Michigan Administrative Code › Department - Licensing and Regulatory Affairs › Bureau of Fire Services › Storage and Handling of Gaseous and Liquefied Hydrogen Systems › Part 3 - STORAGE AND HANDLING OF LIQUEFIED HYDROGEN NFPA 50B › Chapter 2 - Design of liquefied hydrogen systems › Section R. 29.7081 - Piping, tubing, and fittings

Current through Vol. 24-12, July 15, 2024
Rule 81. Sections 2-3.1, and 2-3.4 are reproduced from
						NFPA 50B, and sections 2-3.2, 2-3.2.1, 2-3.3, 2-3.5, 2-3.5.1, 2-3.6 to 2-3.17
						of the storage and handling of gaseous and Liquefied H2
						code are added as follows:
2-3 Piping, tubing, and fittings.
2-3.1 Piping, tubing, and fittings, and gasket and thread
						sealants shall be suitable for hydrogen service at the pressures and
						temperatures involved. Consideration shall be given to the thermal expansion
						and contraction of piping systems when exposed to temperature fluctuations of
						ambient to liquefied hydrogen temperatures.
2-3.2 Material specifications and thickness requirements
						for piping and tubing shall conform to ASME B31.3, "Process Piping." Piping or
						tubing for operating temperatures below -20 degrees Fahrenheit (-29 degrees
						Celsius) shall be fabricated from materials meeting the impact test
						requirements of Chapter III of ASME B31.3 when tested at the minimum operating
						temperature to which the piping can be subjected in service.
2-3.2.1 Aluminum shall not be used with liquefied
						H2 piping except for ambient air vaporizers.
2-3.3 Joints in piping and tubing shall be made by
						welding, brazing, or flanged. Brazing materials shall have a melting point
						above 1,000 degrees Fahrenheit (538 degrees Celsius). Flanged connection shall
						use a gasket that is suitable for H2.
2-3.4 Means shall be provided to minimize exposure of
						personnel to piping operating at low temperatures and to prevent air condensate
						from contacting piping, structural members, and surfaces not suitable for
						cryogenic temperatures. Insulation shall be of noncombustible material and
						shall be designed to have a vaportight seal in the outer covering to prevent
						the condensation of air and subsequent oxygen enrichment within the insulation.
						The insulation material and outside shield also shall be of adequate design to
						prevent attrition of the insulation due to normal operating conditions.
2-3.5 Uninsulated piping and equipment that operate at
						liquid hydrogen temperatures shall not be installed above asphalt surfaces or
						other combustible materials to prevent contact of oxygen enriched liquefied air
						with such materials. Drip pans may be installed under uninsulated piping and
						equipment to control drips and vaporize condensed liquefied air.
2-3.5.1 Where insulation materials are used, the
						insulation shall be compatible with the equipment with which the insulation is
						in contact.
2-3.6 A piping system shall be substantially supported
						and protected against physical damage and excessive stresses arising from
						settlement, vibration, expansion, or contraction. Supports for aboveground
						piping shall be constructed of noncombustible material.
2-3.7 Aboveground piping systems shall be protected from
						corrosion in compliance with recognized standards. Underground piping system
						shall be in compliance with section 5-3.
2-3.8 Aboveground piping systems shall be marked in
						accordance with the following:
(a)
					 Marking shall include the name of the gas and direction of flow
					 arrow.
(b) Marking for piping
					 systems shall be provided at the following locations:
(i) At each critical process control
					 valve.
(ii) At wall, floor, or
					 ceiling penetrations.
(iii) At each
					 change in direction.
(iv) At a
					 minimum of every 20 feet (6.1 meters) or fraction thereof throughout the piping
					 run.
2-3.9 Underground piping shall be installed on a bedding
						of at least 6 inches (15.24 centimeters) of well-compacted backfill
						material.
2-3.10 In areas subject to vehicle traffic, the pipe
						trench shall be of sufficient depth to permit a cover of not less than 18
						inches (45.72 centimeters) of well compacted backfill material and
						pavement.
Exception: In paved areas where a minimum of 8 inches
						(20.32 centimeters) of asphalt paving is used, the depth of the backfill
						between the topmost tier of piping and the paving can be reduced to not less
						than 8 inches (20.32 centimeters).
Exception: In paved areas where a minimum of 6 inches
						(15.24 centimeters) of reinforced concrete paving is used, the depth of
						backfill between the topmost tier of the piping and the paving can be reduced
						to not less than 4 inches (10.2 centimeters).
2-3.11 In areas not subject to vehicle traffic, the pipe
						trench shall be of sufficient depth to permit 6 inches (15.24 centimeters) each
						of bedding and cover of well-compacted backfill material. A greater burial
						depth shall be provided when required by the manufacturer's
						instructions.
2-3.12 Piping within the same trench shall be separated
						by more than 3 times the diameter of the larger adjacent pipe.
2-3.13 Piping to equipment shall be provided with an
						accessible, manual shutoff valve.
2-3.14 Pipe, tubing, fittings, and other piping
						components shall be capable of withstanding a hydrostatic test of at least 3
						times the rated pressure without structural failure as documented by the
						manufacturer.
2-3.15 Underground liquefied H2
						piping shall be vacuum-jacketed. Unjacketed piping shall not be buried and
						shall exit the container annular space above grade.
2-3.16 All natural gas piping shall be installed in
						accordance with R 29.4601 et seq.
2-3.17 All liquefied petroleum gas piping shall be
						installed in accordance with R 29.4001 et seq.