Maintaining a reliable system

Complacency simply isn’t an option. When faced with the statistics, it serves to reiterate just how crucial fire detection and alarm systems are. They are designed to save lives and to save property. Therefore it is absolutely vital, that those responsible for building services need to ensure reliable and long-term protection.

Key features

Anyone looking for guidance should refer to BS 5839-1, which is an advisory engineering code of practice covering fire detection systems. The code identifies the key features that need to be considered to ensure a system provides the highest standards of protection and it covers a whole range of systems from simple manual installations to complex analogue and digital addressable networks supporting many hundreds of detectors and devices.

Manual systems are the simplest form, whereby a system is operated purely by break glass units. However, in most instances, those responsible for building services will be dealing with far more complex and intelligent systems. These will tend to incorporate many different detector types, including smoke, heat and carbon monoxide.

When approaching the installation of a system, it’s vital that the design plans are agreed with all relevant external parties, which can include the fire brigade, the local council and insurers, all of whom could impose specific requirements relevant to their field.

It’s important to remember as part of this process that an alarm given from any single point needs to be heard throughout the building. Alarms can be initiated by manual call points (break glass call points) usually found next to exits with at least one call point on each floor; or by automatic detection. On activation these devices signal back to a control panel, which in turn switches on the sounders. Notification of an alarm can be via sirens, bells, the spoken voice or a range of beacons, or tactile devices such as vibrating pads and pagers for the hard of hearing.

Automatic detection

Larger buildings or offices are likely to have unoccupied areas or common corridors, which means it may be necessary to upgrade systems to include automatic fire detection. Again, this is a key factor to consider as without an automatic response it could lead to a situation where a fire develops to such an extent that escape routes could be affected, even blocked by smoke and flame, before the fire is discovered.

Installing or upgrading a fire detection and alarm system that is linked to an approved Alarm Receiving Centre (ARC) is also worthwhile considering. An ARC can then monitor the system 24/7, with the ability to alert designated keyholders and the fire service as required.

The frequency at which fire alarm maintenance is carried out is determined as a result of a risk assessment under the Regulatory Reform (Fire Safety) Order and it should be no less than twice a year. The code BS 5339-1 underlines the importance of continued maintenance and sets extensive testing requirements. These include weekly tests, carried out by the end user, in which a call point is activated to ensure the sounders operate at the correct volume in each area. At scheduled service visits, all sounders, power supplies, signalling units, interfaces and main control elements must be tested at each visit. In addition all detectors must be tested at least once per year.

Effective operation

Sounders have such an important role to play in routine maintenance procedures, that ADT Fire & Security recently launched a new whitepaper: ‘Fire Alarm Sounder Monitoring and Testing’. The detailed document offers a practical overview of the latest techniques and methods available to building engineers that can ensure the effective operation of sounder devices.

Critical to the success of any fire detection and alarm system is the correct selection, siting and maintenance of the detection devices. Detectors must offer early, reliable detection in the pursuit of safety from fire, yet they must be resilient enough to reject common causes of false and unwanted alarms – such as dust, insects, steam and dirt contamination. A robust risk assessment, which considers the changing risk levels from fire and potential false alarms is a good start towards determining the correct detection medium. Today’s design engineers have many options to choose from including multi criteria, gas, flame, beam, smoke, linear heat and video detection.

Once installed, an agreed programme of preventative maintenance is crucial to the long-term performance of detectors, ensuring they work when needed and don’t signal a false alarm when there is no fire.

The system design and location of detection and activation devices should be routinely reviewed against the way the premises are being used. When there is any change in building use of structure, building services engineers should consult with the system or service supplier, fire prevention officers and building control to ensure that the system will remain compliant with BS 5839.

Tackle problems

Any quarterly tests require all log book entries to be reviewed in order to tackle any reoccurring problems with the system. These tests should also include checks on the system’s battery and all of its connections. In addition, further maintenance should be carried out every two to three years and should include the cleaning of all smoke detectors to ensure freedom from false alarms. Any acid lead batteries should be replaced every four years. However, if the operating temperature exceeds 250ºC continuously, replacement maybe required sooner. In addition, any service organisation should be independently third party accredited – the BAFE SP203 scheme is a good mark of competency and provides added assurance.

In addition to taking on board the latest design, installation and maintenance advice, it is essential that those responsible for fire detection systems do alert themselves to the latest fire detection technology – particularly as we are witnessing the transition from analogue technology to digital technology in fire detection systems.

Digital technology

The introduction of digital technology has proven to be the single biggest leap in terms of fire detection capability in recent years. Digital technology allows for a more robust system in that the signal from the fire detector to the control panel is more reliably transmitted.

Additionally, digital fire detection systems also allow for a greater level of sophistication than analogue based systems.

Given the tough, financial climate there is welcome news for those who may think that upgrading a fire detection system is a costly and complex exercise, is that as technology has progressed the ability to upgrade has become easier and more cost effective.

This is because a consequence of the move to digital technology has been that systems can operate over many cable types meaning that when it comes to refurbishments, existing cables can often be re-used making installation easier for the electrical contractor and helping to minimise the cost of an upgrade. In addition, digital systems can still be used in combination with analogue technology to create hybrid systems.

Statistics from the Office of Communities and Local Government show that there were 385,000 fires in the UK in 2009. Even after all the designing, risk assessments and maintenance – there is no guarantee that a fire won’t start, underlining the continued need for a high quality fire detection and alarm system. Building engineers should look to BS 58 39-1 but this should work hand-in-hand with the latest fire detection technology to help ensure the safety of lives and property.