Detection Professional Blog

Gas Migration: Pin Pointing Underground Gas Leaks

When underground natural gas pipes leak, it is often due to external damage to the buried pipe. Digging, excavation and corrosion are a few common causes of natural gas leaks.

Underground gas leaks tend to migrate along the path of least resistance. Methane, the main component of natural gas, is lighter than air, and can migrate through loose soil, sewer lines and buried conduit.

The gas may find its way to the surface, leaving visible signs of dead or dying grass and other vegetation. Larger, steady gas leaks may produce visible bubbling at the surface or a hissing sound. Most leaks are easily detected by the familiar natural gas odor; a chemical additive called Mercaptan. However, small gas leaks can go undetected by smell, sight, or sound. They can migrate longer distances and become challenging to find.

SENSIT technologies designs and manufactures instruments specifically for natural gas pipeline operators and gas distribution companies to detect gas leaks and identify the possible migration area. These instruments assist utility workers when surveying, pinpointing and repairing leaking pipeline assets.

Instruments such as the Portable Methane Detector (PMD) and (VMD) Vehicle Methane Detector quickly and accurately identify methane (natural gas) leaks along transmission pipes as well as distribution mains and service lines. When used with specially designed probes, the SENSIT GOLD G2 and Trak-it IIIa instruments detect, measure, and pinpoint the source of underground gas leaks.

Many SENSIT instruments have special features to make the process easier, more efficient, and accurate for the user.

Bar Hole Testing involves creating a series of small diameter holes in the ground near the path of the gas pipeline. A probe connected to the instrument is inserted into the hole to draw a gas sample from the ground. Several SENSIT instruments include software that record gas measurements during Bar Hole Tests. The instruments are engineered to quickly alert the operator whenever gas is detected.

Leak Search Mode provides a means of sampling gases at ground level, by using a survey probe or a survey drag tube. The SENSIT GOLD G2 has built in software to record Leak Search results as the operator walks the path of the gas line. If hazardous gas levels are encountered, the instrument will alert the operator.

Leak detection and monitoring are critical disciplines within the natural gas industry. SENSIT Technologies works closely with industry clients to develop detection instruments and technology that improve the safety and efficiency of natural gas systems all over the world.