Applications · Paint booths

Paint Booth Fire Suppression under NFPA 33

A paint spray booth combines an ignition source, atomised solvent overspray, and a confined airflow path — a fire scenario NFPA 33 treats with particular seriousness. Water mist gives OEM and automotive-ancillary paint shops fast knockdown of a solvent pool or overspray fire without the multi-day cleanup and equipment damage a conventional deluge or foam system leaves behind.

Risk

The booth fire scenario

Overspray accumulates on booth walls, filters and ductwork as a combustible film. A source of ignition — static discharge, a faulty fixture, or spontaneous combustion of oily rags — can ignite either the solvent-laden air or the accumulated overspray, and the booth's own airflow can spread flame toward the filter bank and exhaust plenum in seconds.

Design basis

NFPA 33 paired with NFPA 750

NFPA 33 (Standard for Spray Application Using Flammable or Combustible Materials) governs booth construction, ventilation interlocks and permitted suppression methods; water mist systems meeting NFPA 750 are an accepted option. Mistelix booth systems are designed to both standards together — the booth's ventilation interlock, detection, and mist zone are treated as one integrated system rather than bolted-on separately. Read the standard in detail in Paint Booth Fire Suppression under NFPA 33.

Layout

Nozzle layout over the spray zone

Nozzles are arranged in a grid over the spray zone and filter bank, with flame or heat detection lines positioned to catch a fire at floor level or in the plenum before it reaches the exhaust duct.

Paint booth nozzle layoutSpray zoneFlame / heat detection linePanel

Why water mist here

Fast restart, minimal collateral damage

A deluge or foam discharge into a booth can mean days of cleanup, contaminated overspray filters, and corrosion risk to booth electronics and robotics. A water mist discharge uses a fraction of the water, evaporates faster, and lets a production line return to service sooner — a direct line-uptime argument for OEM and auto-ancillary paint shops running tight production schedules.

Reference specification

Booth system parameters

Paint booth design parameters
Operating pressure100–140 bar
Droplet size (Dv0.9)< 200 µm
Standard basisNFPA 33 / NFPA 750
ActivationFlame/heat detection, booth-interlocked

Next step

Request a booth system concept

Send us booth dimensions, airflow direction, and line takt time and we return a concept sized to your production constraints.

Request technical assessment