Paint Booth Exhaust Filter Replacement And Draft Gauge Reading
Authorized procedure for replacing primary and secondary paint arrestor bank filters and performing a draft gauge (manometer) static pressure reading on industrial paint spray booths. Ensures NFPA 33 compliance and optimal airflow.
To establish a standardized method for replacing loaded paint arrestor exhaust filters and verifying the booth's static pressure differential using a digital manometer or Magnehelic gauge. Adherence to this procedure ensures the exhaust system maintains the required containment velocity (typically 100 fpm minimum for crossdraft booths per NFPA 33) and prevents hazardous particulate accumulation in the plenum.
Observation of design static pressure limits prevents motor overload conditions and ensures the fan is operating on the correct section of its performance curve. All recorded data must be signed off by the Maintenance Supervisor and entered into the CMMS within the shift.
Applies to all crossdraft, downdraft, and semi-downdraft industrial paint booths within the facility operating with dry particulate arrestors. Excludes booths equipped with water wash or electrostatic precipitation systems. All maintenance personnel performing this task must have completed the confined space entry (CSE) awareness module and the authorized LOTO provider certification.
- Perform Lockout/Tagout on the exhaust fan disconnect switch upstream of the motor starter. Apply a group lockout if multiple technicians are servicing the booth. Verify zero energy state phase-to-phase and phase-to-ground with a calibrated voltmeter.
- Full paint booth entry requires a Tyvek suit, nitrile gloves, and a properly fitted half-face respirator with P100 organic vapour cartridges. Safety glasses with side shields are mandatory. Ensure respirator seal check prior to entering the contaminated plenum.
- Collected paint overspray and saturated filters are classified as Class I flammable solids. Place used filters directly into a labeled, covered steel waste drum immediately upon removal. Do not allow accumulation on the booth floor. No spark-producing tools or hot work within 10 m of the booth enclosure.
- If the exhaust plenum or filter access chamber exceeds 4 ft in depth, it must be treated as a permit-required confined space. An authorized attendant must be present at the entry point. Continuous Lower Explosive Limit (LEL) monitoring is required during the entire plenum inspection phase.
- Replacement paint arrestor filters — primary (pre-filter) and secondary (final). Ensure minimum MERV 8 or ASHRAE 45% arrestance.
- Digital manometer (Dwyer 477A or equivalent) or Magnehelic gauge (0–5" w.c.) with static pressure tips.
- T25 Torx driver or 11mm nut driver (depending on filter frame retainer hardware).
- LOTO kit: padlock, hasp, danger tag, and group LOTO log sheet.
- Industrial vacuum cleaner with Class H HEPA filtration for plenum debris removal.
- White lithium grease or similar anti-seize lubricant for access door hinge pins and latch mechanisms.
- Tyvek coveralls, nitrile gloves, P100 organic vapour cartridge respirator.
- Fire-rated steel waste drum with lid for disposal of saturated media.