5　Piping Layout for Common Equipment

5.1　Tower piping

5.1.1　The area around tower should be divided into area for piping and that for operation.

Piping shall be routed in piping area，and instruments，manholes and ladders shall be arranged in operation area.

5.1.2　Piping shall be arranged with consideration of manholes，instruments，davits，platforms and ladders.

5.1.3　Towel piping shall be designed in a sequence from top to bottom，and overhead piping，piping with large diameter and piping with special requirements shall be routed at first priority.

5.1.4　Piping from tower top to heat exchangers shall be routed to avoid any liquid pocket.

If tower overhead oil-vapor piping is routed to several heat exchangers in parallel arrangement，they should be symmetrically routed.

5.1.5　The valves in tower side piping should be directly connected to equipment nozzle.

5.1.6　If tower bottom outlet piping is connected to a pump，the elevation of tower shall meet with the net positive suction head required（NPSHR）for pump.And piping shall be routed for the shortest practical run with minimum number of elbows，provided that the requirements for piping flexibility are met.