4.3　Storage and Transportation Facilities

4.3.1　Detectors shall be equipped within fire dikes for liquid tanks for LPG，class Ⅰ and class Ⅱ flammable and combustible liquids according to the following requirements:

1　When the detection point is set on the windward side of the annual minimum wind frequency of the release source，the distance between a combustible gas detection point and a release source should not exceed 15m and that between a toxic gas detection point and a release source should not exceed 2m；

2　When the detection point is set on the leeward side of the annual minimum wind frequency of the release source，the distance between a combustible gas detection point and a release source should not exceed 5m and that between a toxic gas detection point and a release source should not exceed 1m.

4.3.2　Layout of detectors for loading/unloading facilities for LPG，class Ⅰ and class Ⅱ flammable and combustible liquids shall comply with the following requirements:

1　For railway loading/unloading platform with small loading arms，a detector should be installed at every other tank space with the horizontal distance between the detector and loading/unloading port not exceeding 15m；

2　For railway loading/unloading platform with big loading arms，a detector should be installed；

3　The horizontal distance between loading/unloading ports for tank trucks and detector shall not exceed 15m.When a buffer tank is installed in the truck loading/unloading station，arrangement of detectors shall meet the provisions in clause 4.2.1 of the specification.

4.3.3　Detectors for pumps or compressors of the loading/unloading facilities shall be arranged according to the requirements in section 4.2 of the specification.

4.3.4　Detectors for liquefied hydrocarbon loading stations shall be equipped according to the following requirements:

1　For closed or semi-open cylinder-filling workshop，the distance between filling port and detector should be within the range of 5m-7.5m；

2　Inside a closed or semi-open cylinder warehouse，the arrangement of detectors shall comply with the requirements in clause 4.2.2 of the specification.Within open cylinder warehouse，detectors shall be set every 15m-30m along the perimeter of the house，one detector shall be equipped if the perimeter of the house is less than 15m；

3　The distance between the detector and the drainage port or manifold of the surge tank should be within the range of 5m-7.5m.

4.3.5　For closed or semi-open hydrogen cylinder-filling workshop，a detector shall be equipped at its highest point above the filling port in the workshop prone to gas accumulation.

4.3.6　For loading/unloading docks with potential emission of combustible gas，a detector shall be installed within 15m of the horizontal plane of the transfer loading/unload arm.

4.3.7　For storage and transportation facilities storing and transporting toxic gas and liquid，detectors shall be equipped according to the section 4.2 and clause 3.0.10 of the specification.