What is Grease duct?
[[File:Glen_spray.jpg|right|thumb|Grease duct exhaust fan.]] A '''grease duct''' is a duct that vents flammable [[Vapor|vapors]] from commercial cooking equipment such as [[Stove|stoves]] and deep fryers to the outside of the building. It will normally be connected to an [[exhaust fan]]. == Fire hazard == Vapors are created when grease is heated to and beyond its [[vaporization point]]. When it cools, the grease will [[condense]] on colder surfaces. Grease is a flammable [[hydrocarbon]]. == Design == In many places, they will be constructed out of stainless-steel ductwork connected through a series of [[air filter]]<nowiki/>s which will be pulled by a fan and exhausted outside. They will also often have some form of [[fire damper]] in this ductwork connected to the [[fire alarm]] system. <ref>{{cite web |title=Optimizing Your Commercial Kitchen’s Exhaust Duct Ventilation System |url=https://totalfood.com/optimizing-commercial-kitchen-exhaust-duct-ventilation-system/ |website=Total Food Service |accessdate=21 June 2023 |date=18 April 2018}}</ref> == Maintenance and cleaning == These systems must be cleaned sometimes. Many will have certificates issued by the cleaning<ref>{{Cite web|title=Carpet Cleaning {{!}} Upholstery Cleaning - PowerPro|url=https://www.powerprocarpetcleaning.com/|access-date=2023-12-26|language=en-US}}</ref> and maintenance contractors.<ref>{{Cite web|title=Hood Repair & Clean|url=https://empirehoodcleaning.com}} Sunday, 2 May 2021 </ref> Problems with hoods that are not taken care of include poor ventilation, excess heat and smoke, and the potential risk of fires.<ref>{{Cite web|title=Kitchen Exhaust Cleaning - Carolina Filters, Inc.|url=http://www.carolinafilters.com/kitchen-exhaust-cleaning|access-date=2016-01-08|website=www.carolinafilters.com|archive-date=2017-07-21|archive-url=https://web.archive.org/web/20170721101954/http://www.carolinafilters.com/kitchen-exhaust-cleaning|url-status=dead}}</ref><ref>{{Cite web|title=Duct Cleaning|url=https://cleanairductpitt.com/duct-cleaning-faq/}}