'FOG' is the term given to waste fats, oils and greases that are produced as a by-product of the cooking, food-preparation and kitchen clean-down process.
FOG becomes dangerous when it starts to accumulate; either as a significant fire risk in the kitchen extract system, or as an environmental and health risk as it clogs up our sewers (becoming notorius in the media recently with the removal of the Whitechapel 'fatberg' - a 250m blockage of FOG in the London sewer, shown below).
All restaurants that cook with oil produce FOG, whether they specialise in haute-cuisine or fast food, although the rate at which it is produced depends on various factors such as the type of cuisine, format of cooking, frequency of cooking etc.
So what is the chemical composition of waste FOG?
FOG is made up of hundreds of different:
- Long and short chain fatty acids
- Carboxylic acids
- Poly-Aromatic hydrocarbons (PAHs)
- Volatile Organic Compounds (VOCs)
What are the risk factors of these compounds?
|Long & short chain fatty acids|
|Esters||Highly flammable. Inhalation of the fumes from some esters can cause irritation of the mucusmembranes - e.g. the linings of throat, nose etc.|
|Carboxylic Acids||Possible skin irritation.|
|PAHs||With over 100 different types of PAHs, around 15 are thought to be carcinogenic. PAHs are formed when muscle meat - including beef, pork, fish or poultry is cooked over a high temperature and the fat drips onto an open flame, e.g. by frying. They have been found to cause changes in human DNA that may increase the risk of developing cancer.|
|Volatile Organic Compounds||Highly flammable. Irritation of mucus membranes - eyes, nose and throat. Headaches, loss of concentration. Nausea. Damage to liver, kidney and central nervous system. Possibly carcinogenic.|
Factors affecting the composition of FOG
The composition and volume of FOG produced is unique to the type of cooking and cuisine. For example, cooking over an open flame, frying and charbroiling have been shown in scientific research to significantly increase the production of FOG in cooking:
'For every 1,000 pounds of hamburger cooked on conveyor broilers, 25 pounds of emissions are created. The same weight of pepperoni pizza cooked in an oven created just three pounds of emissions. The use of certain oils also could increase emissions. For 1,000 pounds of chicken cooked in a wok with peanut oil, 45 pounds of emissions were produced.' (Source: https://www.acs.org/content/acs/en/pressroom/newsreleases/2010/march/commercial-cooking-elevates-hazardous-pollutants-in-the-environment.html)
As well as food type and cooking format, the volume of FOG produced also depends on:
- The type and volume of cooking oil
- The volume of cooking
- Heating temperature
- Duct architecture - the turbulence and bends in the duct, exhaust velocity and duct insulation
How can Vent AIR help?
Vent AIR is a comprehensive FOG management system for commercial kitchen extracts. It works by dispersing VOC-reduced liquid along the route of the duct to breakdown particles of fats, oils and grease as they flow into the extract. Vent AIR works continually, dispersing the liquid throughout the day to control the levels of FOG accumulation, assisting in keeping it at a continually safe level with a low fire risk.
For a no-obligation site survey, incorporating RC44 please contact us.
SOURCES: https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/cooked-meats-fact-sheet, https://toxtown.nlm.nih.gov/text_version/chemicals.php?id=80, https://cameochemicals.noaa.gov/react/13, https://www.epa.gov/indoor-air-quality-iaq/volatile-organic-compounds-impact-indoor-air-quality#Health_Effects