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ACCIDENT PREVENTION MANUAL FOR INDUSTRIAL OPERATIONS NSC-60 ACCIDENT M PREVENTION MANUAL FOR INDUSTRIAL OPERATIONS ihcluding a statement of methods used in setting up a safety organization, of means used to enlist employee co-operation, and of materials and services offered by the National Safety Council. Prepared by the engineering staff of the Industrial Division, National Safety Council, with assistance from the Statistical and Traffic and Transportation Divisions on problems relating to their fields. Especial appreciation is due the many members of the Manual Committee and to other consultants, who exam ined preliminary drafts and proofs, and who gave inval uable advice by correspondence and in conferenc0. Printed by Wm. H. Pool Co* Chicago, Illinois 1946 111 V) tv-ij INV.'61 1 FOREWORD For some years there has heen need for a compact source of basic information on accident prevention in industry. The body of safety engi neering knowledge has expanded tremendously since the first concerted efforts were made at the beginning of the century to reduce industrial losses. The National Safety Council and many other agencies have in the interim published the result of their experience and research in many forms. Until the publication of this book there has not heen, however, one volume which lias presumed to serve as a ready reference which would put the safety director immediately on the trail of the answer to all hut the molt unusual of his safety problems. The Safe Practices Pamphlets and Data Sheets, long established as technical publications of the National Safety Council, give more extensive discussion to accident prevention problems than does the MANUAL. They are valuable complements to the MANUAL, but in no sense are they super seded by it. Obviously no volume could encompass the details of accident preven tion engineering for every industrial operation, nor even for the operations common to most industries. Industrial safety in specific application means close analysis of the operation in question, the design and control of equip ment and environment so as to reduce the hazard, and the training of the employee toward safe attitudes and practices. The variables of safety in action are infinite. They can be discussed and illustrated in a single volume only in terms of certain common characteristics. The MANUAL is not a textbook covering the general field of accident prevention theory, nor'does it attempt to include the special problems of specialized industries. Neither does it attempt to discuss ways and means by which the employer can properly deal with the off-job hazards of his employees or participate in the public safety problems of his community. The engineering problems of many special industries, and highway, home and farm safety programs are more appropriately a part of other Council p',.,!ications. The MANUAL is a comprehensive source of the "how" of safety, in tended to be kept at hand for frequent and ready reference by the safety director, the safety engineer and the foreman. It sets forth the principles of safety for activities in which the great majority of manufacturing indus trialists engage. It carries these principles into as much detuil as it can without contradicting the premise staled above that the application of acci dent prevention methods to the specific job must remain the responsibility of the engineer. Such application necessarily involves a degree of ingenuity and executive capacity as well as the extensive use of technical materials from the National Safety Council and from other sources. v *V1 \\--C r-- CONTENTS Part Page Foreword............................................................................................................................. v Introduction....................................................................................................................... ix I Plant Design and Layout................................................................................ 1 II Construction and Demolition....................................................................... 33 III Permanent Equipment and Facilities...................................................... 75 IV Guarding and OperatingMachinery...............................................................115 V Materials Handling andStorage..................................................................... 183 VI Electrical Hazards...............................................................................................233 VII Chemical Hazards ........................................................................................ 255 VIII Fire and Explosion Hazards............................................ 4..........................299 IX Flammable Liquids ......................................................................................... 337 X Hand and Portable Power Tools..................................................................379 XI Commercial Vehicle Operation....................................................................409 XII Personal Protective Equipment.....................................................................425 XIII Industrial Hygiene.............................................................................................441 XIV Safety Organization and Program (including accident records and analysis and computation of rates)...................................................... 479 Supplement: NationalSafetyCouncilServices and Materials.......................... 515 Index........................................................................................................................................... 523 eczema, sleepiness and irritability. T fe B L E O F C H E M IC A L H A Z A R D S TABLE OF CHEMICAL HAZARDS--Continued Substance Flash point "F. Auto- ignition Probable safe Explosive limits temperature concentration for % by volume F. 8-hr. exposure Usual mode of entrance to body Signs and symptoms of poisoning Lower Upper antimony (salts) arsenic arsine asbestos barium (compounds) benzene (benzol) bromine metal and sulfides flammable non-flammable peroxide, chlorate, and nitrate produce violent combustion in flammable materials 12 1.5 8 1000 unknown, probably like arsenic 0.15 mg/cu.m.c 1 p.p.m.* 5 million particles per cubic foot7 none adopted 100 p.p.m* 1 p.p.m.* inhalation of dust, ingestion Acute: vomiting, colic, diarrhea, irritation of mouth and throat. Chronic: indigestion, loss of weight and appetite, sometimes severe de-r-m---a-t-i-t-is. --- inhalation of Irritation of skin, loss of hair and dust, ingestion nails, perforation of nasal septum, and direct action hoarse voice, cough, neuralgic on skin and pains, diarrhea. mucous membrane inhalation Headache, nausea, vomiting, chills and shivering, jaundice, dark or bloody urine. inhalation Chronic: shortness of breath, as bestos corns. inhalation or ingestion of soluble salts, direct action on skin Severe dermatitis from the caustic salts, vomiting, dyspnea, abdom inal pain, cyanosis, paralysis. inhalation Chronic: weakness, fatigue, bleed ing from the gums and nose, head ache, dizziness. Acute: inebriation, convulsions, and loss of consciousness. inhalation direct attack on skin and mu cous membranes Irritation of eyes and respiratory tract, irritation and corrosion of skin, probable lung irritation in acute cases. 283  American Standard Allowable Concentration oj Toluene, November 2, 1943 (American Standards Association), wAmerican Standard Allowable Concentration oj X ylene," July 29, 1943 (American Standards Association). a"B. M . Hegted, J. M . McKibbin and Cecil K. Drinker, The Biological, Hygienic, and Medical Properties of Zinc and Zinc Compounds, Supplement 179 to the Public Health Reports (1945). PART XIII INDUSTRIAL HYGIENE Plant facilities: comfort ventilation . . . common ventilation methods . . . industrial illumination ................................................................................................................pp. 441-448 sanitary facilities . . . eating facilities (education of employees, food handling, contamination, dishwashing) .............................................................................pp. 448-453 Plant services: medical service quarters . . . physical examinations . . . personnel and supplies ............................................................................................................. PP- 453-457 Occupational diseases: environmental diseases . . . infections of occupation.... ..........................................................................................................................................pp. 457-460 Industrial poisons: metals and other organic substances . . . radio-active elements . . . metalloids . . . non-metals..........................................................................pp. 460-463 gases . . . organic compounds . . . aromatic compounds....................... pp. 463-466 Industrial skin diseases:..............................................................................................pp. 466-467 Principles of industrial disease control: substitution . . . isolation. . . process revision . . . general exhaust ventilation . . . local exhaust ventilationpp. 467-472 Table XIII-C. Minimum Standards of Illumination.........................................pp. 472-477 Plant Facilities i'actors in comfort ventilation* The comfort, health and efficiency of in- lustrial workers depends, as it does with ill of us, upon the condition of the air jreathed. Industry is repaid amply by di seased production and improved morale of workers for the investment made in proper ventilation of workrooms. After being confined in work places, air undergoes certain physical and chemical dianges which may make it unpleasant or unhealthful. These changes usually include : An increase of carbon dioxide A decrease of oxygen An addition of bacteria An addition of odors An addition of objectionable dust, fumes, gases or vapors *For the engineering aspects of general ventila tion and of exhaust ventilation control systems, see Part I "Design and Layout" and the section on local exhaust ventilation in this Part. See References also. An increase in temperature An increase or decrease of moisture Carbon dioxide. The exhaled air contains approximately 100 times more carbon di oxide than does the air breathed into the lungs. This may increase the carbon di oxide content of the room atmosphere, but is of little or no importance from a venti lation point of view, due to the fact that room air is diluted by air leakage from the outside through structural cracks and crevices. Oxygen. The air breathed into the lungs contains more than 20 per cent oxygen, but the air exhaled contains little more than 15 per cent of this gas, producing a con tinuous decrease of oxygen in the room air. However, it has been determined that the oxygen content of the room air must be reduced to 15 per cent before any ill effects will be noted. Inasmuch as the average breath contains only 20 cubic inches of air, it is improbable that the oxygen content of the air in any 441 462 INDUSTRIAL HYGIENE in suspected cases of poisoning from ex posure to 7.inc, tiiese other toxic elements should not be overlooked. The only significant physiological effect of zinc appears to be metal fume fever. Although of transient character the fever, chills and sweating may be sufficiently se vere to cause disability of one or two days' duration. The salts of this metal have an irritant effect on the skin. Zirconium. No evidence of poisoning due to this metal has been reported. There are, however, certain fire and explosion hazards associated wdth the handling of the powdered metal and its hydride. Industrial poisons (Radio-active elements) Radium, thorium, uranium, radon, x-ray (Sec section on radiation, Page 459.) Industrial poisons (Metalloids) Antimony. The action of antimony is similar to that of arsenic and lead, but not so severe. Antimony can be very irri tating to the skin and mucous membranes. Systemically, it resembles lead in its gastro-intestinal effects, but it usually causes diarrhea instead of constipation. In suspicious cases both lead and arensic must be ruled out. Arsenic. A frequent industrial health hazard results from the arsenic sulfide con tamination of the ores of heavy metals. Arsenic compounds also have wide appli cation in a number of industries. When ever contact with acid occurs, there is a possibility of arsine being formed. Such formation is to be guarded against in the cleaning- of tank cars which have contained concentrated hydrochloric or sul furic acid. Arsine is extremely poisonous, completely destroying the red blood cells in a relatively short time. Manganese. The most frequent source of manganese poisoning is in ore handling, especially in the dusty operations of sepa ration and grinding. Disturbances of the central nervous system similar to those of paralysis agitans occur, progressing from general muscular weakness, tremors of the extremities, spasticity, emotional upsets, speech peculiarity, mask-like expression, and ultimately complete disability. Phosphorus. Formerly frequent in the match and fireworks industry, horribly dis figuring phosphorus poisoning is now sel dom seen. It has been eliminated by the change from the poisonous white form to the innocuous red phosphorus. The poi soning is always chronic. Exposure to phosphine (phosphorus hy dride) may occur rarely in pickling opera tions and in the manufacture of ferrosilicon. This gas causes respiratory and gastro-intestinal disturbances, generalized weakness and, if the exposure is great, con vulsions. Selenium. Of increasing industrial ap plication, selenium and its soluble com pounds are systemic poisons and irritating to the skin and mucous membranes. Tellurium is similar to selenium in its effects and symptonjs. Industrial poisons (Non-metals) Boron. Compounds of boron are toxic, but no industrial poisoning has been re ported. Carbon disulfide, a widely used solvent, is a strong nerve poison if absorbed con tinuously. Chromium. Chromic acid, chromate and dichromate salts are extremely irritating to the skin, eyes and all mucous mem branes. Silicon. The dioxide, so-called "free silica," is the cause of a fibrotic disease of the lungs which, if it progresses, will eventually' limit the respiratory function. Exposure for long periods (usually years) to excessive concentrations of finely divided dust containing high percentages of free silica are followed by the character istic symptoms of this lung disease. Tu berculosis frequently follows. Asbestos causes a similar disability. Sulphur is not a cause of industrial poi soning, but it may produce skin irritation. Some of its compounds, for example, hydrogen sulfide, are extremely toxic. It is not only irritating, especially to the eyes, but it has a marked systemic effect in pro ducing paralysis of the respiratory center. Hydrogen sulfide may be produced in many industries wdiere sulphur-containing compounds, especially sulfides, come in contact with dilute acids. Sulfur dioxide, a common result of gas and coal combustion, has the irritant action of all the acid gases on the respiratory tract. INDUSTRIAL, DISEASE CONTROL 467 protective equipment will do much to pre vent the contact between the skin and the irritant. Aprons, sleeves, gloves, and in fact complete suits of excellent impervious materials are available, and they play a large part in the prevention program when properly used by the worker. See Part X11, "Personal Protective Equipment." Protective creams and ointments espe cially designed for different classes of irri tants are also effective in minimizing skin contact. However, they must be used reg ularly and should be applied several times during a shift. In primary irritation dermatitis, as well as in the sensitization type, personal clean liness plays a large part in prevention. Fre quent washing with a safe industrial soap and warm water will reduce the time dur ing which the irritant can exert its action. All of the above mentioned principles are also effective against the sensitization type of dermatitis. Here it is most essential to prevent the original exposure, which is the fundamental cause of the allergic state with its accompanying exquisite sensitivity. Once this stage is reached, the possibility of preventing irritating contacts becomes extremely difficult, for very minute quan tities of the substance will then produce a response. It is for this reason that care lessness in handling potential sensitizers must be avoided. If skin contact is pre vented from the very beginning, the chance of developing sensitivity is greatly reduced. The value of estimating sensitivity to skin irritants in the pre-placement selec tion of workers has probably been exagger ated. The practical difficulties of the de termination, to say nothing of the frequent transference of workers about a plant and resulting exposure to many different irri tants, make this practice of doubtful value. However, there are two exceptions to this statement: Negroes seem to tolerate skin irritation much more than whites, and women appear to be more susceptible than men. Other than noting these exceptions, little of value will result from selective placements. `'Cutting oil" dermatitis. The most com mon skin afflictions arising from contact with cutting oils and compounds seem to be due to mechanical blocking of the hair follicles by the oil anil foreign particles as well as to the defalling action* on skin which is characteristic of all petroleum products. Bacteriological studies have failed to re veal the presence of significant numbers of pathogenic organisms in the oils. However, if sterilization is considered, it should be by heating only. Antiseptics are undesirable because of the possibility of skin irritation. Periodic removal of the oil from the ma chine, so that it may be strained to remove extraneous material, and thorough cleaning of the machine before replacing it are of ordinary sanitary merit. Frequent change of cutting compounds (oil-water emulsions) is advisable and in expensive. The old emulsion should be discarded, and the machine should be thor oughly cleaned and refilled with a fresh mix. Creams and lotions especially designed for protection against cutting oils may also prove of value. In order to reduce the amount of oil thrown upon the workers, shields and guards should be provided for all high speed machines which produce a spray. Sleeves and aprons are also a pro tection against spray. Other affections of the skin which are of occupational origin include the serious lesions resulting from exposure to paraffin, pitch, coal tar, arsenic, and certain oils. The cutaneous form of anthrax is also an occu pational ailment. Workers exposed to agents which may produce these conditions should be ex amined frequently for the presence of skin changes. Here again personal cleanliness plays a large part in prevention. The use of special protective creams has also been found of value. Principles of industrial disease control It is difficult to measure the seriousness of the occupational disease problem. On the one hand, there are the effects on worker health, on morale, and eventually on production. On the other, there are the evaluations which have been placed on the costs to industry of compensation, medical care and lost wages. These figures have never been adequately collected and analyzed, so that estimates vary from a few hundred thousand dollars to several hundred million dollars. There are two fundamental methods for the control of industrial disease. One is 468 INDUSTRIAL, HYGIENE aimed at the process or operation, the other at the individual worker. The first is essen tially an engineering function and should be concerned principally with preventive measures. While much of this corrective work will follow the occurrence of clinical industrial disease, its prime objective is to see that no disease ever occurs. The second method, which has to do with the worker, is medical in character and, while concerned principally with treat ment, should also be interested in preven tion. Here will be discussed in general the first method, that concerned with lhe con trol of the working environment. Substitution. An ideal method for occu pational disease prevention, but one which can only occasionally be achieved, is the Figure XIII-9, Electrostatic precipitator for the collection of metallic fumes. Courtesy Mine Safety Appliances Co. exchange of a harmless material for one which is toxic, as in the use of steel shot instead of silica sand in abrasive blasting, non-mercurial carrottiug compounds in the production of felt, and the use of less toxic solvents instead of benzol. Such substitu tion can be brought about only when the toxic material is not essential to satisfac tory production. Isolation. For operations in which it is not possible to make substitutions, isola tion or enclosure of the hazardous process offers a measure of success. An effective combination control measure is the use of enclosure and exhaust ventilation combined, as in the modern paint spray booth. Modifications of the complete enclosure may also be utilized. One side, for example, may be open, provided with curtains or a sliding door. Completely enclosed small cabinets are available for sandblasting small objects. These models are equipped with armholes for manipulating the blast hose and with a window through which the oper ation may be observed. Process revision. Occasionally a very simple and effective method of control is so to change the operation as to avoid the health hazard. This may take a variety of forms, such as the use of mechanical meth ods for hand operations, the use of water to subdue dust, careful adjustment of com bustion to avoid poisonous gases, and the control of chemical reactions to reduce the escape of toxic gases and vapors. General exhaust ventilation is designed to control air pollution by means of dilution. Air is either -ashed or pulled into the room by means o' fans or other propelling de vices so that it produces a decrease in the amount of contaminant. General exhaust ventilation has the vir tue of simplicity and relatively low origi nal cost and maintenance. It is particularly effective when large amounts of non-toxic air contaminants must be eliminated, such as smoke, dust, and steam, but it should not often be relied upon to control toxic materials. Two common faults in general exhaust installations are the lack of provision for make-up air, and permitting short circuit ing to occur. In the first case, fans will be inefficient in output and a vacuum may be formed which would create unpleasant drafts through cracks and other openings.