22.4 Spray Application Using Flammable or Combustible Materials
Exception No. 1: Exception No. 1: For spray application of styrene cross-link thermoset resins, Section 17.3 of NFPA 33 shall apply.
Exception No. 2: Exception No. 2: Automatic sprinkler systems for powder coating operations shall be designed for Ordinary Hazard (Group 2), as defined in NFPA 13. [33:9.4.2]
- In addition to meeting the requirements in 9.8.1 of NFPA 33, the optical flame detection system shall also activate one of the following over each zone in which fire has been detected:
- An open head deluge system designed to discharge a minimum density of 24.4 mm/min (0.6 gpm/ft2)
- A carbon dioxide extinguishing system
- A dry chemical extinguishing system
- A gaseous agent extinguishing system [33:9.8.2(1)]
- A wet pipe sprinkler system shall also be provided throughout the spray booth. This system shall meet all the applicable requirements of this standard for Extra Hazard (Group 2) occupancies. [33:9.8.2(3)]
- Sprinklers shall be spaced no more than 3.7 m (12 ft) apart.
- If exhaust ducts are manifolded, a sprinkler shall be located in the manifold at the junction of each exhaust duct with the manifold.
- Sprinklers shall provide a minimum flow of 114 L/min (30 gpm) per head at a minimum of 1 bar (15 psi) pressure.
- Sprinklers shall be ordinary temperature rated, unless required to be higher due to operating temperatures measured in the ducts, in which case the operating temperature shall be at least 28°C (50°F) above the inside temperature of the duct. [33:9.4.6]