A fire blanket is a sheet of fire resistant fabric in a quick release pouch. It works by excluding air from a small contained fire, and it is the only piece of fire equipment most untrained people use correctly first time. That combination of simplicity and effectiveness is why it appears in kitchen provisions far more often than any particular extinguisher does.
The standard and the sizes
Blankets sold in the UK are made to a European standard that classifies them by the test fires they are rated against, including a pan fire test and, for larger sizes, a clothing fire test. Small blankets are for pans. Larger ones are for a person whose clothing is alight or for covering a small item. Buying by size alone without reading the rating is how a pan sized blanket ends up as the provision for a workshop.
Mounting and reach
The pouch is mounted on a wall at a height a person can reach without stretching over anything hot, and on the escape side of the risk. In a kitchen that means beside the door rather than behind the hob. The release tapes must hang free; a blanket in a drawer is not a provision because nobody finds it.
What they do well
Pan fires, small contained fires in bins or on benches, and smothering burning clothing. They leave no residue, do no damage to the room, need no training beyond a sentence, and cannot be used incorrectly in a way that makes the fire worse, which is not true of any extinguisher.
What they do not do
A large fire, a spreading fire, or anything where the blanket cannot cover the whole of the burning surface. A blanket laid over a fire that extends beyond its edges concentrates the heat and does not exclude the air. They are also single use in practice, because handling a used one safely is not something to attempt.
Fire blanket regulations UK kitchens are actually held to
No regulation says a kitchen must have a fire blanket, which is why the search for the rule comes up empty. What applies is the fire safety order's requirement for appropriate firefighting equipment, decided by the fire risk assessment, and in any kitchen with a hob that assessment reaches a blanket almost every time. The standard to buy against is the British and European standard for fire blankets, and the distinction that matters is light duty against heavy duty: a light duty blanket is a domestic product for a pan and is disposed of after use, while a heavy duty one is intended for commercial use. In a commercial kitchen the blanket sits alongside a wet chemical extinguisher for the deep fat fryer rather than instead of it, and the only real rule is placement: on the escape side of the room so that reaching it never means reaching across the hob.
Questions people ask about fire blanket UK
What are fire blankets used for most often?
Contained pan fires in kitchens. That is the ignition source they are provided against and the one they handle best.
Is a blanket reusable after a fire?
Treat it as single use. It will have been heated unevenly, may be contaminated with fat, and there is no practical way on site to establish that it still performs.
Does a blanket need an annual service?
It is not serviced in the way an extinguisher is. It is checked visually for presence, damage and contamination, and replaced when any of those fail or after use.
Is a large fire blanket better than a small one?
For a pan, no: the standard kitchen size is designed for the job and a bigger blanket is harder to handle at arm's length over heat. Large blankets exist for a different purpose, which is a person whose clothing is alight, or laboratory and workshop use where the object is bigger, and in those cases the extra size matters. So the question is what you are protecting. A domestic or catering kitchen wants the standard size mounted within reach of the hob but not above it; a workshop may want both.