A fire detection and alarm (FD&A) system is one of the most crucial electrical components of any building. In the initial stages of every new project the responsibility is largely down to the electrical contractor to carry out the risk assessment and ensure the most suitable FD&A system has been installed. In this industry it is a basic requirement. However, what is less straight forward is the process of selecting the right system in the first place, ensuring it not only suits the property’s fire safety requirements but also meets the latest legislation and standards.
If we break down the process of providing the most appropriate FD&A system, it is about getting the right people, both in terms of competence and responsibility, and having the right paperwork. The documentation requirements are extensive, but not excessive, given the nature of and context for this type of equipment. The necessary paperwork has to satisfy current fire legislation and comply with the requirements of the relevant British Standard code of practice – BS5839-1:2013, which covers the seven different stages – from the initial risk assessment right through to the on-going service, maintenance and modification stages.
When it comes to the FD&A system itself, whether it is a basic conventional non-addressable fire alarm or a fully addressable/programmable solution, the choice of solution varies greatly depending on several factors set out in the fire risk assessment. Any recommendations that stem from the risk assessment will be specific to each individual building and are dependent on the design, size, use and number of occupants in the property.
The right solution requires careful planning and consideration for each building’s unique and specific circumstances. The structure and layout of the building, for example, if the property has very high ceilings, will have significant impact on the choice of FD&A system. The most appropriate detector to use is determined by the height of the site. If reasonably low, a traditional point detector can be used to cover up to a height of 10.5m. For structures over 10.5m high, aspirating smoke detection or beam detection would need to be employed.
Modern aspirating smoke detection systems (ASDs) have an unrivalled ability to detect smoke earlier than any other fire alarm and detection device and can actually be a thousand times more sensitive therefore detecting fires at the earliest possible stages. This high sensitivity and early detection is vital to mission critical and high-risk applications, bringing substantial time benefits and enabling the fastest response to the first signs of smoke.
Aside from providing the highest levels of detection, the primary role of an FD&A system is to aid in the safe and quick evacuation of a building. One of the most effective and efficient solutions is an integrated fire and voice alarm (VA) system that been proven to play a critical part in managing the circulation of people safely in an emergency.
A key part of VA systems is the acoustic design and this is an area that can sometimes lead to confusion for customers. Any FDA solution that relies on sound and voice must have an acoustic design carried out, the trick is knowing when to spend time and money to get it right. The system architecture of a VA system is selected to suit the specific building type and is dependent on its size and structure. Larger applications such as high rise offices or sports stadiums, for example, may present problems that only a design expert or acoustician can solve and may need academic modelling.
Voice Alarm solutions have many advantages, however there are applications where a visual alert would be more appropriate. These Visual Alarm Devices (VADs) effectively act like flashing strobes and are regularly installed as part of FD&A systems to provide a main or a secondary alert for deaf or hard of hearing people. VADs are also frequently used in buildings with high background noise, such as factories, or in situations where an audible alarm would be hazardous, for example, hospital operating theatres.
The new standard setting out the conformance criteria for VADs devices is EN54 Part 23, and it was driven by the Equality Act 2010. When the standard was first introduced, it caused a raft of confusion in the industry. Manufacturers had no products on the market that could meet all of the requirements, so the challenge was to produce a range of products that would fully comply. The complexities surrounding the different categories and various mounting positions set out in the standard also had to be fully understood by anyone involved in the design, commissioning and installation of FDA systems.
Despite the initial confusion and complications surrounding EN54-23, its introduction was certainly warranted, as previously the effectiveness of a VAD could not be determined. In many ways, the new standard has brought simplicity, as all manufacturers now have to present their products’ performance data in exactly the same way, so they can be directly compared and their suitability assessed for specific applications. Gent’s latest range of S-Quad VADs meet and exceed all of the requirements of EN54-23. The devices bring together S-Quad proven sensor, sounder and speech technology with the new compliant high efficiency visual alarms and have been designed for the widest range of building applications.
Another key element when selecting the most suitable overall FD&A solutions is to choose a system that will help to minimise the chance of expensive and unwanted false alarms occurring. There are VA/PA solutions available on today’s market that have different modes to trigger different evacuation procedures depending on whether the public are on the premises. This minimises false alarm disruption and offers the safest evacuation procedure for any member of the public present in the building.
In terms of wired FD&A systems, the powered loop has led the market for a number of years, however the latest wireless systems have also proven to be highly effective for specific types of applications. Wireless systems can offer fire protection where installing cables would be hazardous, such as ducts and voids contaminated by asbestos. The hybrid versions combining the use of both wired and wireless devices means that wireless can be used in areas that need to be treated with sympathy, yet later additions such as ducts, voids and roof spaces can be cabled.
As with all safety equipment, choosing the most suitable FD&A system means examining a range of different elements in order to get the highest level of fire protection for every application. Selecting the right product to suit the purpose and structure of the specific building, while fully complying with the relevant standards is a challenge, but by following the advice of today’s fire industry experts it removes much of the complexity surrounding the most advanced fire detection and alarm systems.
Stuart Brown, business manager Scotland, Gent by Honeywell
