Introduction and scope

This document provides information on the use of air-inflated or air-supported planetariums in educational facilities. The following requirements are based on the applicable provisions of the 2020 Minnesota State Fire Code (MSFC). Inflated or air-supported planetariums are considered temporary membrane structures by the MSFC. 

This document applies to inflatable dome planetariums no greater than 23 feet wide and serving fewer than 50 occupants. 

For larger structures, or where serving more than 50 occupants, contact the fire code official for additional information. In all cases, contact the local fire code official prior to operating a temporary tent or membrane structure. A permit and inspection may be required (MSFC 3103.2). 

Guidelines

• Flame resistance

  • Membrane structures must be composed of materials meeting the flame propagation performance of NFPA 701, Test Method 2. Proof of flame resistance must be demonstrated with an approved label affixed to the structure or by a certificate issued from an approved testing laboratory. (MSFC 3104.2)

• Location of planetariums

  • Planetariums must not obstruct any required means of egress including doorways, corridors, aisles, and aisle access ways. (MSFC 1031.2)
  • Planetariums must not impair or delay the operation of any fire sprinkler or fire detection device.
    • The highest point of the planetarium must be located at least 18 inches below fire sprinkler deflectors. (MSFC 315.3.1)
    • The highest point of the planetarium must not extend higher than 85 percent of the ceiling height when located beneath fire detection devices (MSFC 901.4 & NFPA 72 (2016)17.5.2) 
  • Planetariums must be located at least 36 inches from any potential source of ignition, including light fixtures. (MSFC 305.1)

• Occupant load

  • The maximum occupant load inside planetariums is limited to 7 square feet per person. (MSFC 3107.11 & 1004.5.1) 

• Egress illumination

  • Egress illumination of at least one foot-candle is required within the planetarium. (MSFC 3103.12.7)
    • Because planetariums must operate under reduced lighting levels, an acceptable alternative method of compliance is for an attending staff member to carry an operable flashlight, or other approved portable lighting source. The lighting source shall be used when students are entering and exiting the structure. 

Means of egress

• Number and size of exits

  • Planetariums must be provided with at least one compliant exit when serving nine or fewer occupants. Two exits are required when serving 10 or more occupants. Each exit opening must be at least 36 inches wide. (MSFC 3103.12)
  • It’s acknowledged that many existing, inflatable-membrane planetariums are only provided with a single exit opening, and that exit may not meet the minimum opening dimensions required by the MSFC. In such cases, the following alternative compliance method may be approved by the fire code official for domes no greater than 23 feet wide and serving fewer than 50 occupants. 

• Alternative egress compliance method

  • Standby personnel: At least two staff members must be available at all times to assist in emergency evacuation — one inside the planetarium and one outside the planetarium. (MSFC 3107.17)
  • Emergency evacuation: The standby personnel must be trained and practiced in the procedure for lifting a sidewall of the planetarium in order to facilitate emergency egress. The technique employed must ensure that the air-supported structure does not collapse. These actions must be practiced by staff prior to each use of the planetarium. For structures that have an attached flooring material, which would prohibit a sidewall from being lifted for egress, the alternative egress method cannot be used. (MSFC 3107.17)
  • Emergency procedures: Written emergency plans must be established and approved by the fire code official. Emergency procedures must be explained to occupants prior to entering the planetarium, which includes the instructing of occupants to move to the center of the planetarium in the event of an emergency so the outside wall can be lifted by the assigned standby personnel. (MSFC 404.2.1)

Operational provisions

• Standby personnel: At least two staff members must be available at all times to assist in emergency operations — one inside the planetarium and one outside the planetarium. (MSFC 3107.17)
• Portable fire extinguishers: Two portable fire extinguishers, each having a minimum 2-A:10-B:C rating, must be readily accessible to staff — one located inside the structure and the other located outside the structure within 30 feet travel distance. (MSFC 3107.9)
• Electrical: The use of portable electrical equipment and extension cords must comply with MSFC Section 604.
• Emergency plans and procedures: Written emergency plans specific to the use and operation of the planetarium must be established and approved by the fire code official. (MSFC 404.2)