Smoke Detectors & Air Conditioning

[Dpbeavan]

Help needed please!

I work in a new office building which has a computer server room about 100m2 with a ceiling height of about 4 m.  This room contains alot of expensive computer equipment and the room is cooled using four  ceiling monted airconditioning units.

The building has a conventional fire alarm and detection system installed however, now our insurers are saying that the single conventional detector installed in the middle of the computer server room is not suitable due to the air conditioning degrading its detection rate.

They say we need a VESDA system to replace the smoke detector.  But as this is a brand new building and the server room was designed in along with the air conditioning is this not a problem for the contractors who built it?

I suppose I need to know whether a conventional smoke detection sat between four air conditioning units meets British Standards.

Can anyone shed some light on this?

[colin todd]

Have a look at BS 6266, which advocates a density of around 25 sq metres per head for critical electronic equipment rooms.

[Ashley Wood]

Was the room that now contains the IT equipment always intended to do so? Without a doubt if it was and this was known by the contractors then you have a case against them. As Colin says, BS6266 details the qty of detectors required in an A/C served area.

If I have a client who is looking to use an area for IT, I would always recommend a VESDA type system be used. These systems are much better at detecting fine smoke particles in high air movement areas.

Going back to the problem you have, this could be worse if you have a floor and ceiling void and no protection. Also, have you considered installing an inert gas extinguishing system? If the IT equipment is business critical this should be considered.

Best regards

Ashley Wood

[Allen Higginson]

You could use a small designed aspirating system (as a secondary detection system which could be set up to give an alert on the main panel)  to monitor the air "leaving" the room.These could in turn shut down the air conditioning and so leaving the existing detector to operate in a "normal" enviroment.

[Dpbeavan]

Thankyou for your replies.  With regards to BS 6266 - I understand this was changed in 2002 and believe my building was designed and built in 2001/2002.  Would I be right in saying that the previous version of BS 6266 was just as specific about the detector requirement in A/C served areas?  Does BS 6266 just identify an increase in the number of detectors to compensate for AC or is it specific about type and location aswell?

With regards to a possible solution to the problem the suggestion from Buzzard905 seems an excellent idea with the installation of a small aspirating system to shut down the air conditioning allowing for prompt investigation and also for the normal dection systems to kick in - could anyone suggest a ball park figure for installing such a system for this 100m2 room.  It would have to use air sampling in the room itself as the ac units are split systems with air no ducting.

Can I also say that as a new comer to this forum I am particularly impressed and very grateful for your help.

[Fishy]

Were the contractors asked to design to BS 6266?  If they were simply asked to comply with the law, 6266 isn't really relevant, because its only about the protection of kit, not people.  Whilst one would hope that competent contractors would have asked whether asset protection is a requirement, you can't blame them if they were sticking to the brief they were given.

[wee brian]

This isnt really a problem for the original contractor as it stems from the requirements of your insurer.

Insurers do not have set standards, they take a view on the specific risks that you ask them to cover. This is a bit like backing a horse from their point of view and in this case they aren't happy with the odds.

A different insurer (for that matter another surveyor from the same firm) may well have a different view.

Vesda can be much more sensitive than a conventional smoke detector and are often used to protect sensitive electronics. The smoke alarm is there to protect the people in the rest of the building not the computers themselves.

If you do install a VESDA (or similar high sensitiviy aspirating system) then you should consider if this should trigger a power down on the kit in the room.

A vesda will pick up a single resister burning out on a pcb before its hot enough to ignite the machine it is in. this is a great way of saving valuable equipment but a man with a soldering iron will have the same effect. (needs thorough management of the room).

[Allen Higginson]

In fairness,there should be no soldering in this room if their is already smoke detection present (but,as Brian says,management of access to the room should be in place to overcome the problems should the need arise to solder).I wouldn't go as far as shutting down the actual equipment in the room from an ASD though - the early signal should lead to an early investigation into the cause.

On a side issue,ASD are being used more now for life conditions as,in the case of "accommodation" in one young offenders institution that I am involved in,they are basically tamper proof with the sampling port being flat to the ceiling (unless they start sticking moisturing cream over the sampling port and bringing up an air flow fault!!).

[Graeme]

" in one young offenders institution that I am involved in

Buzz

watch they don't keep you in .

Second thoughts-it's a YOUNG offenders place!!!

[colin todd]

The old BS 6266 said the same thing. it does give some guidance on siting but not a lot.

[Allen Higginson]

" in one young offenders institution that I am involved in

Buzz

watch they don't keep you in .

Second thoughts-it's a YOUNG offenders place!!!

OI!! - there's a time and a place for that sort of comment (oh,I forgot - you don't visit there no more!)