Part B smoke alarms

[emphasis303]

Hello Everyone

What are the requirements of Part B in regards to smoke and heat detectors in flats?

The building contains 3 flats spread across the 1st and 2nd floors.

I understand at least 1 smoke and heat detector in each kitchen, which must be mains integrated, also t&e or 3 core if its only one alarm in a single flat?

If the kitchen is open plan will one located near the kitchen be fine, also what are the spacing requirements for common areas i.e stairs etc.

Many Thanks

 

[PrenticeBoyofDerry]

New and refurnished single dwellings,
require:
*at least one on each floor
*within in 7 m of kitchen and living rooms or other areas where fires may start (ie garage)
* Installed according to manufacturers instructions
* at least 300mm from any wall or ceiling light
* be interconnected
*be permanently wired by separate way in CU or supplied via local regular lighting circuit.
* have battery back up
* Preferably not RCD protected but if electrical safety requires the use of RCD, either the smoke alarm circuit should be protected by single RCBO or the RCD protection of smoke alarm circuit, should operate differently to that of the socket outlets.

 

[jeds]

As long as the flats are no more than two storeys and comply with all other requirements you need smokes to each landing in the common stair which should be linked together and also linked to a heat detector in each flat. You must also make sure you get 75db at the bedhead which might require sounders in the flats.

On top of that each flat has a stand alone smoke system which will depend on layout. This system is NOT linked to the communal system.

 

[emphasis303]

Thanks for your replies

When you say the communal area smokes must be linked to the heat detectors in the flats what exactly does that mean?

Does it mean that for instance if the alarm in one flat goes off then that will also sound the alarms in the communal areas? Which will then sound the alarms in each flat?

Thank you

 

[jeds]

No. Think of it this way. There are generally two types of fire; smouldering type fires that might be relatively cool but create a lot of smoke, and proper fires that create a lot of heat. (and usually smoke)

Within a flat you have a system of smoke alarms to pick up any smoke fires. As long as these fires are detected early they can usually be controlled within the flat so they don't need to be connected to the communal system. Most of them will be burning the toast or a smoky frying pan. You don't want the communal system going off every time this happens.

In the communal area you also have a system of smoke alarms. This will pick up any fire in the communal areas - which obviously all flats need to know about - and will pick up any smoke percolating from within the flats. Which might occur if a smoky fire starts in a flat but nobody is home.

The communal system should also be linked to a heat detector within the flats. This is usually located in a corridor near the kitchen door. The principle is that heat detectors need a significant amount of heat to trigger - so they only really go off when there is a proper fire. In this case the heat detector in the other flats will also fire. Obviously if there is a proper fire producing heat in any flat then all occupiers need to know.

It's not perfect but it's the generally accepted model for two storey flats. If there are scenarios that wouldn't be covered because of a particular layout, or something, then this should really be considered and the design adapted accordingly.

 

[emphasis303]

Thank you for explaining it so clearly.

This might be an obvious question but in order to link the communal area alarms with the heat sensors near the kitchen area would a fire alarm control panel be required?

Once again thank you for your help.

 

[jeds]

No.