Webster Mechanical Engineering (WME) provides forensic investigations of property loss incidents involving commercial cooking equipment.

The cooking appliances, the exhaust hood, and the grease duct system must be capable of capturing the grease laden vapors and transporting them outdoors in accordance with NFPA 96 Ventilation Control and Fire Protection of Commercial Cooking Operations. The cooking appliances that create grease laden vapors, and the exhaust hood and grease duct system must be protected by a dedicated fire suppression system. The fire suppression system must be capable of extinguishing fires on the cooking surfaces, and within the exhaust hood and the grease duct assembly simultaneously while shutting off the fuel supply to the cooking equipment.

WME provides on-site and laboratory investigations of commercial cooking equipment, exhaust hoods, grease ducts, and fire extinguishing systems involved in commercial structural fires based on and in accordance with:


  • NFPA 96 Ventilation Control and Fire Protection of Commercial Cooking Operations
  • NFPA 54/ANSI Z223.1 National Fuel Gas Code
  • ANSI Z83.11 Gas Food Service Equipment
  • UL 710 Exhaust Hoods for Commercial Cooking Equipment
  • UL1046 Grease Filters for Exhaust Hoods
  • UL 1978 Grease Ducts
  • ASTM E2336 Standard Test Methods for Fire Resistive Grease Duct Enclosure Systems
  • UL 2221 Standard for Tests of Fire Resistive Grease Duct Enclosure Assemblies
  • NFPA 17A Standard for Wet Chemical Extinguishing Equipment
  • UL 300 Standard for Fire Testing of Fire Extinguishing Systems for Protection of Commercial Cooking Equipment
  • ANSI/IKCA C10 Standard for Cleaning of Commercial Kitchen Exhaust Systems

The selection and design of the exhaust hood and grease duct is dependent on the size and type of cooking equipment present. The fire suppression system design is based on the size of the exhaust hood and grease duct, and on the type and location of the cooking equipment present.

The cooking equipment, exhaust hood, grease duct, and fire suppression system are in effect a single system. The entire system must be constructed, installed, inspected, maintained, and cleaned by trained, qualified, and certified personnel in accordance with the relevant codes and standards listed above in order to functioned as designed.

When properly designed, installed, inspected, maintained, and cleaned, the exhaust system can reasonably be expected to contain and extinguish a cooking fire. When a cooking fire spreads to the adjacent structure, the entire system must be examined to determine the cause of the fire and the conditions that led to the spread of the fire.