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 supply.

• 这种应用强调必须防止下列消防系统物质，如甘油，润湿剂，积滞水和非饮用级别的水由于泵吸或虹吸作用回流到饮用水供应系统中。