Positioning of Smoke and Heat Detectors

[admin]

All smoke detectors have similar spacing requirements, heat detectors also all have similar spacing requirements although these are different to smoke detectors. According to BS5839 for general areas the spacing between any point in a protected area and the detector nearest to that point should not exceed 7.5m for a smoke detector and 5.3m for a heat detector.



The above are the maximum areas that can be covered by an individual detector. In order to ensure that coverage is provided into the corners of rooms and to ensure that there is no gap at the junction point of multiple detectors, spacings have to be reduced.



To ensure complete coverage for square layouts, spacings between detectors and walls should be reduced to 5m for a smoke detector and 3.5m for a heat detector.



To ensure complete coverage, spacings between detectors should be reduced to 10.0m between smoke detectors and 7.0m between heat detectors



For corridors less than 2m wide only the centre line need be considered therefore it is not necessary to reduce detector spacings in order to provide complete coverage. Therefore for smoke detectors spacing becomes 7.5m from a wall and 15.0m between detectors. For heat detectors the spacing becomes 5.3m to a wall and 10.6m between detectors.



The above data is based on flat level ceilings; for pitched ceilings or ceilings with a non-flat surface, spacings will alter. For pitched ceilings use the data below, for other ceiling types refer to BS5839 for comprehensive guidance. Where detectors must be mounted onto a pitched ceiling, a detector should be mounted near to the apex but spacing can be increased by 1% for each 1° of slope up to 25%. ‘Near’ is defined as within 600mm for smoke detectors and within 150mm for heat detectors.

[ali pachino]

are those drawings from the Cooper Lighting And Safety Fire Systems catalouge, 'cause i have that book (good read).

[mike]

ali pachino Wrote:are those drawings from the Cooper Lighting And Safety Fire Systems catalouge, 'cause i have that book (good read).

they certainly are;)

[Graeme]

sit the IFA advanced course and see how to space detectors outwith the above.

gave me a sore head

[mike]

Graeme Wrote:sit the IFA advanced course and see how to space detectors outwith the above.

gave me a sore head

Did for me to Graeme, especially degree's of slope etc, I was starting to lose the will to live:(

[douglas docherty]

mike Wrote:

Graeme Wrote:sit the IFA advanced course and see how to space detectors outwith the above.

gave me a sore head

Did for me to Graeme, especially degree's of slope etc, I was starting to lose the will to live:(

You'll have to do it again on the Advanced Commissioning course, but only a couple of pitch angles, and a few cellular ceiling questions. How to win a quote by using less detectors than someone else, and using the kit to the limit. On a good note, design engineers generally stick to the basic principles so that they don't get caught short, but handy to know if required to create a fire design solution for a client.

[Northern Engineer]

if anyone knows its you doug.. resident guru was it 100% in fia units lol

if i had the cash id sit myself to try improve chances of getting a job... dont really want to come off tools after building up the experience over the years, and the keys!!

[Graeme]

douglasdocherty Wrote:

mike Wrote:

Graeme Wrote:sit the IFA advanced course and see how to space detectors outwith the above.

gave me a sore head

Did for me to Graeme, especially degree's of slope etc, I was starting to lose the will to live:(

You'll have to do it again on the Advanced Commissioning course, but only a couple of pitch angles, and a few cellular ceiling questions. How to win a quote by using less detectors than someone else, and using the kit to the limit. On a good note, design engineers generally stick to the basic principles so that they don't get caught short, but handy to know if required to create a fire design solution for a client.

done all 6 Doug.

The Advanced commissioning was pretty straight forward except for the spacing in a cell type ceiling which i found a wee bit tricky in the alloted time.

I have to be honest and say that i do not use the spacings to try and save on detectors for quotes,i just stick to the BS spacings.

I dont use the tollerance factor much unless i have to

[douglas docherty]

Did them all years ago, but have just completed a round robin of them all again to keep them up to date with the new amendments etc, and have been spending some time going round the manufacturers courses again to keep my CPD updated and keep myself abreast of the latest industry and product releases.

Sorry Andy,
Dropped a mark on the advanced design ( alarms ), and on the adv commission.

[Graeme]

douglasdocherty Wrote:Did them all years ago, but have just completed a round robin of them all again

glutten for punishment? lol