11.9 Permanent Membrane Structures.

• 11.9.1 Application.
  • 11.9.1.1 General. The provisions of Section 11.1 shall apply.
  • 11.9.1.2 Use of Membrane Roofs. Membrane roofs shall be used in accordance with the following:
  • (1) Membrane materials shall not be used where fire resistance ratings are required for walls or roofs.
  • (2) Where every part of the roof, including the roof membrane, is not less than 20ft (6100mm) above any floor, balcony, or gallery, a non combustible or limited-combustible membrane shall be permitted to be used as the roof in any construction type.
  • (3) With approval of the authority having jurisdiction, membrane materials shall be permitted to be used where every part of the roof membrane is sufficiently above every significant fire potential, such that the imposed temperature cannot exceed the capability of the membrane, including seams, to maintain its structural integrity.
  • 11.9.1.3 Testing. Testing of membrane materials for compliance with the requirements of Section 11.9 for use of the categories of non combustible and limited combustible materials shall be performed on weathered-membrane material, as defined in 3.3.169.5.
  • 11.9.1.4 Flame Spread Index. The flame spread index of all membrane materials exposed within the structure shall be Class A in accordance with Section 10.2.
  • 11.9.1.5 Roof Covering Classification. Roof membranes shall have a roof covering classification, as required by the applicable building codes, when tested in accordance with ASTME 108, Standard Test Methods for Fire Tests of Roof Coverings, or ANSI/UL 790, Test Methods for Fire Tests of Roof Coverings.
  • 11.9.1.6 Flame Propagation Performance.
  • 11.9.1.6.1 All membrane structure fabric shall meet the flame propagation performance criteria contained in Test Method 2 of NFPA 701, Standard Methods of Fire Tests for Flame Propagation of Textiles and Films.
  • 11.9.1.6.2 One of the following shall serve as evidence that the fabric materials have the required flame propagation performance:
  • 11.9.1.6 Flame Propagation Performance.
  • 11.9.1.6.1 All membrane structure fabric shall meet the flame propagation performance criteria contained in Test Method 2 of NFPA 701, Standard Methods of Fire Tests for Flame Propagation of Textiles and Films.
  • 11.9.1.6.2 One of the following shall serve as evidence that the fabric materials have the required flame propagation performance:
  • (1) The authority having jurisdiction shall require a certificate or other evidence of acceptance by an organization acceptable to the authority having jurisdiction.
  • (2) The authority having jurisdiction shall require a report of tests made by other inspection authorities or organizations acceptable to the authority having jurisdiction.
  • 11.9.1.6.3 Where required by the authority having jurisdiction, confirmatory field tests shall be conducted using test specimens from the original material, which shall have been affixed at the time of manufacture to the exterior of the structure.

• 11.9.2 Tensioned-MembraneStructures.

  • 11.9.2.1 The design, materials, and construction of the building shall be based on plans and specifications prepared by a licensed architect or engineer knowledgeable in tensioned-membrane construction.
  • 11.9.2.2 Material load sand strength shall be based on physical properties of the materials verified and certified by an approved testing laboratory.
  • 11.9.2.3 The membrane roof for structures in climates subject to freezing temperatures and ice buildup shall be composed of two layers separated by an air space through which heated air can be moved to guard against ice accumulation. As an alternative to the two layers, other approved methods that protect against ice accumulation shall be permitted.
  • 11.9.2.4 Roof drains shall be equipped with electrical elements to protect against ice buildup that can prevent the drains from functioning. Such heating elements shall be served by onsite stand by electrical power in addition to the normal public service. As an alternative to such electrical elements, other approved methods that protect against ice accumulation shall be permitted.

• 11.9.3 Air-Supported and Air-Inflated Structures.

  • 11.9.3.1 General. In addition to the general provisions of 11.9.1, the requirements of 11.9.3 shall apply to air-supported and air-inflated structures.
  • 11.9.3.2 Pressurization (Inflation) System. The pressurization system shall consist of one or more operating blower units. The system shall include automatic control of auxiliary blower units to maintain the required operating pressure. Such equipment shall meet the following requirements:
  • (1) Blowers shall be powered by continuous-rated motors at the maximum power required.
  • (2) Blowers shall have personnel protection, such as inlet screens and belt guards.
  • (3) Blower systems shall be weather protected.
  • (4) Blower systems shall be equipped with backdraft check dampers.
  • (5)Not less than two blower units shall be provided, each of which has capacity to maintain full inflation pressure with normal leakage.
  • (6) Blowers shall be designed to be in capable of overpressurization.
  • (7)The auxiliary blower unit(s) shall operate automatically if there is any loss of internal pressure or if an operating blower unit becomes inoperative.
  • (8) The design inflation pressure and the capacity of each blower system shall be certified by a professional engineer.
  • 11.9.3.3 Stand by Power System.
  • 11.9.3.3.1 *A fully automatic standby power system shall be provided. The system shall be either an auxiliary engine generator set capable of running the blower system or a supplementary blower unit that is sized for 1 times the normal operating capacity and is powered by an internal combustion engine.
  • 11.9.3.3.2 The stand by power system shall be fully automatic to ensure continuous inflation in the event of any failure of the primary power. The system shall be capable of operating continuously for a minimum of 4 hours.
  • 11.9.3.3.3 The sizing and capacity of the standby power system shall be certified by a professional engineer.
  • 11.9.4 Maintenance and Operation.
  • 11.9.4.1 Instructions in both operation and maintenance shall be transmitted to the owner by the manufacturer of the tensioned-membrane, air-supported, or air-inflated structure.
  • 11.9.4.2 Annual inspection and required maintenance of each structure shall be performed to ensure safety conditions. At least biennially, the inspection shall be performed by a professional engineer, registered architect, or individual certified by the manufacturer.
• 11.9.5 Services.
  • 11.9.5.1 Fired Heaters.
  • 11.9.5.1.1 Only labeled heating devices shall be used.
  • 11.9.5.1.2 Fuel-fired heaters and their installation shall be approved by the authority having jurisdiction.
  • 11.9.5.1.3 Containers for liquefied petroleum gases shall be installed not less than 60in. (1525mm) from any temporary membrane structure and shall be in accordance with the provisions of NFPA 58, Liquefied Petroleum Gas Code.
  • 11.9.5.1.4 Tanks shall be secured in the upright position and protected from vehicular traffic.
  • 11.9.5.2 Electric Heaters.
  • 11.9.5.2.1 Only labeled heaters shall be permitted.
  • 11.9.5.2.2 Electric heaters, their placement, and their installation shall be approved by the authority having jurisdiction.
  • 11.9.5.2.3 Heaters shall be connected to electricity by electric cable that is suitable for outside use and is of sufficient size to handle the electrical load.