Only if the gas pressure were above the maximum value allowed by regulations (400 mm.W.C.) would it be necessary to install a pressure reducer on the gas pipeline outside the heating plant.

• 根据规程当气体压力大于允许的最大压力（400mm水柱），在加热设备（译注：如锅炉-燃烧器装在上的加热设备，不能译成加热工厂）外面气体管道上需要安装减压器。