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FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Technical Advice => Topic started by: GB on August 15, 2016, 08:51:55 PM
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A studio / open plan flat - the statement that cooking facilities should be remote from the exit point.
I have had a search on the forum and other publications with no justification of any distance - can anyone point me to any research or similar data / information on this issue?
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Subjective one, I've not seen a definition for remote as such. But 1.8m seems to be used commonly.
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9m is what is shown in the diag 3 in ADB.
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Yes I have seen 1.8m with it being related to the distance in ADB Diagram 25.
Does the 9m in ADB Diagram 3 relate more to travel distance within an open plan Apt rather than a distance from the cooking facilities?
I have also seen 4.5m being used as in ADB Diagram 14 relating to the distance away from an opening in a floor.
I can't see anything in the NHBC Open Plan Apts document justifying any distance and no other research paper discussing the issue which must be a common topic.
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Diagram 25 is in an external situation (a vented fire).
9m in Diag 3 is the max allowable travel distance but the diag also shows the arrow head to the 9m dim terminating at the kitchen units. I would have thought that to achieve a situation where the cooking facilities "do not prejudice the escape route" then the distance needs to be not less than the actual TD.
Diaq 14 is not a cooking risk or a flat.
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The situation I have seen had sprinklers, LD1 and calcs to justify the radiated heat allowable at 1.8m.
I would suggest without an engineered solution, a risk assessor should look at the 45 degree rule as a benchmark standard.
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Thanks Colin, I fully agree that Diagram 25 & Diagram 14 is not fully relevant - only pointing out what I have come across, not what I propose or endorse.
I would suggest that the distance from cooking facilities within Studio Apts of 9m from the exit point is not the most common occurrence but I may be incorrect in that assumption.
I have come across Studio Apts where the furthest distance to the exit point is less than 9m from any point in the room therefore how could you achieve 9m as in Diagram 3?
I wouldn't have a problem if there was evidence to back up why it should be 9m or any other distance for that matter but I can't see anything to back up why the position within Diagram 3 is the one that should be followed.
It appears to be a grey area open to interpretation but using distances which as you quite rightly point out are not fully relevant.
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the principal is simple enough
cookers catch fire "a lot". if you have a cooker next to your door then you will get trapped "a lot".
AFD and sprinklers are irrelevant. You'll already have a smoke alarm in the flat, any additional detection wont help much and you're probably awake anyway. by the rime the sprinkler goes off, your fire is already one that you wont want to walk up and shake hands with.
so how far should it be from the door.
as a few folk have said, some people have done some plausible sums that say about 1.8m is about right.
could you comfortably walk within 6 feet of a chip pan fire? yes, I think I could. (always check sums with your brain)
QED
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Like all diagrams in the ADB, Diagram 3 simply illustrates the principle, it's ideal from the point of view of fire safety but the flat would most likely have no external windows.
My experience (and I was involved in the design and enforcement of flats design for over 40 years) is that as prices have increased and flats become ever more compact, most developers and building control ignore this recommendation. The most common current design for studio flats, in my experience, is to have modular bathrooms and kitchens immediately inside the flat entrance door with the sleeping living area beyond.
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Bear in mind that the 9m shown in ADB is the maximum travel distance and not the distance the kitchen area should be from the exit. The question should be: in the opinion of the assessor would a fire in the kitchen area prevent relevant persons escaping from the premise?
Remember ADB is guidance not legislation.
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Mike just to point out there's no assessor or relevant persons- these are domestic premises!
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The guidance says that the circulation route should be covered by smoke detection and the kitchen area covered by heat detection. If the cooking facilities are 1.8m from the exit then it is likely that the SD will be continually going off.
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GB do you hail from bonnie scotland because it appears that rule applies there,
Technical Handbook 2013 - Domestic - Complete. http://www.gov.scot/Topics/Built-Environment/Building/Building-standards/publications/pubtech/th2013domcomp
2.9.7 Escape within dwellings - open plan option with suppression and enhanced early warning
Open plan layouts are becoming more popular with modern living styles. For this option (see table to clause 2.9.2), the following guidance should be followed for open plan layouts provided the kitchen is remote from the exit door. ect
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The situation I have seen had sprinklers, LD1 and calcs to justify the radiated heat allowable at 1.8m.
I would suggest without an engineered solution, a risk assessor should look at the 45 degree rule as a benchmark standard.
Sounds a bit dodgy to me - sprinklers or automatic smoke detection won't help you if you're in the same room as the fire, & radiant heat calc's alone don't take into account smoke & toxic gases.
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Don't overlook BS9991 as a design document.
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Thanks Kurnal that's what I was just typing and quoting.
BS9991:2015 gives a lot more information on this so worth a look.
For example, the travel distance of 9m may be extended to 20m if AWFSS and an LD1 fire detection and alarm system is installed.
Cooking facilities should be sited away from the flat entrance door and internal escape route.
So that brings us back to the original post of what is remote, away or adjacent to the door. This would infer to me radiated heat is the issue. As wee Brian has said, can you comfortably walk past a chip pan fire at 6m? Yes. When justified with radiated heat calcs the AI or fire service are satisfied.
There are several other limitations such as ceiling height and sizes of open plan flats (16mx12m) and kitchens greater than 8m x 4m should be enclosed.
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JT you quote WB at 6m . Wee b said ok at 6 feet. Big difference.
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Typo Colin. 6ft is correct, I go by 1.8m in any case.
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9991 says that the cooking appliance should not be adjacent to the entrance. The 9991 guidance appears to be taken from the NHBC Foundation document, which only considers one open plan layout in which the cooker is off the circulation route by about 1.8m but mid way between the enclosed bedroom and the entrance door, so for part of the escape route you are moving away from the cooker ,i.e. with your back to the cooker.
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yes, 1.8m is about 6 feet!. the 9m is a travel distance and nothing to do with the question at hand.
tbh, my mum set fire to a chip pan and then carried it into the garden (not recommended) her arms are a bit less than 6' long.
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She was very lucky. I remember a very distressing fire in which an elderly lady tried to carry a burning chip pan into the communal areas of a sheltered housing scheme (into a dead end corridor) as she walked forward the draught caused by her movement caused the fire plume to envelop her upper body and head. She dropped the pan spilling the burning oil down her clothing and overcome by the effects she died a painful death at the entrance door to her flat.
Everybody- ban the pan, if you need to fry chips buy your family members a thermostatic deep fat fryer.
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Brian, ever since fire safety codes went metric I have believed the myth that 1.8m=6 feet. So I have always quoted my height on hospital forms as 1.82m, in the naive belief that if I added an inch to 1.8m it would be right for my height of 6'1''. At a hospital appointment last year they told me I was 1.86m, so I told them either I had grown or their thingy was wrong. They measured me three times, while I patiently began to explain that I always remember that 1.8m is 6 feet. They looked puzzled and equally patiently explained that 1.8m was NOT 6 feet, so where did I get that from. They did not understand the answer F***** fire safety codes.
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I'm surprised at you Colin falling into the metrication trap of mixing your units. Adding an inch to 1.8m indeed! No wonder you were confused.
Much of the timber retail / DIY industry fell into the same nightmare in the 1970s when suppliers started supplying in metric lengths and many retailers, right up till about 1980 decided that 2m = 6 "metric feet" for sales and pricing purposes.
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Interesting read ... I've seen a number of design proposals and justifications from designers and fire engineers for positioning the cooker next to the door. This is very common in the current commercial model for student accommodation. Personally I don't buy the generic 1.8m 'rule'. I have seen some of these situations modelled and have seen justification for cookers much closer to the door than one might think. Very much depends on the design fire however. Seems to be a bit of an industry wide wide issue with inconsistent approaches from regulators, both LA and AI.
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Basic fire safety principle - don't let the fire get between you and your exit. The cooker represents the highest risk in the accommodation. There is only one exit. Human weaknesses including absent mindedness, distractions, intoxications frequently result in cooking equipment unattended. I would take some convincing that modelling takes account of the fire development that can arise from such human factors.
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Kurnal, I fully agree there are many factors to be considered ... the human element is actually probably more complex than the fire phenomena. What is worth consideration however, if we ignore radiant heat for a moment and model the ?code complaint? layout (Diagram 3 of AD-B) from the perspective of smoke the room becomes untenable very quickly, this is the case for wherever you sight the cooking facility. In simple terms unless you are awake, or are awoken by the fire alarm very quickly then there is little chance of survival. It?s begs the question how ?safe? the approved code compliant solution is.
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None of the general fire safety codes take account of tenability in the room or origin in any meaningful way and there are pointers in other codes such as BS5839-1 category L3 that confirm that the detection is only to protect the means of escape outside the room involved in fire. It has long been a frustration for many of us that this goes against the philosophy of the current legislation- some people are more relevant than others! Some fire brigades have been pro-active in going beyond the standards and requiring smoke detection in all rooms but there is no empirical data to prove the value of this or otherwise. Similarly BS9991 and the BRE report provide for bedrooms that are inner rooms in some circumstances.
I was careful to avoid stereotyping but the fire death statistics for young men indicate a combination of alcohol and chip pans are a significant issue. Similarly students from overseas have different catering needs and frying can be very common amongst some nationalities. All of my former university clients used to tell me frying was banned, my inspections proved this not to be the case and the Universities involved would never enforce their policies. Similarly most had policies of verification before calling the fire service- the worst case involved a 15 minute response time by security staff just to get across the site. Not relevant to the siting of the cooker of course.
There are two sides to potential fire deaths - tenability in the room is one factor, and rescue by the fire brigade another factor. If the fire is next to the door then potential rescuers will be further delayed in entering the room to carry out the rescue. I accept this is likely to be statistically insignificant with no data to prove my argument either way. Just good old common sense. And besides its as much about escaping safely without injury as about dying in a fire.