Exhaust Hood Cleaning & Filter Replacement
Last updated: January 2025
Grease-laden exhaust hoods are one of the highest fire-risk systems in a commercial kitchen. NFPA 96 compliance isn't optional — it's the standard that keeps your kitchen, your staff, and your building from becoming a fire scene. Understanding what needs cleaning, how often, and what to look for is non-negotiable.
NFPA 96: What the Code Requires
NFPA 96 (Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations) mandates that exhaust hoods, grease removal devices, and exhaust ducts be cleaned to bare metal at specific intervals depending on cooking volume.
The Cleaning Process (What Professionals Do)
Qualified hood cleaning services disassemble duct joints to access all interior surfaces, not just what they can spray from the ends.
Commercial-grade alkaline degreasers applied at 150–200°F under pressure. Cold water and household cleaners do not dissolve carbonized grease.
All interior surfaces of the hood canopy, filters, and accessible ductwork. The entire system to the point of penetration through the roof.
Baffle filters removed and cleaned in a heated tank. Replace if metal is warped, corroded, or damaged beyond cleaning.
⚠️ Fire Department Inspection Risk
During a fire department inspection, if grease accumulation is visible from the outside of the ductwork or hood, or if the hood cleaning tag shows an overdue date, the inspector can issue a citation and in many jurisdictions shut down cooking operations until the system is brought into compliance. Keep your cleaning receipts — they are your legal defense.
When Filters Need Immediate Replacement
- • Warped or bent filter frames — creates gaps that allow grease-laden vapor to escape without capture
- • Rusted or corroded filter surfaces — structural integrity compromised; replace don't repair
- • Missing or damaged rivets and fasteners — filter security is compromised in a fire
- • Cracked or melted filter mesh — high-heat cooking without proper filtration can cause this
Who Should Clean Your Hood?
NFPA 96 requires cleaning by a qualified professional with documented training in grease removal. General kitchen cleaning staff are not qualified for full hood cleaning — they lack the equipment and training to clean to bare metal inside ductwork. Find certified exhaust hood cleaning services on HotSide.
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