BS 5839: Part 3: 1988 and automatic hold open devices.

[Underground]

As I haven't a copy of this to hand, can anyone tell me how close a detector should be to either side of a door with magnetic hold open devices fitted.  Office situation for compartmentation - no sleeping risk.

I thought that they had to be within 3 metres, but I can only find "within a reasonable distance".

Please can anyone else advise?

Many thanks.

[Graeme]

part 3 does not cover detector positionings as far as i can remember

[Underground]

OK.

Can anyone tell me how close a detector should be to either side of a door with magnetic hold open devices fitted.  Office situation for compartmentation - no sleeping risk.

I thought that they had to be within 3 metres, but I can only find "within a reasonable distance".

Please can anyone else advise?

Many thanks.

[Ricardo]

Underground

Taken from the current Technical Handbook supporting the Building(Scotland) Regulations 2004, for hold open devices, it says,"self closing fire doors can be fitted with hold open devices as specified in BS 5839:Part 3:1988, provided the door is not an emergency door, a protected door serving the only escape stair in the building(or the only escape stair serving part of the building)or a protected door serving a fire-fighting shaft.

It is important that hold open devices deactivate on operation of the fire alarm, therefore some buildings will need automatic fire detection to be installed. Electrically operated hold open devices should therefore deactivate on operation of:
An automatic fire alarm system designed and installed in accordance with BS 5839-1:2002(category L5) determined on the basis of a risk assessment.
Any loss of power to the hold open device, apparatus or switch, and a manually operated switch fitted in postion at the door..

An example of a category L5 fire alarm system could incorporate only 2 smoke detectors, one installed on either side of the door and postioned not less than 500mm and not more than 3m from the door.

hope this is of some use to you.

[Underground]

Thanks Ricardo - that is of help - but does anyone know if a similar mention of a distance is made in English regulations anywhere please, else I will rely on the Scottish Regs as above.

Thanks.

[kurnal]

I recently tried to find the same info because at the back of my mind I am sure there used to be a requirement in the codes covering England and Wales that specified the same 3 metre rule.

But after much searching  I came to the conclusion that it was a throwback to the early days of magnetic hold open devices, when L3 meant escape routes only and not rooms off escape routes, and that the 3metre rule ensured there was a detector on either side of a door held open. I think that when the categories were clarified (the 1988 edition of BS5839?) the 3 metre rule was dispensed with and wording to the effect that the area should be covered by automatic fire detection and alarm system in accordance with the recognised categories for life safety systems in BS5839 - which really hits the spot I think. There would be no point in providing additional detectors close to the door in a room just to meet the 3 metre rule when that room already has sufficient detectors sited in accordance with the standard.