(a) General. Pressure-vacuum relief valves intended for use on tank vessels must be approved for such use by the Commanding Officer, U.S. Coast Guard Marine Safety Center. Applications for approval may be delivered by visitors to the Commanding Officer, Marine Safety Center, U.S. Coast Guard, 2703 Martin Luther King Jr. Avenue SE., Washington, DC 20593, or transmitted by mail to: Commanding Officer (MSC), Attn: Marine Safety Center, U.S. Coast Guard Stop 7430, 2703 Martin Luther King Jr. Avenue SE., Washington, DC 20593-7430, in a written or electronic format. Information for submitting the VSP electronically can be found at http://www.uscg.mil/HQ/MSC.

(b) Drawings and specifications. Manufacturers desiring approval of a new design or type of pressure-vacuum relief valve shall submit drawings in quadruplicate showing the design of the valve, the sizes for which approval is requested, method of operation, thickness and material specification of component parts, diameter of seat opening and lift of discs, mesh and size of wire of flame screens.

(c) Pre-approval tests. Before approval is granted, the manufacturer shall have tests conducted, or submit evidence that such tests have been conducted, by the Underwriters' Laboratories, the Factory Mutual Laboratories, or by a properly supervised and inspected test laboratory acceptable to the Commandant (CG-ENG), relative to determining the lift, relieving pressure and vacuum, and flow capacity of a representative sample of the pressure-vacuum relief valve in each size for which approval is desired. Test reports including flow capacity curves must be submitted to the Commanding Officer, USCG Marine Safety Center.

[56 FR 35827, July 29, 1991, as amended by CGD 95-072, 60 FR 50467, Sept. 29, 1995; CGD 96-041, 61 FR 50734, Sept. 27, 1996; USCG-2001-10224, 66 FR 48620, Sept. 21, 2001; USCG-2004-18884, 69 FR 58350, Sept. 30, 2004; USCG-2007-29018, 72 FR 53967, Sept. 21, 2007; USCG-2009-0702, 74 FR 49238, Sept. 25, 2009; USCG-2013-0671, 78 FR 60160, Sept. 30, 2013; USCG-2016-0498, 82 FR 35092, July 28, 2017]