AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - CHAPTER 311S AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - LONG TITLE Empowering section VerDate:01/04/1999 (Cap 311, section 43) [1 April 1999] L.N. 47 of 1999 (L.N. 379 of 1998) AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 1 (Omitted as spent) VerDate:01/04/1999 (Omitted as spent) AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 2 Interpretation VerDate:31/03/2005 In this Regulation, unless the context otherwise requires- "certificate" (證書)- (a) means a certificate issued under section 5; (b) (Repealed L.N. 218 of 2004) "competent examiner" (合資格檢驗師) means a registered professional engineer in the building services, gas, chemical, environmental, marine and naval architecture or mechanical discipline under the Engineers Registration Ordinance (Cap 409); "existing petrol filling station" (現存油站) means a petrol filling station which was in operation immediately before the relevant date; "latest certificate" (最新近的證書), in relation to a regulated vehicle or petrol filling station, means the most recent certificate- (a) issued in respect of the vehicle or station, as the case may be; and (b) received by the owner of the vehicle or station, as the case may be; "operator" (操作員) means a person who is engaged in the unloading of petrol from a regulated vehicle to a petrol storage tank; "owner" (擁有人), in relation to a petrol filling station, includes a person who owns part of the station; "petrol delivery tank" (運油缸) means a tank in a regulated vehicle from which petrol is unloaded into a petrol storage tank; "petrol dispenser" (加油機) means an installation in a petrol filling station- (a) used or intended to be used for dispensing petrol into the fuel tank of a motor vehicle (whether or not also for dispensing petrol into any other container); (b) designed or constructed for housing a petrol meter and any above ground level petrol and vapour recovery piping; and (c) designed or constructed for hanging a petrol pump nozzle; (L.N. 218 of 2004) "petrol filling station" (油站)- (a) subject to paragraph (b), means premises equipped with an installation designed or constructed to dispense petrol, either directly or through a separate container, into the fuel tank of a motor vehicle or a vessel; (b) does not include such premises served by barges; "petrol storage tank" (貯油缸)- (a) subject to paragraph (b), means a storage tank in a petrol filling station into which petrol from a regulated vehicle is unloaded, whether in the form of a bulk storage tank or 2 or more storage tanks; (b) does not include such tanks which store petrol for a specified process; "Phase I vapour recovery system" (第I期汽體回收系統) means a system which is designed or constructed in such a way that petrol vapour displaced from a petrol storage tank in the course of unloading petrol into the tank is recovered by the system in the petrol delivery tank from which petrol is being unloaded; (L.N. 218 of 2004) "Phase II vapour recovery system" (第II期汽體回收系統) means a system which is designed or constructed in such a way that by means of a vacuum created by a mechanical pump installed in the system, petrol vapour displaced from the fuel tank of a motor vehicle in the course of dispensing petrol into the tank is recovered via a coaxial dispensing hose installed in the system in the petrol storage tank from which petrol is being dispensed; (L.N. 218 of 2004) "pressure/vacuum valve" (調壓排氣閥) means a dual purpose valve- (a) with pressure settings in accordance with the manufacturer's specifications; and (b) which allows relatively small pressure increases or decreases to occur within a petrol storage tank or pipe to which it is connected without allowing vapour venting to the atmosphere or air in-breathing into the tank or pipe; "regulated vehicle" (受管制車輛) means a motor vehicle which is constructed or adapted primarily for the delivery of petrol and is used to deliver petrol to a petrol filling station situated in Hong Kong whether for retail or not; "relevant date" (有關日期) means 31 March 2005; (L.N. 218 of 2004) "vapour recovery system" (汽體回收系統)- (a) in relation to a regulated vehicle, means any Phase I vapour recovery system with which the vehicle is installed; (b) in relation to a petrol filling station, means- (i) all Phase I vapour recovery systems with which the station is installed; and (ii) all Phase II vapour recovery systems with which the station is installed. (L.N. 218 of 2004) (L.N. 218 of 2004) "certificate" (證書) "competent examiner" (合資格檢驗師) "existing petrol filling station" (現存油站) "latest certificate" (最新近的證書) "operator" (操作員) "owner" (擁有人) "petrol delivery tank" (運油缸) "petrol dispenser" (加油機) "petrol filling station" (油站)- "petrol storage tank" (貯油缸) "Phase I vapour recovery system" (第I期汽體回收系統) "Phase II vapour recovery system" (第II期汽體回收系統) "pressure/vacuum valve" (調壓排氣閥) "regulated vehicle" (受管制車輛) "relevant date" (有關日期) "vapour recovery system" (汽體回收系統) AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 2 Interpretation VerDate:01/04/1999 In this Regulation, unless the context otherwise requires- "certificate" (證書)- (a) means a certificate issued under section 5; (b) includes a copy of such a certificate; "competent examiner" (合資格檢驗師) means a registered professional engineer in the building services, gas, chemical, environmental, marine and naval architecture or mechanical discipline under the Engineers Registration Ordinance (Cap 409); "existing petrol filling station" (現存油站) means a petrol filling station which was in operation immediately before the relevant date; "existing regulated vehicle" (現存受管制車輛) means a regulated vehicle which was registered under Part IV of the Road Traffic Ordinance (Cap 374) immediately before the relevant date; "latest certificate" (最新近的證書), in relation to a regulated vehicle or petrol filling station, means the most recent certificate- (a) issued in respect of the vehicle or station, as the case may be; and (b) received by the owner of the vehicle or station, as the case may be; "operator" (操作員) means a person who is engaged in the unloading of petrol from a regulated vehicle to a petrol storage tank; "owner" (擁有人), in relation to a petrol filling station, includes a person who owns part of the station; "petrol delivery tank" (運油缸) means a tank in a regulated vehicle from which petrol is unloaded into a petrol storage tank; "petrol filling station" (油站)- (a) subject to paragraph (b), means premises equipped with an installation designed or constructed to dispense petrol, either directly or through a separate container, into the fuel tank of a motor vehicle or a vessel; (b) does not include such premises served by barges; "petrol storage tank" (貯油缸)- (a) subject to paragraph (b), means a storage tank in a petrol filling station into which petrol from a regulated vehicle is unloaded, whether in the form of a bulk storage tank or 2 or more storage tanks; (b) does not include such tanks which store petrol for a specified process; "pressure/vacuum valve" (調壓排氣閥) means a dual purpose valve- (a) with pressure settings in accordance with the manufacturer's specifications; and (b) which allows relatively small pressure increases or decreases to occur within a petrol storage tank or pipe to which it is connected without allowing vapour venting to the atmosphere or air in-breathing into the tank or pipe; "regulated vehicle" (受管制車輛) means a motor vehicle which is constructed or adapted primarily for the delivery of petrol and is used to deliver petrol to a petrol filling station situated in Hong Kong whether for retail or not; "relevant date" (有關日期) means the day appointed under section 1; "vapour recovery system" (汽體回收系統) means a system by which petrol vapour displaced from a petrol storage tank receiving petrol is recovered in the petrol delivery tank from which petrol is being unloaded. "certificate" (證書) "competent examiner" (合資格檢驗師) "existing petrol filling station" (現存油站) "existing regulated vehicle" (現存受管制車輛) "latest certificate" (最新近的證書) "operator" (操作員) "owner" (擁有人) "petrol delivery tank" (運油缸) "petrol filling station" (油站) "petrol storage tank" (貯油缸) "pressure/vacuum valve" (調壓排氣閥) "regulated vehicle" (受管制車輛) "relevant date" (有關日期) "vapour recovery system" (汽體回收系統) AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 3 Vapour recovery system to be installed VerDate:31/03/2005 (1) No person shall own a regulated vehicle unless it is installed with a Phase I vapour recovery system. (2) No person shall own a petrol filling station unless- (a) each petrol storage tank of the station is installed with a Phase I vapour recovery system; and (b) each petrol dispenser of the station is installed with a Phase II vapour recovery system. (L.N. 218 of 2004) AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 3 Vapour recovery system to be installed VerDate:01/04/1999 (1) Subject to section 8, no person shall own a regulated vehicle unless the regulated vehicle is equipped with a vapour recovery system which complies with the test requirements specified in Schedule 1. (2) Subject to section 8, no person shall own a petrol filling station unless each petrol storage tank installed for the use of the station is equipped with a vapour recovery system which complies with the test requirements specified in Schedules 2 and 3. AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 4 Testing and examination VerDate:31/03/2005 (1) The owner of a regulated vehicle or petrol filling station shall cause its vapour recovery system and all pipes connected therewith to be tested and examined by a competent examiner in accordance with the test requirements specified in section 8A- (L.N. 218 of 2004) (a) upon the completion of the installation of the system and before the system is put into use for the first time; (b) immediately after any modifications have been effected to the system and before the system is put into use again; and (c) at least once every period of 12 months. (2) In subsection (1)(b), "modifications" (改裝) means the replacement or relocation of- (a) a petrol storage tank installed with the vapour recovery system; or (b) the vapour recovery piping, but excluding the coaxial dispensing hose to which it is connected. (L.N. 218 of 2004) "modifications" (改裝) AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 4 Testing and examination VerDate:01/04/1999 (1) The owner of a regulated vehicle or petrol filling station shall cause its vapour recovery system and all pipes connected therewith to be tested and examined by a competent examiner- (a) upon the completion of the installation of the system and before the system is put into use for the first time; (b) immediately after any modifications have been effected to the system and before the system is put into use again; and (c) at least once every period of 12 months. (2) A competent examiner shall carry out the test in accordance with- (a) in the case of a regulated vehicle, the test requirements specified in Schedule 1; (b) in the case of a petrol filling station, the test requirements specified in Schedules 2 and 3. AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 4A Further tests required by Authority VerDate:31/03/2005 (1) If the Authority considers that any part of the vapour recovery system of a regulated vehicle or of a petrol filling station is not functioning properly in the course of unloading or dispensing petrol, as may be appropriate, he may serve a notice in writing on the owner of the vehicle or station, as the case may be, requiring the owner to cause further test and examination to be carried out in respect of any part of the system by a competent examiner in accordance with the test requirements specified in section 8A within the period specified in the notice. (2) The Authority may take into account the following matters in determining whether the vapour recovery system of a regulated vehicle or of a petrol filling station is functioning properly- (a) whether the system is in operation in the course of unloading or dispensing petrol, as may be appropriate; (b) whether the system has any mechanical damage or defect; (c) whether there is any objectionable odour in the station in the course of unloading or dispensing petrol, as may be appropriate; (d) whether there is any leakage of petrol from the system in the course of unloading or dispensing petrol, as may be appropriate. (3) The owner of a regulated vehicle or petrol filling station on whom a notice under subsection (1) is served shall cause further test and examination to be carried out in accordance with the notice. (L.N. 218 of 2004) AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 5 Competent examiners and certificates VerDate:31/03/2005 (1) If, after having carried out the test and examination required under section 4 or 4A, a competent examiner is satisfied that the vapour recovery system of a regulated vehicle or of a petrol filling station complies with the test requirements specified in section 8A, he may issue a certificate in a form specified by the Authority to the owner of the vehicle or station, as the case may be. (2) A competent examiner shall not issue a certificate containing any statement or information which he knows or reasonably ought to know to be false or misleading in a material particular. (L.N. 218 of 2004) AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 5 Registration of certificate VerDate:01/04/1999 (1) When the competent examiner is satisfied that the vapour recovery system of a regulated vehicle or petrol filling station complies with the relevant test requirements as referred to in section 4(2), he shall deliver to the Authority- (a) a certificate in a form specified by the Authority duly signed by him; and (b) a certified true copy of the drawing of the vapour recovery system installed to the regulated vehicle or petrol filling station, as the case may be, indicating the locations and sizes of the inlets, vents, pressure/vacuum valves, safety valves and petrol storage tanks. (2) Where the Authority receives a certificate and drawing under subsection (1) from a competent examiner- (a) the Authority shall- (i) register the certificate by entering particulars of the certificate in a register kept by him for the purpose; (ii) keep the drawing in the register; (iii) endorse on the certificate that it has been registered; and (iv) deliver the certificate as so endorsed to the competent examiner; (b) the competent examiner shall issue the certificate to the owner of the regulated vehicle or petrol filling station to which the certificate relates within 14 days after the receipt of the certificate from the Authority. AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 6 Display of certificate VerDate:31/03/2005 (1) The owner of a regulated vehicle or petrol filling station shall display the latest certificate showing his compliance with the requirements on testing and examination under section 4 or 4A at a conspicuous location on the vehicle or in the station, as the case may be. (2) The owner of a petrol filling station shall not carry out, or cause or permit to be carried out, any unloading of petrol from a regulated vehicle to a petrol storage tank in the station unless there are the latest certificates displayed in respect of the vehicle and the station in accordance with subsection (1). (3) The owner of a petrol filling station shall not dispensed, or cause or permit petrol to be dispensed with any petrol dispenser of the station into the fuel tank of a motor vehicle or any other container unless there is the latest certificate displayed in respect of the station in accordance with subsection (1). (L.N. 218 of 2004) (L.N. 218 of 2004) AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 6 Display of certificate VerDate:01/04/1999 (1) The owner of a regulated vehicle or petrol filling station shall display the latest certificate showing his compliance with the requirements on testing and examination under section 4 at a conspicuous location on the vehicle or in the station, as the case may be. (2) The owner of a petrol filling station shall not carry out, or cause or permit to be carried out, any unloading of petrol from a regulated vehicle to a petrol storage tank in the station unless there are the latest certificates displayed in respect of the vehicle and the station. AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 6A Prohibition of dispensing petrol VerDate:31/03/2005 The owner of a petrol filling station shall not dispensed, or cause or permit petrol to be dispensed with a petrol dispenser of the station into the fuel tank of a motor vehicle or any other container if he knows or reasonably ought to know that any Phase II vapour recovery system with which the dispenser is installed is not in operation in the course of dispensing petrol. (L.N. 218 of 2004) AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 7 Operation VerDate:01/04/1999 (1) An operator shall not carry out, or continue to carry out, the unloading of petrol from a regulated vehicle to a petrol storage tank if the vapour and liquid connections of the vapour recovery systems of the vehicle and the tank are not completely interconnected. (2) Where any leakage of petrol occurs during the unloading of petrol from a regulated vehicle to a petrol storage tank, the operator shall stop the unloading as soon as is practicable and not recommence the unloading until satisfied that there will be no further leakage of petrol. AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 8 Exemptions VerDate:31/03/2005 Paragraph (b)(ii) of the definition of "vapour recovery system" in section 2, sections 3(2)(b) and 6A and section 2.1 of Part 1 of Schedule 2 and Part 2 of that Schedule shall not apply in relation to all existing petrol filling stations until the expiry of 36 months immediately following the relevant date, with the exception of any existing petrol filling station which has each of its petrol dispenser installed with a Phase II vapour recovery system within 36 months immediately following the relevant date. (L.N. 218 of 2004) AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 8 Exemptions VerDate:01/04/1999 This Regulation shall not apply to an existing regulated vehicle or existing petrol filling station until the expiration of 12 months immediately following the relevant date. AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 8A Test requirements VerDate:31/03/2005 The test requirements specified for the purposes of sections 4, 4A and 5 are- (a) in the case of the vapour recovery system of a regulated vehicle, the test requirements specified in Schedule 1; (b) in the case of the vapour recovery system of a petrol filling station, the test requirements specified in Schedule 2. (L.N. 218 of 2004) AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 9 Offences and penalties VerDate:31/03/2005 (1) A person who contravenes section 3(1), or the owner of a regulated vehicle who contravenes section 4(1) or 4A(3), commits an offence and is liable on conviction to a fine of $200000 and to imprisonment for 6 months. (L.N. 218 of 2004) (2) A person who contravenes section 3(2), or the owner of a petrol filling station who contravenes section 4(1), 4A(3), 6(2) or (3) or 6A, commits an offence and is liable on conviction to a fine of $200000 and to imprisonment for 6 months. (L.N. 218 of 2004) (2A) A competent examiner who contravenes section 5(2) commits an offence and is liable- (a) on a first conviction, to a fine at level 5; (b) on a second or subsequent conviction, to a fine at level 5 and to imprisonment for 3 months. (L.N. 218 of 2004) (3) The owner of a regulated vehicle who contravenes section 6(1), or the owner of a petrol filling station who contravenes section 6(1), commits an offence and is liable on conviction to a fine at level 5. (4) An operator who contravenes section 7(1) or (2) commits an offence and is liable- (a) on a first conviction, to a fine at level 5; (b) on a second or subsequent conviction, to a fine at level 5 and to imprisonment for 3 months. AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 9 Offences and penalties VerDate:01/04/1999 (1) A person who contravenes section 3(1), or the owner of a regulated vehicle who contravenes section 4(1), commits an offence and is liable on conviction to a fine of $200000 and to imprisonment for 6 months. (2) A person who contravenes section 3(2), or the owner of a petrol filling station who contravenes section 4(1) or 6(2), commits an offence and is liable on conviction to a fine of $200000 and to imprisonment for 6 months. (3) The owner of a regulated vehicle who contravenes section 6(1), or the owner of a petrol filling station who contravenes section 6(1), commits an offence and is liable on conviction to a fine at level 5. (4) An operator who contravenes section 7(1) or (2) commits an offence and is liable- (a) on a first conviction, to a fine at level 5; (b) on a second or subsequent conviction, to a fine at level 5 and to imprisonment for 3 months. AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SECT 10 (Omitted as spent) VerDate:01/04/1999 (Omitted as spent) AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SCHEDULE 1 STATIC PRESSURE PERFORMANCE TEST FOR THE VAPOUR RECOVERY SYSTEM OF A REGULATED VEHICLE VerDate:31/03/2005 [section 8A] (L.N. 218 of 2004) 1. General This procedure applies to the determination of the five-minute static pressure performance of a vapour recovery system of a regulated vehicle by fluid mechanical principles. 2. Determination of compliance 2.1 The outlet of any vent pipe serving the vapour recovery system shall be fitted with a pressure/vacuum valve. 2.2 For tests in sections 5.1 and 5.2, the following requirements shall be complied with the maximum allowable pressure change in 5 minutes for the petrol delivery tank of a regulated vehicle shall be as tabulated below which has been- (a) pressurized to 4.48 kPa (457 mm water column, gauge); or (b) evacuated to -1.49 kPa (152 mm water column, gauge vacuum). Capacity of a petrol delivery tank or a compartment (litres) Allowable pressure change in 5 minutes per petrol delivery tank or compartment tested (kPa (mm water column, gauge)) 9475 or more 0.127 (13) 5685 to 9474 0.186 (19) 3790 to 5684 0.245 (25) 3789 or less 0.314 (32) 2.3 For tests in section 5.3, the maximum allowable pressure change in the vapour return line in 5 minutes (difference between initial and final pressures) shall be 1.25 kPa (127 mm water column, gauge). 3. Principle and summary of test procedure The regulated vehicle is to be tested in a location where it will be protected from direct sunlight. The petrol delivery tank on the regulated vehicle is to be pressurized, isolated from the pressure source, and the pressure drop recorded to determine the rate of pressure change. A vacuum test is to be conducted in the same manner. 4. Test equipment 4.1 Source of air or inert gas capable of pressurizing tanks to 6.9 kPa (704 mm water column, gauge). 4.2 Low pressure (1.25 kPa (127 mm water column, gauge) divisions) regulator for controlling pressurization of tank. 4.3 Water manometer with 0 to 6.22 kPa (0 to 635 mm water column, gauge) range, with scale reading of 0.01 kPa (1 mm water column, gauge). 4.4 Test cap for vapour line with a shut-off valve for connection to the pressure and vacuum supply hoses. The test cap is to be equipped with a tap for connecting the manometer. 4.5 Caps for liquid delivery line. 4.6 Vacuum pump of sufficient capacity to evacuate tank to -2.49 kPa (254 mm water column, gauge vacuum). 4.7 Pressure and vacuum supply hose of 6.4 mm internal diameter. 4.8 In-line, pressure-vacuum relief valve set and checked to activate at 6.9 kPa (704 mm water column, gauge) and -2.49 kPa (254 mm water column, gauge vacuum) and with a capacity equal to the pressurizing or evacuating pumps. 5. Test procedure 5.1 Static pressure performance, positive pressurization 5.1.1 Static pressure performance measurement (a) Check all the pressure/vacuum valves serving the petrol delivery tanks to ensure that they are working properly. (b) Open and close the dome covers. (c) Connect static electrical ground connections to tank. Attach the delivery and vapour hoses, remove the delivery elbows and plug the liquid delivery fittings. (d) Attach the test cap to the vapour recovery line of the regulated vehicle. (e) Connect the pressure and vacuum supply hose and the pressure-vacuum relief valve to the shut-off valve. Attach the pressure source to the hose. Attach a manometer to the pressure tap. (f) Connect compartments of the petrol delivery tank internally to each other if possible. (g) Apply air pressure slowly, pressurize the tank, or alternatively the first compartment, to 4.48 kPa (457 mm water column, gauge). (h) Close the shut-off valve, allow the pressure in the petrol delivery tank to stabilize (adjust the pressure if necessary to maintain 4.48 kPa (457 mm water column, gauge)), record the time and initial pressure. (i) At the end of 5 minutes, record the final time and pressure. 5.1.2 Pressure change from 4.48 kPa (457 mm water column, gauge) (a) Calculate the pressure change from 4.48 kPa (457 mm water column, gauge) to the final pressure, and compare the pressure change to the requirements in section 2.2. (b) Repeat for each compartment if they were not interconnected. 5.2 Static pressure performance, negative pressurization This procedure does not apply unless pressurized air lines or other equipment penetrate the petrol delivery tank headspace. 5.2.1 Static pressure performance measurement (a) Check all the pressure/vacuum valves serving the petrol delivery tanks to ensure that they are working properly. (b) Connect vacuum source to the pressure and vacuum supply hose. (c) Slowly evacuate the petrol delivery tank, or alternatively the first compartment, to -1.49 kPa (152 mm water column, gauge vacuum). Close the shut-off valve, allow the pressure in the petrol delivery tank to stabilize (adjust the pressure if necessary to maintain -1.49 kPa (152 mm water column, gauge vacuum)), record the time and initial pressure. At the end of 5 minutes, record the final time and pressure. 5.2.2 Pressure change from -1.49 kPa (152 mm water column, gauge vacuum) Calculate the pressure change from -1.49 kPa (152 mm water column, gauge vacuum) to the final pressure, and compare the pressure change to the requirements in section 2.2. 5.3 Internal vapour valve performance, positive pressurization 5.3.1 Static pressure performance measurement (a) After completing the pressure and vacuum tests, pressurize the petrol delivery tank as in section 5.1 to 4.48 kPa (457 mm water column, gauge). (b) Close the petrol delivery tank's internal valve(s) including the internal vapour valve(s), thereby isolating the vapour return line and manifold from the petrol delivery tank. (c) Relieve the pressure in the vapour return line to atmospheric pressure. (d) Seal the vapour return line and after 5 minutes record the gauge pressure existing in the vapour return line and manifold. 5.3.2 Pressure change from 4.48 kPa (457 mm water column, gauge) Calculate the pressure change from 4.48 kPa (457 mm water column, gauge) to the final pressure, and compare the pressure change to requirements in section 2.3. AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SCHEDULE 1 STATIC PRESSURE PERFORMANCE TEST FOR THE VAPOUR RECOVERY SYSTEM OF A REGULATED VEHICLE VerDate:01/04/1999 [sections 3 & 4] 1. General This procedure applies to the determination of the five-minute static pressure performance of a vapour recovery system of a regulated vehicle by fluid mechanical principles. 2. Determination of compliance 2.1 The outlet of any vent pipe serving the vapour recovery system shall be fitted with a pressure/vacuum valve. 2.2 For tests in sections 5.1 and 5.2, the following requirements shall be complied with the maximum allowable pressure change in 5 minutes for the petrol delivery tank of a regulated vehicle shall be as tabulated below which has been- (a) pressurized to 4.48 kPa (457 mm water column, gauge); or (b) evacuated to -1.49 kPa (152 mm water column, gauge vacuum). Capacity of a petrol delivery tank or a compartment (litres) Allowable pressure change in 5 minutes per petrol delivery tank or compartment tested (kPa (mm water column, gauge)) 9475 or more 0.127 (13) 5685 to 9474 0.186 (19) 3790 to 5684 0.245 (25) 3789 or less 0.314 (32) 2.3 For tests in section 5.3, the maximum allowable pressure change in the vapour return line in 5 minutes (difference between initial and final pressures) shall be 1.25 kPa (127 mm water column, gauge). 3. Principle and summary of test procedure The regulated vehicle is to be tested in a location where it will be protected from direct sunlight. The petrol delivery tank on the regulated vehicle is to be pressurized, isolated from the pressure source, and the pressure drop recorded to determine the rate of pressure change. A vacuum test is to be conducted in the same manner. 4. Test equipment 4.1 Source of air or inert gas capable of pressurizing tanks to 6.9 kPa (704 mm water column, gauge). 4.2 Low pressure (1.25 kPa (127 mm water column, gauge) divisions) regulator for controlling pressurization of tank. 4.3 Water manometer with 0 to 6.22 kPa (0 to 635 mm water column, gauge) range, with scale reading of 0.01 kPa (1 mm water column, gauge). 4.4 Test cap for vapour line with a shut-off valve for connection to the pressure and vacuum supply hoses. The test cap is to be equipped with a tap for connecting the manometer. 4.5 Caps for liquid delivery line. 4.6 Vacuum pump of sufficient capacity to evacuate tank to -2.49 kPa (254 mm water column, gauge vacuum). 4.7 Pressure and vacuum supply hose of 6.4 mm internal diameter. 4.8 In-line, pressure-vacuum relief valve set and checked to activate at 6.9 kPa (704 mm water column, gauge) and -2.49 kPa (254 mm water column, gauge vacuum) and with a capacity equal to the pressurizing or evacuating pumps. 5. Test procedure 5.1 Static pressure performance, positive pressurization 5.1.1 Static pressure performance measurement (a) Check all the pressure/vacuum valves serving the petrol delivery tanks to ensure that they are working properly. (b) Open and close the dome covers. (c) Connect static electrical ground connections to tank. Attach the delivery and vapour hoses, remove the delivery elbows and plug the liquid delivery fittings. (d) Attach the test cap to the vapour recovery line of the regulated vehicle. (e) Connect the pressure and vacuum supply hose and the pressure-vacuum relief valve to the shut-off valve. Attach the pressure source to the hose. Attach a manometer to the pressure tap. (f) Connect compartments of the petrol delivery tank internally to each other if possible. (g) Apply air pressure slowly, pressurize the tank, or alternatively the first compartment, to 4.48 kPa (457 mm water column, gauge). (h) Close the shut-off valve, allow the pressure in the petrol delivery tank to stabilize (adjust the pressure if necessary to maintain 4.48 kPa (457 mm water column, gauge)), record the time and initial pressure. (i) At the end of 5 minutes, record the final time and pressure. 5.1.2 Pressure change from 4.48 kPa (457 mm water column, gauge) (a) Calculate the pressure change from 4.48 kPa (457 mm water column, gauge) to the final pressure, and compare the pressure change to the requirements in section 2.2. (b) Repeat for each compartment if they were not interconnected. 5.2 Static pressure performance, negative pressurization This procedure does not apply unless pressurized air lines or other equipment penetrate the petrol delivery tank headspace. 5.2.1 Static pressure performance measurement (a) Check all the pressure/vacuum valves serving the petrol delivery tanks to ensure that they are working properly. (b) Connect vacuum source to the pressure and vacuum supply hose. (c) Slowly evacuate the petrol delivery tank, or alternatively the first compartment, to -1.49 kPa (152 mm water column, gauge vacuum). Close the shut-off valve, allow the pressure in the petrol delivery tank to stabilize (adjust the pressure if necessary to maintain -1.49 kPa (152 mm water column, gauge vacuum)), record the time and initial pressure. At the end of 5 minutes, record the final time and pressure. 5.2.2 Pressure change from -1.49 kPa (152 mm water column, gauge vacuum) Calculate the pressure change from -1.49 kPa (152 mm water column, gauge vacuum) to the final pressure, and compare the pressure change to the requirements in section 2.2. 5.3 Internal vapour valve performance, positive pressurization 5.3.1 Static pressure performance measurement (a) After completing the pressure and vacuum tests, pressurize the petrol delivery tank as in section 5.1 to 4.48 kPa (457 mm water column, gauge). (b) Close the petrol delivery tank's internal valve(s) including the internal vapour valve(s), thereby isolating the vapour return line and manifold from the petrol delivery tank. (c) Relieve the pressure in the vapour return line to atmospheric pressure. (d) Seal the vapour return line and after 5 minutes record the gauge pressure existing in the vapour return line and manifold. 5.3.2 Pressure change from 4.48 kPa (457 mm water column, gauge) Calculate the pressure change from 4.48 kPa (457 mm water column, gauge) to the final pressure, and compare the pressure change to requirements in section 2.3. AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SCHEDULE 2 TEST REQUIREMENTS FOR VAPOUR RECOVERY SYSTEM OF PETROL FILLING STATION VerDate:31/03/2005 [sections 8 & 8A] PART 1 VAPOUR TIGHTNESS TEST FOR VAPOUR RECOVERY SYSTEM OF PETROL FILLING STATION 1. General 1.1 This procedure applies to the determination of the vapour tightness of the vapour recovery system of a petrol filling station. 1.2 In this Part, "pressure/vacuum valve" (調壓排氣閥) means a dual purpose valve which allows relatively small pressure increases or decreases to occur within a petrol storage tank or pipe to which it is connected without allowing vapour venting to the atmosphere or air in-breathing into the tank or pipe. 2. Determination of compliance 2.1 The outlet of any vent pipe serving the vapour recovery system of a petrol filling station shall be fitted with a pressure/vacuum valve with the following pressure settings- (a) positive pressure within the range from 0.872 kPa (88.9 mm water column, gauge) to 0.622 kPa (63.5 mm water column, gauge); and (b) negative pressure within the range from -2.49 kPa (254.0 mm water column, gauge) to -1.49 kPa (152.4 mm water column, gauge). 2.2 The vapour tightness of the vapour recovery system of a petrol filling station shall be tested in accordance with the Vapour Recovery Test Procedure TP-201.3—Determination of 2 Inch WC Static Pressure Performance of Vapour Recovery Systems of Dispensing Facilities ("TP-201.3 Procedure") adopted on 12 April 1996 and amended on 17 March 1999 by the Air Resources Board of the California Environmental Protection Agency. 2.3 The final five-minute pressure performance of the vapour recovery system shall not be lower than the minimum allowable final pressure set out in Table 1B of the TP-201.3 Procedure. PART 2 AIR TO LIQUID VOLUME RATIO TEST FOR VAPOUR RECOVERY SYSTEM OF PETROL FILLING STATION 1. General This procedure applies to the quantification of the air to liquid volume ratio of the petrol pump nozzle of the vapour recovery system of a petrol filling station. 2. Determination of compliance 2.1 The air to liquid volume ratio of the petrol pump nozzle of the vapour recovery system shall be tested in accordance with the Vapour Recovery Test Procedure TP-201.5—Air to Liquid Volume Ratio Test adopted on 12 April 1996 and amended on 1 February 2001 by the Air Resources Board of the California Environmental Protection Agency. 2.2 The air to liquid volume ratio shall be within the range of 0.8 to 1.2. (Schedule 2 replaced L.N. 218 of 2004) "pressure/vacuum valve" (調壓排氣閥) AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SCHEDULE 2 PRESSURE DECAY TEST FOR THE VAPOUR RECOVERY SYSTEM OF A PETROL FILLING STATION VerDate:01/04/1999 [sections 3 & 4] 1. General This procedure applies to the determination of the tightness of vapour recovery system of a petrol storage tank in a petrol filling station. 2. Determination of compliance 2.1 The outlet of any vent pipe serving the vapour recovery system shall be fitted with a pressure/vacuum valve and shall be located at least 3.75 m above the ground level. 2.2 The following requirements shall also be complied with- Ullage* (litres) Minimum acceptable remaining pressure after 5 minutes (kPa (mm water column, gauge)) Ullage (litres) Minimum acceptable remaining pressure after 5 minutes (kPa (mm water column, gauge)) 1895 0.92 (94) 11370 2.17 (221) 2274 1.12 (114) 13265 2.22 (226) 2653 1.29 (132) 15160 2.26 (231) 3032 1.44 (147) 17055 2.29 (234) 3411 1.54 (157) 18950 2.31 (236) 3790 1.62 (165) 28425 2.36 (241) 5685 1.89 (193) 37900 2.39 (244) 7580 2.04 (208) 56850 2.41 (246) 9475 2.12 (216) 113700 2.45 (250) * For the intermediate values of ullage space, interpolation between values should be made as set out in section 6 for the calculation of the minimum acceptable remaining pressure. 3. Principle and summary of test procedures 3.1 The integrity of the vapour recovery system must be proven to ensure its proper operation. A system which will not hold pressure may permit the release of liquids or vapours. The pressure decay test is a low pressure testing method which is performed with all components connected to the piping. 3.2 Fuel dispensing must be suspended during the test since any fuel dispensed will cause a loss of pressure which may be erroneously interpreted as a leak. Vents and vapour processing equipment are plugged and each vapour-return piping run is pressurized with nitrogen to a pressure equal to 2.49 kPa (254 mm water column, gauge). The nitrogen source is then disconnected and the system is allowed to stand under pressure for a period of 5 minutes. The gauge is read to determine the extent of any pressure loss or decay. The results of the test are influenced by the volume of nitrogen in the system and the ullage in the tank. 4. Test equipment 4.1 Nitrogen cylinder and regulator High pressure commercial grade nitrogen gas cylinder equipped with a two-stage pressure regulator and grounding device. 4.2 Pressure relief valve Pressure relief valve set and checked to activate at 6.9 kPa (704 mm water column, gauge). 4.3 Pressure gauge or manometer 0 to 2.49 kPa (0 to 254 mm water column, gauge) pressure gauge or water manometer readable to 0.01 kPa (1 mm water column, gauge). 4.4 Vent plug Threaded or friction-fit plug. 4.5 Test fitting Test fitting for introducing nitrogen into the system and connecting a gauge. 4.6 Stopwatch Stopwatch with accuracy to within 0.2 second. 5. Pretest procedures 5.1 Initial safety procedures. Blockade the work area. Eliminate identifiable sources of ignition, including electrical power to electrical devices associated with vacuum-assist systems, if installed. 5.2 Determine the tank ullage by deducting the fuel in each tank from the tank's capacity. There must be a minimum ullage of 30% of the tank capacity, but not less than 1895 litres for an acceptable test. Vent pipes may be manifolded during the test to achieve the required minimum ullage. 5.3 Check all the pressure/vacuum valves serving the petrol storage tanks to ensure that they are working properly. 5.4 Remove all dry-break caps. 5.5 Install the test fitting at an accessible point in the vapour-return system downstream of any vapour check valve. 5.6 Install the pressure relief valve. 5.7 Secure the nitrogen cylinder and attach the grounding device to the tank or piping. Connect the nitrogen supply to the test fitting. 5.8 Plug the vents. 6. Test procedures 6.1 Open the nitrogen cylinder and regulate the delivery pressure to not more than 135 kPa. Pressurize the vapour recovery system. Maintain the flow of nitrogen until the pressure and flow stabilize, indicating that the temperature and vapour pressure in the tank have stabilized. 6.2 When the pressure reaches 2.49 kPa (254 mm water column, gauge), close the nitrogen cylinder valve and start the stopwatch. 6.3 At the end of each minute, record the gauge pressure. 6.4 At the end of 5 minutes, record the final test pressure. 6.5 Compare the final test pressure to the requirements in section 2.2. To determine the minimum acceptable remaining pressure (P) for the intermediate values of the ullage space, interpolate between values in the table. For example, to calculate the minimum acceptable remaining pressure (P) for 4500 litres ullage, use the values for 3790 litres and 5685 litres ullage, as follows- (4500 - 3790) P = 1.62 + ---------------- x (1.89 - 1.62) (5685 - 3790) = 1.72 kPa Therefore, the minimum acceptable remaining pressure for 4500 litres ullage is 1.72 kPa (175 mm water column, gauge). 7. Concluding the test 7.1 Carefully unplug the vents and allow any remaining pressure to escape. 7.2 Remove the test fitting. 7.3 Disconnect the nitrogen cylinder grounding device. AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SCHEDULE 3 (Repealed L.N. 218 of 2004) VerDate:31/03/2005 AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SCHEDULE 3 EFFECTIVENESS TEST FOR THE VAPOUR RECOVERY SYSTEM OF A PETROL FILLING STATION DURING UNLOADING OF PETROL VerDate:09/04/1999 [sections 3 & 4] 1. General This test procedure is used to determine the effectiveness of vapour recovery system in a petrol filling station by monitoring any petrol vapour released from the vent pipes during unloading of petrol from a regulated vehicle to a petrol storage tank. 2. Determination of compliance The following requirements shall be complied with- (a) any pressure readings recorded in sections 6.4 and 6.5 shall be lower than the pressure setting of the pressure/vacuum valves; (b) any measured maximum vapour concentration in section 6.6 shall not exceed 100% of the lower explosive limit. 3. Principle and summary of test procedures During petrol unloading from a regulated vehicle to a petrol storage tank, the pressure at the vapour side of the petrol storage tank is measured. To assess the effectiveness of vapour recovery, the measured values are compared with the setting of the pressure/vacuum valves installed in the system. Vapour leakage is monitored to ensure no leakage from the system. 4. Test equipment 4.1 Pressure gauge or manometer Pressure gauge or manometer capable of measuring 0 to 7.84 kPa (0 to 800 mm water column, gauge), or the highest pressure setting of the pressure/vacuum valves installed in the system, whichever is higher, with scale reading of 0.01 kPa (1 mm water column, gauge). 4.2 Test fitting Test fitting for connecting the pressure gauge or manometer to the vapour recovery system shall be installed at a position on the vapour side of the vapour recovery system between the petrol storage tank and the pressure/vacuum valve fitted to the vent pipe of the petrol storage tank. The position of the test fitting shall be so selected to represent the highest pressure variation in the system. 4.3 Stopwatch Stopwatch with accuracy to within 0.2 second for timing the measurement intervals. 4.4 Combustible gas detector A portable hydrocarbon gas analyser with associated sampling line and probe using catalytic oxidation to detect and measure concentrations of combustible gas in air. 4.4.1 Safety Personnel shall assume that the combustible gas detector will be operated in an explosive atmosphere and comply with all pertinent regulations. 4.4.2 Range Minimum range of 0 to 100% of the lower explosive limit expressed as propane (0 to 21000 ppm). 4.4.3 Probe diameter Sampling probe with internal diameter of 0.625 cm. 4.4.4 Probe length Probe sampling line of sufficient length for easy manoeuvrability during testing. 4.4.5 Response time Response time to 90% of the final stable reading of less than 8 seconds for detector with sampling line and probe attached. The detector response time shall be equal to or less than 30 seconds. 5. Pretest procedures 5.1 Acquire the factory certified pressure settings of the pressure/vacuum valves fitted to the vent pipes connected to the vapour recovery system and check to ensure that they are working properly. 5.2 Initiate safety procedure. Blockade the work area. Eliminate identifiable sources of ignition. 5.3 Install the test fitting to the vapour recovery system and connect the pressure gauge or manometer to the test fitting. 5.4 Connect all the liquid and vapour pipes for unloading of petrol from the regulated vehicle to the petrol storage tank. For manifolded storage tanks, the tank with the shortest pipe length to the corresponding pressure/vacuum valve shall be selected for the testing. 5.5 Perform a visual inspection to ensure that the vapour and liquid connections of the vapour recovery system of the regulated vehicle and the petrol storage tank are completely interconnected. 5.6 The quantity of petrol to be unloaded to the petrol storage tank shall be of a full compartment of the regulated vehicle. 5.7 The ullage of the petrol storage tank before unloading shall be at a level such that the tank can receive all the petrol to be unloaded. 5.8 Calibrate the combustible gas detector with 2.1% by volume (21000 ppm) propane in air for 100% lower explosive limit response. Calibration gas shall be traceable to the Standard Reference Materials of the National Institute of Standards and Technology, U.S.A. 6. Test procedures 6.1 Stop petrol dispensing from the petrol storage tank(s) in the system at least 5 minutes before the test. 6.2 Record the pressure gauge or manometer readings just before the unloading operation. 6.3 Unload the petrol in the regulated vehicle to the petrol storage tank. Start the stopwatch when the unloading begins and stop the stopwatch at the conclusion of the delivery. 6.4 Record the pressure gauge or manometer readings every 30 seconds during the unloading operation. Record any sudden change of pressure readings. 6.5 Continue to record the pressure gauge or manometer readings every 30 seconds for a period of at least 5 minutes after conclusion of the unloading operation. Record any sudden change of pressure readings. 6.6 Monitor possible vapour leak from any point of the petrol unloading and vapour recovery system including the pressure/vacuum valves using the combustible gas detector during the entire testing period, in accordance with the following procedures: (a) Probe distance The detector probe inlet shall be 2.5 cm from the potential leak source. The distance can be maintained during monitoring by putting a 2.5 cm extension on the probe tip. (b) Probe movement Move the probe slowly (approximately 4 cm/s). If there is any meter deflection at a potential leak source, move the probe to locate the point of the highest meter response. (c) Probe position The probe inlet shall be positioned in the path of the vapour flow from a leak so as to maximize the measured concentration. (d) Leak checks Leak checks shall be performed individually with a fresh air purge between each leak check. Each leak check shall have a duration of less than twice the instrument response time (typically, less than 16 seconds). Longer leak checks are invalid. The probe must be purged with fresh air for more than 2 instrument response times (more than 16 seconds) between individual leak checks. (e) Wind Attempt to block the wind from the area being monitored. (f) Recording Record the measured maximum vapour concentration with the location for each leak being monitored. 6.7 Petrol dispensing from the petrol storage tank(s) may be resumed after the measurement in section 6.5. 6.8 Disconnect all the testing instrumentation from the vapour recovery system after the testing. 6.9 Compare the pressure readings recorded in sections 6.4 and 6.5 and the measured maximum vapour concentrations recorded in section 6.6 to the requirements in section 2. (L.N. 95 of 1999) AIR POLLUTION CONTROL (PETROL FILLING STATIONS) (VAPOUR RECOVERY) REGULATION - SCHEDULE 3 EFFECTIVENESS TEST FOR THE VAPOUR RECOVERY SYSTEM OF A PETROL FILLING STATION DURING UNLOADING OF PETROL VerDate:01/04/1999 [sections 3 & 4] 1. General This test procedure is used to determine the effectiveness of vapour recovery system in a petrol filling station by monitoring any petrol vapour released from the vent pipes during unloading of petrol from a regulated vehicle to a petrol storage tank. 2. Determination of compliance The following requirements shall be complied with- (a) any pressure readings recorded in sections 6.4 and 6.5 shall be lower than the pressure setting of the pressure/vacuum valves; (b) any measured maximum vapour concentration in section 6.6 shall not exceed 100% of the lower explosive limit. 3. Principle and summary of test procedures During petrol unloading from a regulated vehicle to a petrol storage tank, the pressure at the vapour side of the petrol storage tank is measured. To assess the effectiveness of vapour recovery, the measured values are compared with the setting of the pressure/vacuum valves installed in the system. Vapour leakage is monitored to ensure no leakage from the system. 4. Test equipment 4.1 Pressure gauge or manometer Pressure gauge or manometer capable of measuring 0 to 7.84 kPa (0 to 800 mm water column, gauge), or the highest pressure setting of the pressure/vacuum valves installed in the system, whichever is higher, with scale reading of 0.01 kPa (1 mm water column, gauge). 4.2 Test fitting Test fitting for connecting the pressure gauge or manometer to the vapour recovery system shall be installed at a position on the vapour side of the vapour recovery system between the petrol storage tank and the pressure/vacuum valve fitted to the vent pipe of the petrol storage tank. The position of the test fitting shall be so selected to represent the highest pressure variation in the system. 4.3 Stopwatch Stopwatch with accuracy to within 0.2 second for timing the measurement intervals. 4.4 Combustible gas detector A portable hydrocarbon gas analyser with associated sampling line and probe using catalytic oxidation to detect and measure concentrations of combustible gas in air. 4.4.1 Safety Personnel shall assume that the combustible gas detector will be operated in an explosive atmosphere and comply with all pertinent regulations. 4.4.2 Range Minimum range of 0 to 100% of the lower explosive limit expressed as propane (0 to 21000 ppm). 4.4.3 Probe diameter Sampling probe with internal diameter of 0.625 cm. 4.4.4 Probe length Probe sampling line of sufficient length for easy manoeuvrability during testing. 4.4.5 Response time Response time to 90% of the final stable reading of less than 8 seconds for detector with sampling line and probe attached. The detector response time shall be equal to or less than 30 seconds. 5. Pretest procedures 5.1 Acquire the factory certified pressure settings of the pressure/vacuum valves fitted to the vent pipes connected to the vapour recovery system and check to ensure that they are working properly. 5.2 Initiate safety procedure. Blockade the work area. Eliminate identifiable sources of ignition. 5.3 Install the test fitting to the vapour recovery system and connect the pressure gauge or manometer to the test fitting. 5.4 Connect all the liquid and vapour pipes for unloading of petrol from the regulated vehicle to the petrol storage tank. For manifolded storage tanks, the tank with the shortest pipe length to the corresponding pressure/vacuum valve shall be selected for the testing. 5.5 Perform a visual inspection to ensure that the vapour and liquid connections of the vapour recovery system of the regulated vehicle and the petrol storage tank are completely interconnected. 5.6 The quantity of petrol to be unloaded to the petrol storage tank shall be of a full compartment of the regulated vehicle. 5.7 The ullage of the petrol storage tank before unloading shall be at a level such that the tank can receive all the petrol to be unloaded. 5.8 Calibrate the combustible gas detector with 2.1% by volume (21000 ppm) propane in air for 100% lower explosive limit response. Calibration gas shall be traceable to the Standard Reference Materials of the National Institute of Standards and Technology, U.S.A. 6. Test procedures 6.1 Stop petrol dispensing from the petrol storage tank(s) in the system at least 5 minutes before the test. 6.2 Record the pressure gauge or manometer readings just before the unloading operation. 6.3 Unload the petrol in the regulated vehicle to the petrol storage tank. Start the stopwatch when the unloading begins and stop the stopwatch at the conclusion of the delivery. 6.4 Record the pressure gauge or manometer readings every 30 seconds during the unloading operation. Record any sudden change of pressure readings. 6.5 Continue to record the pressure gauge or manometer readings every 30 seconds for a period of at least 5 minutes after conclusion of the unloading operation. Record any sudden change of pressure readings. 6.6 Monitor possible vapour leak from any point of the petrol unloading and vapour recovery system including the pressure/vacuum valves using the combustible gas detector during the entire testing period, in accordance with the following procedures: (a) Probe distance The detector probe inlet shall be 2.5 cm from the potential leak source. The distance can be maintained during monitoring by putting a 2.5 cm extension on the probe tip. (b) Probe movement Move the probe slowly (approximately 4 cm/s). If there is any meter deflection at a potential leak source, move the probe to locate the point of the highest meter response. (c) Probe position The probe inlet shall be positioned in the path of the vapour flow from a leak so as to maximize the measured concentration. (d) Leak checks Leak checks shall be performed individually with a fresh air purge between each leak check. Each leak check shall have a duration of less than twice the instrument response time (typically, less than 16 seconds). Longer leak checks are invalid. The probe must be purged with fresh air for more than 2 instrument response times (more than 16 seconds) between individual leak checks. (e) Wind Attempt to block the wind from the area being monitored. (f) Recording Record the measured maximum vapour concentration with the location for each leak being monitored. 6.7 Petrol dispensing from the petrol storage tank(s) may be resumed after the measurement in section 6.5. 6.8 Disconnect all the testing instrumentation from the vapour recovery system after the testing. 6.9 Compare the pressure readings recorded in sections 6.4 and 6.5 and the measured maximum vapour concentrations recorded in section 6.6 to the requirements in section 2.1.