Fire and smoke alarms: the law

Where and what to buy

There are two types of interlinked alarms that meet the rules:   

• sealed battery alarms: these must be sealed tamper-proof units and have long-life lithium batteries which can last up to 10 years - you can fit these alarms yourself  

• mains-wired alarms: these are cheaper than battery alarms but must be fitted by a qualified electrician – these should be replaced every 10 years 

Both types of alarms are interlinked by radio frequency and do not need WiFi.   

If you also need a carbon monoxide alarm and it is battery-operated, it must have a sealed battery for the duration of its lifespan.   

Alarms with replaceable batteries   

Replaceable batteries cannot be used because the sensors in the alarm degrade over time and so will not be able to detect heat or smoke. This is why the alarm has a limited lifespan.  Sealed, tamper-proof battery units must be used because they are safer than those which allow the user to change the batteries.   

There have been several tragedies over the years where alarms failed because their batteries expired, or people have removed them. Any alarm you buy will have information on how long it lasts, which can be up to 10 years.    

Where to buy alarms

 There is no list of approved suppliers or fitters. We cannot endorse or recommend specific products or suppliers. A general internet search such as ‘radio -interlinked sealed battery powered smoke and heat alarms’ should bring up results of alarms that are compliant with the standards. 

You can buy both types of alarms online or in store from a number of retailers, and any qualified electrician can fit the mains-wired type.   

You need to check that each alarm complies with the following standards:   

• smoke alarms BS EN14604:2005   

• heat alarms BS 5446-2:2003   

• carbon monoxide detector British Kitemark EN 50291-1   

More information on the standard, including the types of alarms, is in the Tolerable Standard Guidance Chapters 16 and 17. 

Please note that the Nest Protect System will not meet the standard. This is because they do not meet the requirements for a heat alarm under the relevant British Standard. British Standard (BS 5839-6:2019) states that only heat alarms should be installed in kitchens.   

Marketing material from suppliers   

We do not endorse any supplier. If a company has used the Scottish Government logo on its marketing material this is misleading and can be reported to Trading Standards on 0808 164 6000.