There’s a variety of methods used to proactively test pipes for leaks. Not all leaks are easily detectable, and they might otherwise go unnoticed until extensive damage is done. This is the reason for proactive testing. One method we commonly use at Line Locators is known as Smoke Testing.
The basic idea is fairly simple. A visible, non-toxic smoke is generated using a variety of different methods. The smoke is then forced into the pipe system at an access point (for example, a manhole) using a high-pressure fan. If everything is properly sealed then you will only see smoke escaping from areas such as vent pipes and storm drains. If you see smoke escaping from anywhere else then you have located a problem.
When a Smoke leak is detected, the area in which the smoke was seen is marked and often photographed. The idea of this test is not to pinpoint an exact location, but to determine that there is indeed a leak. It also gives you a general idea of where that leak is.
The Peculiar Thing About Smoke Leak Detection
The peculiar thing about this type of test is that it actually requires an open, ventilated system. A closed system would prevent air movement and not allow the smoke to flow freely. This makes it ideal for testing rainwater drainage systems, as well as sewer systems. Consequently, smoke testing can also be used to ensure the proper function of the system as a whole. For example, the vent on your roof immediately above a bathroom allows sewer gases to escape into the atmosphere, rather than letting them enter your house. If during the test no smoke is seen coming from the vent it could mean the vent itself is blocked. Not seeing smoke can sometimes be just as much of a problem.
Ensuring the integrity of sewer lines is extremely important for both health reasons and safety reasons. A leaking pipe can allow raw sewage to escape into surrounding groundwater, or it can allow mud and water to be artificially introduced into the system. This can cause problems with flow or even completely block pipes. A leak might also allow a variety of poisonous and explosive gases to be released. One such example is methane. In its natural form, it is both colorless and odorless, making it virtually imperceptible.
Smoke Testing To Installed Water and Gas Pipes
Smoke testing can also be used on newly installed water and gas pipes. The entire system can be checked for leaks before it is sealed and any water or gas is introduced. This eliminates the potential for costly damage and project delays. It’s particularly useful with copper pipe, which has to be soldered. Once the system is pressurized it becomes much more difficult to effect a repair.
Smoke testing does have its limitations, however. As a general rule, it should not be used during periods of heavy rainfall. Higher than normal levels of groundwater can prevent the smoke from escaping a damaged pipe, making the test inconclusive. Natural blockages within a drain system, such as fallen branches and leaves, can also impede testing by restricting the flow of smoke.