Angus has been involved in developing and writing British and International Fire & Safety standards since the mid-1980s. The list of standards that he has participated in is impressive and includes BS5839-1, BS8629, EN54-18 and ISO7240-2. Angus utilises his extensive experience to provide an authoritative perspective on the key issues that affect the Fire & Security Industry today.
Critical facilities that require electricity to operate must be engineered such that the power or control features required are able to continue to be available for the required duration.
Techniques that are adopted might include placing the power where the load function is located - such as the case for self-contained emergency lighting, or using fire resistant cables - such as are used in fire detection and fire alarm systems.
In the case of emergency lighting, the design criteria for the system is that the emergency lighting must operate for at least 1 hour after the failure of power - this is considered sufficient for most situations. It is accepted that a single luminaire might fail if exposed to fire conditions. Special applications that require more onerous criteria may require special engineering.
In the case of fire detection and fire alarm systems, the requirements are different for detection and alarm. The requirement for detection is that the system should continue to operate without degradation to the point where fire is detected, whereas for alarm, the alarm devices must continue to operate for at least 30 minutes after fire is detected. In the case of domestic residential alarms 15 minutes is considered sufficient, because once the alarm is raised, members of a household will likely take responsibility for themselves and their families. People in public buildings may act differently, so the alarm signal must continue until everyone has moved to a safe location.
In the case of Evacuation Alert systems, the operational requirements are quite different to those of fire alarm systems, although the technology used is similar.
Evacuation Alert systems are provided for the use of the Fire and Rescue Service, FRS, in high rise blocks of flats. Under normal fire situations, the building is designed to support a ‘stay-put’ policy. That is, it is considered that the residents will be less at risk if they stay in their flats, while the FRS seek to deal with the fire.
However, if the fire cannot be contained and extinguished, the FRS can use the Evacuation Alert system to initiate an evacuation of part or all of the block of flats.
By definition, the decision to deploy the Evacuation Alert system may be taken some considerable time after the fire is first detected.
This paper considers the engineering required for Evacuation Alert systems in high-rise buildings.
Cable Types
Two types of cables are used in the fire detection and fire alarm industry. These cables are specified in BS 5839-1.
Standard grade fire resistant cables, tested in accordance with BS EN 50200 with a survival time of 30 minutes, corresponding to class PH 30. These cables are used in most fire detection and fire alarm systems and are considered to be suitable for being able to support the operation of the fire detection system to the point where fire is detected. They are also considered likely to be able to survive in moderate fire conditions to support alarm functions. The cables are tested at 830oC.
Examples of standard grade fire cables is Prysmian FP200 gold or Draka Firetuf.
Enhanced fire resistance cables are tested to meet BS EN 50200 with a survival time of 120 minutes and a test temperature of 940oC, corresponding to class PH120. They are also tested for 120 minutes to BS 8483-2. These cables are required to be used when the cables must withstand fire for a prolonged period, which is anticipated in buildings over 30 metres high, or where there is delayed or multiphase alarm operation.
Enhanced fire resistance cables are specified for Evacuation Alert systems, because it is anticipated that the building might be on fire for a considerable time before the system is deployed and at that point it is essential that the system operates as intended.
(Note: Standard grade fire resistant cable can be used for the mains supply to the Evacuation Alert system.)
The Enhanced fire cable performance tests were originally designed around MICC cable, but other soft skinned cables are now available that meet the enhanced performance criteria, such as Prysmian FP Plus.
Other applications for fire safety, such as fireman’s lifts etc. specify cables complying with BS 8519. Some cables might be compliant with both BS 5839-1 and BS 8519 standards.
Many fire resistant cables are also low smoke and fume, LSF. That is, the cables do not emit noxious fumes when burning. However, it is not true to assume that LSF cables are also fire resistant. The assessment tests for LSF and fire resistance are completely different.
System topology
When Evacuation Alert systems were originally conceived it was assumed that access to service system components inside flats might be problematic. Therefore, BS 8629, requires that the system can be tested without having to access flats and it was intended that manufacturers ensured that replaceable components, such as batteries, were not located inside flats.
However, after publication of the first draft of the standard, it became evident that many were interested in retroffiting Evacuation Alert systems to existing blocks of flats. This was never seriously considered for the first draft. As a result there is interest in using radio technologies to avoid the cabling costs associated with retrofitting wired systems. Radio evacuate devices will require the use of batteries and so battery replacement must be carefully considered when considering a radio system.
It was assumed that at least one flat in the block might be completely destroyed by fire, before the Evacuation System is deployed. The standard therefore requires that isolators are used so as to ensure that any number of open or short circuit faults in a flat does not disable any of the Evacuation Alert system outside the flat. This is extended to include any number of flats. Where the fire is spreading in common areas, or where multiple flats are involved in the fire, the system is to be designed such that the effect of faults in cables is limited. Isolators and loop circuits and multiple circuits are all utilised to ensure the best system reliability and that the requirements of the standard is met.
A single fault in a common area circuit should not disable more than one evacuate zone. An evacuate zone would be normally one floor, but a floor might be subdivided into multiple evacuate zones on complex or very large buildings.
In the event of two faults in an evacuate circuit in common areas, the area of disablement should be limited to a maximum of three floors. This would normally be achieved by multiple loops, with each loop feeding up to three floors.
Cables for these circuits should be single circuits. Multi-core cables, where several evacuate circuits are contained in a single sheath, are precluded from the standard.
It was assumed that a single control and indicating equipment, EACIE, would be used and sited where required by the FRS. However, on very large systems it might be advantageous to network multiple EACIE, such that the power supplies for the system are distributed around the building. This will often assist in reducing cable length, volt drop and may make the system more fault tolerant. Care should be taken with respect to the interconnections between EACIEs to ensure that a fire might not disable large parts of the system. Interconnections between EACIE cabinets should be in the form of a fault tolerant loop, and the go and return paths of the loop should be routed through different fire compartments. If this is not possible then the go and return cables should be separated as much as possible. A minimum separation distance of 300mm is recommended.
Got a question about Evacuation Systems? Need help installing a Fire Alarm or Emergency Evacuation System? Get in touch today!
For over 45 years, Fixfire® has been providing quality products, systems and services for Life & Property Protection. Whatever your requirement, please call our Compliance Team for expert advice and a refreshingly different approach.
Freephone 08000 891999
Following the recommendations of BS5839 Part 1 2017 (Fire Alarm British Standard), it is a mandatory requirement to have an up to date, clear and accurate Fire Alarm Zone Chart adjacent to your Fire Alarm Control Panel and any repeater panels you have in your premises.
The purpose of the Zone Chart is to assist persons responding to an alarm to quickly identify the specific location in the building and to help the Fire Brigade understand the building layout before they enter.
When the Fire Alarm System is installed, the building is divided into Fire Zones. Any Manual Call Point (Red Box) or Fire Detector that is fitted will trigger a particular zone when activated.
The Zone Chart shows the division of each zone area with a ‘You are Here’ arrow to identify the position of the Fire Alarm Panel. The view of the building should be orientated in relation to the Fire Alarm Panel position to minimise confusion.
What is involved in producing a Zone Chart?
- Hard copy
- Or preferably AutoCAD (dwg) format
You have a legal duty of care to dispose of waste legitimately and safely via a licensed waste carrier. Failure to do so can result in prosecution, even if you have outsourced the disposal to a third party.
The Fixfire® Extinguisher Recycling Process is your reassurance that any Fire Extinguishers we remove from your premises have been disposed of in a safe and legal manner. 97% of each processed Fire Extinguisher is recycled.
Our contracted Extinguisher Recycling Unit (ERU) is a dedicated facility offering a service for the safe processing and recycling/disposal of fire extinguishers. The facility operates closely with the local Water Authority and the Environment Agency to develop safe, efficient and environmentally friendly processes, ensuring that ISO14001 certification is upheld.
Got a question about Fire Extinguisher Disposal? Need Fire Safety Compliance advice? Get in touch today!
For over 45 years, Fixfire® has been providing quality products, systems and services for Life & Property Protection. Whatever your requirement, please call our Compliance Team for expert advice and a refreshingly different approach.
Freephone 08000 891999
False Fire Alarms remain a huge concern within the education sector- interrupting already carefully scheduled, planned and well-prepared lessons or even causing major disruption and distress to exams.
Clearly, these false alarms cause significant inconvenience and disruption to students, staff, and visitors. They compromise everyone’s safety in the school and present a significant risk to the local community since the Fire Brigade will prioritise the school over other emergency callouts.
Solutions you should consider:
The first and most straightforward way is to use anti-tamper products.
Fixfire® supplies a wide range of solutions designed to protect Fire Alarm Devices from inadvertent damage or deliberate misuse/vandalism.
Products include:
- Local plastic cover flaps which attach directly to manual call points.
- The stopper consists of a clear, tamperproof, tough polycarbonate cover, frame and spacer that retrofits over a break glass call point. When lifted to operate the break glass unit, its optional battery powered integral sounder emits a piercing 96dB (at 1m). Immediate attention is drawn to the area and a prankster will either run or be caught!
- A range of steel web stoppers designed to protect fire detectors and warning devices. They are constructed from heavy-duty galvanised steel rod which is plastic-coated for durability and external use.
- A range of polycarbonate enclosures are available for the protection of devices such as fire alarm control panels and associated control equipment. The enclosures combine tough rugged construction with stylish design and offer excellent protection with a key lock for authorised access.
We also provide anti-tamper devices for fire extinguishers and associated products.
KeyCall® is a patented anti-ligature Fire Alarm and Access Control call point. It is designed to use the same key as the doors, providing simple operation for staff whilst eliminating nuisance activations by service-users.
KeyCall® has been developed by Fixfire® specifically for approved applications where standard versions would be vulnerable to abuse.
It is one of the best solutions for SEN schools and it is also compatible with a wide range of Conventional and Addressable Fire Alarm Systems.
Got a question about False Fire Alarms? Need Fire Safety Compliance advice? Get in touch today!
For over 45 years, Fixfire® has been providing quality products, systems and services for Life & Property Protection. Whatever your requirement, please call our Compliance Team for expert advice and a refreshingly different approach.
Freephone 08000 891999
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