Your Guide To Smoke Alarms & Fire Safety

There are three basic types of fire alarms or smoke detectors:

  • Battery powered alarms. These are simple to install and only require basic DIY skills.
  • Wired alarms. Can only be installed by a professional electrician.
  • Business premises fire alarm systems. Can only be installed by a commercial building fire alarm specialist contractor. Not only will specialist electrical skills for installation be required but also an in-depth understanding of how the alarms function together with the various levels of safety legislation and regulations that are in force and govern the use of this type of fire alarm.

A fire alarm or smoke detector price for installation comparison shown in the table below will at a glance give an indication of the costs involved.

Smoke Alarm type Duration Material Cost labour Cost
Simple stand-alone battery alarms. 1 to 2 hours £50 £100 to £150
Direct wired alarms. 4 to 5 hours £130 £150 to £200
Business fire alarm system. 1 week £1500 £1500


Remember that these prices and durations are indicative only and will vary depending on

  • What part of the country the work takes place.
  • The complexity of the job.
  • The type of detectors used.
  • What legislation needs to be complied with.

Role Of Smoke Alarms & Safety

Fire prevention and the protection of life and property are very important and must not be jeopardised by underspending or bad management. In an ideal world, every property would be connected to the local fire station and the firefighters would automatically know when and where a fire was taking place. In practice, of course, this would be just impractical, almost impossible and with the sensitivity of domestic smoke alarms that are on sale they would be turning up at your house every time you made toast and the kitchen smoke alarm was activated.

So in practice, there are a number of hierarchies of hazard and risk. In private houses, it is considered the minimum to have a smoke alarm on each floor outside the bedroom doors and one downstairs, possibly in the front hallway. Most alarms that are installed in a newbuild house are mains electricity hard-wired smoke detectors and are linked so that when one alarm is activated, they all are.

In rented houses, they have to be mains powered and interconnected smoke alarms even if the house is not new.  Remember that although single battery powered detector alarms can be installed by an amateur, it is extremely important that hard-wired alarms be installed by a professional electrician.

In commercial buildings, schools, colleges and public buildings the requirements are even stricter. Not only are there alarms fitted at appropriate locations, but there are also different types of fire extinguishers available. Sometimes, usually in schools and hospitals, fire service smoke alarms connect the establishment to the station house.  The main factor that defines all these different cases is one of cost vs risk of many people becoming harmed in the case of a fire. Obviously, if there is little risk and not many people at risk then the type of smoke alarm installation will not be very sophisticated and correspondingly low cost, something along the lines of a smoke alarm battery powered detector or a simple wired smoke alarm connected to the mains electricity. Conversely, if the property is considered high risk because flammable substances are stored there and there are many people at risk then a smoke and fire alarm will be installed either connected as a wired smoke detector or more commonly these days installed as a system of wireless smoke alarms.


The type of smoke detector battery fitted inside some of the best smoke alarms is actually those whose purpose is to provide a backup for the mains electricity powered system. They are rechargeable from the mains and only come into play if there is a power outage. These power cells are lithium batteries and generally have a 10-year lifespan. Because of this, they are not usually replaceable as a spare part, but after the 10 years is up, simply replace the whole unit.

The other type of battery that commonly goes inside smoke and fire detectors is a 9v PP3 rectangular type battery. Sometimes however other types are used such as the AA and the AAA batteries, especially in the cheaper models. Once you have replaced the battery (any type) press the test button on the alarm that will let you know that the smoke detector system is once more up and running.

Smoke Detector Benefits

A smoke alarm is a device that in the event of a fire, smoke detectors inside the device energise a circuit which results in an alarm. There are in fact two main systems that are commonly used in domestic fire alarm smoke detectors.

  • This type uses a beam of light to detect smoke.
  • This type uses radiation detectors to register whether smoke is present.

Both types rely on the fact that smoke in a chamber will obscure the amount of light or block the radiation being detected. Any decrease in the intensity of either will automatically set off the alarm.

Although not exactly a smoke alarm, a carbon monoxide detector is considered as essential as a smoke alarm in the home or in fact anywhere where an open fire or any heating systems involving burning fuel are installed. Carbon monoxide is a poisonous, colourless and odourless gas produced by the incomplete combustion of wood, fossil fuels and in fact any flammable substance. The combustion of carbon in oxygen is usually a two-step process. When a flammable substance burns it initially uses oxygen to produce carbon monoxide. The Carbon monoxide then burns again to produce carbon dioxide. It makes sense then that if there is not enough oxygen available for complete combustion then carbon monoxide will never convert into non-poisonous carbon dioxide. What makes carbon monoxide so dangerous is its extreme reactivity with any oxygen available. If animals (including humans) inhale carbon monoxide, the gas reacts with the oxygen already in the blood, depriving the brain and other organs of life-giving oxygen. It is for this reason that fossil fuel heaters must be regularly checked to ensure they are burning efficiently.  Open fires can be just as bad because with modern building and insulation techniques there is less likely to be any draughts in a room replenishing oxygen that has been used in combustion. The result is incomplete combustion which will always produce carbon monoxide. In order to prevent unconsciousness and death, carbon monoxide detectors should be installed in every room that has a fire.

Features To Look For In Smoke Alarms

When it comes down to it, even the best smoke detector will not give proper safety coverage if it is installed incorrectly and with disregard for any instructions given by the manufacturer especially if it is a DIY installation. It is for this reason that the best detectors will be those that are the simplest to install with the least number of possible mistakes that could occur.

The types that only a professional can install (hard wired in domestic settings and alarm systems in commercial or public buildings) will depend on the level of expertise needed to install. In these cases, simple installation or modular installation will result in more efficient operation, lower installation charges and hopefully lower maintenance costs.

Simple battery powered alarms are always the easiest and simplest to install, only requiring the correct placement, the fitting of two fixings in the ceiling and the connection of the correct battery. As long as the manufacturer’s instructions are followed to the letter then this type will do exactly what is intended.  It must be mentioned at this stage that some smoke detectors are designed with disabilities in mind. For householders with hearing impairment, there is no reason why a flashing light cannot replace the sonic alarm signal. These will, however, have to be installed correctly by a professional.

For directly wired alarms, the only variation between this and the simple DIY alarms is that a professional electrician is required to install the power supply and connect alarm triggers (remember that when one activates, they all activate). In case of a power outage, these ones also have a back-up rechargeable battery that needs to be periodically checked.

The commercial alarm systems are the most complex and theoretically, are the type with the most features to go wrong.

The main features to look for include.

Battery powered Hard wired Commercial alarm systems
Reasonable purchase price Reasonable purchase price Reasonable installation price
Clear installation instructions Clear installation instructions Finance or monthly payment scheme
Easy to install Ease of installation Compatibility with existing security alarms
Long battery life. Does not require separate wiring circuit Competent and qualified installation company
Easy availability of battery Loud alarm signal Compliance with relevant regulations
Easy battery replacement Compliance with national and international regulations Comprehensive call-out and maintenance programme
Loud alarm signal Simple maintenance procedures
Compliance with national and international regulations Qualified electricians

The features listed above are generalisations and will vary depending on your own individual and unique circumstances. Always get advice from a professional before choosing which alarm system is correct for you. Having said that, for most domestic situations the simple battery powered detectors are quite adequate but for new builds, you will find that hard-wired alarm systems are fitted as standard.

Doing It Yourself

That depends on the type of system you have. The simple battery powered detectors are designed for ease of installation and are perfectly suitable for the DIY market. As long as you follow the manufacturer’s instructions exactly there should be no problems.

If you have a hard-wired detector, then there should be no problems as long as you are just replacing an old detector for a new one. If however there is any wiring work to be done, compliance issues to consider or anything more complex it is always best to employ a qualified electrician or fire alarm installation contractor to do the work. It is worth contacting your home insurance company about this because you may be under an obligation to employ professionals with certain qualifications or who belong to specific professional organisations in order to be covered under the insurance policy.

If you have a property into which members of the public have access then you will find that your property needs to comply with specific fire regulations. You will also have to employ a specialist company who belong to specific professional organisations in order to comply. Contact your local authorities for advice.

To finish

Ultimately all these features and the regulations with which your fire alarm system must comply, boil down to whether the installation will keep you, your family, the people who visit and your property safe. Any system of alarms, no matter how simple or how complex will ultimately fail if they do not do what they have been designed for. This comes down to ensuring the detectors are sited correctly, are properly detecting changes in the ambient atmosphere, are correctly interpreting the information and are communicating this information to you the owner.

Be wary of detectors that seem too cheap because these may be substandard imports that do not comply fully with the regulations. These will give the homeowner a false sense of security and may ultimately be the cause of deaths, injury and property damage.

Smoke detectors, fire alarms and carbon monoxide detectors all have their place in our lives and will all perform a certain function if installed correctly and in compliance with specific regulations. Always make sure that whatever fire alarms or related detectors you choose are fit for purpose or else you may as well not bother having them fitted at all.

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