How are tests of drainage and vent systems accomplished?

Three types of tests are generally used. These include the water test, air test, and smoke test.

If a water test is made, the test is applied to the sanitary plumbing system inside the building by sections or in its entirety. The water test is conducted by closing all openings in the pipe with approved testing plugs to the highest opening above the roof and then filling the system completely with water and noting if leaks exist.

An air test is made by attaching a test apparatus or air compressor to a suitable opening after other openings have been closed off and then forcing air into the sanitary system until there is a uniform pressure in the system to balance a mercury column 10 inches high or a pressure of 5 pounds per square inch on the entire sanitary system for at least a 12-minute period of time. Pipes must be found free from defects and leaking joints.

Normally, buildings four or more stories high are tested in sections. Smoke tests are usually used in sanitary pipe systems if there is a possibility that the system has become defective. After all system openings have been properly sealed, a dense smoke is forced under pressure into the system equivalent to a 1-inch water column for at least a 12-minute period with visual tests for smoke leaks during this period.