Route to safety

HERE IN the UK, blocks of flats fall into two broad classes: those that comply with the Building Regulations 1991 or later and those that don’t. Residential buildings – such as conversions – that don’t fully comply with the Building Regulations and where fire might spread from one dwelling to another should have compensating provisions such as communal fire alarms installed.

Residential buildings fully compliant with the Building Regulations will have effective compartmentation. This means that a fire in one flat should not affect anyone except the occupants of that flat. In this case, the normal approach is for no communal fire alarm to be installed, which means that other occupants are not warned of the fire and are expected to ‘Stay Put’ in their dwellings unless they find out about the blaze and choose to leave.

As the Grenfell Tower disaster so tragically highlighted, the problem is there are many blocks of flats that are supposed to comply with the Building Regulations, but which have serious failings, not just due to the installation of combustible cladding, but also problems such as poor fire-stopping.

Out of control

An evacuation alert system (EAS) is used by the Fire and Rescue Service to alert the occupants of high-rise residential buildings that a fire is burning out of control or that they don’t have sufficient resources on scene to deal with it. Such systems differ from normal fire detection and fire alarm systems in a couple of important ways.

First, an EAS is a manually controlled system for use only by the Fire and Rescue Service. It has no fire detection devices or manual Call Points. Instead, it has a secure control panel with simple toggle switches to operate groups of warning devices called ‘evacuation alert devices’. BS 8629 refers to these panels as evacuation alert control and indicating equipment (EACIE).

Second, whereas a fire alarm usually operates early in a fire, an EAS is one of last resort intended for use when a fire is out of control. This means that the controls and interconnections for an EAS need to be more resilient than would be the case for a normal fire alarm.

In most cases, if the Fire and Rescue Service believes that some occupants of a building need to be evacuated, firefighters will simply knock on doors to alert the occupants. However, if widespread evacuation is necessary, alerting occupants manually may put those firefighters above the fire and without water or breathing apparatus at risk, whereas an EAS will be safer, more effective and enable more crew members to fight the fire. The decision to use an EAS will depend on the safety of escape routes.

When the Grenfell Tower Inquiry Phase 1 report emerged, it made a very clear recommendation that there should always be a ‘Plan B’ and that an EAS should be installed not just in new buildings, but also in all existing high-rise residential buildings. This recommendation has not made its way into legislation as yet, but Government highlights strong support for such systems and is working on this with the National Fire Chiefs’ Council. The expectation is that this will be included in a revision of Approved Document B during 2021.

Concentrating on EACIE

Different manufacturers’ EACIE should still have a similar appearance, functionality and operation and be simple and intuitive for the Fire and Rescue Service to operate. These solutions should be sited indoors near the main Fire and Rescue Service entry point and be clearly labelled. The top control switch should be 2.2 metres above the floor, which is intended to discourage casual vandalism, whule the EACIE will not be opened during an incident unless the officer in charge decides to use the system.

Unlike a normal fire alarm, standby power needs to last for 72 hours and 30 minutes in alarm or for 24 hours if an emergency generator is provided.

Alert devices in flats are grouped in one or more zones per floor. There are no alert devices in common areas. Alert sounders should comply with EN 54-3 and use the same 500 Hz to 1 kHz signal throughout the building. Audibility is based on BS 5839-6 – ie 85 dB(A) – at all open bedroom doors and on BS 5839-1 – ie 60 dB(A) – for all other rooms. One sounder installed by the entrance door inside each flat will normally suffice.

BS 8629 doesn’t recommend that every flat should be equipped to alert the hard of hearing or the deaf. However, it does say that it should be possible to add suitable devices (for example more sounders, visual alarm devices, vibrating pillow pads and/or vibrating pagers) when they’re needed. All should comply with BS 5446-3.

The electronics of the EACIE are based on EN 54-2 and EN 54-4, which are the standards for fire alarm control panels and power supplies in BS 5839-1. The external cabinet is intended to withstand casual vandalism and so needs to comply with STS 205 or LPS 1175. It has a high-security lock graded to EN 1303, with access via copy-protected keys. The building safety manager, a role that’s expected to be created by the Building Safety Bill, should ensure the Fire and Rescue Service and the maintenance contractor have the correct keys.

Controls and indicators

The Fire and Rescue Service controls are simple toggle switches for each zone of alert devices. Up is ‘Off’, down is ‘On’. Pushing the switch back up turns the alert devices off again. Next to each toggle switch is a zone ID that should tie up with the floor labelling now included in Approved Document B, a red LED to show that this zone has been selected and a yellow fault LED.

Importantly, in order to prevent the Fire and Rescue Service from carrying out a simultaneous evacuation by accident, no ‘whole building’ or ‘Evacuate All’ control is provided.

There are also indicators for power present, power fault and general fault, plus a button to silence the fault warning sounder. Maintenance controls and indicators must neither be visible, nor available to the Fire and Rescue Service. Any faults need to be attended to quickly, so it’s recommended that the fault output is monitored by an Alarm Receiving Centre (ARC) or similar.

The scope of BS 8629 excludes systems with pre-recorded or live speech messages or two-way speech communication. This could be due to concerns that speech messages may not be understood by all residents. However, voice alarms and voice sounders play a repeating alert tone and message so should be at least as effective as simple sounders for non-English speakers.

An EAS may be hard-wired or wireless. Installation is based on BS 5839-1, except that an EAS is, as stated, intended only for when a fire is spreading out of control, whereas fire alarm systems normally operate as soon as fire is detected, which means that all cables should be enhanced fire-rated (including those installations in flats).

Communal wiring comprises one or more loops with one loop used for up to four floors (including the ground floor), two loops for up to ten floors and three loops for eleven or more floors. Current limitations mean there’s a limit as to how many alert devices can be powered from a loop so in practice more loops may be fitted.

All circuits must be monitored for open and short circuit faults up to the last alert device in each flat. Communal wiring must not loop in and out of flats even if there’s only one evacuation sounder. This is because a fire spreading to the flat above could isolate all the flats in-between. Wiring must be spurred off the loop via short-circuit isolators.

Interfaces may also be grouped together on each floor, which reduces the number of interconnections and avoids the need for interfaces outside each flat. This may also allow for additional power supplies to operate alert devices for the hard of hearing.

Wireless systems

Wireless types of EAS need a comprehensive survey and components should comply with EN 54-25. Most wireless alert devices have a claimed primary battery life of three-to-five years with a secondary battery to keep them working when the main battery dies. Therefore, it will be necessary to gain access to each flat to change batteries before they fail. That can often prove difficult as occupants are often at work when service visits take place.

The installation and commissioning organisation should be able to demonstrate its competence. BAFE’s SP207 Scheme will give confidence that the work has been undertaken by a competent organisation.

Commissioning includes checking that the zone labels are correct, tie up with floor signs and are clearly legible, checking that toggle switches and indicators work correctly and measuring sound levels in each flat.

The EAS should be inspected, tested and serviced by a competent individual every six months. This includes testing the Fire and Rescue Service toggle switches, which means that the keys need to be made available at each visit. Alert sounders should be tested every 12 months, flat-by-flat, for no more than ten seconds by listening at the door, although alert devices with a self-test facility can be checked by one person, which saves much time and money. It will be necessary to enter each flat to check the operation of visual and tactile alert devices. If maintenance isn’t carried out, the system’s compliance certificate will not be renewed, subsequently leaving the ‘Responsible Person’ at risk of prosecution.

User responsibilities

A single, named member of the premises’ management team should supervise all aspects of the EACIE and ensure that the Fire and Rescue Service is aware of and familiar with it, that monthly visual inspection and professional inspection and maintenance is taking place and that the system log (be it paper-based or electronic) is up-to-date and available. There are no requirements for the building safety manager to open the EACIE and test the alert devices.

They should also make sure that all residents clearly understand what to do if the alert devices operate in their flat and that material changes to any flat don’t in any way compromise the operation of the alert devices.

There’s no technical reason not to integrate systems. Consider, for example, integrating the EACE with fire alarms in flats. If BS 5839-6 Grade D or Grade C fire alarm signals were connected via I/O units to the communal loop, nothing would show or sound on the EACIE so there would be no confusion, but the signals could be sent on to an ARC.

Under normal circumstances, the ARC operators would be instructed to log the events, which will mostly be false alarms, and take no other action. If the residential systems were engineered to reduce false alarms, that would be even better. However, if the Fire and Rescue Service was called out to a fire, firefighters could ask ARC operators to state which alarms are operating, thus providing very useful information about fire spread during an emergency.

It’s likely that guidance will continue to rule out the installation of communal fire alarm systems in purpose-built blocks of flats. This means that, if nothing else is done, the Fire and Rescue Service will have no way of warning people to evacuate if the worst should happen. Installing an EAS solves this problem, and also allows the ‘Responsible Person’ to demonstrate to the building safety regulator that they’ve taken all reasonable precautions to keep people safe.

Andy Scott is Founder and Director of C-TEC and SigNET (www.c-tec.com)