J stands for water supply pipe; W represents the watt unit of sewage pipe or drainage pump; F stands for waste pipe; Pc stands for hard plastic pipe; Ct stands for cable trough; Cp stands for metal hose; SR stands for steel trunking; RC stands for water gas pipeline; CT stands for cable trough laying; SR stands for laying along the steel cable; CLE stands for laying along or across columns; We advocate laying along the wall; CC stands for underground laying along the cast-in-place slab.