Look at the types of cooking oils available. Some have higher flash points than others. Most cooking oil fires happen because the oil is not changed regularly. As an oil gets old its FFA (Free Fatty Acids) increase and the flash point comes down. Also, most of the cooking oil fires in both the 'point of sale' market and the industrial cooking market occur in the extract ducts. This is due to poor hygiene and regular cleaning. If oil builds up in the duct again the FFA levels increase and eventually auto ignition takes place. So, to help prevent fires change the oil regular, clean the duct and maintain the equipment so that the fryer temperature cut off is working correctly. Alternatively, look at high pressure water mist systems as these extinguish, cool and do not contaminate the equipment and kitchen area.
Best regards
Ashley Wood