It’s been some time since I witnessed my first oil fire test but it’s still fresh in my mind. We stood tentatively waiting for the oil to auto-ignite. Two burners, wide open below a 75 litre pan which was emitting a foul stink that had me retreating to the partitioned viewing area. The firefighter stood stoically meters away from the heating oil. Later he would tell me that it was to acclimatize to the heavy acrid haze.
Then the oil ignited. Barely noticeable at first with low flames that then started to grow. The firefighter sprung to life to turn the gas burners off. Almost silently the oil continued to burn. I was back in the room by now, eyes watering from the sting of oil in the air. We moved quickly to remove the surplus heating and measuring equipment ready for the fire to be tackled. I was used to wood fires which crackled and hissed so loudly that we would need to shout to count down the pre-burn time. With this fire, our footsteps echoed around the large burn hall.
When it was time I counted the firefighter down and he released the extinguishant into the centre of the oil pan. The flames protested momentarily but then faded back slowly and eventually extinguished. After the anticipation waiting for the oil to ignite it had been a spectacle of sorts but nothing like as violent as a heptane fire. Still the danger of the oil was well understood. I had to monitor the temperature of the oil after the fire. 200C and holding steady. This was horrible stuff.
According to Home office statistics, chip pans used to account for 20% of accidental dwelling fires but due to prevention awareness by the Fire and Rescue Service (FRS) combined with changes to cooking habits, this has declined significantly*.
From my experience testing fire products it’s easy to understand how an oil fire could escalate in a tragic accident. The fires are relatively small initially. It must be tempting to throw water into the pan or try to remove the pan outside. In the moment of panic, I can emphasis how someone may make a mistake that can have terrible consequences.
The FRS has publicized the dangers of these two actions through numerous campaigns. If the pan is doused with water the water quickly boils and the pockets of gas that are created can throw oil from the pan. Taking the pan outside or opening a door feeds the fire with a sudden rush of oxygen and enlarges the flames. Just moving the hot oil pan has its own dangers.
These factors make oil fires very difficult to extinguish and require equipment specific to the application. Published standards cover these technologies: Fire blankets EN 1869:2019, Hand-applied units PAS 2013-1:2013, Fixed systems BS 8489. The standard for small fire extinguishers (BS 6165) is expected to be published with the inclusion of tests for oil fires. My first oil fire testing had been in accordance with EN3-7:2004+A1:2007 for a fire extinguisher specifically adapted for oil fires.
After I’d completed the day conducting oil fire tests I returned to the hotel and moved quickly past reception whilst being very aware of the pungent oil on my clothes. I passed someone in the corridor and tried to keep a wide birth whilst trying not to brush the walls. I could feel the oil on my skin still. I’d had the foresight to take a bin bag back with me and I promptly sealed my clothes away as soon as I got back into the room. I’d been cured of any partiality to fatty foods. The prospect of an oil fire was never going to be an issue in my house after that experience.
Statistics show that fires are dropping each year but fires do still occur. The London Fire Brigade advises the following for pan fires:
- Don't tackle the fire yourself and don't try to move the pan
- Never throw water over a fire as it could create a fireball
- Turn off the heat – but only if it's safe to do so
- Leave the room, close the door, shout a warning to others, and call 999**
*Home Office – Focus on trends in fires and fire-related fatalities – Stephanie Bryant and Isabel Preston – 12 October 2017
Author: Robert Hearty
BSI Fire Team Leader