Installing a Restaurant Hood: A Step-by-Step Overview
Installing a restaurant exhaust hood the right way means passing inspection the first time. Here's a step-by-step overview of a code-compliant NFPA 96 hood installation.
A commercial kitchen hood installation looks simple from the outside — hang the hood, connect the duct, mount the fan. But the fire marshal, the mechanical inspector, and the health inspector all sign off on different pieces, and a single missed clearance or misaligned suppression nozzle can send you back to square one.
Here is the actual sequence of a code-compliant restaurant hood installation.
Step 1: Plan the System Before You Order
Before anything is bought or delivered:
Confirm hood Type (1 or 2) based on your cooking equipment
Size the hood: 6" minimum overhang past cooking surface on open sides
Calculate exhaust CFM
Design the duct route with slope back toward the hood, minimum access panel spacing per NFPA 96
Spec the fire suppression system and coordinate nozzle placement with hood and appliances
Plan make-up air to replace exhausted air (roughly matched CFM)
Submit drawings to the local AHJ (authority having jurisdiction) if required
Step 2: Rough-In and Structural Support
Before the hood arrives on site, your framers, electricians, and plumbers should have:
Framed or reinforced the ceiling structure to support hood weight (hoods often exceed 200 lbs, and code requires a minimum 4:1 safety factor on hangers)
Run electrical for hood lights, control panel, and any make-up air unit
Roughed in gas piping with the manual and automatic shutoff points
Cut and framed the roof penetration for the grease duct
Step 3: Hang the Hood
Use threaded rod hangers (typically 3/8" or 1/2") anchored into structural framing — not just drop ceiling grid
Hang so front edge is no more than ~48 inches above the cooking surface (varies by hood style)
Level the hood in both directions before final tightening
Confirm 6" overhang past all open sides of cooking equipment
Install baffle filters and light bulbs; test lights
Step 4: Install the Grease Duct
Grease duct must be liquid-tight with continuous welds or listed factory joints (NFPA 96 §7.5)
Maintain 18" clearance to combustibles for standard duct, or reduced clearance per the listing for UL 1978 factory-built duct (UL 1978)
Slope duct back toward the hood or a listed grease reservoir — no low spots
Install cleanout / access panels per NFPA 96 spacing requirements (every 20 ft horizontal, at each change of direction)
Perform a light test to verify liquid-tightness (turn on a work light inside the duct, look for any pinholes of light escaping — none allowed)
Step 5: Set the Exhaust Fan and Roof Curb
Set an insulated, pitched roof curb matched to fan base dimensions
Flash and seal the curb to the roof membrane
Mount an upblast fan for Type 1 grease systems (never downblast for grease)
Install the hinged base kit so cleaners can access the duct riser
Wire the fan through a disconnect within sight of the fan per NEC
Verify fan rotation direction and belt tension (or ECM programming) at startup
Step 6: Install Fire Suppression
Route wet-chemical piping from the tank cabinet to nozzles
Position nozzles per the manufacturer's UL 300 listing over every appliance
Install manual pull-station on the egress path
Connect gas / electric shutoff to the suppression control head
Tag the system with hydrostatic test date and licensed installer's information
Have the system inspected and certified before final walkthrough
Step 7: Make-Up Air and Balancing
Install and start up make-up air unit (MUA) or passive intake
Verify MUA CFM roughly equals exhaust CFM
Balance the system: measure hood face velocity, verify capture and containment, confirm the kitchen is at slight negative pressure relative to the dining room
Deliver Test and Balance (TAB) report to the owner and AHJ
Step 8: Inspection and Sign-Off
Expect at least three inspectors:
Mechanical inspector — duct, clearances, MUA, TAB report
Fire marshal — suppression system, pull-station, gas shutoff, hood spacing
Health inspector — hood type, filter presence, cleanliness, general kitchen readiness
Have your hood cut sheet, fan curve, suppression cert, and TAB report on site and organized. Inspections that fail almost always fail on paperwork, not physical installation.
We'll Ship You a System That's Ready to Install
Mr. Hood USA supplies matched hood, duct, and fan packages for restaurants, food trucks, and commercial kitchens — with the documentation your inspector will ask for.