Michigan Administrative Code
Department - Licensing and Regulatory Affairs
Bureau of Fire Services
Storage and Handling of Gaseous and Liquefied Hydrogen Systems
Part 2 - STORAGE AND HANDLING OF GASEOUS HYDROGEN NFPA 50A
Chapter 2 - Design of Gaseous Hydrogen Systems
Section R. 29.7021 - Pressure relief devices
Current through Vol. 24-16, September 15, 2024
Rule 21. Section 2-2.3 is reproduced from NFPA 50A, and sections 2-2, 2-2.1, 2-2.2, and 2-2.4 to 2-2.7.1 of the storage and handling of gaseous and Liquefied H2 code are added as follows:
2-2 Pressure relief devices.
2-2.1 H2 containers shall be protected from credible overpressure scenarios by a relief device installed in accordance with the ASME International, "Boiler Pressure Vessel Code," section VIII division 1 sections UG 125 through 137, adopted by reference in section 8-1. When all credible overpressure sources are external to the container, the relief device(s) need not be installed directly on the container. In such cases, the relief devices may be installed in the piping between the container and the source(s) of overpressure and a block valve may be installed between the relief device(s) and container, provided the source of overpressure is blocked from the container.
2-2.1.1 Fully over-wrapped carbon composite containers shall be protected by thermally activated pressure relief devices acceptable to the department based on the best interests of public health, safety, welfare and the environment.
2-2.2 Pressure relief devices, when installed, shall be arranged to discharge upward and unobstructed to the open air in such a manner as to prevent any impingement of escaping gas upon the container, adjacent structures, or personnel. The vent and piping system from relief device(s) shall be designed and installed in accordance with CGA G-5.5.
2-2.3 Pressure relief devices or vent piping shall be designed or located so that moisture cannot collect and freeze in a manner that would interfere with proper operation of the device.
2-2.4 Pressure relief valves for gaseous H2 service shall not be fitted with manual relief (lifting devices).
2-2.5 Pressure relief valves for gaseous H2 systems, if externally adjustable, shall be provided with a means for sealing the adjustment to prevent tampering.
2-2.5.1 If at any time it is necessary to break such a seal, the valve shall be removed from service until it has been reset and sealed in accordance with design, certification, and installation code specified in section 2-2.1.
2-2.6 Pressure relief valves shall be tested at least every 5 years.
Exception: Non-ASME relief valves used for blocked-in portions of piping as thermal relief valves will not be tested.
2-2.7 Excess flow control shall be provided for pressurized H2 piping systems above 15 psig when system design allows their application to add a significant measure of safety for break, rupture, or open valve (to atmosphere) conditions.
2-2.7.1 The location of excess flow control shall be as specified as in either of the following situations:
(a) Where piping originates from a source located in a room or area, the excess flow control shall be located within the same room or area.
(b) Where piping originates from a bulk source, the excess flow control shall be as close to the bulk source as possible.
Exception: The above requirements shall not apply to piping for inlet connections designed to prevent backflow, piping pressure relief devices, or systems containing 450 scf of H2 gas or less.
