Local codes may vary slightly for ductwork depending on the state. This document is therefore intended as a general guideline only. The installer of the system is responsible for knowing all pertinent current local codes.

1. Directionality: Vertical runs are generally preferred as they will have a lower impact on the system static pressure (a crucial component in exhaust fan selection). For similar reasons, it is also better to install the duct in the most direct route to the fan as possible. Static pressure needs to be calculated for each duct curve.

2. Metal gauge: Exhaust ducts must be made either of 16 gauge carbon steel or the slightly more expensive option of 18 gauge stainless steel (not frequently used). Some other metals might be listed as well, though they are not commonly used by installers of commercial kitchen hoods.

3. Duct branches: Branching is used to lead a one duct into two or more separate ducts. 30 degree and 40 degree angles are generally recommended. The size of the primary duct leading to the exhaust fan, must be the size of the sum of the ducts leading to it from the opposite side.

4. Access: Every part of the duct should remain accessible for future maintenance. Access is defined as the ability for high pressure water to come into direct contact, while maintaining pressure, with the inner surface of the duct. branching, horizontal runs, excessively long vertical runs, and changes in direction via elbows, may necessitate alternative access points. Access panels must be leak proof while remaining available for use (easily opened and resealed).

5. Welding: In compliance with NFPA 96, all duct joints must be welded liquid tight. The weld is to be applied to the external surface of the ductwork. This does not pertain to access panels.

This overview is not comprehensive, and is intended to provide a general understanding of the scope of work involved in a commercial exhaust system ductwork.

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CafeBuilders is a premier national installer of exhaust hoods for restaurants and other commercial facilities. CafeBuilders is an active advocate of safety regulations for the industry on both the local and on the federal level in the United States. Licensed installers my request information on installation guidelines, modifications, and updates from Cafebuilders by emailing support@cafebuilders.com. Contractors and facility managers my request a CafeBuilders installation quote by filling out the hood installation form.

This weak we were taken to a job site, an already operating and rather busy restaurant. This food facility was relatively small, with an 8 foot commercial kitchen hood system at the center of a 1000 ft kitchen built to serve two drive-through windows on each of its sides. The facility would occasionally become inundated with smoke, leaving the restaurant managers with the routine option of opening side doors with a blow fan placed adjacent to it. This was obviously not sustainable, not to mention a very serious fire hazard, and so CafeBuilders was hired to fix it.

We immediately noticed that the restaurant exhaust fan was not commensurate to the size of the hood, and to the length of the duct system. The previous installers had placed a 0.3 horse powered fan for this restaurant, whereby the immediate appearance of the facility suggested a fan with no less power than a 1/2 horse powered fan. On further assessment of the duct and the hood we came across the problem of the duct being far to narrow and the hood plenum as being far to covering (about half of the exhaust filters fell behind the plenum; utterly inefficient).

CafeBuilders got these guys a new Captive Aire exhaust fan, we switched out the entire duct system (a 12″ X 10″ duct system for a solid 14″ x 14″), and we even cut out the extra overlap within the exhaust hood plenum. For all practical purposes, this duct replacement, fan replacement, and exhaust hood plenum dimension adjustment felt more tedious than if we had done the job from scratch. Moreover, we soon realized that the interlocking for the hood fire suppression system had not been configured (how they ever passed inspections, remains a mister). The customer also ended up paying for the kitchen hood installation twice, and all the while it could have been avoided.

Commercial hood installation is significantly different from the procedure as it applies to residential hoods. Their is no one size fits all here. Every job requires engineering oversight, an understanding of the building architecture, and a comprehensive know-how of fire suppression system functionality is key. We suggest that restaurant owners view the hood installation procedure as a series of interconnected procedures. Architectural understanding must be coupled with electrical knowledge, and that with fire safety code accompanied by mechanical know-how.

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CafeBuilders is a premier national installer of exhaust hoods for restaurants and other commercial facilities. CafeBuilders is an active advocate of safety regulations for the industry on both the local and on the federal level in the United States. Licensed installers my request information on installation guidelines, modifications, and updates from Cafebuilders by emailing support@cafebuilders.com. Contractors and facility managers my request a CafeBuilders installation quote by filling out the hood installation form.

We decided to put out this PR after our Arizona crew ran into several exhaust system malfunctions which were by all means installation related. “It’s a terrible feeling to make a hood purchase, only to realize several months down the road that the thing is hard wired not to function the way it’s supposed too” said CafeBuilders president, Donald Kelly.

So here’s to all of the up and coming restaurant business entrepreneurs: What you need to know abut exhaust hood maintenance befor installing a hood.

Access panels matter: If the duct is really long, or if it has sharp curves, it will need access panels installed. Failure to install this will run you into maintenance problems down the road. Grease removal will be extremely difficult, near impossible perhaps, for future cleaners.

The panels need to be installed and sealed properly. They should be facing the right direction (directly adjacent to a pipe in a tight workspace is probably not the best use of an “access” panel), and tightly sealed in order to prevent leakage onto the ceiling tiles.

Safety guidelines: Tightening nuts and bolts is a matter of safety. Inspectors do not notice such details, so be sure that an installers’ ‘having a bad day at work’ does not come to haunt you down the road.

Welding and caulking: This is crucial to preventing leakage of both grease, and of water when the cleaners come to do their thing. More damage can be done than the initial cost is able to prevent – so do make sure to take it into consideration.

Learn more>>>

CafeBuilders is a premier national installer of exhaust hoods for restaurants and other commercial facilities. CafeBuilders is an active advocate of safety regulations for the industry on both the local and on the federal level in the United States. Licensed installers my request information on installation guidelines, modifications, and updates from Cafebuilders by emailing support@cafebuilders.com. Contractors and facility managers my request a CafeBuilders installation quote by filling out the hood installation form.

Learn more>>>

CafeBuilders is a premier national installer of exhaust hoods for restaurants and other commercial facilities. CafeBuilders is an active advocate of safety regulations for the industry on both the local and on the federal level in the United States. Licensed installers my request information on installation guidelines, modifications, and updates from Cafebuilders by emailing support@cafebuilders.com. Contractors and facility managers my request a CafeBuilders installation quote by filling out the hood installation form.