Unsightly, perhaps. Necessary, 100%
Restaurant kitchen exhaust fans not only remove the potentially odorous and toxic products of combustion that are unavoidably created through the cooking process, but they are also crucial to saving lives in the event of fire by helping to remove flames and smoke from the space.
Therefore, if any part of the kitchen exhaust fan, grease duct, or hood are not installed as per the NFPA-96 Standard for Ventilation Control and Fire Protection, it puts the public—and your employees—at risk.
The Importance of Proper Kitchen Exhaust Fan Installation
Case Study #1
A field review on a Vancouver restaurant where the installing contractor approved sheet metal screws and fire stopping in lieu of proper welding or an industry standard fastening method, revealed that it’s important to understand that proper installation is as important as the actual fan.
It might look secure and be deemed usable at first glance. However, upon closer examination, this method was not up to standards.
According to NFPA – 96 Section 8.1.4., Sentence 4:
The fan shall be connected to the exhaust duct by flanges securely bolted as shown in Figure 220.127.116.11(a) through Figure 18.104.22.168(d) or by a system specifically listed for such use.
Kitchen Exhaust Fan Installation Process
Case Study #2
During another restaurant inspection, we found the contractor had connected a flexible duct between the grease duct and the kitchen exhaust fan, rather than taking the time to measure and weld the two together directly.
In standard HVAC systems, this is okay because the system isolates the vibration and noise. However, in a commercial kitchen, this would likely fail in the event of fire and allow smoke build-up.
As per NFPA – 96 section 8.1.4. Sentence 5:
Flexible connectors shall not be used.
Kitchen Exhaust Fan Connection to Roof
Case Study #3
In this picture we have 3 issues:
Improper Kitchen Exhaust Termination
Case Study #4
Another restaurant, another problem. In this case, the mechanical engineer signed off on an installation that leaves the exhaust vent inside the space! This duct is connected to a Class 2 hood and the cooking appliances are electric.
Forget citing the code that states how many things are wrong with this scenario, it’s basic common sense that the exhaust needs to escape to the outdoors, not within the space.
Do Your Due Diligence When Hiring a Contractor and Engineer
When hiring an engineer and contractor, ask for resumes, previous client work, and even references. Research the restaurants they have designed for and fact-check! Cross-reference the mechanical engineer on EGBC to see if they have been reported for any misconducts, or —even worse—if they’ve ever been suspended.
If you have any questions about the mechanical, plumbing or hood fire suppression for your restaurant, give us a call! We always have time to discuss the details.