Document Jrodv0zdYQRmrNGZe3vEdVJea

1160 Federal Ritolat / Vol. 46. No. 2 / Monday. January 5,1961 / Propped Rule* 4. By adding Reference Method 21 to Appendix A as follows: A pftoixlix A--Reference method* *** Method 21. Determination of Volatile Organic Compound Leak* 1. Applicability and Principle 1.1 Applicability Tbit method applies to the determination of volatile organic compound (VOC) leaks from organic process equipment. These sources include, but are not .limited to. valves, flanges and other connections, pumps and compressors, pressure relief devices, process drains, open- ended valves, pump and compressor seal system degassing vents, accumulator vessel vents, and access door seals. 1.2 Principle. A portable Instrument is used to detect VOC leaks from individual sources. The instrument detector la not specified, but it must meet the specifications and performance criteria contained in paragraph 2.1. 2. Apparatu 11 Monitoring Instrument. The monitoring instrument (hull be a* fellows; 11.1 Specifications. a. The VOC instrument detector shall respond to the organic compounds being processed. Detectors which may meet this requirement include, but are not limited to. catalytic oxidation, flame ionization, infrared absorption, and photoionization. b. TV i'''trument shall be intrinsically safe iur operation in explosive atmosphere* as dt' bv 'he ncnilcuble U.S.A Standards (e.fc,. i iti in . '-V Code by the National Fire Prevention Asaor.ii.tion). c. The instrument shall be ablu to measure the leak definition concentration specified in the regulation. d. The instrument shall be equipped with a pump so that a continuous sample is provided to the detector. The nominul sample flow rate shall be 1-3 liters per minute. e. The scale of the instrument meter shall be reudal.le to -t. 5 percent of the specified leak definition concentration 2.1.2 Performance Criteria. The instrument must meet the following performance criteria. The definitions and evaluation procedures for each parameter are given in Section 4. 2.1.2.1 The instrument response time must he 30 seconds or less. The response time must be determined for the instrument system configuration to be used during testing, including dilution equipment. The use of s system with s shorter response time than that specified will reduce the time required for field component surveys. 2.1.2.2 >Calibration Precision: The calibration precision must be less than or e iuai to 10 percent of the calibration gas ' aUltt. 2.121 Quulity Assurance. The instrument shall be subjected to response time snd c-W'ration precision tests prior to being ! service The calibration precision ,i... ne repeated every 6 months ' -r -deration or replacement' ;.t u.-t ctor is required, the li be retested and a new S ua! i> ass mure test schedule will apply. Tha responsa time last shall be repeated if eny modifications to ths sample pumping system or flow configuration Is made that would change the response time. 2.3 Calibration Cases. The monitoring instrument is calibrated In terms of parts per million by volume (ppmv) of the compound specified in the applicable regulation. The calibration gases required for monitoring and instrument performance evaluation are a zero gas (air. 3 ppmv VOC) snd e calibration gas in air mixture approximately equal to the leak definin'. 'cifled in tits regulation. If cylinder calibration gas mixture* are used, they must be analyzed and earthed by the msnfacturer to be within 2 percent accuracy. Calibration gases may be prepared by the user according to any accepted gaseous standards preparation procedure that will yield a mixture accurate to within 2 percent. Alternative calibration gas species may be used In place of the calibration compound If a relative reaponse factor for each Instrument is determined so that calibrations with the alternative species may be expressed as calibration compound equivalent! on the malar readout 3. Procedures 3.1 Calibration. Assemble and start op the VOC analyzer snd recorder according tothe manufacturer's instruction*. After the appropriate warmup period and aero or internal calibration procedure, introduce the calibration gas into the instrument sample probe. Adjust the Instrument meter readout to .correspond to the calibration gas value. If a dilution apparatus is used, calibration must Include the instrument and dilution apparatu* assembly. Tha nominal dilution factor may be used to establish a scale factor for converting to an undiluted basis. For example. If a nominal 10:1 dilution apparatus is used, the meter reading for a 10.000 ppm calibration would be set at 1.000. During field surveys, the scale factor of 10 would be used to coiL'crt measurement* to an undiluted basis. :i.2 Individual Source Surveys. 3.2.1 Cats (--Leak Definition Based on Concentration Value. Place the probe inlet at the surface of the component interface where leakage could occur. Move the probe along the interface periphery while observing the instrument readout If an increased mater leading is observed, slowly probe the interface where leakage is Indicated until the maximum meter reading it obtained. Leave the probe inlei at this maximum reading locations for approximately two times the instrument response time. If the maximum observed meter reading ia greater that the leak definition In tha applicable regulation, record and report the result as specified in the regulation reporting requirement*. Examples of tha application of this general technique to specific equipment type* are: a. Vslvt*--The most common source of leaks from valve* la at tha aaal between the etem and housing. Place the probe at the interface where the stem exist* the packing gland and sample the etam circumference. Also, place (he probe at tha interface of the packing gland take-up flange seal and sample the periphery. In addition, survey valve housings of multipart assembly at tha surface of all interfaces when leeks can occur. b. Flanges and Other Connections--For welded flanges, places the probe st the outer edge of the flange-gasket interface and sample around (he circumference of the flange. Sample other types of nonpermam.nl joints (such as threaded connections) with a similar traverse. c. Pumps and Compressors--Conduct a circumferential traverse at the outer surface of the pump or compressor shaft and seal interface. If the source is a rotating shaft, position the probe inlet within one centimeter of the shaft-seal interface for the survey. If the housing configuration prevents a complete traverse of the shaft periphery, sample all accessible portion*. Sample all other joints on the pump or compressor housing where leakage can occur. d. Pressure Relief Devices--The configuration of most pressure relief devices prevents sampling at the scaling seat interface. For those devices equipped with an enclosed extension, or horn, place the probe Inlet st approximately the center of the exhaust are* to the atmosphere for sampling. e. Process Drains--For open drains, place the probe inlet at approximately the center of the area open to the atmosphere for sampling. For covered drain*, place the probe at the surface of the cover interface and conduct a peripheral traverse. L Open-Ended Lines or Valves--Place the probe Inlet si approximately the center of the opening to the atmosphere for sampling. g. Seal System Degassing Vents and Accumulator Vent*--Place the probe inlet at approximately the canter of the opening to the atmosphere for sampling. h. Assess Door Seals--Place the probe inlet at the surface of ths door seal interface and conduct a peripheral traverse. 3X2. Case 11-Leak Devinition Based on "NO Detectable Bnission". a. Determine tha local ambient concentration around the source by moving the probe inlet randomly upwind and downwind st distance of one to two meters from the source. If an interference exists with this determination due to a nearby emission or leak, ths local ambient concentration may be determined at distances closer to the source, but In no case shall ths distance be less than 25 centimeters. Note the ambient concentration and then move the probe inlet to the surface of the source snd conduct a survey as described in 3.2.1. If a concentration increase greater than 2 percent of the concentre lion-based leak definition is obtained, record and report the results as specified by the regulation. b. For those cases where the regulation requires a specific device installation, or that specified vent* be ducted or piped to a control device, the existence of these conditions shall be visually confirmed. When tha regulation also requires that no detectable emissions exist, visual observation* and sampling surveys are required. Examples of this technique are. L Pump or Compressor Seals--If applicable, determine the type of shaft seal. Perform a survey of the local are* ambient VOC concentration and determine if detectable emissions exist as described in 3X2.S. 11.8ael system degassing vents, accumulator vessel vents, pressure relief DTH 000031752 Foe'era*. R*;'.i'.u / i o device*--If applicable, t (nerve whether or not the applicable ducting or piping e> its. Also, determine if any sources nxist in the ducting or piping where emissions enuid occur prior to tha control device If the required ducting or piping exist* ttnd there Hru no sources of where the emissions ould bo vented to the atmosphere prior to the control device, then it is presumed that no detectable emissions ere present. 4. Instrument Performance Evaluation Procedures 4.1 Definitions 4.1.1 Calibration Precision. The difference between the average VOC concentration indicated by the meter readout for consecutive repetition* and the know concentration of a test gas mixture. 4.1.2 Response time. The time interval from a step change in VOC concentration at the input of the tempting system to the time at which 90 percent of the enrrusponding final value is reached-el displayed on the instrument readout meter. 4.2 Evaluation Procedures. At the beginning of the instrument performance evaluation test, assemble and start up the instrument according to the manufacturer's instructions for recommended warmup period and preliminary adjustments. If a dilution apparatus (s usad during field surveys, the evaluation procedure must be performed on the instrument-dilution system combination. 4.2.1. Calibration Precision Test. Make a total of nine measurements by alternately using zero gas and the specified calibration gas. Record the meter readings (example data sheet shown in Figure 21-1). 4.2.2 Response time Test Procedure. Introduce zero gas into the Instrument sample probe. When the meter reading has stabilised, switch quickly to the specified calibration gat. Measure the lime from concentration twitching to 95 percent of final stable reading. Perform this test sequence three timet end record the results (example dilla sheet given in Figure 21-2). 4.3 Calculations. All results are expressed as mean values, calculated by: X I II n x 1 1 X1 Where: X, . VAUM OF TM MMOMMCSrra. X Sum of the individual vahtoa. e s Mean value, n Number of dala points. sum coot ssea as w