Tall buildings
Quantum leap The key challenges, current trends and technologies required for achieving end-to-end fire security in mixed-use high-rise buildings are outlined by Stefan Haug.
M Stefan Haug is regional marketing manager EMEA for Bosch Building Technologies.
Top right: the Plac Unii building in Warsaw, Poland contains a shopping centre as well as offices, bars, restaurants and a car park. (Shutterstock)
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odular IP-based fire systems are the only answer for establishing fire safety in modern multi-purpose buildings that require adaptability for change of use. While stricter legislation regulating sprinklers, building materials, and fire alarm systems has greatly improved overall safety standards in high-rise buildings, incidents still occur. According to a recent report from the National Fire Protection Association, an average of 40 people are killed and 520 are injured every year in high-rise building fires, mostly apartment buildings, in the US. The report also notes that thanks to stricter security, only 4% of high-rise fires spread from room to room, and only 2% to another floor. In low-rise buildings, these numbers are twice as high. Compared to low-rises, achieving end-to-end fire security in high-rise buildings poses a unique set of challenges. The most significant is the risk to human lives, as 73% of all high-rise building fires occur in building types that contain large numbers of people: hotels, apartments, or multi-family housing, dormitories, facilities that care for the sick, and office buildings. In addition, as the level of technology and automation in buildings increases, so does the potential for cable fires and other electrical fires. As a result, security systems need to be able to detect and localise the source of a fire as fast as possible, while facilitating a coordinated evacuation approach to lead people on all floors to safety. With these requirements in mind, IP-based fire alarm systems are emerging as the way forward. Networked on digital infrastructure, addressable systems of panels and detectors provide fire detection at an early stage, plus exact localisation of the fire source. They integrate with other key systems such as sprinklers, video surveillance and access control and can be combined with voice evacuation to direct people out of dangerous areas as quickly and precisely as possible. Most of all, IP-based fire alarm systems are easily scalable and adjustable to changing customer demands, for instance in mixed-use buildings. On the subject of scale, high-rise buildings require alarm systems that can bridge long distances vertically – not horizontally like a campus or factory building. From the standpoint of an IP-based system, however, there is no significant difference between vertical and horizontal distances, since these systems have been built for the very purpose of connecting panels, sensors, and controls over extended areas. Panels in modern IP fire systems such as the modular fire alarm panel 5000 Series by manufacturer Bosch can be placed 40km apart and allow for management in separate zones, also across tall buildings. A typical network can encompass 20 panels with up to 32,000 detection points. In day-to-day operations, IP-networked fire alarm systems provide integrated solutions for the five main challenges facing fire security in modern high-rise buildings: evacuation,
false alarm management, resilience, interfacing, and futureproofing and scalability. Today’s high-rise buildings can contain over 100 floors and hold several thousand occupants at the same time. This calls for a carefully organised approach to evacuation to avoid panic and prioritise evacuation of people near immediate danger zones. In this context, IP enablement is not simply a technical evolution, but a quantum leap in human safety. Fully integrated alarm and voice evacuation systems operate in unison and allow dynamic, multi-stage evacuations in the event of emergency. Providing security personnel with a direct view of the location of a fire or danger source, IP-based systems ensure that safety responses are targeted logically, enabling those immediately affected to escape the building first. Next, those on adjacent floors above and below evacuate, and finally those at the top and bottom floors of the building. The management of false alarms is a key concern for safety. Security experts agree that more than three false alarm per year may undermine the credibility of a hotel’s fire system and make guests perceive alarm evacuations as less serious. Experts estimate that around 20% of today’s false alarms have an undetermined cause. Consensus exists that analogue systems are prone to false alarms from electromagnetic radiation. In that light, IP-based systems have proven highly resilient against false alarms due to their capacity for using multi-point verification of an actual fire. In the event of an actual fire, the fire alarm system needs to be able to accommodate for loss of panels and cable infrastructure. A breakdown of cables also causes erroneous signals from devices on the network that need to be filtered out. A distributed system, ideally IP-based, can test its own integrity and offer built-in redundancy to deal with emergency situations. The fire system in a high-rise building also needs to interface with systems such as video surveillance, access control, and voice address for evacuation. Studies have demonstrated that voice alarm with clear instructions significantly improves fire evacuation time compared to mere noise alarms and presents a significant time gain of up to 30% for emergency response teams. At Bosch we have developed our Smart Safety Link to further improve safety by creating a
< INDUSTRIAL FIRE JOURNAL < third quarter 2018 Read our e-magazine at www.hemmingfire.com
