Frequency of kitchen exhaust cleanings is always a matter of concern when discussing service with new clients and building relationships with current clients.  The International Kitchen Exhaust Cleaning Association outlines the NFPA 96 code for frequency on their FAQ’s page:

The ultimate goal of the Fire Protection Act is to reduce the risk of a fire in your commercial kitchen.  As we all know, though, there are always going to exceptions to any rule, and the NFPA 96 addressed this in Annex A:

“A.11.6.2:  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…which is scraped along the duct surface.  For example, a measured depth of (0.078 in.) indicates the need to remove the deposition risk.  The system would also include point measurement in critical areas.  For example, (0.125 in.) in a fan housing requires cleaning.”

What does this all mean?  Basically, there are guidelines and then there are specifics to getting the hoods cleaned.  Let say your restaurant used hickory wood in the grill.  By code, you should expect the hood over the grill to be cleaned on a monthly frequency.  Now let’s say you are killing it volume wise, and the grease and creosote levels in the system are reaching the .078 in. (which is 1/8”) faster than a month between cleanings.  You could potentially be at risk for fire spreading one week, two weeks, or maybe longer before your next scheduled vent hood cleaning.

Side note:  Eric Kimberling has a very informational article of the dangers of creosote levels in your solid fuel exhaust system:

Most of us are getting our hoods cleaned on a quarterly frequency, and in most cases, this is accurate timing based on code and accumulation.  There are always equipment and cooking methods that produce higher levels of grease vapors such as grilling steaks and burgers, using a char broiler, or any wok cooking.  Spikes in business such as grand openings and holiday seasons could also cause your exhaust system to accumulate faster.  Any part of the system that has 1/8” of accumulation requires a cleaning, whether it has been three months or not.

The IKECA grease comb is a vital tool in the kitchen exhaust cleaning industry.  Hood Boss has developed a pocket sized version available to its clients upon request.  Please call our office if you feel your system may be at risk and we would be happy to get you a grease comb reading.