Enforcement Advisory: #194: Gasoline Dispensing Facility: Appropriate Use of TP-201.5 - Air to Liquid Ratio (A/L) Test

This page last reviewed December 17, 2015


Gasoline Dispensing Facility
Appropriate Use of TP-201.5
Air to Liquid Ratio (A/L) Test

Number 194

March 30, 2001


The Enhanced Vapor Recovery procedure amendments are effective April 1, 2001. The majority of the amended procedures are used for certification of vapor recovery systems. However, TP-201.5, Air to Liquid Ratio, is also used for start-up, annual, and compliance testing. This advisory explains the appropriate use of TP-201.5.

The new TP-201.5 reduces vapor exposure to the tester and saves time by reducing the amount of gasoline dispensed. However, currently installed assist systems have been certified using the 1996 version of TP-201.5. Thus, A/L start-up, annual, and compliance tests for systems certified prior to April 1, 2001 (all currently installed systems) shall be conducted using the 1996 TP-201.5, or an approved alternative, until the Air Resources Board (ARB) has determined if the 2001 and 1996 versions give equivalent results. Approved alternatives to the 1996 A/L test, such as the VacuCheck, VacuSmart or BAAQMD ST-39, may continue to be used for existing facilities, unless otherwise specified by the local air district.

The new TP-201.5 has several significant changes, some of which are listed below:

  1. The vapors in the test tank are "recovered", reducing air ingestion into the UST.
  2. Equipment requirements have been set to standardize test equipment.
  3. Specific volume meter calibration procedures have been added.
  4. Pre-test and post-test equipment leak checks are required.
  5. The dispensed volume has been changed from 7.48 gallons to a range of 4.5 - 5.0 gallons.
  6. Only one test run is required, except that three (3) test runs are averaged for "borderline" failures that occur on the first test run.

The ARB has placed a high priority on conducting field tests to ascertain equivalency between the "new" and "old" versions of TP-201.5 so that the benefits of the new procedure can be realized as soon as possible. The equivalency results will be provided in future advisories.

You can get copies of the new and "repealed" (1996) versions of TP-201.5 via the Air Resources Board website at http://www.arb.ca.gov/testmeth/vol2/tp201_5.pdf and http://www.arb.ca.gov/testmeth/vol2/1996tp201_5.pdf, respectively.  For questions on this advisory, please contact the Vapor Recovery and Fuel Transfer Branch at (916) 327-0900.