Chapter 1 – Introduction, Page 1-2___________________________________________________________
Introduction
Air Quality is becoming a major concern in America’s large cities and as a result, many commercial kitchens will
require pollution control equipment in their exhaust systems to comply with the increasing demands of
environmental control agencies. In addition, pollution control equipment is being used for kitchens in high-rise
buildings allowing the exhaust to discharge out the side of the structure which saves the cost of running the
duct up many floors to the roof.
Pollution control in kitchen exhaust systems has typically been accomplished by any one of the following
methods - gas fired incinerators, scrubbers, filtration units or electrostatic precipitators. Incinerators and
afterburners literally burn the pollutants and, while effective, can be very costly and hazardous to operate.
Scrubbers consist of a water bath and extraction baffles to remove the pollutants and though quite effective on
grease removal, they typically require the addition of high efficiency filters to abate smoke below control
agencies’ standards. Filtration units use a series of impingement filters to remove the pollutants and if done
properly can be quite effective on both smoke and grease.
The Gaylord pollution control unit, trademarked ClearAir, can be manufactured with either electrostatic
precipitation (ESP) or Filtration (TPF). Gaylord Industries has been manufacturing ESP’s specifically designed for
commercial kitchen exhaust systems since the early 1970’s, longer than any other manufacturer.
However, when initial cost is a greater concern the TPF unit is a sound alternative.
The ClearAir ESP unit is available in several configurations, as illustrated on the following pages, ranging
in capacity from 1000 to 32,000 CFM (472 to 15,102 L/s). Most models can include exhaust fan and
odor abatement equipment as an option.
Basic Facts About Smoke
Smoke particles are extremely small and not visible to the human eye unless thousands of them are
grouped together to form what we see as smoke. Individual particles are measured in units called
microns and one micron equals 1/25,400 of an inch (1/64,516 of a cm).
Smoke generated by commercial cooking equipment has a particulate size of 0.15 microns and it is these
very small particles that smoke abatement equipment must remove from the airstream. The amount of
smoke being discharged from a kitchen exhaust duct is measured in terms of its density, referred to as
opacity - the degree to which emissions block light. A 100% opacity level would be solid black and 0%
would be perfectly clear. Control agencies that have adopted smoke pollution ordinances are requiring an
opacity level of no more than 20%, which is a very light blue smoke.
Typically, heavy smoke producing cooking such as charbroiling creates an opacity level of 60% to 70%. Opacity
readings are taken by the human eye by viewing the smoke being discharged and then assigning a
percentage of opacity to what is seen. Though this method is quite subjective, it is the method practiced
by control agency inspectors who are trained and certified in determining opacity percentages.
