The United States Pipeline and Hazardous Materials Safety Administration (“PHMSA”) clarified in an April 5th letter the Hazardous Materials Regulations (“HMR”) applicable to securement of rail tank car closures.

The PHMSA was responding to an October 20, 2016 question posed by SGS Petroleum Service Corporation (“SGS”).

SGS asked whether:

. . .chains are required on caps or plugs used to secure openings on product and vapor valves located inside the top housing on DOT Specification 111 tank cars.

PHMSA responded that the answer depends on the design as previously approved by the Association of American Railroads Tank Car Committee.

The agency stated:

. . .As prescribed in § 179.200-17(a)(1), bottom outlet reducers, closures, and their attachments are required to be secured to the car by 3/8-inch or 1/4-inch chain under certain conditions.

The HMR is stated to not contain a similar provision for top fittings (such as liquid and vapor valves on DOT Specification 111 tank cars).

PHMSA does note that § 179.3 and 179.200-16 require the tank car design and top loading and unloading devices to be approved by the Association of American Railroads Tank Car Committee. As a result, a chain is stated to be required on a liquid or vapor line closure, such as a pipe plug, if the tank car design as approved by the Association of American Railroads Tank Car Committee includes a chain attached to the closure.

A copy of the April 5th letter can be downloaded here.