Door closers and fire doors

[D.M. Procida]

Can a bit of paint really be as good as a specially-made door costing £200?

The doors must be the original ones, so from the 1930s.

Daniele

[fred]

Why are you paying 200quid for a 30min fire door?

[D.M. Procida]

Thanks for all the responses. One interesting thing - the building control officer told the architect that linked mains smoke alarms in the rooms on the first floor would be acceptable as an alternative to new fire doors there, though I admit that by this point I was quite pleased at the thought of fire doors.

Daniele

[BigWallop]

Stick with fire doors and battery smoke alarms. I'd rather have a warning and a haven of safety in the rooms rather than a warning with less protection behind a less resistant door.

[John Rumm]

Not sure I follow the logic. I would have thought that fire doors with interlinked mains alarms with battery backup was a better bet. Why not have the safe haven of a fire door, *and* the earlier warning you are likely to get with interlinked alarms?

[D.M. Procida]

It may all be moot now...

Our house was on the market, but the credit got crunched right at the wrong moment for us, and we couldn't find anyone who wanted to buy it.

Having paid out now for an architect's plans, planning permission, etc etc etc, not to mention some preliminary building repairs, we have an offer from a buyer with ready cash.

So, either we:

spend a total of about £90,000 for a loft extension and major rebuilding works on a house worth about £215,000 in the current market, or:

sell the house for £215,000, and live in rented accommodation until the market bottoms out of its freefall, and then buy something that will be suitable without needing £thousands of work on it.

An extra £90,000 right now won't get us a house with all the things that our £90,000 work would, but if prices fall another 20% it will.

However, I really don't like the idea of gambling with something as basic as a home, which is what the second option is, effectively. I don't even like the idea of a house as an investment. It's a place to keep you as safe and happy as possible, not something to juggle for possible future financial advantage.

So possibly, no fire doors for us.

Daniele

[BigWallop]

If the choice is having safety zones compared to just early warning, I think I'd choose the safe haven option. Battery powered smoke detectors are cheap compared to the installation of a mains interlinked detector system, and has less maintenance worries, and they give early warning just as good in a domestic installation.

The accessories that go with a hard wired interlinked system are, maintenance contracts, which insurance companies insist upon if you have such systems installed. The replacement of more expensive back-up battery packs at least every 5 years, which the insurance company insists upon. The weekly testing and result recording of the system, which the insurance company insists upon.

I'd rather have the Battery DIY Smoke Detectors placed around the house, which can also be interlinked

fire doors, than go through the mains systems hassle for a domestic situation.

Just personal preference on my part, mind.

[John Rumm]

Indeed, but that is not the only choice on offer. Have both.

The interlinked mains alarms cost much the same, and about a quid more for the ones with battery backup. Wiring and installation is pretty straight forward.

I can't agree that individual alarms will give equally good warning - in some circumstances they *may* give as good a warning, however in may they certainly won't (the variability obviously changing with house layout etc). An alarm going off in a hall is going to take longer to wake people than all the alarms going off - including the one right outside the bedrooms. This is especially true with three storey properties or loft conversions. (where interlinked alarms are required by building regs)

The battery is a PP3, same as any other alarm:

weekly testing and result recording of the system, which the insurance

Perhaps it might be a requirement in a commercial premises, but not in a domestic one. In fact most domestic insurance policies don't even require that smoke alarms be fitted, let alone specify how they are powered.

Having installed mains alarms with battery backup, I can't say it is really much hassle - took about one and a half hours to do three on three storeys, including the provisioning of a dedicated circuit.

You can run a 1.0mm T&E to the first from a dedicated circuit, or from a nearby lighting circuit. Thence a 3&E to the other alarms. If you don't fancy running cables then use wireless interlinked ones in the same way

and fire doors, than go through the mains systems hassle for a domestic

Well in my mind, its the interlinking that is the important bit.

The mains powering just reduces the hassle of changing batteries so often, and also reduces the possibility of there being no alarm when required because a battery has failed (or more likely) been removed.

[tony sayer]

It seems to me that perhaps it would be better driven off a circuit like a lighting one as if say the dedicated one were to fail or be more likely accidentally tripped off, no one would notice that whereas they'd be far more likely to do something about a lighting circuit that wasn't working;!....

[D.M. Procida]

Presumably they let you know if the circuit has failed.

Daniele

[tony sayer]

Indeed hence the reason for doing just that!..

[D.M. Procida]

I meant, presumably the alarms let you know if their circuit has failed.

Daniele

[tony sayer]

Well if there battery backed not all will tell you and if the batteries haven't been replaced or have more then likely been borrowed;!..

[John Rumm]

In the cases where alarms are required (like a loft conversion adding a third storey) then you then must use battery backup alarms if you are powering them from a non dedicated circuit. The logic being that alarms alone are highly unlikely to trip a circuit, whereas a shared circuit might be tripped by something else and lose the alarms. Most mains powered alarms also have a "mains on" LED so you can see at a glance if they are not powered.

Under the 16th edition regs one would have likely placed alarms on a non RCD protected circuit. IMO they are probably still better powered that way when a dedicated circuit is in use, but with a suitably screened cable.

[tony sayer]

Is that strictly the case that they MUST be battery backed on anything other then a dedicated circuit?..

No I very much doubt they would, and seeing there're not earthed even;)..

Yes but that would be noticed very quickly..

Yep so they might .. but take the case of a HIMO do you really think that say some 20 odd year old house sharers would even look?..

Screened against what?..

[John Rumm]

That was my experience based on the building regs a the time I did my loft conversion. However I have just had a read through the current version:

of the commented changes is that all alarms should now have a backup power supply.

The current wording is:

"Power supplies

1.19 The power supply for a smoke alarm system should be derived from the dwellinghouse's mains electricity supply. The mains supply to the smoke alarm(s) should comprise a single independent circuit at the dwellinghouse's main distribution board (consumer unit) or a single regularly used local lighting circuit. This has the advantage that the circuit is unlikely to be disconnected for any prolonged period. There should be a means of isolating power to the smoke alarms without isolating the lighting.

1.20 The electrical installation should comply with Approved Document P (Electrical safety).

1.21 Any cable suitable for domestic wiring may be used for the power supply and interconnection to smoke alarm systems. It does not need any particular fire survival properties except in large houses (BS 5839-6:2004 specifies fire resisting cables for Grade A and B systems). Any conductors used for interconnecting alarms (signalling) should be readily distinguishable from those supplying mains power, e.g. by colour coding.

Note: Mains-powered smoke alarms may be interconnected using radio-links, provided that this does not reduce the lifetime or duration of any standby power supply below 72 hours. In this case, the smoke alarms may be connected to separate power circuits (see paragraph 1.19)

1.22 Other effective options exist and are described in BS 5839-1:2002 and BS 5839-6:2004. For example, the mains supply may be reduced to extra low voltage in a control unit incorporating a standby trickle-charged battery, before being distributed at that voltage to the alarms."

Perhaps, although on a summers day you could go many hours unprotected...

Screened so as to provide earthed enclosure of the cable. i.e. to meet

17th edition requirements for the protection of cables, where you can only have a non RCD protected cable hidden in the fabric of the building if it >=50mm from the surface, or run in a cable like MICC, Earthshield, SWA etc.

[Martin Carroll]

I'm just doing 1st fix on the current job and was reading about this just the other day. I was puzzling over the "There should be a means of isolating power to the smoke alarms without isolating the lighting". I am not sure how this may be achieved?

Cheers

Martin

[BigWallop]

By putting the detectors on their own supply. If the power to the detectors fails, you still have lighting to see where you're going in an emergency. If the lighting circuit fails, you still have fully functioning detectors to warn of danger.

Separating the supply lets you work on the detectors without turning lights off as well.

[Martin Carroll]

In article , BigWallop writes

That's not what it says.

"...or a single regularly used local lighting circuit ........ There should be a means of isolating power ..........."

I understand that if it is on a separate supply then it is can be isolated. However the point of putting it on a lighting supply is that it will not be disconnected for long or if there is a fault then it is obvious (the lights go out!).

Cheers

Martin

[BigWallop]

It is just my preference to keep them separate. Of course, you could take the supply with other regularly used lighting, something that isn't going to leave you in the dark on the staircase or other escape routes, and faults would be more obvious.

But it's just my own preference.