Underground Infrastructure Solutions

Scope Of Work

Subsurface proposes to perform a thorough acoustic surveillance of the pipeline as described. This includes +/- 550 ft. of 16” pipe.

Subsurface Specialists, Inc. (SSI) will utilize Correlator Technology an LC -2100 with transducers designed for large diameter pipe to test the mainline for acoustical leak signals at the available contact points and using the velocity of sound for the designated material. This method will be adequate for any leaks in the immediate area of the available contact points due to the volume and quantity of this particular leak.

We will also use an LD -12 and an LD -18 acoustical amplifier to monitor these contact points.

Due to the characteristics of high pressure leaks and this leak in particular, SSI will utilize Hydrogen Leak Detection equipment combined with compressed air to locate the leak if it happens to be on the mainline. The description suggests a rolled rubber on a joint that only leaks at high pressure. The gas method requires an insertion point which will be established by SSI.

The ambient conditions require that the survey be performed at night in low traffic and lowest possible ambient noise conditions. This necessitates that the line be pumped to pressures 1- to 15 psi above the test pressure during the survey.  

Our experience suggests the survey would be best performed between 10:30 pm and 3:00 am or 4:00 am over two consecutive nights.

Additionally, additional contacts points would be helpful in the pinpointing phase should tracer gas be detected or acoustic signals acquired.