It is mandatory to prevent the reverse flow of fire protection system substances, i.e. glycerin wetting agents, stagnant water and water of non-potable quality from being pumped or siphoned into the potable water line.
英
美
- 这种装置强制性防止消防系统物质,如湿甘油剂,停滞水和非饮用级的水通过泵吸或虹吸进入饮用水系统中。