Residential sprinklers

[Ashley Wood]

I am in the process of preparing a fire strategy document for a client and trying to resolve some very serious issues. My client has a grade 2 listed building that he bought back in 2000 as a ruin. Since then he has developed it and spent millions on bringing it back to its former glory as a fine country house. Initially he intended turning it into saleable apartments or turning it into a residential home. At some stage over the past 7 years he decided to turn it into a luxury hotel and spar complex. He installed sprinklers in the building but under 'residential' codes. Now, this is where it gets interesting, the building is under prohibition! The reason is (and there are lots) inadequate means of escape, travel distances, fire alarm and detection, smoke control (large atria in centre of building), lack of management procedures, containment, etc., etc. He has now installed an L1 system, he has created a 60 min, means of escape, he has fire stopped and lined, he has fitted smoke control and he has this sprinkler.

My question is this, I want to 'trade off' the travel distances on the levels of active protection that he has installed including the sprinklers. The problem is this system has been designed to a domestic/residential standard. before I start arguing with Building control and the fire service chaps am I wasting my time? I can provide loads of test data to back up the benefits of a residential sprinkler system, but with this being a hotel effectively, will they say its not permissible and tell me to go away?

Any help or guidance you may have from experience would be appreciated?

[GB]

Sounds an interesting project to be involved with. My first thoughts would be to check with the insurer wether they would be willing to accept the Residential Standard?. If they are I would suggest completing some modelling with the flow rates etc that you intend to use in order to prove tenability of your strategy. I know modelling is not definitive and the old addage that 'you get out what you put in' to some extent is true, but it is better than nothing.

If the insurer is satisfied and the FRA are open to the concept I would check with them wether full CFD or Zone modelling would satisfy them as part of the strategy. I have been at this point before only to find that they want full CFD which is obviously more time consuming therefore expensive for the client.

Hope this helps.

[nearlythere]

To what degree are the travel distances excessive? Is this the only item outstanding?
Why not provide a fire escape? Being listed is not a big issue when it comes to H&S. Have you discussed the matter with the Heritage people?

[wee brian]

Dont waste your time on modelling  - it would be meaningless.

[Ashley Wood]

Thanks everyone so far for your help. The travel distance from the furthest point, furthest bedroom is 25 meters to the only stairs.

The heretage person at the local council does not want any external construction and no modifications to the out side of the building! He would rather it stay a ruin!

[kurnal]

Is that a 25 m protected corridor or does the 25m include stage 1 travel in a room

Very difficult to comment on the basis of your necessarily brief description Ashley.
But if looking for a trade off with the sprinklers we have to be absolutely clear which factors are being traded off. Its the only way to then balance strengths and weaknesses.

Is it residential or domestic sprinkler system? (flow rates and water capacity are different).  

Is the system appropriate to risk and trade off aspirations- this is the fundamental point.

Heres a mischievous point of view- just for argument- I am not suggesting it as a strategy.
One problem in comparing BS9251 with EN12845 is theres a lot of performance and test data available for both. Had your client installed a water mist sytem or an oxygen reduction system the enforcement authorities may not have been so confident in rejecting it

[Ashley Wood]

Kurnal, thanks for that. The travel distance is stage 1. Part of the travel distance is across a gallaried atria! The sprinkler is residential.

[slubberdegullion]

The standard for residential sprinkler systems (9251) makes it quite clear that installations to this standard are appropriate for apartments, residential homes, HMOs, blocks of flats, boarding houses, aged persons homes,nursing homes, residential rehabilitation accommodation and dormitories.  It goes on to say that care should be taken to ensure that any building with a sprinkler system in to this standard should not contain higher fire loadings than would normally be expected in "residential" premises.

It is worth noting that a hotel and spa development (I'm assuming it has a "spa" and not a "Spar!") is likely to have higher fire loads in it than might be expected in residential premises.  It may also have rooms larger than 180 sq m. (the limit for residential sprinklers).  

The idea for residential sprinklers is that a maximum of 4 heads operating at one time and delivering 42 litres per minute each over a total area of up to 60 sq m in a single room will contain any foreseeable fire. You can calculate the design density here - it works out at 2.8 mm per minute - considerably less than the 5mm per minute we would normally expect for a hotel.  

Also the water supply only has to last for 30 minutes (this is possibly less than the required level of fire resistance in the building) and is unlikely to be as reliable as a commercial system with life safety provisions.

This is a very significant point - you are asking to reduce a life safety feature of the building (td) so any compensatory feature must be to a life safety standard.

I'm not trying to be obstructive here - I, of course, don't know the precise circumstances of the case - but I wanted to present some of the potential counter-arguments to yours.

As regards your last comments to kurnal, the whole distance cannot be stage 1 - that is the part in the bedroom.  Stage 2 would be the bit outside the room.

And this travel across a galleried atrium sounds as though it needs very careful consideration - it's not completely unfeasible - but it's likely to be!  Is there a fire separated alternative?

And, kurnal, would you accept those alternative systems you talk of?!  I guess you would want very detailed analysis before you did.  I think you'd be unlikely to get proposals you'd be happy with.

Stu

[kurnal]

Its that balancing act that the enforcement agencies have to carry out when assessing something completely new.
On the one hand you dont want to stifle technical progress and stop progress for the sake of it but where the technology is new and largely unproven many enforcers are reluctant to offer any significant trade off to make installation cost effective. Its a chicken and egg situation- take water mist - very well proven in the marine environment but there does seem to be some reluctance on the part of the manufacturers to fund and undertake major testing and comparisons in the built environment, because until the systems become more widely accepted and realistic trade offs allowed the investment will not be viable. Some agencies are accepting the ad hoc demonstrations offered by some of the suppliers as sufficient evidence to back up the IMO tests, others are not.

We all throw the rule books away sometimes, where other factors come into play- we are happy to accept almost any solution in the remote hotel in a castle on a Scottish island where there is no water supply, no fire brigade, no alternative employment and a listed building that would otherwise be a ruin.

[Ashley Wood]

Firstly, where I come from every thing ends in R i.e spa spaRRrr. Secondly, Kurnal, spot on, this is remote, no mains water just the river wensum, at least 30 minutes for first response appliance. My client went ahead and installed the sprinkler prior to my appointment. I have since got them to install an L1 detection system, vesda and improve their compartmentation. The brigades sticking point is the single staircase means of escape. English heritage do not want an external means of escape as it will ruin the appearance (Hello, it was a ruin!).

The area being protected by vesda is the atria. It is this that has the galleried landings that the escapees turn out on to in the event of evacuation.

[kurnal]

Just to go back in a circle to your original posting Ashley, whats the nature of the atrium and at what level are the galleries, whats the fire risk within?
With early detection and sprinklers to inhibit fire growth for few minutes is there any chance that the ASET may exceed the RSET by a reasonable margin?
As you mentioned first of all is there potential for  someone handy with an abacus to do some sums?

[slubberdegullion]

Can't criticise rs, ooh arrrr.  The very town I live in changed from Brigstow to Bristollll because of our tendency to put an l on the end of words that end in vowels.  What a good ideal!!

A common layout of such a building is as per the section below.



Is yours like this Ashley?  With the staircase accessed off the galleries that surround the atrium?

If so, then it is your task to show that the ocupants of the bedrooms will be out of their bedrooms and clear of the atrium galleries well before the smoke layer has dropped to endanger those occupants.

In the type of converted building you are talking about, this is very difficult to achieve unless you ensure that either there is a fully calculated smoke and heat exhaust ventilation system installed or there is absolutely no way that any fire in the building will discharge any smoke into the atrium.  If there can be no smoke in the atrium then the known evacuation procedures of hotel residents (i.e. very little response) can be satisfactorily catered for.  

Stu

[Ashley Wood]

The atria is basically what you have shown Stu. The fire load at the base of the atria is low, I have advised them not to put any furniture, etc. (common with stately homes). No carpets are on the floor as they are all marble/stone. There are basically four corners and each corner has 3 bedrooms. 3 bedrooms open onto a corridor and this then (via a fire door) opens onto the atria. The head of the atria is made of glass and there will be a motorised panel for fire service use to purge the atria of smoke. The vesda will be sampling at the head of the atria. Full L1 system throughout building. There is a lower ground floor, ground floor and 1st and 2nd floors. The fire service have put a prohibition on the use of the 1st and 2nd floors until a fire strategy and engineered solution can be found. The prohibition is due to the single escape stairs.

I am working on the ASET and RSET now.

[John Webb]

As Stu points out, the water application from a domestic system is a bit under the 5 mm/sqm/min one would expect from the ordinary hazard group 3 system normally installed in hotels and many other places. This is of course also designed to have many more heads open and still achieve the required density.
However, I still think there is enough evidence available to show that a domestic installation will control a fire sufficiently within an area to stop it spreading outside that area at the very least. Taken in conjunction with the L1 system, I would have thought that this would give ample time to escape.
My only concern would be if, for some reason, two systems were trying to operate at the same time; would the water supply be able to cope? This situation would imply that an arsonist was at work, however?

My only other suggestion is that the atrium is pressurised on actuation of the FA so that smoke from any room on fire is kept out of the escape route through the atrium. Taken in conjunction with the motorised panel in the head of the atrium it might also serve to clear any smoke that had got in, with or without FRS intervention, after the building was cleared and the fire dealt with.

[Ashley Wood]

Interesting points John. The water supply should not be a problem as I have advised them that they must have a dedicated supply for 30 minutes and an electric and diesel pump.