Rule 40. Sections 4-3.2 to 4-3.6 are reproduced from NFPA 50A, and sections 4-3.1, 4-3.7 to 4-3.9, and table 4-3.9 of the storage and handling of gaseous and Liquefied H2 code are added as follows:
4-3 Special rooms.
4-3.1 Floor, walls, and ceiling shall be constructed of noncombustible or limited-combustible materials. Interior walls or partitions shall have a fire resistance rating of at least 2 hours, shall be continuous from floor to ceiling, and shall be securely anchored. At least 1 wall shall be an exterior wall. Windows and doors shall be located so as to be readily accessible in case of emergency.
Exception: Window glazing may be of plastic.
4-3.1.1 If access to the room from outside the primary structure is not possible, access from within the primary structure shall be made through 1 vapor-sealing 2-hour self-closing fire door.
4-3.2 Ventilation shall be as provided in section 4-2.2.
4-3.3 Explosion venting shall be as provided in section 4-2.3.
4-3.4 There shall be no sources of ignition from open flames, electrical equipment, or heating equipment.
4-3.5 Electrical equipment shall be in accordance with Article 501 of NFPA 70, National Electrical Code, for Class I, Division 2 locations.
4-3.6 Heating, if provided, shall be by steam, hot water, or indirect means except that electrical heating shall be permitted to be used if in compliance with 4-3.5.
4-3.7 Room ventilation.
4-3.7.1 The ventilation shall be at least 1 cubic feet/minute/square feet (0.3 cubic meters/minute/square meters) of room area, but not less than 1 cubic foot/minute/12 cubic feet (0.3 cubic meters/minute/3.7 cubic meters) of room volume and shall be designed such that an accumulation of H2 at a concentration equal to or greater than 25% of the lower flammability limit shall not occur in any part of the room.
4-3.7.2 Where installed, a gas detection system shall be equipped to sound an alarm and visually indicate when a maximum of 25% of the lower flammable limit is reached. At 40% of the lower flammable limit the gas detection system shall shut down the hydrogen system and provide notification to the system operator.
4-3.7.3 Any failure of the ventilation system shall immediately shut down the fueling system and provide notification to the system operator. Reactivation of the fueling system shall be by manual restart and shall be conducted by trained personnel.
4-3.7.4 The gas detection system shall function during ventilation system maintenance operations.
4-3.7.5 A ventilation system for a room within or attached to another building shall be designed to ensure that all areas serviced by the ventilation system meet performance requirements in accordance with section 4-3.7 during the normal operating conditions and during alarm conditions.
4-3.8 Warning signs.
4-3.8.1 Access doors shall have warning signs with the words "WARNING - NO SMOKING - NON ODORIZED FLAMMABLE GAS - NO OPEN FLAMES. The wording shall be in plainly legible, bright red letters not less than 1 inch (2.54 centimeters) high on a white background.
4-3.9 Indoor attended fast-fill fueling.
4-3.9.1 Attended indoor fast-fill fueling system shall be in accordance with subsections (a) to (k) of this section.
Exception: A dispensing area ventilation system is not required when the fuel delivery per refueling event is less than those listed in table 4-3.9. Table 4-3.9
Room Size (m3) | Maximum fuel delivery per refueling event that does not require room ventilation (kg) |
1000 | 0.8 |
2000 | 1.7 |
3000 | 2.5 |
4000 | 3.3 |
5000 | 4.2 |
Mich. Admin. Code R. 29.7040