Installation requirements for safety valves

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1. The safety valve should be installed vertically and close to the equipment or pipeline being protected. If close placement is not possible, the total pressure drop from the protected equipment or pipeline to the inlet pipeline of the safety valve shall not exceed 3% of the set pressure value of the safety valve. 　　2. A maintenance platform should be provided for the safety valve. When installing safety valves with a large weight, the possibility of lifting them after removal must be taken into account; a lifting rod should be provided if necessary. 　　3. Long-radius elbows should be used for the inlet pipeline of the safety valve. 　　4. The design of the safety valve outlet pipeline should ensure that the back pressure does not exceed a certain value set by the safety valve. Standard spring-loaded safety valve, with a back pressure not exceeding 10% of the valve’s set pressure. 　　5. When the medium discharged into the vent main or flare main contains condensate or condensable gases, the outlet of the safety valve should be above the main ； Otherwise, drainage measures should be taken. 　　6. The outlet pipe of the safety valve in a closed system should be connected at a 45° angle to the main pipe, in the direction of flow of the medium, so as to prevent condensate in the main pipe from flowing back into the branch pipes; this also helps to reduce the back pressure on the safety valve.
7. When cut-off valves are installed on the inlet and outlet pipes of the safety valve, single-plate gate valves should be used, and these valves should be sealed with lead. The valve stem should be positioned horizontally to prevent the valve plate from sliding down in case the pins that connect the valve stem to the valve plate become corroded or loose. When a safety valve is equipped with a bypass valve, this valve shall be sealed with lead. 8. The outlet of the safety valve should have no resistance to flow, in order to avoid backpressure. If a drain pipe is installed, its inner diameter must be larger than that of the safety valve’s outlet. Care must be taken to prevent freezing at the valve’s discharge point. For containers containing flammable or toxic, highly toxic substances, the drain pipe must lead directly to a safe location outside or to a facility where such materials can be properly disposed of; no valves shall be installed on the drain pipe. 9. No valves shall be installed between the pressure-bearing equipment and the safety valve. For containers holding flammable, explosive, toxic, or viscous media, a stop valve may be installed to facilitate replacement and cleaning; its structure and diameter must not interfere with the proper operation of the safety valve. 10. The cross-sectional area of the connecting pipe between the safety valve and the boiler or pressure vessel must not be smaller than the flow cross-sectional area of the safety valve. When multiple safety valves are installed on the same pipe, the cross-sectional area of that pipe should be at least 1.25 times the total flow cross-sectional area of those safety valves.