This regulation applies to the setting of gate valves, globe valves, ball valves, butterfly valves and pressure reducing valves of petrochemical plants. See the relevant regulations for the setting of check valves, safety valves, regulating valves and steam traps. This regulation does not apply to the setting of valves on underground water supply and drainage pipelines.
1. The principle of valve arrangement
1.1 Valves should be set according to the type and quantity shown on the Pipe and Instrumentation Diagram (PID). When the PID has specific requirements for the installation location of certain valves, it should be set according to the process requirements.
1.2 The valve should be arranged in a place that is easy to access, easy to operate and maintain. Valves on rows of pipes should be arranged centrally, and consideration should be given to setting up operating platforms or ladders.
2. Requirements for the installation position of the valve
2.1 When the pipe gallery pipeline of the incoming and outgoing device is connected with the main pipe on the pipe gallery of the whole plant, a shut-off valve must be set. The installation position of the valve should be arranged on the side of the device area, and the necessary operating platform or maintenance platform should be set up.
2.2 Valves that require frequent operation, maintenance and replacement should be located in an easily accessible place on the ground, platform or ladder. Pneumatic and electric valves should likewise be placed in easily accessible locations.
2.3 Valves that do not need to be operated frequently (only used when opening and stopping) should also be arranged in a place where temporary ladders can be erected if they cannot be operated on the ground.
2.4 The height of the center of the valve handwheel from the operating surface is between 750~1500mm, the most suitable height is 1200mm, and the installation height of the valve that does not need to be operated often can reach 1500~1800mm. When the installation height cannot be lowered and frequent operation is required, the design should be provided with an operating platform or step. Valves on pipes and equipment for hazardous media shall not be set within the height of a person’s head.
2.5 When the height of the center of the valve handwheel from the operating surface exceeds 1800mm, it is advisable to set up a sprocket operation, and the chain distance of the sprocket should be about 800mm, and a sprocket hook should be set up, and the lower end of the chain should be hung on a nearby wall or pillar so as not to affect the passage of the channel
2.6 When the valve is set in the pipe ditch, when the ditch cover plate can be operated, the handwheel of the valve should not be lower than 300mm under the ditch cover plate, and when it is lower than 300mm, the valve extension rod should be set up to make its handwheel within 100mm under the ditch cover plate.
2.7 The valve arranged in the pipe trench needs to be operated on the ground, or the valve installed below the upper floor (platform) can be set up with a valve extension rod to extend to the ditch cover plate, floor slab, and platform for operation, and the hand wheel of the extension rod is 1200mm away from the operating surface. Valves with nominal diameters less than or equal to DN40 and threaded connections should not be operated with sprockets or extension rods to avoid damaging the valves. In general, the valve should be operated with as little sprockets or extension rods as possible.
2.8 The distance between the valve handwheel arranged around the platform and the edge of the platform should not be greater than 450mm. When the valve stem and handwheel extend into the top of the platform and the height is less than 2000mm, it should not affect the operation and passage of the operator, so as to avoid personal injury.
