21 Dec Multiple challenges in multi-use buildings
Paul Pope, Head of System Integration and Technical Support, Apollo Fire Detectors, explores the challenges associated with fire detection in multi-use buildings, and outlines the ways in which the latest detection technology is helping to overcome these challenges.
Designing a fire detection and alarm system is a complex matter irrespective of the project, but designing a fire detection system for large, multi-use buildings can be particularly challenging due to the numerous considerations that need to be taken into account; from the use of space and the movement of people, to the need for phased evacuation and specifying the right detection for the different environments.
Over the past decade, the Middle East has witnessed a boom in the construction of new multi-use buildings that
combine residential, hospitality, office space and retail all within a single address. No two multi-use buildings are exactly the same; the use of the spaces in the building, the number of staff and visitors/residents and the frequency and type of activities and events taking place within the building will vary significantly. For this reason, it is essential that building specialists, system designers, installers and manufacturers work closely together.
Developing a phased evacuation strategy
One of the greatest challenges when designing a fire detection system for multi-use building is managing an evacuation in the event of a fire. The early warning of a fire and the safe exit of occupants requires the input of experienced specialists right from the initial consultation and design stage all the way through to the commissioning, installation and ongoing building management.
Over recent years, fire detection has started to become more multi-functional, with many devices integrating with security and Building Management Systems (BMS). A key factor to this will be gateway connections, with fire detection and alarm systems intelligently communicating with the Building Management Systems (BMS) to initiate the control of fire protection measures, shutting down air conditioning, stopping passenger lifts safely at the appropriate level and controlling smoke/heat dampers.
It is vitally important when integrating the fire detection and alarm system with BMS that the connectivity is designed with survivability in mind. The performance specification and installation for this type of integration must be engineered with integrity and redundancy in accordance with the building’s fire and evacuation strategy.
Given the scale of most multi-use buildings, it is likely that a ‘phased’ emergency and personal evacuation plan will be required for the safe exit of occupants (including disabled and sensory impaired people), and to assist the firefighters with access. The latest fire detection and alarm systems can support vertical and horizontal phased evacuation ‘Cause and Effect’ – methodology, which will provide the required automation or manual override of the alarm zones needed to facilitate the building’s evacuation strategy. This avoids unnecessarily evacuating building users who are not at risk due to their position in the building in relation to the fire.
Phased evacuation fire detection and alarm systems, must be designed and installed correctly to maintain system survivability and integrity during fire and emergency conditions.
Another consideration in multi-use buildings is the fact that some building users will potentially be unfamiliar with their surroundings (guests in a hotel, for example), possibly orientated to a different time zone and speaking different languages – all these issues need to be accounted for in the event of an incident.
It is essential that fire detection and evacuation strategies provide simple and concise methods of notification and guidance to allow for a safe controlled evacuation in a timely manner. Frequent training on the emergency evacuation plan should take place so that all employees and occupants are familiar with its contents. Regular evacuation drills should take place with a record of the results reviewed and recorded.
Choosing the right technology
When it comes to choosing the right fire detection technology for multi-use buildings, it is vital that every area of the building is assessed to ensure the appropriate type of detection is used for the differing fire risks. When designing a fire protection system, it is important to understand and identify the characteristics and fuel material of a potential fire, the environment in which the detector will be sited and the risk of fire.
Prior to deciding which technology is suitable for an installation, system specifiers and installers are first faced
with the question of protocol. Protocol is the ‘language’ that is used by intelligent fire detection devices to communicate with each other. Some manufacturers do not disclose the nature of their protocol to anyone else because they offer a complete system; the protocol is therefore said to be ‘closed’. Others, like Apollo Fire Detectors, share their protocol with competent third parties to design and develop compatible products. This is referred to as an ‘open’ protocol.
Questions should then be asked as to which technology should be chosen for the different areas of the building and how it can be applied to ensure accurate and reliable fire detection. The types of fire that can occur can vary from slow smouldering fires to rapidly flaming fires with little smoke. Manufacturers have developed different types of detectors for different types of fires and environments:
Optical smoke detectors are good for a wide range of smoke types symptomatic of early stages of fire. They use a proven technology and offer improved designs for airflow and drift compensation. They are suited to detecting slow burning, smoldering fires which produce large smoke particles and are often used in areas such as bedrooms, escape corridors, and electrical switch rooms.
Heat detectors offer protection in environments that are dirty or smoky in normal conditions, such as kitchens or garages. They are also effective in areas that contain high levels of airborne particles such as water vapor and exhaust fumes. However, there is no early warning of fire.
Multisensor detectors offer a combination of smoke and heat sensors. For their sheer flexibility, multisensors are the best general-purpose detectors currently available. They combine optical readings with temperature change to give a rapid response to the widest range of fires of any detector type, dramatically improving rejection of unwanted alarms.
Carbon monoxide (CO) detectors provide good early warning of deep-seated, smoldering fires and are unaffected by common sources of unwanted alarms such as steam, cooking or dust. However, CO detection should only be used in addition to general purpose smoke detectors, never as a substitute.
Analogue addressable fire detection technology is an ideal choice where accurate identification of a fire is important because each individual detector can be pinpointed. When combined with a graphical display of the building, this information will indicate to building management staff and attending fire and rescue personnel exactly where and how the fire is spreading and, consequently, where their resources should be focused.
Modern and technologically advanced fire detection solutions, such as Apollo’s analogue addressable Soteria®
range, are ideally suited to purpose built multi-use modern buildings as they significantly improve the detection of smoke, enhance the reliability of the detection process and reduce the risk of false alarms.
Featuring an optical sensing technology called PureLight®, Soteria® detects smoke particles entering its chambers. A cone sensing chamber allows light from the LED to be entirely absorbed, reducing reflections in the chamber. The detectors also incorporate an advanced chip sensor which significantly improves the detection of smoke and enhances the reliability of the detection process.
Sleek low-profile detectors are well suited for use in the Middle East as less dust penetrates the outer casing and ideally should be designed to be less sensitive to any dust that accumulates over long periods of time.
The Soteria® range uses Apollo’s latest open protocol software, CoreProtocol®, providing a digital protocol fire
loop communication and system control thus end users benefit from increased power on the loop and greater flexibility and choice for any future changes to the system as it supports soft/auto addressing.
For multi-use buildings, another benefit of the latest sophisticated fire detectors is that they are equipped with different operating modes, so that the sensitivity level of each device can be tuned to match the likely environmental conditions. A very high sensitivity level would be selected for computer rooms, for example, while a lower sensitivity setting would be used for areas with high levels of contamination. The ability to tune the sensitivity of a fire detector to local environmental conditions can dramatically reduce false alarm incidents.
Future-proofing a multi-use building
There is a vast array of legislation and standards that govern the protection of buildings and their occupants. The consequences of not bringing all these together and ensuring the highest levels of fire detection, safety and evacuation can have tragic results.
Those involved in the fire safety planning process should not be afraid to draw upon the knowledge and expertise of reputable fire and alarm manufacturers to help them assess what products are best suited to their planned system. Manufacturers can also recommend how their products can be best implemented within a strategy and designed to accommodate any potential building developments, thereby future-proofing the property for the inevitable changes that will be made over the years.