Commercial kitchen exhaust hood cleaning is the scheduled removal of grease, carbon, and creosote from the entire exhaust path of a cooking operation, required by NFPA-96 at intervals of 1, 3, 6, or 12 months depending on cooking volume. PowerWashingExpert is a Metro Detroit based commercial cleaning contractor. Every cleaning ends with a dated certificate, an inspection sticker, and before and after photos for your fire inspector and insurance carrier.
Why NFPA-96 Matters for Your Restaurant
NFPA-96, Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations, is the national fire code that governs your hood, filters, duct, and rooftop fan. It is adopted by the Michigan Fire Prevention Code and enforced by your local fire marshal. A missing certificate is an immediate violation. A grease fire in an uncleaned duct is the single most common path to an insurance claim denial for a food service operator.
The National Restaurant Association reports that cooking equipment is involved in over half of all restaurant structure fires, and grease buildup in the hood or duct is the leading ignition source. Source: NFPA research, Structure Fires in Eating and Drinking Establishments, November 2023. The math is straightforward. Grease is fuel. Heat and ignition are already present. A clean duct breaks the chain.
NFPA-96 Cleaning Schedule by Cooking Volume
NFPA-96 Section 11.4 sets four cleaning intervals. The interval is based on the type of cooking and the volume, not the size of the hood.
| Cooking Type | Minimum Cleaning Frequency | Typical Operations |
|---|---|---|
| Solid fuel (wood, charcoal) | Monthly | Wood fired pizza, BBQ smokehouses, charcoal grill steakhouses |
| High volume | Quarterly (every 3 months) | Full service restaurants, 24 hour diners, busy hotel kitchens |
| Moderate volume | Semiannually (every 6 months) | Fast food, quick service, casual dining, delis |
| Low volume | Annually (every 12 months) | Churches, day camps, seasonal concessions, small bakeries |
What a Full NFPA-96 Hood Cleaning Includes
A real cleaning is not surface polish. It is bare metal removal of grease from every accessible surface between the cooktop and the rooftop outlet. Here is the actual scope of work we perform on a standard single hood system:
- Pre cleaning walk. Identify access panels, hidden duct runs, fan type, and problem areas. Cover floors, tape appliances, and bag electrical.
- Hood filters. Remove all baffle filters. Soak in hot degreaser solution. Rinse to bare metal.
- Hood interior. Scrape, degrease, and hot water rinse the hood plenum, lip, and interior panels down to metal.
- Horizontal duct run. Open access panels along the horizontal duct. Scrape and wash all four interior surfaces.
- Vertical duct. Access at every change of direction and the base of the roof penetration. Scrape and wash.
- Rooftop exhaust fan. Tilt the fan housing, scrape the fan blade and housing interior, wash, and restore.
- Hinge kits and access panels. Inspect, replace any damaged gaskets, and label access panels with the date.
- Post cleaning photos. Before and after at every access point, included in your report.
- Certificate and sticker. Signed certificate of cleaning, dated inspection sticker applied inside the hood.
Where We Clean to Bare Metal
NFPA-96 Section 11.6.12 requires cleaning of all "accessible areas of the exhaust system" to bare metal where possible. Areas that cannot reach bare metal must be flagged for access panel installation. We document both on your report.
Certificate of Cleaning and Inspection Sticker
The paperwork matters as much as the cleaning. Your fire inspector wants to see three things inside the hood: a dated sticker, a certificate on file, and no visible grease on the filters. Your insurance underwriter wants the same certificate on file before they renew your policy. We send the certificate by email within 24 hours of the job and keep duplicates on file for five years in case you lose yours.
The inspection sticker is placed inside the hood, visible from below, and shows the company name, phone number, technician name, date of cleaning, and next due date. This sticker is what your fire marshal looks for during the annual inspection.
Insurance and Liability Implications
Commercial property insurance policies for restaurants almost always include a maintenance clause for cooking exhaust. Translated from insurer language: if you did not clean the hood on schedule and a grease fire occurred, the carrier can deny the claim. The dollar figures are significant. The average restaurant fire claim is over $50,000 before business interruption, per industry data. A denied claim means your operator pays that out of pocket.
The certificate of cleaning is the documentation that protects you. It proves maintenance was performed on schedule. We maintain your service history and can send multi year records to your insurer on request.
Restaurant Types and Typical Cleaning Frequency
Here is what we see across our Metro Detroit accounts. Use this to calibrate your own schedule.
- Full service casual dining: Quarterly. High grease load from fryers, broilers, and saute stations.
- Steakhouse with charbroiler: Quarterly, sometimes monthly in heavy volume months.
- Fast food and QSR: Every 6 months. Consistent moderate volume.
- Pizza with wood fired oven: Monthly for the wood fired line, quarterly for the rest.
- Hotel kitchen: Quarterly for main line, semiannual for banquet kitchen.
- School cafeteria: Annual during summer break, with a mid year check.
- Deli, bakery, coffee shop with limited cooking: Annual.
Pricing and What Affects Your Quote
Metro Detroit commercial hood cleaning generally runs between $350 and $2,500 per job. The variables that move the price are honest ones, worth understanding before you get a quote.
- Hood count and length. One 8 foot hood is quick. A 24 foot triple hood over a full cooking line is three times the work.
- Duct run length. A rooftop penetration directly above the hood is simple. 40 feet of horizontal duct zigzagging through a building is not.
- Fan type and roof access. A hinged upblast fan on a flat roof is easy. A sealed centrifugal fan behind an equipment screen is a two person job.
- Grease load. A hood cleaned on schedule for years is faster than one that has been neglected for 18 months.
- Access panels. If the duct needs additional access panels cut and installed to meet NFPA-96 inspection requirements, that is quoted separately.
Need an Inspection Before You Commit?
We do free pre cleaning walks. We will open your existing access panels, scope the duct, photograph the current state, and quote flat rate. If the system needs additional access panels to fully comply with NFPA-96, we quote that too so you know before the job starts.
Metro Detroit Scheduling and Service Area
Most Metro Detroit restaurants cannot shut down during business hours for a hood cleaning. We schedule overnight, typically between 11 pm and 6 am, so your kitchen is ready for breakfast or lunch service the next day. Weekend scheduling is available for operations that close one day per week. Our primary service area includes Bloomfield Hills, Birmingham, Troy, Royal Oak, Southfield, Farmington Hills, Auburn Hills, and the rest of Oakland County. See our commercial power washing Bloomfield page for the full area list.
If you are weighing the in house versus contractor decision, read our reasons to hire a professional pressure washing service guide. For a deeper dive on the NFPA-96 standard, visit our restaurant hood cleaning NFPA-96 reference.