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 3 - Location of Gaseous Hydrogen Systems › Section R. 29.7035 - Vaults for aboveground containers

Current through Vol. 24-12, July 15, 2024
Rule 35. Sections 3-3 to 3-3.2 of the storage and
						handling of gaseous and Liquefied H2 code are added as
						follows:
3-3 Vaults for aboveground containers. Vaults may be
						installed aboveground, underground or partially buried.
3-3.1 General. Aboveground containers may be installed in
						vaults that meet the requirements of section 3-3. Except as modified by the
						provisions of section 3-3, vaults shall meet all other applicable provisions of
						these rules.
3-3.2 Vault design and construction. Vaults shall be
						designed and constructed to meet the following requirements:
(a) The walls and floor of the vault shall be
					 constructed of reinforced concrete at least 6 inches (15.24 centimeters)
					 thick.
(b) The top of an
					 aboveground vault shall be constructed of noncombustible material and shall be
					 designed to be weaker than the walls of the vault to ensure that, in the event
					 of any explosion, the thrust occurring inside the vault is directed upward
					 before destructive internal pressure develops within the vault. The top of an
					 at-grade or below-grade vault shall be designed to relieve or contain the force
					 of any explosion occurring inside the vault. The walls of a vault, which are
					 partially below-grade, shall extend not less than 4 feet (1.2 meters) above
					 grade.
(c) The top and floor of a
					 below-grade vault and the container foundation shall be designed to withstand
					 all anticipated loading from vehicular traffic, where applicable.
(d) The walls and floor of a below-grade
					 vault shall be designed to withstand anticipated soil and hydrostatic loading.
					 The vault shall be liquid tight.
(e) Adjacent vault may share a common
					 wall.
(f) The vault enclosure shall
					 not have openings except those necessary for access to, inspection of, and
					 filling, emptying, and venting of the container.
(g) When required, the vault shall be
					 designed to be wind and earthquake resistant, in accordance with good
					 engineering practice.
(h) The vault
					 shall be provided with an open and continuous vent to provide ventilation to
					 dilute, disperse, and remove any vapors. This continuous vent line shall
					 terminate 12 feet (3.7 meters) abovegrade.
(i) Each vault shall be provided with a means
					 for personal entry, which shall only be at the top of the vault to allow for
					 the visual inspection of the container and piping surfaces. At each entry
					 point, a warning sign that indicates the need for procedures for safe entry
					 into a confined space shall be posted. Each entry point shall be secured
					 against unauthorized entry and vandalism.
(j) The vault shall be provided with an
					 approved means to admit a fire suppression agent.
(k) The loading and unloading transfer
					 connection for abovegrade vaults shall terminate outside the vault.
(l) Provisions shall be made for the normal
					 operation of valves without entering the vault.
(m) A vault shall be located not less than 15
					 feet (4.6 meters) from buildings and property lines.
(n) Container selection and arrangement.
					 Containers shall be listed for aboveground use. Each container or manifolded
					 system, shall be in its own vault and shall be completely enclosed by the
					 vault, and securely fastened to the floor of the vault. Sufficient clearance
					 between the container and the vault shall be provided to allow for visual
					 inspection and maintenance of all the vault surfaces as well as the tank and
					 its appurtenances.
(o) The vault
					 shall be provided with a continuous H2 gas leak
					 detection device with an audible alarm set at 25% of the LEL and will render
					 the system inoperable. The H2 leak detection device
					 shall function during system maintenance operations.