Codes
Wet Chemical Extinguishing Systems, better known as Hood and Duct Systems, play a crucial role in preventing cooking fires. Wet Chemical Extinguishing Systems use a liquid spray that hits the burning surface, rapidly abating kitchen fires fueled by fats and oils.
Wet Chemical Systems must follow NFPA 17A and manufacturing installation guidelines. Below is the link to NFPA Standard 17A and the requirements for a Hood and Duct System: