteria. Each company may define its criteria based on a single method or a combination of methods in a tiered approach. Each method has unique merits. The following examples can be used singularly or in combination as a tiered approach. Buildings with occupancy criteria above the company pre defined occupancy criteria should be evaluated further. See Example 3 in Appendix E, which applies these criteria to hypothetical situations. 2.5.3 EMERGENCY ROLE a. Definition of occupied and unoccupied: A company may define qualitative criteria for occupied and unoccupied buildings. For example, occupied buildings could be defined as those that personnel occupy while doing the major part of their work, such as control rooms, laboratories, and office buildings. An unoccupied building would then be one that personnel visit infrequently to perform brief tasks or monitor the process. b. Occupancy load may be defined as the total integrated time for the full- or part-time occupants in the building. In this case occupancy load would be obtained by adding the hours that each person spends in that building. The number of personnel present in the building is a function of the normal daily activities and the time of day. The occupancy load is normally expressed as the inhabited time over a specific period, based on an annual average. Some factors to The job duties of occupants during an emergency should be considered. Buildings should be considered for further evaluation if the occupants are required to stay in the building or personnel are required to enter a building during an emergency. Examples of buildings that may be subject to an emergency role are control rooms and emergency response shelters. Buildings that are evacuated in the event of an emergency (for example, satellite control rooms) should be considered for further evaluation to ensure that evacuation can be accomplished safely. 2.5.4 CHANGES IN OCCUPANCY When changes cause the building occupancy to increase or the emergency role of the building changes, the building should be reevaluated using this recommended practice or the company equivalent. Copyfi<|hl by the AMERICAN PETROLEUM INSTITUIE{API) In Oct 0-1 li.11:43 1996 API RP*7S2 IS AB3B3mil)3GS8Hc1b2 200 i Management of Hazards Associated With Location of Process Plant Buildings 7 SECTION 3--EXPLOSION ANALYSIS A three-stage process for analyzing explosion hazards to occupants of process plant buildings is diagrammed in Figure 2. Each box in the flowchart is numbered with the corresponding section in this publication that discusses the information for that box. The analysis process may be used for both new and existing buildings and is intended to provide the user with multiple options. The user should recognize that as one progresses through the flowchart, the analysis becomes more complex. Some users may elect to perform all three steps. Others may wish to perform Stage 3, Risk Management, after completing Stage 1, Hazard Identi fication. This flexibility allows the users to select the best option to meet their specific requirements. 3.1 Stage 1--Building and Hazard Identification This section helps teams performing process hazards anal yses (PHAs) or site-specific building evaluations to identify buildings that could potentially be impacted by an explosion. 3.1.1 PROCESS SAFETY INFORMATION The starting point for identifying and evaluating risks resulting from the location of process plant buildings is to gather information on site-specific parameters that can influ ence the likelihood or severity of an explosion. Process safety information as identified by OSHA 29 CFR 1910.119(d) can provide basic information on the process unit, process condi tions, and materials handled. The amount of information required increases with each evaluation stage of the process. Table 1 indicates some typical information needs. 3.1.2 MATERIALS OF CONCERN Flammable materials such as light hydrocarbons and chemicals, gases, or heavier hydrocarbons that are processed at elevated temperatures, pressures, or both may have the potential for a vapor cloud explosion (VCE) upon release. Examples of materials that may form vapor clouds upon release include ethane, propane, and butane, and related olefins (ethylene, propylene, and butylene). Under some release conditions, such as elevated temperatures, less volatile materials may also form a vapor cloud. Explosion overpressure may be developed from explosions involving a boiling liquid expanding vapor explosion (BLEVE), vapor cloud explosion, chemical decomposition (such as ethylene oxide), or mechanical failure of a pressure vessel. See Example 1 in Appendix E, which applies the preceding information to a hypothetical situation. 3.1.3 SITE-SPECIFIC CONDITIONS Although some facilities may handle materials with VCE potential, site-specific conditions may preclude a VCE. Factors that influence the potential for a VCE include the degree of congestion and confinement, plant layout, spacing between areas, sources of ignition, topography, drainage, the amount of material released, and the release rate. In partic ular, the potential degree of congestion and confinement should be considered, as these are often the key factors contributing to the magnitude of an explosion. In performing the review for site-specific conditions, common equipment arrangement including pipe racks, columns, vessels, and other plant equipment in proximity to one another should be considered. Experience has shown that these conditions can provide sufficient congestion that may lead to a VCE. If flammable materials are processed in an open plant environ ment and they are released at sufficiently low rates, it is unlikely that a VCE will develop. Process conditions such as operating temperatures, pres sures, and inventory of material in equipment are also sitespecific conditions that may affect VCEs. Emergency response that results in closing of isolation valves, the depressuring of equipment, and the shutdown of the process may be effective in reducing the total quantity of material released. The effectiveness of such actions in preventing or reducing the severity of a VCE will depend upon the magnitude and the initial release rate, the time required to detect the release and complete the emergency response actions, the time required for the release to subside, and the location of potential ignition sources. Table 1--Examples of Process Safety Information Needs by Stage Stage 1 2 3 Examples ofTypical Information1 Material Safety Data Sheets Occupancy Emergency role ofbuilding Depending on the evaluation used, information needs may include Stage 1 information Inventories of materials Temperatures, pressures, tad flow rates Building construction, materials, dimensions Distances between process units and buildings Frequency data for explosions in similar plants Depending on the analysis process, information needs may inctude Stages I and 2 information Site incident history Complete building design and construction details Operating procedures Description of passive and active mitigation systems Maintenance and inspection standards and records Other pertinent information on the existing process safety management systems CopyiH|lil by the AMERICAN PETROLEUM INSIIIUIE(API) fii Od 04 11:11:43 1996 TfFI RFT7T2 T3" 8 API Recommended Practice 752 See Example 2 in Appendix E, which applies the preceding information to a hypothetical situation. 3.1.4 OCCUPANCY COMPARISON Once it has been determined that site-specific conditions may contribute to an explosion impacting the building, the plant buildings should be compared with the company's predefined occupancy criteria. Buildings exceeding the criteria should be further evaluated. Buildings that do not exceed the occupancy criteria may be evaluated using a building checklist as discussed in Section 6. 3.2 Stage 2--Building Evaluation Stage 2, "Building Evaluation," provides a process for evaluating the hazards to buildings. Evaluation options include the following: a. Design or compare to industry and company standards (Section 3.2.1). b. Consequence analysis (Section 3.2.2). c. Screening risk analysis (Section 3.2.3). Any combination of the evaluation options may be used, with the understanding that the methodologies become increasingly complex. The user should be aware that all the methodologies listed in this section of the recommended practice have limitations in identifying the actual potential effects of the hazards to buildings and their occupants. These limitations, discussed below, should be understood and matched with the purpose of the evaluation before using or selecting the methodology. 3.2.1 DESIGN OR COMPARE TO INDUSTRY AND COMPANY STANDARDS Industry groups, insurance associations, the government, and many companies have developed standards or guidelines for building design and spacing that are intended to provide protection against die effects of explosions. Many of these standards are based on experience. Because the size and congestion of units have increased, the distances specified in some standards may not apply to newer facilities. The user should understand the objectives of the spacing standards. Many of the spacing standards are based on broad assumptions of process and plant conditions and not on sitespecific conditions such as possible operating conditions, confinement, and process conditions, all ofwhich may have an effect on the potential for a significant overpressure. These variables should be considered when using any stan dard, including company standards. For example, the user should remember that some standards were developed specifically for chemical processing units and not for petroleum refineries. In general, insurance-industry stan dards are designed to protect property and minimize business interruption in the event of an incident rather than to protect personnel. A list of some available industry, insurance, and government standards is in Appendix A. See Example 4 in Appendix E, which applies the preceding information to a hypothetical situation. 3.2.2 CONSEQUENCE ANALYSIS The objective of consequence analysis is to estimate the magnitude of an explosion, evaluate its effects on a building, and relate the damage sustained by the building to the degree of potential injury or damage to the occupants and/or equip ment inside. Consequence analysis usually involves the selection of evaluation-case events that include size and duration of expected release. The evaluation-case events of concern may be identified through the PHA process. Both passive and active independent mitigation systems should be considered. Passive mitigation systems include inherent design features such as layout and spacing or design of the equipment that limits the size of an explosion. Examples of active mitigation systems include features such as automatic detection and isolation valves to reduce the quantity of mate rial released, automatic shutdown systems, and automatic water spray systems. There are several methods available for calculating explo sion overpressure, such as the TNT-equivalency, MultiEnergy, and Baker-Strehlow. Additional information on explosion calculation methods is available in Section 4-3 of Guidelines for Evaluating the Characteristics of Vapor Cloud Explosions, Flash Fires, and BLEVEs, published by the Center for Chemical Process Safety (CCPS). If the calculated overpressure exceeds the design for the building, further evaluation should be considered necessary. If the building can adequately protect the occupants from the effects of an explosion, the building can be eliminated from further evaluation, and a building checklist may be completed. Hazard evaluation tools may be used to prioritize buildings for consideration, based on various factors. Hazard evaluation methods may not account for all site-specific conditions that could lead to significant overpressure. Techniques that take into account some site-specific conditions, such as the Dow Fire and Explosion Index and Mond Index, have also been used. The results of these indices should be considered in conjunction with other factors, rather than as stand-alone criteria. These other factors should include an evaluation of the effects of confinement and/or congestion-induced turbu lence on the potential for explosion overpressure. As part of the consequence analysis, the building's response to the overpressure should be considered. The building's response to an explosion will vary, depending on such things as the building's structural design, materials of construction, orientation, and source of the explosion. Table 2 summarizes explosions by source, type, attributes of the impulse, and possible hazards to building occupants. Copyright by the AMERICAN PETROLEUM INSIIIWE(APl) l ii Oct 04 11:11:43 10% API RP*?S2 "IS m Qfi3 Management of Hazards Associated With location of Process Riant Buumngs 9 Table 2--Summary of Possibte Explosion Effects on Buildings* Source of Explosion Vapor doud of flammable material Condensed phase chemical reaction Dust doud Type of Explosion Deflagration Deflagration or detonation Deflagration Release of flammable boiling liquid (BLEVE) Physical expansion and deflagration Rapid loss of confinement of high-pressure gas Physical expansion Nature of Blast Wave Moderate to high overpressure of long duration High overpressure of short duiation Low to high overpressure of long duration Moderate overpressure of long duration High overpressure of short duration Possible Hazards to Building Occupants Building response to the explosion wave, fire, and combustion products Building response to the explosion wave, projectiles, and ground shock Boildtag response to the explosion wave, fire, combustion products fire, combustion products, building response to the `explosion wave, and projectiles Building respoose to the explosion wave, and projectiles Tins list should not be considered an all-inclusive fist Some buildings in process plants have some inherent capacity to resist explosion loadings if they meet local building codes and company building standards for environ* mental loads such as wind and snow. However, the build ings* response to explosive load within the process plant will vary depending on construction types, building styles, and siting considerations over the life of the process plant Addi tionally, the buildings may have been expanded or modified since theiroriginal construction. Hie variety of construction techniques for buildings makes exact determination of building responses to explosion toads difficult Buildings should be evaluated based on their specific structural design. As a means to illustrate potential effects on building components, Table 3 is provided. This table shows approxi mate values and should not be used for design purposes. Table 4 indicates effects ofoverpressure on different types of buildings. Table S indicates typical effects ofoverpressure on people. In a consequence analysis, it may be assumed that building occupants could incur injuries if the integrity ofthe building is exceeded. A simple and conservative approach for use in screening evaluations is shown in Table 4. The actual relationship between explosion effects and building damage depends on many parameters including overpressure and impulse of the explosion. Additionally, building parameters such as mate rial of construction, configuration, dimensions of thickness and span, and details of reinforcement and connections play an important part in building evaluations. When additional evaluation is necessary, a detailed analysis of these parame ters should be considered in a structural analysis of the building. Table 4 may be used for screening purposes. 3^3 SCREENING RISK ANALYSIS A screening risk analysis may be used to determine approximate aggregated and individual risk to occupants of a process plant building. This method provides for coupling estimates of event frequency with explosion consequences to determine risk to a process plant building occupant. This risk may then be compared to company risk acceptance criteria to identify buildings requiring further analysis. The steps for the screening risk analysis may include the following; a. Identify die process plant buildings and their construction features in proximity to processes where explosions might occur. Table 3--Overpressure Effects on Various Building Components Building Component Glass Glass Reflected Overpressure (psi) 0.2 0.5-1.0 Wooden flame l .0-2.0 Steel cladding 1.0-10 Coocrete-asbestos dadding 1.0-2.0 Brick dadding 10-3.0 Unreinforced Masonry 1.0-3.0 Component Response Breaking Shattering with body penetrating velodties Structural failure and potential collapse Internal damage to walls, ceilings, and fumishin| Shattering Blown-in Wall collapse, possible shattering Source: 77k Effects ofNucUar Weapons by Glustone (1964). Copying by Hie AMfRICAN (TfROLtlJU INSHfUfr(APl) l .i Oct 04 11:11:43 19% API RP*7S2 15 TIT 10 API Recommends) Practice 7S2 Table 4--Overpressure Effects on Various Building Types Building Type Peak Side-on Overpressure (psi) Consequences Wood-frame trailer or shack 1.0 Isolated buildings overturn. Roofs and walls collapse 2.0 Complete collapse 5.0 Total destruction Steel-firame/metal siding pre-engineered building 1.5 5.0 Sheeting ripped ofT and internal walls damaged. Danger from falling objects Building frame stands, but cladding and internal walls are destroyed as frame distorts Total destruction Unreinforced masonry bearing wall building 1.0 Partial collapse of walls that have no breakable windows 1 -25 Walls and roof partially collapse 15 Complete collapse 3.0 Tots! destruction Steel or concrete frame wAinreinforced masonry infill or cladding 1.5 2.0 25 5JO Walts blow in Roof slab collapses Complete frame collapse Total destruction Reinforced concrete or masonry shear wall building 4.0 6.0 12.0 Roofand wall deflect under loading. Internal walls damaged Building has major damage and collapses Total destruction Source: The Effects ofNuclear Weapons by Glasstooe (1964). b. Determine the explosion loading (overpressure and.dura tion) for each event for each target building using the TNTequivalency, Multi-Energy, Baker-Strehlow, or other method. c. Determine the frequency of explosions, based on histor ical or industry data for the type of process unit at' the facility. Information may be limited, and the user should carefully evaluate the applicability of any such information before using the analysis. See Appendix C for more informa tion on typical data for explosion frequency. d. Determine the vulnerability of occupants (probability of fatality) in the target building versus overpressure (overpres sure as a function of the type of building construction). See Appendix C for more information on vulnerability of occu pants. e. Calculate the risk to an individual from a single event by multiplying the explosion frequency, the percentage of time that the individual occupies the building, and the vulnera bility estimated for building occupants. To obtain the total individual risk to an occupant, add the risks from all poten tial explosion events. The total risk for the most exposed individual is the maximum individual risk. Other means of expressing individual risk exist, and the user may wish to refer to the CCPS's Guidelinesfor Chemical Process Quan titative Risk Analysis. f. Calculate the aggregate risk to all building occupants. One simple way of expressing aggregate risk would be to deter mine the weighted average occupancy of the building by summing, for all individuals, the fraction of time that each individual occupies the building. Next multiply the weighted average occupancy by the explosion frequency and the vulner ability estimated for building occupants. To obtain the total aggregate risk to all occupants, sum the risks from all potential events. There are a variety of means for expressing aggregate risk, and the user may wish to refer to the CCPS's Guidelines for Chemical Process Quantitative Risk Analsyis. g. Compare the calculated risk with the company's risk acceptance criteria to determine whether additional study is required. The screening risk-analysis method provides an additional level of evaluation because the frequency of the incident has been included in the evaluation. By identifying risk rather than just the consequences, additional buildings not posing signif icant risk to the occupants may be identified. Screening risk analysis may require more time and effort to complete than those methods previously discussed. Additionally, the use of industry versus site-specific data may not account for factors such as maintenance history, process safety management Table 5--Typical Overpressure Effects on Unprotected People Response Eardrum rupture Fatal head injury Serious lung damage Fatal bodily injury Threshold Overpressure (psi) 5 8* I01 II* Source: The Effects ofNuclear Weapons by Glasstooe (1964). *Values are for a 1654b individual and n 0.05-sec positive phase explosion duration. Copyright by the AMERICAN PETROLEUM INSIIIUTE{API) Iti Od 0-1 11:11:45 1996 API RP*7S2 TS SSb Management op Hazards Associated With Location op Process Plant Buildings 11 (PSM) effectiveness, age and condition of the unit, confinement/congestion, and so forth. See Example 6 in Appendix E, which applies the preceding information to a hypothetical situation. 3.2.4 BUILDINGS REQUIRING FURTHER EVALUATION The evaluation process in Stage 2 helps identify buildings with sufficient hazard to building occupants to justify either further evaluation or an additional risk assessment. Those buildings that do not need additional evaluation or assess ment may benefit by a checklist review, as shown in Example 9 in Appendix E, to verify that routine risk-reduc tion measures have been taken. 3.2.5 ADDITIONAL EVALUATION If a building has been determined to require additional evaluation, the user may wish to explore more than one method in Stage 2 before concluding that a risk assessment in Stage 3 is needed. 3.3 Stage 3--Risk Management 3.3.1 RISK ASSESSMENT A risk assessment identifies and analyzes specific events or scenarios either qualitatively or quantitatively. The assess ment evaluates the frequency and the consequences of scenarios, and defines an overall potential risk to the building occupants. The techniques for evaluating conse quences found in Section 3.2.2 may be useful in the risk evaluation of an explosion. 3.3.1.1 Identifying Events of Concern A list of potential scenarios may be developed during the PHA or during the evaluation of a building. Most of the scenarios will result from a loss of containment of a flammable liquid or gas, but other scenarios resulting in explosion effects should be considered. A typical list of scenarios may include die following: a. Pressure failure of a vessel or piping component, resulting in a major leak. b. Corrosion perforation in piping or a vessel, or a loss of a vessel connection. c. Inadvertent opening of a valve or connection to the atmo sphere. d. Overfilling a vessel or tank, e. Mechanical impact or brittle failure of equipment f. Failure of pump packing or a mechanical seaL g. Transfer operations involving loading and unloading. h. Chemical reactions that may result in runaway reaction. Several factors should be considered when selecting scenarios. These may include the following: a. Previous incident history: A history of previous incidents at a facility may indicate an increased potential for an explo sion that could impact process plant buildings. b. Industry experience: Available industry incident informa tion should be considered when identifying possible scenarios of concern. c. Process conditions: Certain process conditions, such as extremely high or low temperatures and pressures, reactive or corrosive process materials, and exothermic reactions, may increase the possibility of an explosion. Process mate rials (such as hydrogen and hydrogen sulfide, which may induce degradation of materials of construction), frequent cycling of the process, and mechanical vibration are exam ples of conditions that could cause an explosion. d. Effectiveness of PSM systems: The effectiveness of a facility's PSM program is fundamental in reducing the frequency of events that lead to serious incidents. e. Maintenance and inspection: A maintenance and inspec tion program verifies that pressure-retaining equipment, including piping and pressure relief valves, are inspected regularly to reduce the likelihood of an explosion. Functional testing programs verify that mitigation systems, such as protective systems and emergency controls, will operate when needed. f. Othersafeguards: Other safeguards that should be consid ered in developing a list of scenarios may include, but are not limited to the following: 1. Passive mitigation, such as spacing and equipment placement 2. Minimizing ignition sources through electrical classifi cation. 3. Administrative controls, such as a hot work permit system. 4. Monitoring systems for early detection of loss of containment (such as, hydrocarbon or toxic detectors, fire detectors, and process control system). 5. Mitigation systems (such as, water spray and fire moni tors). 6. Emergency depressurization and deinventory systems. 7. Emergency response. 33.1.2 Qualitative Risk Qualitative risk determination is an experience-based eval uation ofrisk. Additional information on qualitative risk deter mination can be found in Chapter 7 ofthe CCPS's Guidelines forHazard Evaluation Procedures. After scenarios ofconcern are identified, those that have the potential to impact process plant buildings may be ranked by using a risk matrix similar to that shown in Figure 3 and the resulting ranking shown in Table 6. Specific description of likelihood and consequence categories need to be defined if using this risk matrix. Companies performing qualitative risk assessments may consider developing a risk-ranking matrix based on company-specific risk criteria. Cofiyiiiihl by the AMERICAN PUROltUM INS!ITUTE(API) t.i (Id 04 11:11:4J 1996 API RP*7S2 SS s^sm?nss^7 12 API Recoumenoeo Practice 7S2 Table 6--Sample Risk-Ranking Categories Number Category Description I Unacceptable Should be mitigated with high priority by engineering and/or administrative controls to a risk ranking of III n Undesirable Should be mitigated with engineering and/or administrative controls to a risk ranking of III m Acceptable with controls Should be verified that procedures or controls are in place IV Acceptable as is No mitigation required Source: Slightly modified from Guideline! for Hazard Evaluation Procedures, 2nd editioo. Copyright I992by the American Institute ofChem ical Engineers; reproducedby permission of the Center for Otemical Process Safety of AIQiE. 3.3.1 .3 Quantitative Risk A quantitative analysis for risks to building occupants may use a range of techniques, including fault tree analysis and event tree analysis. For specific details on undertaking a quan titative risk analysis, refer to CCPS's Guidelinesfar Chemical Process Quantitative Risk Analysis, Chapters 2 and 3. 3.3.2 DECIDING WHETHER RISK REDUCTION IS APPROPRIATE In any risk assessment, after the risks are determined, a decision needs to be made as to whether risk reduction measures should be taken. This usually is done by comparing the assessed risk with the company's risk accep tance criteria. When additional risk reduction is suggested, the risk should be reevaluated with the risk reduction measures in place in order to verify that risk has been sufficiently reduced. 3.3.3 RISK ACCEPTANCE CRITERIA The typical risk-ranking matrix, shown in Figure 3, contains qualitative risk acceptance criteria, where certain combinations ofevent likelihood and severity clearly require action. In contrast, quantitative risk decision criteria assign specific numerical values to tolerable risk. A company should establish risk acceptance criteria before initiating a risk assessment Assistance in developing qualitative and quantitative risk acceptance criteria are avail able from a number of sources5-6 and can be used to compare work conditions in different industries in order to develop risk acceptance criteria.* * *Loss Prevention in the Process Industries, \folume I. Frank P. Lees. 1980. *CCPS. Guidelinesfor Chemical Process Quantitative Risk Analysis, 1989. and Guidelinesfor Evaluating Process-Plant Buildingsfor External Explo sion and Fire (work in progress). Consequence category Increasing severity Source: Guidelinesfor Hazard Evaluation Procedures. 2nd edition. Copyright 1992 by the American Institute of Chemical Engineers; reproduced by pennissioo of the Center for Chemical Process Safety of AlChE. Figure 3--Sample Risk Matrix 3.3.4 RISK REDUCTION Reducing risk to building occupants from the effects of explosions generally falls into two broad categories: a. Prevention: Activities that eliminate or reduce process incidents. b. Mitigation: Activities that reduce the consequences asso ciated with the occurrence. Generally, prevention activities such as modifications in operating and maintenance practices, equipment, mainte nance, inspection, personnel training, and audits may reduce the process incident occurrence rate. Mitigation measures may include Installation of detection and isolation systems, fire suppression systems, structural enhancements, and emergency response planning. 3.3.4.1 Prevention Measures Preventing the incident from occurring should be the first priority in reducing the risk. Some examples of preventive risk-reduction measures may include but are not limited to the following: a. Reducing the inventory of hazardous material. b. Engineering controls such as process controls, emergency shutdowns, and redundant instrumentation. c. Altering process conditions or materials to reduce the potential for runaway reactions or corrosion. CopyiM|hl by the AMERICAN PETROLEUM INSIITUfE(APl) hi Od 04 11:11:43 1996 API RP.752 IS 721 Management op Hazards Associated With Location of Process Plant Buumnqs 13 d. Increasing inspection frequencies for piping and equip ment in corrosive service. e. Upgrading metallurgy of equipment. f. Enhancing work practices such as crane lifting or excava tion to reduce the likelihood of incidents. g. Administrative controls such as permits for hot work, lockout/tagout, line breaking, and so on. 3.3.4.2 Typical Mitigation Measures for Buildings Typical mitigation for process plant buildings may include, but are not limited to the following: a. Relocating personnel or rearranging the room functions within the building. b. Eliminating windows. c. Modifying windows to reduce risk to occupants. Two generic approaches are as follows: 1. Strengthening the glazing and its framing system to resist the design explosion overpressure. 2. Or designing a glazing/framing system that will fail in a manner that minim?< laceration risks to occupants (for example, polycarbonate, tempered glass, or laminated glass with internal catch bars). d. Strengthening doorways and reducing or eliminating glazing in doors. e. Providing structural reinforcement or performing modifi cations to the building to improve flexibility and strengthen the connections. f. Installing external walls for explosion and projectile protection. g. Constructing a new building using explosion-resistant design or siting sufficiently remote for the hazard. h. Designing floor and hub drains to prevent the backflow of explosive vapors. 3.5.4.3 Considerations for Existing ExplosionResistant Buildings Structural evaluation of the building should be considered when the recalculated design explosion overpressure exceeds original design values. This evaluation should review, among other things, the loading assumptions used in die building's structural design in view of current techniques to evaluate explosion effects, die explosion-iesistant-design philosophy at the time ofconstruction, and the as-built details relevant to explosion loadings. 3.3.4.4 Occupancy Reduction Considerations A study of the building's occupancy patterns may yield opportunities to reduce the number of people at risk. The reduction ofpersonnel in a building may be considered, based on the expected building damage and occupant vulnerability. SECTION 4--FIRES Uncontrolled fires in process plants arc typically pool, fire balls, jet, flash fires, or fireballs. These fires may result from or cause explosions within process plants. Pool fires are usually the result of a spilled flammable or combustible liquid, for example, a fire in the dike area ofa storage tank. Jet fires occur at the source ofrelease ofa pressurized flammable material, for example, a ruptured natural gas pipeline. A jet fire impinging on a vessel may be a source ofheat input that results in failure of a vessel containing a pressurized flammable liquid, causing a BLEVE. Flash fires usually involve flammable materials, combustible dusts, or vapors, that are mixed sufficiently with air to bum after being exposed to an ignition source. A fireball usually involves a large flammable release that bums quickly, until radiant heat being the primary concern. The combustion products from a fire may enter the building and, depending on the burning material, may create respiratory problems, physiological hazards, fire within the building, or hazards from the lack of visibility, which could hinder egress from the building. Figure 4 provides an example of a tool that may be used to evaluate fire hazards to building occupants. 4.1 Materials of Concern Buildings that are located in the proximity of equipment that processes flammable material may be exposed to a fire. This recommended practice applies to flammable materials covered under OSHA 29 CFR 1910.119. 4.2 Building Occupancy Once it has been determined that site conditions may contribute to a fire, the plant buildings should be compared with the company's predefined occupancy criteria for fire hazards. See Section 2.5 for additional information on occu pancy criteria. 4.3 Spacing Unless a building is directly involved in a fire, the fire hazard to the structure is low for most types of construction. Radiant heat effects are significantly reduced by distance. Buildings made of noocombustible construction materials and even some combustible materials are generally of minimal concern unless the building has direct flame impingement Appendix A lists, as a general reference, several industry and Copying by the AMERICAN PEIROLEUM INSIIlUIE(APl) In Oct 04 11:11:43 1996 API RP*752 JS QT8BmiMflM 14 API Recommended Practice 752 insurance standards for separation distance and spacing for fire hazards and not personnel protection. The user should be aware that standards are developed for various purposes. In general, insurance industry standards are designed to protect property and minimize business interruption in the event ofan incident The user should determine the appropriateness of the standard to the application. See Example 7 in Appendix E, which applies the preceding information to a hypothetical situation. 4.4 Mitigation and Emergency Response The hazards for occupants in a building exposed to an external fire depend on the building's materials of construc tion. distance from the fire, and systems to prevent flammable vapor ignition. The design of most buildings may provide enough time for the occupants to leave the building, for the fire suppression measures to be activated, and for emergency response plans to be implemented. Generally, the emergency response plans for the building should include appropriate measures for the occupants to take, such as sheltering-in-place, using personnel protective equipment (PPE) for escape, or--depending on wind condi tions--evacuating in a safe, upwind or crosswind direction. Also, procedures for ensuring a safe process shutdown should be considered if the process is solely controlled from the building that is being evacuated. 4.5 Risk Reduction for Fire 4.5.1 PREVENTION MEASURES Generally, preventing the incident from occurring should be the first priority in reducing the risk. Some examples of preventive risk-reduction measures may include, but are not limited to the following: a. Reducing the inventory of hazardous material. b. Altering process conditions or materials to reduce the potential for runaway reactions or corrosion. c. Implementing inspection programs for piping and equip ment. d. Upgrading materials of construction. e. Enhancing work practices such as crane lifting and exca vation to reduce the likelihood of incidents. f. Providing administrative control such as permits for hot work, lockout/tagout, line breaking, and so forth. g. Installing properly classified electrical equipment to prevent ignition of flammable materials. 4.5.2 MITIGATION MEASURES Typical mitigation measures for reducing hazards to budding occupants from an external fire may include, but are not limited to these: a. Providing physical separation from the fire event by distance or barriers. b. Providing appropriate fire-resistant exterior construction. Figure 4--An Analysis Process for a Fire c. Providing properly designed fire and smoke suppression equipment inside and outside the building, which may include the following: 1. Fire-fighting/suppression systems for the building and outside monitors or water spray in appropriate locations to address a possible fire. 2. Building ventilation controls, which detect combustion products, stop fresh air intake, and stop air circulation within the building. 3. Providing area drainage to direct spill from the building. d. Providing escape routes in the emergency response plan for each building. e. Installing isolation valves. f. Installing spill containment. Copyright by the AMERICAN PETROLEUM INSmUTE(APl) I n Oct 04 11:11:43 1996 API RP*752 IS - 367 Management of Hazards Associated Wrrw Location of Process Plant Buildings SECTION 5--TOXIC MATERIALS 15 Toxic materials released to the atmosphere in process plants can affect building occupants. Figure 5 may be used to evaluate toxic material effects on building occupants. Toxic vapors may enter a building and cause impairment and/or physiological harm to the occupants, depending on the material released, its concentration, and the exposure duration. The combustion products from a fire may enter the building and may create respiratory problems, physiological hazards, or hazards due to the lack of visibility to building occupants. 5.1 Toxic Material of Concern Buildings that are located in the proximity of equipment that process volatile, acutely toxic materials specified in 29 CFR 1910.119, Appendix Ashould be evaluated. 5.2 Building Occupancy Once it has been determined that site conditions may contribute to a toxic release, the plant buildings should be compared with the company's predefined occupancy criteria for toxic releases. See Section 2.5 for additional information on occupancy criteria. 5.3 Site Conditions The meteorological dispersion of a toxic material depends on many site-specific factors, including the physical proper ties and release conditions of the material, the quantity released, the weather conditions, obstacles, and the direction and source of the release. The dispersion of these gases may be modeled using a variety of techniques. The amount and speed of entry of the toxic material into a building depend on the location and size of the entry point, exterior concentration of the gas, and relative pressure between the interior and exterior of the building. Entry points can be open or unsealed windows or doors, vent stacks, fresh air makeup openings, instrument cabling or conduit, or sewer connections that are unsealed. An explo sion may also cause structural damage, which may allow toxic material to enter the building. 5.4 Mitigation and Emergency Response The dispersion dynamics of a gas cloud may allow suffi cient time for the occupants to appropriately respond to the release. A ventilation system that (a) controls fresh air makeup, (b) is equipped with a toxic gas detection alarm, and (c) provides automatic or manual air intake shutdown capability may be an effective means to control the ingress of toxic materials. Generally, the emergency response plan should include 3.1.1 (to note) Figure 5--An Analysts Process for a Toxic Release appropriate measures for building occupants to take, such as shelter in place, use personnel protective equipment (PPE) for escape, or--depending on wind conditions--evacuate in a safe, upwind or crosswind direction. Also, a method for ensuring a safe process shutdown should be considered and factored into the emergency response plan when the process is controlled solely from the building that is being evacuated. See Example 8 in Appendix E, which applies the above information to a hypothetical situation. Copytiijtil by the AMERICAN PEIROLEUM INSTUUIE(APl) fri Od 0-1 11:11:45 1996 API RP*7S2 *?S 0ABBttl03699em 213 16 API Recoacnoed Practice 752 5.5 Risk Reduction for Toxic Release 5.5.1 PREVENTION MEASURES Generally, preventing the incident from occurring should be the first priority in reducing the risk. Some examples of preventive risk-reduction measures may include, but are not limited to the following: a. Reducing the inventory of hazardous material. b. Altering process conditions or materials to reduce the potential for runaway reactions or corrosion. c. Providing inspection programs for piping and equipment d. Upgrading metallurgy of equipment e. Enhancing work practices for activities such as crane lifting and excavation to reduce the likelihood of incidents. 5.5.2 MITIGATION MEASURES The hazards to building occupants from a release of toxic materials depend on the (a) factors affecting the dispersion of the toxic material, (b) location of the building, (c) control of the ventilation system in the building, (d) infiltration rate into the building, and (e) effectiveness of the building's emergency response plans. Time is usually a very important factor in reducing occupant vulnerability. Typical mitigation measure for reducing the hazards to building occupants from a toxic material release may include, but are not limited to the following: a. Ventilation system controls with appropriate detection, which stop the flow of a contaminated air supply to the building. b. Use of elevated iotake stack for potential releases of heavier-than-air materials. c. An emergency response plan, which may include safe shel ters in the building and clearly identified evacuation routes. d. A detection and alarm system for early notification of a release. e. Appropriate PPE for the building occupants. f. Reductions in the number of people in the building. g. Pressurized ventilation systems. h. Review of locations of gas infiltration into die building for possible sealing. SECTION 6--BUILDING CHECKLIST Even those process plant buildings identified during the various analyses as not presenting a significant hazard to occupants may still benefit from a checklist review to verify that routine risk-reduction measures have been taken. Appendix D shows an example of typical questions included on a building checklist. SECTION 7--PROCESS SAFETY MANAGEMENT DILIGENCE The credibility of the techniques discussed in this publica tion are founded on the continuing and improving practice of process safety management (PSM) within a process facility. Practicing PSM will help to reduce the likelihood of serious events. Additionally, it can assist in identifying measures to mitigate the consequences to the occupants from the hazards. Applicable references concerning the specific PSM activities include the CCPS, Guidelinesfor Technical Management of Chemical Process Safety and Plant Guidelinesfor Technical Management ofChemical Process Safety. To maintain the currency of the techniques and validity of the assumptions discussed in this publication, it is important for a facility to assess its PSM activities by systematic auditing. Copyright by the AMERICAN PETROLEUM INSTUUIE(API) I ri Oct 04 11:11:43 1996 API RP*752 IS 1ST APPENDIX A--BIBLIOGRAPHY OF ADDITIONAL READING This appendix provides a list of guidelines, standards, codes, specifications, and publications that may be useful in evaluating hazards to building occupants. The user should evaluate each document for its suitability and application as described in Section 3.2.1, and use the most recent edition. A.1 Explosion Baker, W. E., P. A. Cox, P. S. Westine, J. J. Kulesz and R. A. Strahlow, Explosive Hazards and Evaluation, Else vier Scientific Publishing Company, 1983. CIA7 Process Plant Hazard and Control Building Design--An Approach to the Categorization. Department of Defense TM5-1300, Structures to Resist the Effects ofAccidental Explosions, U.S. Army. AMCR 385-100, U.S. Army Safety Manual. MIL-STD-882C, Military Standard System Safety Program Requirements. FM FM 7-45S, Process Control Houses and Other Structures Subject to External Explosion Damage. FM 7-44, Spacing of Facilities in Outdoor Chemical Plants. JKP IRInfonnation IM.8.0.1.1, Oil and Chemical Properties Loss Potential Estimation Guide. IM.2-5-2, Plant Layout and Spacingfor Oil and Chemical Plants. Minimizing Damage to Refineries from Nuclear Attack, Natural and Other Disasters, Maynard M. Stephans. Nolan, P.F. and C.WJ. Bradley, A Simple Techniquefor the Optimization ofLay-Out and Location for Chemical Plant Safety, Department of Chemical Engineering, Polytechnic of the South Bank, Borough Road, London, England SE1 OAA. Page, Robert. "Technical Aspects of Unconfined Vapor Cloud Explosions and the TNT Model," Industrial Fire Safety, May/June 1993. A.2 Fire AIChE Center for Chemical Process Safety of AIChE, Guidelines for Engineering Designfor Process Safety.* * 'Chemical Industries Association, The Chemical Industry Safety, Health, and Environmental Council (CISHEQ, U.K. *Fctory Mutual Engineering Corporation, 1151 Boston Providence Turn pike, Norwalk. Massachusetts 02062. Industrial Risk Insurers, Eastern Region, 85 Woodland Street, Hanford, Connecticut 06102. Dow Chemical, Fire and Explosion Index Hazard Classi fication Guide. Stull, Daniel R., Fundamentals of Fire and Explosion, AIChE Monograph Series, No. 10, Volume 73. API Recommended Practice 2510, Design and Construction ofLiquified Petroleum Gas (LPG) Installations. Recommended Practice 2508, Design and Construction of Ethane and Ethylene Installations at Marine and Pipeline Terminals, Natural Gas Processing Plants, Refineries, Petrochemical Plants, and Tank Farms. FM8 FM 7-44, Spacing of Facilities in Outdoor Chemical Plants. IRP IM.2.52, Plant Layout and Spacingfor Oil and Chemical Plants, Imperial Chemical Industries The Mond Index, 2nd ed. NFPA10 The Fire Protection Handbook, 17th ed. Edited by Arthur E. Cote, Editor-in-Chief, and Jim L. Linville, Managing Editor. The Society ofFire Protection Engineers (SFPE) Hand book of Fire Protection Engineering, 1st ed., Phil J. DiNenno (ed.). NFPA 30, Flammable and Combustible Liquids Code. NFPA 58, Standard for the Storage and Handling of Liquid Petroleum Gases. NFPA 59A, Standardfor the Production, Storage and Handling ofLiquified Natural Gases. NFPA 80A, Recommend Practice for the Protection of Buildingsfrom Exterior Fire Exposures. NFPA 496, Standardfor Purged and Pressurized Enclo suresfor Electrical Equipment in Hazardous Locations. A.3 Toxic Material AIChE Dow Chemical, Chemical Exposure Index API Recommended Practice 2031, Combustible-Gas Detec tion Systems and Environmental Operational Factors Influencing Their Performance. NFPA10 NFPA 496, Standardfor Purged and Pressurized Enclo suresfor Electrical Equipment in Hazardous Locations. ^National Fire Protection Association, One Batterymarch Park, Quincy, MA 02269-9101. 17 CopytH|hl by llte AMERICAN I'CIROIEUM INSTIIUIE(APl) I'riOcI 04 11:11:43 1996 ABDOO103641 APPENDIX B--EXPLOSION, FIRE, AND TOXIC RELEASE PHENOMENA, AND HAZARDS TO THE OCCUPANTS OF PROCESS PLANT BUILDINGS The information contained in this appendix is derived in part from Guidelinesfor Evaluating the Characteristics of Vapor Cloud Explosions, Flash Fires, and BLEVES (1994), American Institute of Chemical Engineers, with permission of its Center for Chemical Process Safety. For more detailed information, consult the above reference. The primary events of concern for occupants of process plant buildings are explosion, fire, and release of toxic materials. B.1 Structural Design and Analysis for Explosion Resistance The structural design and analysis should be performed by a structural engineer familiar with explosion design. In order to perform this task, it is necessary to establish the pressure* versus-time relationship of the load as it applies to the different parts of the building. This determination should be performed with input from experts on the process and be based on a thorough knowledge of the postulated explosion scenarios. However, it is important to realize that these explosion design criteria are only an approximation. B.2 Explosion Phenomena Explosions in process plants occur because of the loss of containment of a pressurized gas or pressurized boiling liquid, the rapid combustion of a flammable or finely divided solid material, or the uncontrolled reaction ofchemical mate rials. B.2.1 EXPLOSION B.2.1.1 Explosions may occur through a variety of mech anisms and may take one or more of the following forms: B.2.1.1.1 Vapor cloud explosion (VCE): A VCE is the result of a flame front propagating through a mixture of air and flammable gas or vapor. The flame front must propagate with sufficient velocity to create a pressure wave. For a VCE to occur, several conditions must be met These include (a) a release of flammable material, (b) sufficient mixing with air that results in a flammable mixture, (c) ignition, (d) confine ment, and (e) congestion within the flame path, which tends to accelerate the flame front. The explosion intensity of a VCE can vary greatly and is determined by the flame speed. The flame speed in turn is affected by the turbulence created within the vapor cloud. One of the key factors creating turbulence in a vapor cloud is the degree of congestion within the release area. Experience has shown that normal process plant design and equipment spacing may create enough congestion to cause turbulence and rapid flame prop agation. A high-pressure jet release may also produce suffi cient turbulence to increase the rate of flame propagation. The rate of release and the elapsed time before ignition will determine the amount of material involved in a VCE, and thus affect the overpressure and duration of the explosion wave. B.2.1.1.2 Boiling liquid expanding vapor explosion (BLEVE): A BLEVE results from the rapid release of a pres surized liquid above its atmospheric boiling point, usually caused by the rapid failure of its containment vessel. The failure often is caused by flame impingement on the vessel's vapor space, which weakens the metal to the point of rupture. A BLEVE may produce an explosion wave, frag mentation, and, if flammable material is involved, a fireball B.2.1.1.3 Physical explosion: A pressurized system may produce an explosion upon catastrophic rupture or failure of the equipment Depending upon the failure mechanism that leads to the release, fragmentation of the container may also result Released gas or fluid may ignite, resulting in a VCE or fire. B.2.1.1.4 Chemical explosion: An uncontrolled chemical reaction with sufficient energy may cause a failure of the vessel, resulting in overpressure and missile effects. B.2.1 JZ The damage to buildings and subsequent injury to the occupants from an explosion may be caused by the explosion wave, missile fragments, or fire. BJ2JZ EXPLOSION LOAD The typical blast load is characterized by a rapid rise in pressure to a peak value, a period of decay to ambient pres sure (positive phase), and a period in which the pressure drops below ambient (negative phase). The explosion load differs with the various parts of the building. The front wall receives a larger pressure (reflected pressure) than do the back wall, side walls, and roof. The passage of the explosion wave across the building is a diffraction process as the wave bends and interacts with the geometry of the structure. Consequently, each area of the building--depending on its location and orientation--is subject to an explosion pressure that is different from the pressure on other areas of the buildiog. The shape of the loading curve, as well as the duration of the load, depends on many parameters, such as the character istics of the explosion (detonation, deflagration, pressure vessel rupture), material and quantity released, ignition source (location of the explosion), degree of confinement, distance from the explosion, possible obstructions in the path of the pressure wave, and the orientation of the loaded surface relative to the direction of the explosion wave. 19 Copyrujtit by the AMERICAN PETROLEUM INSTITUTE(API) Fri Ocl 04 11:11:43 1996 API RP?S2 ^S 20 API Recommended Practice 752 The material involved in the explosion is converted into a high-pressure gas at high temperatures and a rapidly expanding shock front. The pressure behind the explosion wave is the incident pressure. When the incident-pressure shock front strikes the front wall of the building, the pressure rises from ambient to the reflected pressure, which is a func tion of the incident pressure. For each pressure range, there is a particle or wind velocity that causes a dynamic pressure on objects in the path of the wave. The magnitude of the drag force that results from this effect is a function of the particle velocity, particle density, and object geometry. The explosion loading on an object comprises two components: the loading due to the overpressure (incident and reflected) and the loading due to drag forces induced by the particle motion. For buildings, only overpressure is important--drag forces are significant, compared to overpressure loads, only for slender objects such as lamp posts. The explosion wave's potential to cause building damage is time dependent and directly related to the shape and size of the explosion wave's pressure-time curve. The impulse value is used in conjunction with the dimensions of the building, orientation of the building, and speed of the explo sion wave to determine the net and instantaneous loading on a building from an explosion wave. B^3 HAZARDS TO BUILDING OCCUPANTS FROM EXPLOSIONS The response of the building to the explosion wave is related to the distance of the building from the explosion event, the type of building construction, and materials of construction. Ground shock may also occur from an explo sion; however, its effects on buildings and occupants are considered insignificant compared to airborne effects. A collapse or partial collapse of the building normally poses the greatest hazard to building occupants in an explo sion scenario. Building components such as lighting fixtures, suspended ceilings, and furnishings, which may dislodge or topple and possibly injure the occupants, should be evalu ated. Breakable objects, primarily glass, may be a hazard to occupants. Normally open penetrations, or the nearly instan taneous loss of window, wall, or door integrity, create open ings in the building and decrease the reflected overpressure. The explosion conditions are transferred to the interior of the building, creating possible hazards for the occupants, including the possibility of an individual being thrown against stationary objects and/or being injured by flying debris. These hazards are of concern around large openings such as windows, doors and associated entry areas, and hall ways where the explosion effects may be channeled. The external attachments and interior furnishings are potential hazards to occupants if these items are displaced and impact with building components or occupants. There is a low likelihood of injury to occupants from an external projectile impacting the building, because external projectiles produce extremely localized effects on buildings in comparison to explosion loadings, which involve the entire building. B.3 Fire Generally, process fires will be in the form of one or a combination of the following: a. Jetfire: A liquid or gas release under pressure that bums from its release point. The stability, magnitude, and distance of the flame are a function of the release pressure, wind direction, hole size, flame direction, and other site-specific variables. b. Poolfire\ A release of flammable liquid, including liquid from releases of a two-phase material that forms a fire in which the flammable material bums above the liquid surface. c. Flash fire: The combustion of a flammable gas or vapor and air mixture, in which the flame propagates through the mixture such that negligible or no damaging overpressure is generated. d. Fireball: A burning fuel-air cloud whose energy is emitted primarily in the form of radiant heat. The inner core of the cloud consists almost completely of fuel; whereas, the outer layer (where ignition first occurs) consists of a flammable fuel-air mixture. As the buoyancy forces of bot gases increase, the burning cloud tends to rise, expand, and assume a spherical shape. Fires expose process plant buildings to radiant heat and products of combustion that may enter the building. Gener ally, fires do not impact process plant buildings as severely as do explosions. Their effects occur over a period of time, and emergency response and mitigation can reduce the impact B.4 Toxic Materials Certain materials, when released, may present a toxic exposure to personnel. In some cases, the material released may contain both toxic and flammable substances and may present potential for fire, explosion, and/or toxic exposure. Generally, the releases of toxic materials, unless corrosive, will not affect buildings. However, ingress into the building can occur with exposure to personnel. Ingress usually occurs in a time frame that allows for emergency response and miti gation. Copy*i<)hl by the AMERICAN PETROLEUM INSIITUTE(APl) rri Oct 04 11:11:43 1996 API RP*72 RS D71ffl380W3ttW5 RbR APPENDIX C--DAMAGE CATEGORIZATION FOR BUILDINGS AND VULNERABILITY OF OCCUPANTS TO EXPLOSION OVERPRESSURE As part of the risk screening for explosion in Section 3.2.3, information is required on the vulnerability of occu pants to injury and on generic frequency of occurrence for process units. The information presented in this appendix is one company's approach for these items and is an example only. Each company should develop its own approach. C.l Vulnerability of Occupants To assess the vulnerability of occupants within a given building from explosion overpressure, the following infor mation is required: a. Type of building. b. Overpressure relationship for each type of building. c. Damage-vulnerability relationship. C.1.1 BUILDING TYPES Buildings within facilities have a wide range of design and construction features; however, the most important is building structure. The following types of major structures can be found: a. B1: Wood-frame trailer or shack. b. B2: Steel-frame/metal siding or pre-engineered building. c. B3: Unreinforced masonry bearing wall building. d. B4: Steel or concrete framed with reinforced masonry infill or cladding. e. B5: Reinforced concrete or reinforced masonry shear wall building. C.1.2 OVERPRESSURE DAMAGE FOR BUILDING TYPES Damage estimates have been obtained from past incidents, effects on buildings from testing nuclear weapons, and other sources. The overpressure shown are appropriate for the different building types. a. Wood-frame trailer or shack, B1: From observation of destruction by severe storms, it is inferred (for permanent buildings) that an explosion loading of approximately the design wind pressure or about 0.2 psi would mark the onset of serious damage to these buildings. Pressures of about 1 psi could overturn an isolated building and partially destroy temporary building complexes. b. Steel-frame/metal siding or pre-engineered building, B2: The frame in this type of building provides support to the roof, which is independent of the walls. Information is avail able in the literature on explosion performance from war records. These records indicate that sheeting is ripped off and internal walls are damaged at overpressures >1.5 psi; the building frame stands but cladding and walls are damaged at > 2.5 psi, and complete building collapse occurs at > 5 psi. c. Unreinforced masonry bearing wall building, B3: This type of building is similar to domestic/small commercial buildings. The walls collapse about 1.0 psi and total building collapse occurs about 1.5 psi. d. Steel or concrete framed w/reinforced masonry infill or cladding, B4: This type of building regularly suffers damage in storm conditions; however, this type of building provides robust performance under explosion loading. Wall damage may occur at 1.0 psi. The roof slab may collapse at 2.0 psi and total building collapse at 2.5 psi. e. Reinforced concrete or masonry shear wall building, B5: The building is generally designed for 2.0 psi, so very minor damage will occur. The roof and walls will deflect under loading and internal wall damage at about 4.0 psi. The building has major damage and possible collapse at 6.0 psi. C.1.3 OVERPRESSURE DAMAGE AND VULNERABILITY RELATIONSHIP11 Assumptions on the relationship between damage and vulnerability of occupants (probability of fatality) were derived from several sources. The following general data was identified: a. Building destruction: A vulnerability of 1.0 was chosen for buildings subject to a blast significantly greater than that leading to building collapse, based on extrapolation (shown on dotted lines in Figure C-l). b. Building collapse: A vulnerability level of 0.6 was chosen based on building collapse data from earthquakes, war, and past incidents. c. Minor damage: On the basis of studies reported by Lees12, it was assumed that the vulnerability of occupants would be 0.01 from minor damage, such as broken windows. C.1.4 OVERPRESSURE VERSUS VULNERABILITY NOMOGRAM An overall summary of the relationship between levels of overpressure and vulnerabilities to occupants for building types is shown in Figure C-1, "Overpressure Versus Vulner ability." C.2 Generic Frequencies of Explosions The process plant under consideration should be divided into process units of isolatable inventories, with release ''For additional information, see CCPS, Guideline} for Evaluating Process-Plant Buildings for External Explosion and Fire (work in progress). lJLoit Prevention in the Process Industries, Volume l. Frank P. Lees. 1980. 21 Copyiiqhl by Ihe AMERICAN PETROLEUM INSWUTE(API) hi 0d U4 11:11:43 1996 API RP*7S2 9S 07^gBD099Wb ATS 22 API Recommenoed Practice 752 Note: Figure taken from CCPS, Guidelines far Evaluating Process' Plant Buildingsfar External Explosions end Fires (work in progress). Figure C-1--Sample Overpressure Versus Vulnerability frequencies estimated for failures of pipes, valves, flanges, pumps, compressors, and other equipment. This would be supplemented with failures from other events such as earth quakes, floods, tornadoes, and effects from adjacent units in order to build a comprehensive listing of release scenarios. Knowledge of the likelihood, release size, and duration of individual scenarios would then be combined with vapor cloud dispersion distances and direction to site-specific igni tion sources in order to calculate the overall frequency of occurrence for major explosions impacting plant buildings. A simple approach for risk screening was taken by one member company. The company developed a historical record of all major explosions and an estimate of the number of plant years of operating experience to arrive at estimated frequencies of explosions for generic process units. This information is shown in Table C-l for specific refinery units. Companies may wish to develop similar data for their operations. If not, the generic data shown could be used when a company is performing a screening risk-analysis. Cupynqht by the AMERICAN PEIROLEUM INSIlIUTEfAPI) hi Oct 04 11:11:45 1996 API RP*7S2 T5 Management of Hazards Associated With Location of Process Plant Buuxngs Table C-1--Generic Frequencies of Major Explosions (see note) Process Unit Frequency of Explosions/Year of Operation Alkylation Cal cracking Cat reforming Crude Hydrotreating Hydrocracking All units 5.1 xUH* 6.5 x l(H 2.6 x KH 4.9 x 10-* 10 x 1(H 5.6 x l(H 4Jx 1(H Note: Information in this table is derived from the following sources: OSH ROM Occupational Safety and Health on CD-ROM, Major Incident Database (MHIDAS), UKAtomic Energy Authority, July 1993; Engineering Services Loss Database, Sedgwick Engineering Limited, Sedgwick House, The Sedgwick Centre, London El 8DX; and Worldwide Refuting Report, Oil and Gas Journal, Penwetl Publishing Company, December 23,1991. kA frequency of 5.1 x KH explosions/year of operation is the same as ooe explosion in 1961 years of operation. 23 Copyiiqhl by Ihe AMERICAN PETROLEUM INSWUlE(APl) I ti (kl 0-1 11:11:43 1996 api rp*7S2 is m b?a m APPENDIX D--PROCESS PLANT BUILDING CHECKLIST* The following is an example of a building checklist Some of the questions in the checklist may not apply to all work sites; likewise, additional questions may be necessary. PROCESS PLANT BUILDING CHECKLIST Building: |aF,r Questions Date: Name: ^fes ^o I-JA* Remarks FT 1. Is the building located up wind of the hazard? EFT 2. Is the building included in an emergency response plan for fire and toxic release? Are the occupants trained on emergency response procedures? Are evacuation instructions posted? 1 E 3. Are large pieces of office equipment or stacks of materials within the building adequately secured? 1 E 4. Are the lighting fixtures, ceilings, or wall-mounted equipment well supported? Are process controls mounted on interior walls? E S. Is there heavy material stored on the ground floor only? 1 E 6. Have all the exterior windows been assessed for potential injury to occu pants? EFT 7. Are there doors on the sides of the building opposite from an expected explo sion or fire source? 1 FT 8. Are there exterior and interior fire suppression equipment available to the building? 1 FT 9. Is there a detection system within the building or in the fresh air intake to detect hydrocarbons, smoke, or toxic materials? ] FT 10. Is the air intake properly located? 1 FT 11. Can the ventilation system prevent air ingress or air movement within the building? Are there hydrocarbon or toxic detectors that shut down the air intake? Does the building have a pressurization system? 1 FT 12. Are there wind socks visible from all sides of the building? I EFT 13. Is there a building or facility alarm or communication system to warn building occupants (of an emergency)? 1 T 14. Is there sufficient bottled air or fresh supplied air for the occupancy load' 1 EFI IS. Are all sewers connected to the building properly sealed to prevent ingress of vapors? *E "Explosion; F=Firc; T sToxic: NA = Not Applicable. This checklist may or may not be appropriate for every particular circumstance. Copyti<)hl by ll>e AMERICAN PflROtfUM INSIIUJIC(API) F.i 0:1 04 lUMJ 19% API RP*7S2 IS SDH APPENDIX E--EXAMPLES The examples in this appendix are intended to guide the user in applying the concepts presented in this publication. Each example is designed to illustrate a specific aspect of the application of this publication, and does not attempt to convey the complexity or to make trivial the issues associated with location of buildings in process plants. The numerical criteria used as standards for occupancy or risk acceptance in the examples are not intended to serve as numerical guides. The numbers used in these examples are solely for illustration purposes and do not reflect recommended numerical criteria. Each company should select criteria reflecting its needs. Example 1--Materials of Concern (Section 3.1.2) Problem 1: A sweet crude oil treating and storage facility has an office 35 feet from the process equipment Because the unit contains more than 10,000 pounds of flammable liquid, the facility is covered by OSHA process safety management regulations. Solution: Due to the conditions in which the crude oil is processed at this facility, it was concluded that the risk of vapor cloud explosions (VCEs) is low, and that die primary concern is fire. Figure 4 should be used to evaluate the hazard to building occupants. Example 2--Site-specific Conditions (Section 3.1.3) Problem 1: An occupied shipping office for a large automated chemical warehouse handling solid products extends out from the warehouse on the north side. The manufacturing process for this product contains flammable gases and dust The product is manufactured, compounded, and packaged in a separate building 200 feet to the south of the warehouse, and explosion venting for the building has been designed to release to the south. Solution: The shipping office is eliminated from further study because the site-specific condition of the process plant building directs the effects of a potential explosion away from the occupied building. A building checklist may be completed. Example 3--Occupancy Criteria (Section 2.5.2) Problem 1: A company's internal criterion for occupancy load is 400 hours per week. A cafeteria is located within a refinery complex with process units located on three sides. The closest unit containing hydrocarbon is 250 feet away. The cafeteria is open from 6:00-8:00 AJ411:0Q A.M.-1:00 P.M., and 6:00-7:00 P.M. on a daily basis. Approximately 200,600, and 150 people, respectively, use the facility for each meal on weekdays. About 100 people per meal use the facility on weekends (each individual averages 0.5 hour in the building). Solution: The occupancy load is calculated as: Breakfast (0.5 hour x 200 people x 5 days) + (0.5 x 100 x 2) = 600 Lunch (0.5 hour x 600 people x 5 days) + (0.5 x 100 x 2) = 1,600 Evening (0.5 hour x 150 people x 5 days) + (0.5 x 100 x 2) = 475 The occupancy load is 2,675 hours per week. Therefore, evaluation of the building using Section 3.2 should be considered necessary. Problem 2: The same company has two permanent trailers. Another trailer is to be added. A process unit is 200 feet from the trailers. A question of siting of the trailers was raised. The existing trailers house eight individuals. The assigned personnel spend, on average, six hours per day in the trailers. In addition, two meetings are held that average six people for six hours per day, four days a week. Solution: The occupancy load is calculated as: 6 hours x 8 people x 5 days = 240 6 hours x 6 people x 4 days x 2 meetings = 288 27 Copyru|h! by the AMFR1CAN PETROLEUM INSWUlE(APl) hi Oct 04 11:11:43 1996 API RP*7S2 S5 036431 H'UO 22b 28 API Recommended Practice 752 The total occupancy load i$ 528 hours per week. This exceeds the internal criterion of 400 hours per week. The company decided that the best option for reducing risk was to aot install the new trailer at this location, and to move one of the existing trailers to a different location. The Building Checklist may be completed. Problem 3: A company has tiered occupancy criteria of (1) occupancy load of 300 hours per week, (2) occupied more than 50 percent of the time, or (3) more than 40 people in the building for one hour. A metal-clad building is used to house maintenance offices and serve as a warehouse. The building is approximately 350 feet from the closest process unit and 750 feet from the flammable storage area. The building is occupied by two warehouse personnel and one supervisor 40 hours per week. Additionally, the maintenance department has 65 personnel who average 2 hours per day, five days a week, including 1 hour per week for a safety meeting in the building. Solution: Since the first and third tier of the occupancy criteria were exceeded, further evaluation using Stage 2 or 3 (Section 3.2 or 3.3) should be considered necessary. The company decided to proceed with further evaluation using Stage 2. Problem 4: A company has established an occupancy load criteria for individuals assigned to the building more than 40 percent of the time. A shelter is provided for operators' use in the process unit The shelter is occupied by four people less than 30 percent of the time. Employees are required to leave the building in the event of an emer gency. Solution: No further evaluation is required because the building does not meet the occupancy criteria. A building check list may be completed. Problem 5: A small field laboratory in a chemical plant has been designated as an emergency shelter during gas releases. The building is designed to prevent ingress of gases. Solution: Since the building is an emergency shelter, and is designed to prevent ingress of toxic releases, no further eval uation is required. A building checklist may be completed. However, if there is a potential for an explosion, further evaluation should be considered necessary using Stage 2 or 3 (Section 3.2 or 3.3). Example 4--Design and Spacing Standards (Section 3.2.1) Problem 1: An engineering building at a refinery is about 500 feet from the closest process equipment The building's occupancy load is over 400 personnel hours and the building is of masonry/steel-frame construction. Solution: The company's standard states that for processing units, the distance for this building type should be more than 400 feet from the hazard. A building checklist may be completed. Problem 2: An existing control building is designed for 10 psi overpressure and is 150 feet from the process unit Solution: The applicable internal company standard on building design indicates that this building meets the current standard. Since the spacing is greater than the required minimum spacing, no further explosion evaluation is required. A building checklist may be completed. Example 5--Consequence Analysis (Section 3.2.2) Problem 1: A control building designed for a 3 psi overpressure is about 100 feet from a Depropanizer. The Overhead Accumulator holds 4000 gallons of propane at 110*F and 210 psig. A process hazards analysis (PHA) concluded that a release could involve a severed 2-inch pipe, and would occur in a congested area. Solution: The overpressure was calculated to be 3 psi at 150 feet, using the multi-energy method. This exceeds the design of the building. Based on these results, additional evaluation should be considered necessary. Copytujhl by the AMERICAN PETROLEUM INSTITUTED) hi Ocl O-l 11:11:11 10% API RP*75S *iS O7AfiD0Dtt649fll lb2 Problem 1: Solution: Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Management op Hazards Associated With Location of Process Punt Buujmngs 29 Example 6--Screening Risk Analysis (Section 3.2.3) A refinery has a Light F-mfe Unit containing propane/butane. A building ofmasonry construction with windows is 50 feet from the process with a fractionator 60 feet away. The original building boused only the control room with two operators. The building has been expanded to accommodate a change room and several offices. The control room is occupied by two personnel all the time on eight-hour, five-days-a-week shifts. The change room has an occupancy of ten for one hour per day, seven days a week. The offices have five people for nine hours per day, five days a week. This solution is based on the steps outlined in Section 3.2.3 of this recommended practice as follows: The building meets the definition ofB3, unreinfbtced masooery with supporting walls, as indicated in Section C12. In calculating the overpressure, the choice of methods is up to the user. A release scenario from the fraction ator, using the multi-energy method, yielded an overpressure of 5.2 psi at the control building, based on a release scenario developed during the PHA. The frequency of explosions should be based on acompany's specific experience. If data or company-specific experience is not available, then the generic information in Appendix C could be used. From Section C.2, a frequency of 4.3 x 10-4 is used for all refinery units, since a Light Ends Unit is not listed in Appendix C. The vulnerability of occupants is reticulated using Section C.13. Given the building type (B3) and overpres sure (5.2 psi) from Figure C-l in Appendix C, the vulnerability of occupants is 1.0. The maximum individual risk is calculated by multiplying the explosion frequency, individual occupancy fraction, and vulnerability of occupants. The maximum individual occupancy load is calculated by deter mining the maximum number of hours per week spent inside the building by anyone (9 hours/day x 5 days/week = 45 hours/week) and dividing by 168 hours/week. The individual risk is as follows: 4.3 x KM (explosion frequency) x 0.26 (maximum individual occupancy) x 1.0 (vulnerability of occupants) = 1.1 x 10-4 The maximum individual risk from the Light Ends Unit is 1.1 x 104. The maximum individual risk from two adjacent units is 6.3 x 104 and 3.7 x 10-3. Thus, the total maximum individual risk for the maximum exposed individual in the building is the following: 1.1 x 104 + 6.3 x 104 + 3.7 x 10-3 = 4.4 x 10-3 The total risk of 4.4 x 10-3 calmfatcd in Step 5 is compared to the internal company risk decision criteria. The following criteria will be used for this example: >1.0 x 10-3 1.0 x 10-3 to 1.0 x 10-5 < 1.0 x 10-5 Risk mitigation or further risk assessment is required. Risk reduction should be considered. Further risk or assessment reduction need not be considered. The value of total risk is greater than 1.0 x 10-3. Based on these criteria, risk mitigation or further risk assess ment should be considered necessary using Stage 3, Risk Management The risk assessment screening indicated that either risk mitigation or further risk assessment is required. The cost of mitigfrriftn measures relative to the costs of a risk analysis should be considered. If the mitigation costs are relatively high, then a risk analysis may be conducted to improve the confidence level of these screening results. Possible risk-reduction measures to be considered include the following: a. Modify process or install emergency shntdown system. b. Move some of the population to reduce the occupancy load. c. Modify the building by providing separate supports for the roof. d. Move the control building. An evaluation of the most cost-effective approach for each of these options should be considered necessary. Copyii()lit by the AMERICAN PHROICUM INSWUIE(API) hi Oct 04 11:11:43 1996 API RP*752 *15 on 30 API Recommended Practice 752 Problem 1: Solution: Problem 1: Solution: Problem 1: Solution: Example 7--Fire (Section 4.0) A noncombustible control room/office building is 100 feet from a pumping row in a refinery unit handling flammable materials. The pumping row is diked, and an automatic water/foam spray system is provided. For the purposes of this example, the materials and site conditions preclude the potential for explosion or jet fire. Figure 4 was used to evaluate the hazard to building occupants. The quantity of material handled exceeds 10,000 pounds. The building does not meet the company's internal standard for locations 150 feet from flammable pumping stations. There is a building emergency response plan to vacate the building in the event of a nearby fire, and the fire brigade will respond to control the fire. Also, the water/foam spray system on the pumps can be activated from the building to minimize the effects. Based on the mitigation and emergency response capability, no additional Ere evaluation should be consid ered. A building checklist may be completed. Example 8--Toxic Release (Section 5.0) A chemical plant uses ammonia in a process. The ammonia is stored in a 15,000-gallon tank and is pumped to the processing unit. The storage tank is 250 feet from the engineering building. Figure 5 was used for the evaluation. Ammonia is listed in OSHA 29 CFR 1910.119, and the stored amount exceeds the specified threshold quantity. All occupied buildings on-site that could be impacted by an ammonia release are provided with pressurization and fresh air supply shutdown systems to preclude entry of ammonia. Additionally, ammonia detectors are located around the storage tank and pump as well as in each building air intake. Based on the pressurization system, which prevents ingress of ammonia, no further toxic evaluation should be considered necessary. A building checklist may be completed and the emergency response actions for occupants defined. Example 9--Building Checklist (Section 6.0) In Example 4, Problem 1, an engineering building was evaluated and it was determined that no further eval uation was required. It may be considered for a final review using a building checldist See the completed Building Checklist that follows. CapytkjM Uk AMI RICAN PUROlfUM INSU1UI[.(API) I ri Oct 04 11:11:45 1996 API RP*7S2 IS QV3AKHb(fl^3^3 T3S Management of Hazanos Associated With Location of Process Plant Buildings 31 The following is an example of a building checklist Some of the questions in the checklist may not apply to all work sites; likewise, additional questions may be necessary. PROCESS PLANT BUILDING CHECKLIST Building: Engineering E,F,r Questions Date: February 29,1994 Y Name: J. Alderman N 1^A* Remarks FT 1. Is the building located up wind of die hazard ? EFT 2. Is the building included in an emergency response plan for fire and toxic release? Are the occupants trained on emergency response procedures? Are evacuation instructions posted? E 3. Are large office equipment or stacks of materials within the building adequately secured? / / Library and file room equipment need proper anchoring. E 4. Are the lighting fixtures, ceilings, or wall-mounted equipment well supported? Are process controls mounted on interior walls? / Ceiling tile and lights need better anchoring. E 5. Is there heavy material stored on the ground floor only? / E 6. Have all the exterior windows been assessed for potential injury to occupants? / Evaluate the need for windows on south side of building. EFT 7. Are there doors on the sides of the building opposite hem an expected explosion or Ere source? FT 8. Are there exterior and interior fire suppression equipment available to the building? / Fire monitors in range of building. FT 9. Is there a detection system within the building or in the fresh air intake to detect hydrocarbons, smoke, or toxic materials? / Smoke and toxic gas in air intake. FT 10. Is the air intake properly located? / Intake on process side of building. FT 11. Can the ventilation system prevent air ingress or air / System is not capable of movement within the building? Are there hydrocarbon or pressurizing the building. toxic detectors that shutdown the air intake? Does the No automatic shutoff of air intake. building have a pressurization system? FT 12. Arc there wind socks visible from all sides of the building? EFT 13. Is there a building or facility alarm or communication system to warn building occupants.(of an emergency)? / T 14. Is there sufficient bottled air or fresh supplied air for the occupancy load? EF1' 15. Are all sewers connected to the building properly sealed to prevent ingress of vapors? / / E=Exploioo; FsFue; aod TsToxic. Thil checklist may or may not be appropriate for every particular circumstance. Copytiqhl by the AMERICAN PflROlEUM INSTITUIC(API) fri Oct W 11:11:4J 1996 API RP*7S5 T5 (KHBBe00ffl$3&RB4 S71 American Petroleum Institute 1220 L Street, Northwest Washington, D.C. 20005 Copytiijtil by Hie AMERICAN PETROLEUM INSWUIE(API) hi Ocl 04 II 11:43 1996 Order No. 855-75201