Fire alarm

[Paul Chick]

Hi Guys,

Just got a job to install a fire alarm, easy enough. Just want to know roughly how many heads i will need to cover a 380m2 area with a vaulted roof??

Thanks alot

Paul

 

[scotsparky78]

Hi Paul, to what design are you proposing? L1, L2, L3 ? Is this a new build or a refit? All is dependent upon the use of the building and in most cases the insurance company of the building will advise what they would like.

Obviously the Fire Authority is a good start although the onus is always on you!

 

[Paul Chick]

Hi Mate, its pretty much L1. The building is an old commercial unit that they are splitting into 3 separate units each with their own system. Basically its just a massive open space, bit like a garage with a back and front door.

 

[scotsparky78]

Is the vaulted roof open or is there a false ceiling with the vault roof above? I would say 5m/7.5m between detectors - If its a hidden vault roof then void detection, i usually put drop down LED indicators to identify hidden detectors.

Are you doing relays to AHU and gas valve?

 

[Paul Chick]

Its just a open vaulted roof, ill play it safe and go 5m. That drop down LED indicator is a good idea :biggrin: Now ive wired alot of alarms but ive always had drawings and never had to commission them myself, is that easy enough?

 

[Guest123]

Detectors no further apart than 7M, any void greater than 800mm in height will require detection, remote indicators for concealed voids, interface units for any mechanical plant, MCP's at each external exit door and at each change of compartment.

If they are to be seperate units, you will need to asses the cause & effect of an alarm situation. Any electronically operated doors will also require interfacing, additional beacons in disabled W/C's, sound levels need to be assessed with additional visual indication if necessary.

The above is a brief outline of things to consider, your own risk assessment will highlight & pinpoint any other issues.

Maintenance of the system is as important as the installation

Design of a fire alarm system is a minefield and remember, its your arse on the line if it all goes pear shaped.

As Sotty said, input from those concerned will be paramount.

Hope this helps.

Sent from my BlackBerry 9800 using Tapatalk

 

[tazz]

Sorry guys where are we getting the spacing of 5-7m between detection...?
The radius of a smoke detector in 7.5m, heat 5m. Circle edge to edge is 15m
therfore the squared area is aprox 10m x10m. to overlap the the circle edge therfore is 10m safe spacing between detection if design cannot be calculator by cad drawings.
If we are looking at open areas, warehouse type premises, would be well worth looking at beam detection, will cut down on installation costs