Although most hood cleaning companies have their customer’s best interest in mind, they are not in the kitchen on a day to day basis. Grease accumulation within the exhaust system is best monitored by the restaurant staff between cleanings. Kitchen Exhaust Cleaning Companies initially set up the frequency of the hood cleanings by determining which category the restaurant the cook line falls into listed on the NFPA 96 Table 11.4 below.
NFPA 96 Table 11.4 Exhaust Cleaning Inspection Schedule
|Type or Volume of Cooking
|Systems serving solid fuel cooking operations
|Systems serving high-volume cooking operations such as 24-hour cooking, charbroiling or wok cooking
|Systems serving moderate-volume cooking operations
|Systems serving low-volume cooking operations, such as churches, day camps, seasonal business or senior centers
This is a guide line for inspection, not cleaning. Once this frequency has been set by the hood cleaning company, it is best to monitor the grease build up within the hood system between services. Once your system reaches grease accumulation of .078 inches, the system should be schedule to be cleaned. You can measure the grease accumulation in your hood by using a Grease Depth Comb. If you do not have one, call your hood cleaning company to see if they can get you one to keep on site at your restaurant.
You and your vent hood cleaning company can set up an initial cleaning frequency, however it is your responsibility to monitor the system between the predetermined frequencies. The vent hood cleaning company will not know if your volume picks up causing the kitchen exhaust system to need a cleaning sooner than your predetermined frequency.
Hood Boss recommends having your General Manager or Kitchen Manager be responsible for monitoring the grease build up in your system using the grease comb. We recommend that monitoring start one month prior to the predetermined frequency set. If a cleaning is required before the normal frequency, you should notify your cleaning company of your need to schedule service. Protect your kitchen from fire, potential fines from the Fire Marshall, and even shutting down of your restaurant by having a simple monitoring process of your system in place.
We hope you found this article helpful. If we can be of assistance to you please give Hood Boss a call at 972-704-1812.
NFPA 96 Reference Material
NFPA 96, 11.6.2 States that “Hoods, grease removal devices, fans, ducts, and other appurtenances shall be cleaned to remove combustible contaminants prior to surfaces becoming heavily contaminated with grease or oily sludge.”
NFPA 96 goes on to explain this code in Annex A, A.11.6.2 “Hoods, grease removal devices, fans, ducts, and other appurtenances should be cleaned to remove combustible contaminants to a minimum of 50um (0.002in.).
When to Clean: A measurement system of deposition should be established to trigger a need to clean, in addition to a time reference based on equipment emissions.
The method of measurement is a depth gauge comb, shown in figure A.11.6.2, which is scraped along the duct surface. For example, a measured depth of 2000um (0.078 in.) indicates the need to remove the deposition risk. The system would also include point measurement in critical areas. For example, 3175 um (0.125 in.) in a fan housing requires cleaning.