Method 27
Determination of Vapor Tightness of Gasoline Delivery Tank Using Pressure Vacuum Test
40 CFR Part 60, Appendix A-8
From the method — regulatory text
Sections 1.0 and 2.0 of Method 27—Determination of Vapor Tightness of Gasoline Delivery Tank Using Pressure Vacuum Test, as published at 40 CFR Part 60, Appendix A-8. Retrieved 10/07/2026. The full method is on the eCFR.
1.0 Scope and Application
1.1 Applicability. This method is applicable for the determination of vapor tightness of a gasoline delivery collection equipment.
2.0 Summary of Method
2.1 Pressure and vacuum are applied alternately to the compartments of a gasoline delivery tank and the change in pressure or vacuum is recorded after a specified period of time.
EssentialRegs notes
Our plain-English reading of Method 27. Not the method text.
What it measures
Whether a gasoline cargo tank, such as a tank truck compartment, holds pressure and vacuum, shown by how much the internal pressure changes over a fixed time.
How it works
The tank is sealed, pressurized to a set level and left to stabilize. The pressure is then recorded over a set time. The same procedure is repeated under vacuum. The pressure change in each test is compared with the allowable change given in the rule that invokes the method.
Equipment
A pressure source and a vacuum source with regulation, a pressure-measuring device such as a manometer, and fittings that connect to the tank's vapor and product connections.
When a rule cites it
Vapor-tightness testing and certification of gasoline tank trucks and similar delivery tanks that load at terminals and bulk plants. Rules that require loading only into certified tanks refer to this test.
Notes for compliance staff
Method 27 tests the cargo tank itself. Leaks from a loading rack's piping and couplings are a separate matter handled under other requirements. The pass criterion comes from the invoking rule.
Cited by
Provisions in the corpus whose text cites Method 27. Subscribers land on the provision in the regulation reader; visitors see a preview of it (the GP05 sample opens in full).
The sections marked as regulatory text above are reproduced from the CFR. Everything under ‘EssentialRegs notes’ is our reference copy, not the method. The method as published in the CFR controls.