Planning an evacuation in high-rise residential buildings – what you need to know
The publication of the amended Part B of the Building Regulations in June 2022 brought significant changes to fire safety including new mandatory requirements for evacuation planning. Ken Bullock, Business Development Manager for Evacuation Alert Systems at Advanced, explains
Fire safety guidance has been strengthened for high-rise residential buildings. Since the Grenfell fire there have been many years of uncertainty, but we are now starting to see some clarity as an industry following the publication of the amended Approved Document B (Fire Safety) of the Building Regulations on June 1, 2022. A positive step in the right direction to improve fire safety in high-rise residential buildings, the amended Building Regulations aim to assist fire and rescue services in England and meet recommendations from Phase One of the Grenfell Tower Inquiry.
This new fire safety guidance provides clearer fire safety rules for the design or construction of residential developments. Within the document there are three key changes to highlight which involve: evacuation; secure information; and materials.
Arguably, the most significant amendment to Part B when it comes to evacuation is the mandatory requirement for new residential developments over 18m to incorporate an evacuation alert system.
An evacuation alert system is vital to help fire and rescue services (FRS) inform residents of a change in evacuation strategy during an incident. This gives FRS an additional tool to use on the ground, alongside existing methods of evacuation, improving resident safety. To comply with the amended Part B, an evacuation alert system should be provided in accordance with BS 8629: 2019 Code of Practice for the design, installation, commissioning, and maintenance of evacuation alert systems for use by fire and rescue services in England. (The BS 8629 Code of Practice is applicable to any height of building not just those over 18m.)
The system recommended by BS 8629, for which Advanced and other companies have developed a bespoke solution, allows the fire services to control evacuation floor by floor according to the severity and location of the fire. The guidance states that the evacuation alert control system should be installed where a ‘stay put’ policy is in force, so that it can be used to facilitate a timely and ordered evacuation for all residents. (Although the amendments to Part B give new clarity since it is now mandatory to have an evacuation alert system in all new build high-rise buildings over 18m.) It must be standalone, with its only function being to assist FRS in the evacuation of the building.
To ensure total dependability and system integrity, it must also be completely independent of the fire system, as well as from other building management systems and apparatus such as lifts, gas valves, air conditioning and smoke control systems.
The BS 8629 standard also recommends that local FRS should play an active role in the operation, and operational specification of every new system. This helps to guarantee it is fit for purpose, as well as ensuring that personnel are familiar with it in readiness for an emergency situation.
BS 8629 states that the evacuation system must include evacuation alert control and indicating equipment that can be operated by the fire and rescue services, along with audio and/or visual alarm devices in each apartment, providing clear evacuation signals to building occupants. Most importantly, any compliant system must be simple and intuitive so that it can provide straightforward support to fire brigade personnel coordinating the evacuation of a high-rise residential building.
At Advanced our EvacGo Evacuation Alert System is designed as an easy way to meet BS 8629 and so can offer peace of mind to those responsible for a building that by choosing this system they are complying with Building Regulations. Advanced is currently one of a handful of manufacturers to offer an evacuation alert system housed within a box specially designed by Gerda Security to meet stringent antitamper standards.
The integrity of any BS 8629-compliant evacuation system is a key factor in its design and specification since it must be assumed that the fire will already be advanced by the time it comes into action. This means cable infrastructure must be protected, and circuit isolators need to be installed at the entry and exit points to each zone, as well as prior to cable entry into each flat. The precise rules differ according to the height of the structure. In buildings with fewer than ten storeys, two simultaneous faults on a single circuit should not disable the evacuation devices on more than half the number of storeys with flats. In buildings with ten storeys or more, two simultaneous faults on an evacuation circuit should not disable the evacuation devices on more than a third the number of storeys with flats. Any fault on a single flat’s evacuation device should not be permitted to affect any other device elsewhere on the system.
Power supplies for evacuation alert systems also need to comply with BS EN 54-4 requirements. If mains power fails, standby batteries must maintain the system in operation for at least 72 hours and 30 mins with all evacuation alert zones active.
Regular maintenance and testing are also vital and full inspections should be undertaken every six months by a qualified engineer. A yearly test must be completed on each sounder to verify its ability to function autonomously from the rest of the system.
Another significant amendment to Part B, that will strengthen the information available to fire and rescue services, is the requirement that all new residential buildings over 11m have to include a Secure Information Box that will give fire and rescue services access to important details about a building in the event of a fire.
According to Part B amendments, the Secure Information Box is required to be: sized to accommodate all necessary information; easily located and identified by firefighters; secured to resist unauthorised access but readily accessible by firefighters; protected from the weather.
Part B refers readers to best practice guidance on secure information boxes which can be found in Sections 2 to 4 of the Code of Practice for the Provision of Premises Information Boxes in Residential Buildings published by the Fire Industry Association (FIA).
The third significant amendment in Part B relates to materials. Following the Grenfell Fire it is no surprise that most of the headlines regarding Part B of the Building Regulations have revolved around the changes to materials. The amended Part B includes clearer safety standards for external walls of buildings including a ban on the highest risk metal composite materials panels, those with panels with unmodified polyethylene core, known as MCM PE, for all new buildings of any height. This follows research carried out by the government and evidence heard at the Grenfell Tower Inquiry on the serious fire safety risks associated with this material.
The government previously announced a ban on the use of combustible materials in and on the external walls of new blocks of flats over 18m in England – as well as hospitals, student accommodation and dormitories in boarding schools. The amendments now extend this ban to new hotels, hostels and boarding houses of this height.
At Grenfell unsuitable cladding allowed flames to bridge the gap from apartment to apartment, these changes to materials are therefore designed to make high-rise residential buildings safer by helping ensure that compartmentation is not compromised in this way. As part of an evacuation plan and a fire-risk assessment it is vital to know if a building has a ‘stay put’ policy that passive safety measures have not been compromised and this will help lower the potential risk caused by defective cladding.
The Building Safety Act names HSE as the new Building Safety Regulator in England and as such will enforce compliance of the Building Regulations. The Building Safety Act will place formal responsibilities on those involved in the design and construction of any buildings to ensure compliance with Building Regulations, and will give the regulator greater powers to prosecute for non-compliance. It will be the duty of the people responsible for a building to put in place and maintain a golden thread of information, with their responsibility continuing for the life of the building.
So, what for the future? Although Part B gives new clarity there is still a further raft of fire safety measures that will follow. Amended Part B is designed to meet recommendations from Phase One of the Grenfell Tower Inquiry. Currently, the Part B requirement for an evacuation alert system only covers new build high-rise residential buildings. However, since the Grenfell Tower Inquiry also recommends evacuation alert systems for high-rise residential buildings ‘already in existence’, further regulation may follow.
For further information on Advanced’s EvacGo Evacuation Alert System, to reserve a place on their CPD on evacuation planning and the BS 8629 Code of Practice visit: https://uk.advancedco.com/;
email: EvacGo@advancedco.com; or tel: 0345 894 7000.
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