Smoke testing (mechanical)

The expression probably was first used in plumbing in referring to tests for the detection of cracks, leaks or breaks in closed systems of pipes.

[1] Pre-dating the term itself, smoke tests were performed to detect leaks in wooden sailing vessels at least as early as 1836.

This test can be performed when the plumbing is brand new, but more often it is used to find sewer gas leaks that may plague a building or an area.

Smoke testing may not be done after rain or when ground water is unusually high as this may also prevent detection of defects.

Large downdraft fans, usually powered by gasoline engines, are placed on top of open manholes at either end of the section to be tested.

Defective plumbing systems or dry traps will allow smoke to enter the inside of the house.

Plumes are marked, usually with flags, and defects are noted using measurements from stationary landmarks like the corners of houses.

[6] Smoke can also be used to locate difficult-to-find leaks in the fuel evaporative emissions control (EVAP) system.

A sanitary sewer manhole in Springdale, Arkansas with smoke coming out as a result of smoke testing for leaks
Smoke testing a sanitary sewer produces visible smoke at a residence in Springdale, Arkansas
A hand grasping a small blue apparatus with white smoke emerging from its top
A smoke generator used to visualize air flow. Smoke generators provide a low-cost method to visualize air flow patterns around hazard control measures, including in and around fume hoods and pressure differences between adjacent areas or rooms. [ 7 ]