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FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Technical Advice => Topic started by: Davo on May 19, 2010, 08:17:51 PM
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New build starting soon, 3 floors, 100m x 25m.
Offices and technical including scientific. Critcal Building due to contents.
400 staff, large open areas, compartmented into three per floor. Individual critical areas half or full hour.
L1 detection
FP designed to Doc B
Then surprise agreement to fit sprinklers all areas by the money men!
Goes to Building Regs who apply 9999 principles with said sprinker system and say building is overspecced, save shedloads due to wonderful sprinklers!
Question is (pleads ignorance on sprinklers :()
How far can one relax DocB and in what areas?
davo
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Hard to say without seeing the layout Davo. Much work has been done in this area in respect of domestic and residential but in commercial buildings it tends to be on a case by case basis. Heres a few ideas though- assuming we are talking a proper BSEN 12845 system
Compartmentation- compartment sizes relaxed.
Fire Protection to elements of structure- may be cut by 50%
More freedom to use large areas of uninsulated or even non FR glazing
Potential to take a more relaxed view over dead end conditions, travel distances generally
Potential to reduce exit widths slightly
As always if you wish to send over a few drawings we could have a look to see if it might be cost effective to carry out a design review in view of the decision to install sprinklers, but if you are at the building regs stage then the potential delays to the program may well outweigh any financial benefits. It might cost you a pie and a pint though.
Anyway its about time you had a few overspecced buildings to make up for all the rest.
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From work on sprinkers some 15 years ago (which led the then Home Office to allow them for life safety in department stores and the like) one of the main benefits was increased travel distances - particulaly useful in shops and similar public places. Also reduced smoke ventilation needs (smaller fires).
I'm also guessing you might reduce the FA system perhaps even to an L5 risk-assessed one from a full-blown L1 - but you'd have better knowledge of the building and contents than I have to make that decision.
Will you be taking any precautions to minimise water damage? May be important in the 'scientific' areas if expensive floor-mounted equipment is about?
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Commenting on Johns post , you will find it common practice for the big boy stores to use sprinklers over detection . If my memory serves me right I am sure when they had a big fire at Brent Cross years ago a lot of the merchandise was sold off smoke water damaged .
However the last few refits I have seen within some shopping centres , they seem to be putting more detection in , as well as the sprinklers.
You might find that the sprinklers on the new build may be driven by the Insurance Company .
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They are driven by the insurance companies, as something a client of mine found out too late. Sprinklers are all well and good but they do have certain limitations and they cant stop smoke in the incipient stages of a fire. With early detection you can warn people to get out of a building on fire which insurance companies like alot.It follows you get the fire service there earlier too so damage is limited even if the sprinklers hold it off before fire crews totally extinguish the fire.Smoke and water damge are things insurance companies dont like. Sprinkler systems are only as good as the person who designs them.
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Depending on the criticality and nature of the contents in the scientific areas normal sprinklers may be counter-productive even if satisfactory for life purposes as any water damage of that nature could be devastating and these areas may suit gas systems better or water mist of water is to be used.
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AnthonyB
I did ask for mist originally, AB but our insurerz turned it down some months ago.
I like you have concerns over the damage that may be done. Some very critical areas have a gas system eg computer systems.
Prof
Will run it past my boss.
Official sod turning in two weeks but our internal department wants to revise the layout as it and the whole Force are making substantial civvy staff cuts (keeps head down) across the board.
Sprinkler system specified by the insurerz, am told its similar to T***
davo
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Some good points made so far. A few more points:
1) Sprinklers cause significantly less water damage than fire fighters extinguishing a fire with water from their hoses.
2) Yes, of course, there are better suppression systems available for protecting water sensitive equipment. Building and suppression system designers should take account of this and specify the appropriate supression systems.
3) If they're putting in sprinklers why not give them some credit? They have virtually guaranteed, to about a 95% confidence level, that any fires that do occur will be controlled by a very small number of sprinklers and will not grow beyond a small size.
Kurnal has listed some of the advantages of sprinklers, there are more. If you're following 9999 the advantages are clear and quantified. If you're following other guidance, they are still clear but not always so quantified.
I feel it would be unfair not to offer these compensatory reductions in fire safety provisions. Indeed, if other developers see the cost effective advantages that sprinklers can bring then maybe we might just see sprinklers fitted a little more often, and that would be no bad thing.
Stu
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They are driven by the insurance companies
......amongst others.
Sprinklers are all well and good but they do have certain limitations
Why not tell us what they are then.
Sprinkler systems are only as good as the person who designs them.
or the numerous persons who check the design or the standard the person designed them too. I don't agree with your argument. You could say that anything is only as good as the person who designed it. But sprinkers are checked by quite a lot of people along the way.
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Sorry Chris insurance companies are amongst the most. Fact. Do fire authorities enforce sprinkler systems in most cases ? nope. Does building control? occassionally, but generally not, who else pushes for them? Ive been on the planet too long Chris. My time as an inspector taught me that the insurance companies are far more powerful than any enforcing body. So lets not be silly about this. Limitations of sprinklers are that they dont necessarily put out the fire, you can get water damage, still get possible smoke damage, fire could sheltered inside or underneath something where a sprinkler head cannot effectively reach.
Im not saying sprinklers are a bad thing but there is a myth that they are some kind of magic wonderous all problem solving device that does away with the need for almost any other fire precaution.There are companies who design install and commission there own systems without third party scrutiny. Yes that could be said about a lot of things. My point was not ambiguous. You need to be sure with sprinkler systems that you get something that does the job properly. Im just saying be careful thats all.
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Usually people tend to quote sources rather to prove accuracy, rather than just add the word "fact". In professional circles anyway.
Lots of people are in favour of sprinklers. Consultants, building owners, governments, local authorities, educational authorities. Fire authorities have a limited remit - they only care about safety. It is not their role to care about protection of assets, business, reputation, the emotional effects of a fire, the effect it would have on a business or child's education.
Most fire (99%) are indeed controlled by the sprinklers alone (http://www.bafsa.org.uk/facts.html)
You can indeed get water damage. The same is true of fire fighting. The later comes with a lot more water damage. So you could also argue that there is a lot of limitations of fire fighting. But I don't suppose you'd be suggesting we don't fight fires. Once there is a fire, it tends to be FIRE damage that people tend to be most concearned about.
If a sprinkler head cannot reach a fire, then there is probably a design flaw. But to NOT put them in would surely mean a sprinkler head would not reach the fire, so I'm not bowled over by this argument.
There are companies who put in sprinklers that are not 3rd party accredited? If so, then avoid them. But there are people who might sell dodgy fire extingiushers. Does it mean we should dismiss fire extinguishers are all bad? I suggest not. I suggest we use the same rule for sprinklers then.
You are just saying be careful? That would be good advice. But it is not just what you were saying. You were saying what we can all read you actually said which was a pretty weak argument, in my personal opinion.
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Yes in your personal opinion. People will make their own minds up Chris, with something so fundemental and potentially very beneficial it is important to do the homework on the pros and cons before just running in blindly thinking sprinklers will solve every problem going. So the Government want sprinklers does it. Yes Oh i forgot they have been pushing that for years, is that why its been law to install them in so many buildings for so long?. Building owners? Oh yeah I hear that wherever I go Chris, my clients always suggest sprinklers be installed. Sorry are we saying that sprinklers cant be of life safety benefit and that the fire service shouldnt enforce them by the way? Local authorities and Ed authorities?, yeah thats a great one, when they have the cash of course they like sprinklers, normally its at the expense of maintance or provision of other precautions in their older properties if you want the truth. Funny you see if you attend several conferences like i do each year, talk to people from all areas of the industry , from designers, installers, clients, specifiers, INSURANCE ASSESSORS , and other industry exerts its very strange how i hear the same thing time and time again. Theyre all telling me its the insurance companies which have led the way on requiring sprinkler installation. But hey ho lets not let facts get in the way of a good argument. And the 99 % figure quoted reates to sprinklers under test conditions.
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I would agree that balancing the pros and cons would be a logical way to assess the risk.
I don't think that because your attend some conferences every year that your opinion is any more valid than mine (nor do I know why you wrote insurance assessors in capital letters). I too provide risk management advice to clients who have opinions on the subject. That said, most of them don't know that much about sprinklers. Anyway, this is a discussion forum where people can discuss items like this and attending a few conferences doesn't make your opinion any more valid than mine. I think what makes arguments relevant is the presentation of logical and science based points.
The only time I have ever heard of an insurance company forcing sprinklers on anyone, is where the last building burnt to the ground. If anyone doesn't like what their insurance company wants, just change insurance companies!
So, there are reasons not to install sprinklers. But I've yet to see you mention any of them. The most obvious one would be cost. They cost lots of money. That would be the other half of the cost vs benefit argument.
The benefits are great, they save businesses and they save lives. Your points on their "limitations" are pretty shoddy arguments. But it's an accurate (as much as possible) cost v benefit analysis that should be the backbone for decision on sprinkler installation.
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Chris, a fire officer I know once told me about the horrendous damage (to structure, fittings and stock) caused by sprinkler systems when they operate.
I've often wondered if this is a real problem when weighed against the benefits.
Do you have any idea of the costs of this damage every year? I suppose I am talking about damage caused by the sprinkler system accidentally operating when faulty/damaged and not during a fire (I suppose any damage caused by sprinkler operation during a fire is insignificant compared to what the fire might have caused!)
I can see that they have the potential for causing expensive damage, but I wonder if anyone has the figures.
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In relation to the potential trade-off's for sprinkler systems, "A Guide To Automatic Water Suppression Systems (AWSS) And Their Practical Application" published by CFOA gives some useful pointers. It also makes it clear where trade-off's are not acceptable. This document is more current than "Sptinklers for Life Safety", which was published by BAFSA and quoted in Approved Document B.
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Dr Wiz
There are a number of fire officers who trot out the old wives tales like this and its partly based on ignorance- the fire service tend not to give their people any significant training on sprinkler systems. There may be just a handful in each brigade who are given further info- I was the sprinkler champion in my brigade for a couple of years before I finished but the level of ignorance was quite surprising - my colleagues would come out with all the old wives tales seen in the movies.
Typically 90% of fires are suppressed by just one or two heads immediately above the fire operating, each head incorporates a a self contained heat sensor and acts independently of all other heads. So only those heads that need to operate actually operate. There are very few accidental releases of water recorded- - the industry claims there is a 1 in 14 million chance of accidental operation, based on the number of heads and the number of events.
So the sums in ball park figures look something like this. A fire occurs in a sprinklered warehouse. The fire grows for about 4 minutes before the sprinkler system operates. the alarm is then raised and the brigade are on their way, arriving within say 10 minutes. The 2 sprinkler heads have suppressed the fire and in that 10 minutes have delivered probably 2000 litres of water onto the fire. There is unlikely to be any significant fire damage to the structure of the building and goods in a maximum area of about 20 sq m have been destroyed by burning.
A fire occurs in an unsprinklered warehouse. The alarm is raised at some time- depending on how it is detected. During the 10 minutes travel time for the fire brigade the fire is growing- typical growth of a fire in a warehouse is a doubling in size every second. Some are even faster- high racks of palletted goods for example. So in that 10 minutes the heat output from the fire has doubled 600 times. On arrival the fire service have to set in at least two and maybe more main jets each delivering 600- 900 litres per minute and most likely maintained at full blast for 20 minutes and then at a reduced rate for a further 20 minutes. A most conservative estimate would be that for that same fire the water damage in the unsprinklered warehouse would be 10-15 times greater. And the roof has caved in and most of the goods have been destroyed.
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I cant speak for other brigades around the country but in the FS department, I work in we push sprinklers whenever possible, yes I agree they have limitations & are not a panacea, im thinking a shielded fire, but yes they are worthwhile.
Accidental damge etc is a myth, however TV programmes dont help when for dramatic effect they show lots of heads going off.
Unfortunately when value engineering is carried out its often the sprinkler system that is cut first & if they are not required under legislation then the chances are you aint gonna get them.
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Dr Wiz
There are a number of fire officers who trot out the old wives tales like this and its partly based on ignorance- the fire service tend not to give their people any significant training on sprinkler systems. There may be just a handful in each brigade who are given further info- I was the sprinkler champion in my brigade for a couple of years before I finished but the level of ignorance was quite surprising - my colleagues would come out with all the old wives tales seen in the movies.
Typically 90% of fires are suppressed by just one or two heads immediately above the fire operating, each head incorporates a a self contained heat sensor and acts independently of all other heads. So only those heads that need to operate actually operate. There are very few accidental releases of water recorded- - the industry claims there is a 1 in 14 million chance of accidental operation, based on the number of heads and the number of events.
So the sums in ball park figures look something like this. A fire occurs in a sprinklered warehouse. The fire grows for about 4 minutes before the sprinkler system operates. the alarm is then raised and the brigade are on their way, arriving within say 10 minutes. The 2 sprinkler heads have suppressed the fire and in that 10 minutes have delivered probably 2000 litres of water onto the fire. There is unlikely to be any significant fire damage to the structure of the building and goods in a maximum area of about 20 sq m have been destroyed by burning.
A fire occurs in an unsprinklered warehouse. The alarm is raised at some time- depending on how it is detected. During the 10 minutes travel time for the fire brigade the fire is growing- typical growth of a fire in a warehouse is a doubling in size every second. Some are even faster- high racks of palletted goods for example. So in that 10 minutes the heat output from the fire has doubled 600 times. On arrival the fire service have to set in at least two and maybe more main jets each delivering 600- 900 litres per minute and most likely maintained at full blast for 20 minutes and then at a reduced rate for a further 20 minutes. A most conservative estimate would be that for that same fire the water damage in the unsprinklered warehouse would be 10-15 times greater. And the roof has caved in and most of the goods have been destroyed.
Cheers for this Prof.
I was aware that the film/TV portrayal of every sprinkler head always operating was not how these systems work. But seeing Bruce Willis battling through a tidal wave of water from the sprinkler system is more dramatic!
I take on board your point about how much water the FS will use on a fire anyway, and that it is probably more than what would have come out of the sprinklers to douse a fire. But my question wasn't ever really anything to do with what happens in a fire situation.
The 1 in 14 million chance of accidental operation, that you quote, seems to make the risk look negligable.
The friend I quoted says he is regularly called out to a famous large shopping centre in Kent to witness the devastation caused by accidentally operated sprinklers. I'll take whatever he tells me in the future with a pinch of salt! He and his colleagues obviously dream up some dramatic stories on those long boring night shifts!
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Just off the top of my head, I think 1 in 14,000,000 is the chances of winning the jackpot in the National Lottery. I think the figure quoted by the sprinkler industry for accidental actuation of sprinklers is 1 in 16,000,000. But it doesn't matter what the figure is precisely, what matters is what this statistic actually refers to. I understand that it is the rate of accidental sprinkler bulb failure. In other words, what it is saying is that sprinkler bulbs virtually never fail just of their own accord.
What you're talking about, Wiz, is the accidental discharge of sprinkler systems through some accidental damage, other than simple bulb failure (e.g. a fork lift truck impacting with the pipework or a head). This is, of course, much more frequent than the highly infrequent bulb failure. It is a little misleading of the sprinkler industry to bandy this almost irrelevant statistic of 1 in 16,000,000 around, but I understand their motivation.
There are figures for accidental discharges of sprinkler installations and associated damage statistics and yes, they do cause a bit of damage when they go off and this is not insignificant. However, it is not at all likely to happen in any building and it is not common.
There is a human trait known as 'availability error' that is built into all of us and cannot be avoided. Thousands of sprinkler systems sit there inertly, doing nothing (but ready), unnoticed, nobody paying them any attention. But then a sprinkler head is hit by a fork lift truck in a building somewhere and this is causes a bit of damage and we all hear about it and, maybe, see the cctv images on Youtube and develop a strong image in our mind of the incident. The images and circumstances of this incident are 'available' to us much more than all the thousands of systems where this does not happen and we cannot help but form an impression that the incident is much more likely than it actually is.
Information that is 'available' is always given much more weight by our tiny little brains than it merits. Think about the real risks associated with air travel or fun fare rides and compare that with common perception of the risks.
Going back to sprinklers, the issue of cost benefit has already been discussed in this thread. The best way to determine if sprinklers should be fitted (if not for life safety requirements) is through cost benefit analysis. The results of this will vary with every building. There has been much study of this in the last few years and there is plenty of reading out there for those who want to pursue this. Look to the BRE/CLG for a start.
Here's a thing, imagine if our culture was such that every house in the country has a sprinkler installation. Houses are full of plumbing anyway, it would only be a few more pipes (could the sprinklers even possibly come off the same installation that supplies domestic cold water throughout the house?)(yes). How many people would die because of fire in such a world? I think such a culture would save hundreds of lives every year. Now tell me that sprinklers are bad.
Stu
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I think there must be a particular issue with the people in this Kent shopping centre if they are having sprinkler activation call outs al the time - I've visited & revisited dozens of large & very large shopping centres for over 12 years and the total number of accidental or malicious activations can be counted on one hand.
Your one example doesn't make a case.
It's funny how polar opposite countries can be - The US loves sprinklers and mandates them in a much larger range of premises than we do, yet we have been reducing their usage until recent years (& still are in many premises)
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Chris, a fire officer I know once told me about the horrendous damage (to structure, fittings and stock) caused by sprinkler systems when they operate.
I've often wondered if this is a real problem when weighed against the benefits.
Do you have any idea of the costs of this damage every year? I suppose I am talking about damage caused by the sprinkler system accidentally operating when faulty/damaged and not during a fire (I suppose any damage caused by sprinkler operation during a fire is insignificant compared to what the fire might have caused!)
I can see that they have the potential for causing expensive damage, but I wonder if anyone has the figures.
Perhaps you might want to consider that the chances of 1 sprinkler head going off by accident is 1 in 15 million per head per year. The typical chances of a destructive fire in a warehouse is about between 1 in 100 or 1 in 1,000 years.
I've never actually head of a sprinkler head going off by accident (5 years working for Zurich insurance company) (3 years working for Marsh insurance brokers). But if it did, the insurer would cover it.
You might also consider that places like the British Museum and the British Library all consider sprinklers to be suitable for their contents and stock. Places with priceless contents and public everywhere.
In short summary, it's a non issue. Most of the misconceptions about sprinklers are peddled by people who don't have that much experience of them. Take a trip to the US where you'll see most public buildings sprinklered. Look above you in any big airport or shopping centre. Anyone remeber the last time a sprinkler head sprayed water on them? Anyone even heard of it happening?
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Chris you must feel threatened by me because you kept saying my opinion was no more valid than yours. Ive never said at any point that you were not entitled to your opinion, or that your point was less valid than anyone else's, so please dont make on that I did. I put forward my argument you put forward yours. I agree that scientific research and official facts and figures can sway our opinion, but alas you have heard of lies damn lies and statistics.Guess what Chris you sometimes get a clearer picture from talking to people on the front line rather than rely on biased information from government, especially the last government or trade bodies. Unfortunately you fail to see we actually agree on most ppoints. I say again Mr Houston and Im sorry if this offends you that you need to do your homework with sprinklers. Sorry i have no hardened facts to back that up. So mock me all you like, belittle me with your sarcasm if you wish I dont care, perhaps Kurnal as administrator will be less confrontational and defensive than you are.
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All I would say is that we are bound not to agree with each other from time to time. Most of us have strongly held views about sprinklers, marmite, the opposite sex (of either gender) and politics. It is good that we express our point in a forthright and passionate way. The forum would be boring otherwise.
Sometimes we are all guilty of spouting twaddle. Some of us more than others. (sorry about my claim of 1 in 14million- I quoted the wrong statistic and as Phoenix points out a pretty limited one at that ). I fell for that one because I am receptive and believe in sprinklers despite their limitations. My belief is based on experience as a fire officer, and latterly as a consultant who uses the design freedoms they offer, and I also carry out tests on systems on behalf of clients, write training manuals and train maintenance staff.
All I would ask is that when we do disagree we recognise it as a a difference of opinion between peers and not as a personal criticism or insult. After all none of us has to post here, we all have a choice and despite our differences we all care passionately about our industry to the extent that we are prepared to sit up all hours discussing issues.
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The typical chances of a destructive fire in a warehouse is about between 1 in 100 or 1 in 1,000 years.
You really didn't need to go to that level of accuracy with your probabilities.
Sorry i have no hardened facts to back that up
??? But I don't understand.... You said "fact". Surely that actually means it is a fact? I have seen it before many times on the 'comments' part of Youtube, and it is as good as referencing a specific page of a fully accepted and published scientific report.
Some various examples: (Each one being an indisputable fact.)
"Bikes are better than cars. Fact."1
"A lion would beat a tiger in a fight. Fact"2
"No Mick you retard, cars are better than bikes. Fact."
"Less nature, more sandwiches Hotchick_211. Fact."3
1: MickSuzuki69, Youtube.
2: Hotchick_211, Youtube.
3: SubaruSam1985, Youtube.
4: CTodd1953, Youtube
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Chris you must feel threatened by me because you kept saying my opinion was no more valid than yours. Ive never said at any point that you were not entitled to your opinion, or that your point was less valid than anyone else's, so please dont make on that I did.
Nope. The part where it seemed to me that you implied your opinion was more valid than mine is:
Funny you see if you attend several conferences like i do each year, talk to people from all areas of the industry , from designers, installers, clients, specifiers, INSURANCE ASSESSORS , and other industry exerts its very strange how i hear the same thing time and time again.
So, of course it's a free world and you are entitled to speculate about how I feel. But, I'd still rather discuss the issue of sprinklers and not your speculation about how I feel about the debate.
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The typical chances of a destructive fire in a warehouse is about between 1 in 100 or 1 in 1,000 years.
You really didn't need to go to that level of accuracy with your probabilities.
OK. So I could have been better with the stats, but a well run warehouse doing low risk activities will tend to burn down about once in a thousand years and a shoddy one will burn down every 100 years.
My point was that the risk of water damage from sprinklers is overwhelmingly irrelevant compared to the more real risk of fire.