Appendix A 1. -STATIC LEAK TEST (taken from BAAQMD test procedure ST-30)

Transcription

1 Appendix A 1 l. Applicability -STATIC LEAK TEST (taken rom BAAQMD test procedure ST-30) 1.1 This test procedure is used to quantiy the vapor tightness o vapor control systems installed at any gasoline dispensing acility (GDF) equipped with pressure/vacuum (/) valves, provided that the designed pressure setting o the / valves is a minimum o 2.5 inches o water column (inches H 2 O). Excessive leaks in the vapor control system will increase the quantity o ugitive hydrocarbon emissions and lower the overall eiciencies o both the Stage I and Stage II vapor control systems. 1.2 For those systems equipped with a / valve(s) valve allowed to have a designed cracking pressure less than 2.5 inches H 2 O, the valve(s) valve shall be bagged to eliminate, rom the test results, any low contribution through the valve assembly. The valve/vent pipe connection, however, shall remain unobstructed during this test. 1.3 For those acilities not required to be equipped with a / valve(s) valve, the vent pipe(s) pipe shall be capped. For these installations, the test may be conducted at the vent pipe(s) pipe. 2. rinciple 2.1 The entire vapor control system is pressurized with nitrogen to two (2.0) inches H 2 O. The system pressure is then allowed to decay and the pressure ater ive (5) minutes is compared with an allowable value. The minimum allowable ive-minute inal pressure is based on the system ullage and pressure decay equations. For the purpose o compliance determination, this test shall be conducted ater all back-illing, paving, and installation o all Stage I and Stage II components, including / valves, has been completed. 2.2 For a GDF equipped with a coaxial Stage I system this test shall be conducted at a Stage II vapor riser. For a GDF which utilizes a two-point Stage I system this test shall be conducted at the Stage I vapor coupler, provided that the criteria set orth in Section 6.7 have been met. I the integrity criteria or two-point systems speciied in Section 6.7 are met, this test shall be conducted at the Stage I vapor coupler unless the vapor control system possesses a design which is incompatible with testing at this location.

2 Appendix A 2 3. Range 3.1 I mechanical pressure gauges are employed, the ull-scale range o the pressure gauges shall be 0-2.0, 0-1.0, and inches H 2 O column. Maximum incremental graduations o the pressure gauge shall be 0.05 inches H 2 O and the minimum accuracy o the gauge shall be three percent o ull scale. The minimum diameter o the pressure gauge ace shall be 4 inches. 3.2 I an electronic pressure measuring device is used, the ull-scale range o the device shall not exceed 0-10 inches H 2 O with a minimum accuracy o 0.5 percent o ull-scale. A 0-20 inches H 2 O device may be used, provided the equivalent accuracy is not less than 0.25 percent o ull scale. 3.3 The minimum ullage during the test shall be 25 percent o the tank capacity (total o all tanks i maniolded) or 500 gallons, whichever is greater. The maximum total ullage shall be 25,000 gallons. These values are exclusive o all vapor piping volumes. 3.4 The minimum and maximum nitrogen eed-rates, into the system, shall be one (1) and ive (5) CFM, respectively. 4. Intererences 4.1 Nitrogen shall not be introduced into the system at lowrates exceeding ive (5) CFM as this may bias the results o the test toward non-compliance. 4.2 For vacuum-assist Stage II systems which utilize an incinerator, power to the collection unit shall be turned o during testing. 4.3 For vacuum-assist systems which locate the vacuum producing device in-line, between the Stage II vapor riser and the storage tank, the ollowing shall apply: A valve shall be installed at the vacuum producing device. When closed, this valve shall isolate the vapor passage downstream o the vacuum producing device The storage tank side o the vacuum producing device shall be tested in accordance with the procedures outlined in Section 7 o this method. Compliance shall be determined by comparing the inal ive-minute pressure with the allowable minimum ive-minute inal pressure rom the irst column (1-6 aected nozzles) in Table IB or use the corresponding equation in Section 9.2.

3 Appendix A 3 5. Apparatus The upstream vapor passage (nozzle to vacuum producing device) shall also be tested. Methodology or this test shall be submitted to the Ohio EA, Division o Air ollution Control or approval prior to submission o test results or shall be conducted in accordance with the procedures set orth in the applicable CARB Executive Order. 5.1 Nitrogen. Use commercial grade nitrogen in a high pressure cylinder, equipped with a two-stage pressure regulator and a one psig pressure relie valve. A one psig (maximum) pressure relie valve is required and must be present. In addition, the cylinder o nitrogen must be grounded. 5.2 ressure Measuring Device. Use 0-2.0, 0-1.0, and inches H 2 O pressure gauges connected in parallel, a 0-2 inches H 2 O manometer, or an electronic pressure measuring device to monitor the pressure decay in the vapor control system. The pressure measuring device shall, at a minimum, be readable to the 0.05 inches H 2 O. 5.3 "T" Connector Assembly. See Figure 1 below or example.

4 Appendix A 4 Figure 1 "T" Connector Assembly 5.4 apor Coupler Integrity Assembly. Assemble OW 633-A, 633-B, AND 634-A adapters, or equivalent, as shown in Figure 2 below. I the test is to be conducted at the storage tank Stage I vapor coupler, this assembly shall be used prior to conducting the static leak test in order to veriy the pressure integrity o the vapor poppet. The internal volume o this assembly shall not exceed 0.1 cubic eet.

5 Appendix A 5 Figure 2 apor Coupler Integrity Assembly 5.5 apor Coupler Test Assembly. Use a compatible OW 634-B cap, or equivalent, equipped with a center probe to open the poppet, the appropriate pressure measuring device to monitor the pressure decay, and a connection or the introduction o nitrogen into the system. See Figure 3 below or example.

6 Appendix A 6 Figure 3 apor Coupler Test Assembly 5.6 Stopwatch. Use a stopwatch accurate to within 0.2 seconds. 5.7 Flowmeter. Use a Dwyer lowmeter, Model RMC-104, or equivalent, to determine the required pressure setting o the delivery pressure gauge on the nitrogen supply pressure regulator. This pressure shall be set such that the nitrogen lowrate is between 1.0 and 5.0 CFM. 5.8 Combustible Gas Detector. A Bacharach Instrument Company, Model , or equivalent, may be used to veriy the pressure integrity o system components during this test. 5.9 Leak Detection Solution. Any liquid solution designed to detect vapor leaks may be used to veriy the pressure integrity o system components during this test.

7 Appendix A 7 6. re-test rocedures 6.1 The ollowing saety precautions shall be ollowed: Only grounded nitrogen shall be used to pressurize the system A one psig relie valve shall be installed to prevent the possible over-pressurizing o the storage tank. 6.2 roduct dispensing shall not occur during the test. There shall have been no Stage I deliveries into or out o the storage tanks within the three hours prior to the test. For vacuum-assist Stage II systems, product dispensing shall not occur during the thirty minutes immediately prior to the test. 6.3 Measure the gallons o gasoline present in each underground storage tank and determine the actual capacity o each storage tank rom acility records. Calculate the ullage space or each tank by subtracting the gasoline gallonage present rom the actual tank capacity. The minimum ullage during the test shall be 25 percent o the tank capacity (total o all tanks i maniolded) or 500 gallons, whichever is greater. The total ullage shall not exceed 25,000 gallons. 6.4 For two-point Stage I systems, this test shall be conducted with the dust cap removed rom the vapor coupler. This is necessary to determine the vapor tightness o the Stage I vapor poppet. See Section 6.7 i this test is to be conducted at the Stage I vapor coupler For coaxial Stage I systems this test shall be conducted with the dust cap removed rom the Stage I coupler. This is necessary to insure the vapor tightness o the Stage I vapor poppet eriy that the liquid level in the storage tank is at least our (4) inches above the highest opening at the bottom o the submerged drop tube. 6.5 I the Stage I containment box is equipped with a drain valve, the valve assembly may be cleaned and lubricated prior to the test. This test shall, however, be conducted with the drain valve installed and the manhole cover removed. See subsection or urther details regarding containment box drain valves. 6.6 I the test is to be conducted at a Stage II vapor riser, disconnect the dispenser end o one vapor control hose and install the "T" connector assembly (see Figure 1).

8 Appendix A 8 Connect the nitrogen gas supply (do not use air) and the pressure measuring device to the "T" connector For those Stage II systems utilizing a dispenser mounted remote vapor check valve, the "T" connector assembly shall be installed on the vapor riser side o the check valve. 6.7 I this test is to be conducted at the Stage I vapor coupler on a two-point Stage I system, the procedures set orth in subsections and shall be successully completed prior to testing. The static leak test shall not be conducted at the Stage I coupler at acilities equipped with coaxial Stage I systems Connect the apor Coupler Integrity Assembly to the Stage I vapor coupler. Connect the apor Coupler Test Assembly. Connect the nitrogen supply to the assembly and careully pressurize the internal volume o the assembly to two (2.0) inches H 2 O. Start the stopwatch. Record the inal pressure ater one minute I the pressure ater one minute is less than 0.25 inches H 2 O, the leak rate through the Stage I vapor poppet precludes conducting the static leak test at this location. Repair or replace the aulty component(s) as necessary and restart the test pursuant to Section I the pressure ater one minute is greater than or equal to 0.25 inches H 2 O, the static leak test may be conducted at this location. This criteria assures a maximum leak rate through the Stage I vapor poppet o less than cubic eet per minute Disconnect the apor Coupler Integrity Assembly rom the Stage I vapor coupler. I the requirements o subsection were met, install the apor Coupler Test Assembly to the Stage I vapor coupler. 6.8 All pressure measuring device(s) device shall be bench calibrated using either a reerence gauge or incline manometer. Calibration shall be perormed at 20, 50, and 80 percent o ull scale. Accuracy shall be within two percent at each o these calibration points. Calibrations shall be conducted on a requency not to exceed 90 days. The individual conducting the test shall supply to the Ohio EA or its designated local air agency with proo o equipment calibration meeting the requirements o this Section. 6.9 Use the lowmeter to determine the nitrogen regulator delivery pressures which correspond to nitrogen lowrates o 1.0 and 5.0 CFM. These pressures deine the allowable range o delivery pressures acceptable or this test procedure. Also

9 Appendix A 9 record which regulator delivery pressure setting, and the corresponding nitrogen lowrate, will be used during the test Use Equation 9.3 to calculate the approximate time required to pressurize the system ullage to the initial starting pressure o two (2.0) inches H 2 O. This will allow the tester to minimize the quantity o nitrogen introduced into those systems which cannot comply with the static leak standards Attach the apor Coupler Test assembly to the Stage I poppet or the "T" connector assembly to the Stage II vapor riser. Read the initial pressure o the storage tank and underground piping. I the initial pressure is greater than 0.5 inches H 2 O, careully bleed o the pressure, in accordance with all applicable saety procedures, in the storage tank and underground piping to less than 0.5 inches H 2 O column. 7. Testing 7.1 Open the nitrogen gas supply valve and set the regulator delivery pressure within the allowable range determined in Section 6.9, and start the stopwatch. ressurize the vapor system (or subsystem or individual vapor return line systems) to at least 2.2 inches H 2 O initial pressure. It is critical to maintain the nitrogen low until the pressure stabilizes, indicating temperature and vapor pressure stabilization in the tanks. Check the test equipment using leak detecting solution or a combustible gas detector to veriy that all test equipment is leak tight I the time required to achieve the initial pressure o two (2.0) inches H 2 O exceeds twice the time derived rom Equation 9.3, stop the test and use liquid leak detector, or a combustible gas detector, to ind the leak(s) leak in the system. Repair or replace the aulty component(s) component and restart the test pursuant to Section Close and disconnect the nitrogen supply. Start the stopwatch when the pressure has decreased to the initial starting pressure o two (2.0) inches H 2 O. 7.3 At one-minute intervals during the test, record the system pressure. Ater ive minutes, record the inal system pressure. See the applicable o Table IA (or Equation 9.1) or IB (or Equation 9.2) to determine the acceptability o the inal system static pressure results. For intermediate values o ullage in Table IA and IB, linear interpolation may be employed. 7.4 I the system ailed to meet the criteria set orth in Table I (or the appropriate equation in Section 9), repressurize the system and check all accessible vapor

10 Appendix A 10 connections using leak detector solution or a combustible gas detector. I vapor leaks in the system are encountered, repair or replace the deective component and repeat the test. otential sources o leaks include nozzle check valves, pressure/vacuum relie valves, containment box drain valve assemblies, and plumbing connections at the risers I the acility ails to comply with the static leak test standards and the Stage I system utilizes a non-carb-certiied drain valve equipped containment box, which was installed prior to July 1, 1992, or which a CARB-certiied replacement drain valve assembly is not marketed, the ollowing two subsections shall apply: The drain valve may be removed and the port plugged. Retest the system. I the acility complies with the static leak test standards under these conditions, the acility shall be considered complying with the requirements, provided that the manuacturer and model number o the containment box and the date o installation are submitted with the test results The criteria set orth in subsection shall not apply ater July 1, Ater the remaining system pressure has been relieved, remove the apor Coupler Test Assembly or "T" connector assembly and reconnect the vapor control hose, i applicable. 7.6 I the vapor control system utilizes individual vapor return lines, repeat the leak test or each gasoline grade. Avoid leaving any vapor return line open longer than is necessary to install or remove the "T" connector assembly. 8. ost-test rocedures 8.1 Use the applicable o Table IA or IB, or the applicable o Equations 9.1 or 9.2, to determine the compliance status o the acility by comparing the inal ive-minute pressure with the minimum allowable inal pressure For balance Stage II systems use Table IA or the applicable o Equation 9.1 to determine compliance For vacuum-assist Stage II systems use Table IB or the applicable o Equation 9.2 to determine compliance.

11 Appendix A Calculations 9.1 For Stage II Balance Systems, the minimum allowable ive-minute inal pressure, with an initial pressure o two (2.0) inches H 2 O, shall be calculated as ollows: [Equation 9-1] i N = i N = i N = i N = i N > 24 Where: N = The number o aected nozzles. For maniolded systems, N equals the total number o nozzles. For dedicated plumbing conigurations, N equals the number o nozzles serviced by the tank being tested. = The minimum allowable ive-minute inal pressure, inches H 2 O e = A dimensionless constant approximately equal to = The initial starting pressure, inches H 2 O = The total ullage aected by the test, gallons 9.2 For Stage II acuum Assist Systems, the minimum allowable ive-minute inal pressure, with an initial pressure o two (2.0) inches H 2 O, shall be calculated as ollows: [Equation 9-2] i N = 1-6

12 Appendix A 12 2e i N = 7-12 i N = i N = i N > 24 Where: N = The number o aected nozzles. For maniolded systems, N equals the total number o nozzles. For dedicated plumbing conigurations, N equals the number o nozzles serviced by the tank being tested. = The minimum allowable ive-minute inal pressure, inches H 2 O e = A dimensionless constant approximately equal to = The initial starting pressure, inches H 2 O = The total ullage aected by the test, gallons 9.3 The minimum time required to pressure the system ullage to two (2.0) inches H 2 O shall be calculated as ollows: Where: [Equation 9-3] t 2 = / (1522)F t 2 = The minimum time to pressurize the ullage to two inches H 2 O, minutes = The total ullage aected by the test, gallons F = The nitrogen lowrate into the system, CFM 1522 = The conversion actor or pressure and gallons 9.4 I the policy o the local district requires an allowable tolerance or testing error, the minimum allowable ive-minute inal pressure, including testing error, shall be calculated as ollows:

13 Appendix A 13 [Equation 9-4] -E = 2-1+ E 100 [ ( )] 10. Reporting Where: -E = The minimum allowable ive-minute inal pressure including allowable testing error, inches H 2 O E = The allowable testing error, percent = The minimum allowable ive-minute inal pressure calculated in Equations 9-1 or 9-2, inches H 2 O 2 = The initial starting pressure, inches H 2 O = Atmospheric pressure plus the initial starting pressure, inches H 2 O = Atmospheric pressure, inches H 2 O 10.1 The calculated ullage and system pressures or each ive-minute vapor control system test shall be reported as shown in Form 1. Be sure to include the Stage I system type (two-point or coaxial), the Stage II system type, whether the system is maniolded, and the one-minute pressures during the test. The tester may either provide all inormation listed in Form 1 in the comprehensive test report or include a copy o this orm along with the comprehensive written report.

14 Appendix A 14 Form 1 Source Test Results Static Leak Test Date: Time: Application No. GDF Name and address: Stage II system (check one): apor Balance [ ] acuum Assist [ ] Type: Stage I type (check one): Two point [ ] Maniolded? Yes [ ] Coaxial [ ] No [ ] Tank # roduct grade Actual tank capacity (gallons) Gasoline volume (gallons) Ullage (gallons) Initial pressure o UST, inches H 2 O Number o nozzles served by tank Test location: (A) Stage I vapor coupler or (B) Stage II riser Initial ressure, inches H 2 O (2.0) ressure ater 1 min. (inches H 2 O) ressure ater 2 min. (inches H 2 O) ressure ater 3 min. (inches H 2 O) ressure ater 4 min. (inches H 2 O) Final ressure ater 5 min. (inches H 2 O) Allowable Final ressure: Table IA, Table 1B, Equations 9.1, 9.2 Test Status [ass or Fail] Tests Conducted By: Test Company: Date o Tests: Tests Witnessed By:

15 Appendix A 15 TABLE IA STAGE II BALANCE SYSTEMS RESSURE DECAY LEAK RATE CRITERIA INITIAL RESSURE OF 2 INCHES OF H 2 O MINIMUM RESSURE AFTER 5 MINUTES, INCHES OF H 2 O NUMBER OF AFFECTED NOZZLES ULLAGE, GALLONS > , , , , , , , , , , , , , , , , , , , , , , , Note:For maniolded Stage II Balance Systems, the "Number o Aected Nozzles" shall be the total o all gasoline nozzles. For dedicated return conigurations, the "Number o Aected Nozzles" shall be the total o those nozzles served by the tank being tested.

16 Appendix A 16 TABLE IB STAGE II ASSIST SYSTEMS RESSURE DECAY LEAK RATE CRITERIA INITIAL RESSURE OF 2 INCHES OF H 2 O MINIMUM RESSURE AFTER 5 MINUTES, INCHES OF H 2 O NUMBER OF AFFECTED NOZZLES ULLAGE, GALLONS > , , , , , , , , , , , , , , , , , , , , , , , Note: For maniolded Stage II Assist Systems, the "Number o Aected Nozzles" shall be the total o all gasoline nozzles. For dedicated return conigurations, the "Number o Aected Nozzles" shall be the total o those nozzles served by the tank being tested.