UST Program - LG 113

Certification

Leak rate of 0.005 gph with PD = 97.6% and PFA = 0%

Leak Threshold

A tank system should not be declared tight when chemical marker is detected outside of the tank system.

Applicability

Gasoline, diesel, aviation fuel, fuel oil #4, fuel oil #6, solvents, waste oil, liquefied petroleum gas, natural gas. 
Other fluids may be tested after completion of a compatibility evaluation by the manufacturer.

Tank Capacity

Not limited by capacity.

Waiting Time

Ranges from 5 to 31 days after chemical marker is added to the tank, when “Controlled Leak Points” are not used.
The waiting period may be adjusted below this range when supported by ”Controlled Leak Points” as described below.

Controlled
Leak Points

A “Controlled Leak Point” is a port where chemical marker is injected directly into the soil surrounding the UST to determine the rate at which chemical marker moves.  It can be used to demonstrate that the chemical marker will migrate through the soil to a detection point in a documented amount of time, as described in manufacturer’s procedures.

Chemical
Marker Dosage

Dosage of chemical marker is based on factors including tank size, tank volume, frequency and volume of tank refills, and is determined according to manufacturer's procedures.

Soil
Permeability

Soil present during the evaluation was sandy in texture, with water table 200 feet below the surface.
Type of soil may have an impact on the migration of vapors.
Whenever the chemical marker is used outside of the parameters of the evaluation, such as in frozen soil, “Controlled Leak Point(s)” must be used.

Sampling

When sampling in backfill, radius of influence of each sampling port is a maximum 16 feet.  All tank surfaces must be within the zone of influence of a sampling port.
Sampling can be taken within a vertical or horizontal sampling port.
Sampling port installation and sample collection are conducted per EPA soil gas sampling guidance document SOP#2042.

Sample
Analysis

Two detectors were used during the evaluation: a helium detector with minimum detection level of 2 ppm He, and a gas chromatograph with minimum detection level of 1-10 picograms.  Other analytical equipment with equivalent performance capabilities may also be used.