"Hydrostatic pressure" is the system of testing drains generally adopted by the sanitary authorities in London and elsewhere. The drains are usually tested in convenient sections, being filled with water in each section in such a manner as to subject the whole of the pipes and joints to a head or pressure of water not usually more than 5 feet in height.

Drain Testing And Cleansing Appliances 238

Fig. 208.

Drain Testing And Cleansing Appliances 239

Fig. 209.