1.1 safety technical specification for hydrogen use
1.1.1 pipes and accessories shall be products conforming to national standards and specifications, and shall meet the requirements of hydrogen working pressure and temperature. Hydrogen pipes shall be seamless metal pipes, and cast iron pipes are prohibited.
1.1.2 generally, the pipeline shall be connected by welding or other effective methods to prevent air leakage.
1.1.3 vent pipe, sampling port and purging port shall be set on the pipeline, and their positions shall meet the requirements of gas purging and replacement in the pipeline.
1.1.4 when hydrogen is used for welding, cutting, fuel and protective gas, flame arrester shall be set on the branch pipe of each hydrogen equipment (Group).
1.1.5 pipeline laying shall meet the following requirements:
A. The hydrogen pipeline should be laid overhead and its support should be non combustible. The overhead pipeline shall not be laid on the same support as the cable and the conductive line. When hydrogen pipeline is laid in parallel with gas pipeline and oxygen pipeline, there should be non combustible material pipeline in the middle to separate them, or the clear distance should not be less than 250mm. When laying in layers, the hydrogen pipeline shall be located above. The minimum clear distance between hydrogen pipeline and buildings, structures or other pipelines can refer to relevant regulations.
B. The indoor pipeline shall not be laid in the trench or buried directly. The pipeline laid in the outdoor trench shall be provided with measures to prevent hydrogen leakage, accumulation or channeling into other trenches. The buried depth of buried pipeline shall not be less than 0.7m. The pipeline containing wet hydrogen shall be laid under the frozen layer.
C. Where pipes pass through walls or floors, sleeves shall be provided. There shall be no weld on the pipe section in the sleeve, and the pipe and sleeve shall be filled with incombustible materials.
D. The pipeline shall not pass through the trench, sewer, railway vehicle road, etc., and the casing shall be set when it is necessary to pass through.
E. The pipeline shall not pass through living room, office, power distribution room, instrument room, stairwell and other rooms without hydrogen, and shall not pass through ceiling and technical (clamp) layer. When it is necessary to pass through ceiling or technical (clamp) layer, safety measures shall be taken.
1.1.6 the pipelines and busbars laid overhead or underground inside and outside the room and the gas cylinders connected with them shall be connected and grounded with each other, and the measures for such connection and grounding shall be implemented in accordance with the current relevant provisions of the state.
1.1.7 vent pipe:
A. The vent valve, safety valve and pipeline system of hydrogen storage tank are equipped with vent pipe.
B. The vent pipe shall be made of metal material, and plastic pipe or rubber pipe shall not be used.
C. The vent pipe shall be equipped with flame arrester, which can be connected with the fire extinguishing steam or inert gas pipeline to prevent fire.
D. The outlet of the indoor vent pipe shall be more than 2m higher than the house. The vent pipe of outdoor equipment shall be more than 2m higher than the highest equipment operated nearby.
E. The vent pipe shall be static grounded and within the lightning protection range.
F. Measures shall be taken to prevent rain and snow from entering and foreign matters blocking the vent pipe.
1.2 safety points of hydrogen system operation
1.2.1 the oxygen content of hydrogen input to the system shall not exceed 0.5%.
1.2.2 during the operation of hydrogen system, it is not allowed to knock, overpressure or negative pressure.
1.2.3 when pipes, valves and water sealing devices are frozen, they can only be thawed by heating with hot water or steam, and it is strictly prohibited to use open fire for baking.
1.2.4 soap water or portable combustible gas explosion-proof detector can be used for leakage inspection of equipment, pipeline, valve and other connection points, and open fire is prohibited.
1.2.5 do not discharge hydrogen indoors. Purge and replace, vent and depressurize, and discharge through vent pipe.
1.2.6 in case of a large amount of hydrogen leakage or accumulation, the air source shall be cut off immediately for ventilation, and all operations that may cause cremation shall not be carried out.
1.2.7 the newly installed or overhauled hydrogen system must be subject to pressure test, cleaning and air tightness test, and can be put into use only when it meets the relevant inspection requirements.
1.2.8 for purging and replacement of hydrogen system, nitrogen (or other inert gas) replacement method or water injection and exhaust method can be generally used.
A. Nitrogen shall not contain more than 3% oxygen.
B. The replacement must be complete to prevent residual gas at the dead end.
C. After replacement, the content of oxygen or hydrogen in the system must be qualified for three consecutive times.
1.2.9 during the hot work maintenance of hydrogen system, the maximum hydrogen content in the system and in the hot work area must not exceed 0.4%.
1.2.10 prevent open fire and other exciting energy. It is forbidden to use electric furnace, electric drill, furnace, blowtorch and other tools and hot objects that produce open fire and high temperature; it is forbidden to bring kindling into the forbidden area; copper or beryllium copper alloy tools are selected; cotton work clothes and anti-static shoes are worn.