The effect of sprinklers on a new build

[kurnal]

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.

[Steven N]

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.

[Wiz]

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!

[Phoenix]

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

[AnthonyB]

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)

[Chris Houston]

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?

[Clevelandfire 3]

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.

[kurnal]

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.

[CivvyFSO]

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}

[Chris Houston]

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.

[Chris Houston]

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.