BS5839 Part 1:2002
Overview
Contents Introduction
So why is the current standard being revised?
The brief for the new standard
Changes to structure of current Standard Enhanced certification of Fire Alarm Systems The revised Standard gives structure for Variations and arbitrary figures
Levels of detection
Explanation of categories System fault monitoring Definition of zones
Audibility levels for category M and L systems Installation of sounders
Visual alarms
Fire alarm warning devices for people with impaired hearing Installation of manual call points
Selection of detectors
Protection of stairwells and riser/lift shafts that penetrate one or more ceilings Protection of voids
General spacing of detectors Installation of fire alarm systems Networked systems cable
Fire alarm cable recommendations Installation of cable
Limitation of false alarms Commissioning and handover System testing and maintenance
Introduction
BS5839-1: 1988 will be withdrawn by 15th July 2003. Systems designed to the old standard can be completed to the old standard by mutual agreement with all relevant parties (consultant, end user, insurance company etc.).
The following provides a flavour of some the changes, to understand in full Clymac can arrange for a presentation for you and your colleagues at your premises.
So why is the current standard being revised?
Existing standard 14 years old
Out of date with new technology/standards
Out of touch with common practice
Recommendations needed explanation
Not sufficiently flexible
Not reflective of how contracts operate
No account of risk assessment
Not suitable for certification or audit The brief for the new standard was to:
Reflect new technology/standards (CO detectors, video detector, EN54-2 etc.)
Guidance on reducing false alarms
Commissioning/Maintenance guidance
Review existing Clause 17 (Wiring)
Make more user friendly
Simplify existing code
Remove unnecessary text
Give clear statement of recommendation
Changes to structure of current Standard Current Code
1 = General
2 = Design considerations
3 = Workmanship, installation and commissioning 4 = User responsibilities
New Code 1 = General
2 = Design considerations 3 = Limitation of false alarms 4 = Installation
5 = Commissioning/Handover 6 = Maintenance
7 = User responsibilities
Enhanced certification of Fire Alarm Systems Current Code
1 = Installation & Commissioning
2 = Testing (which includes the following) Modifications
Routine inspection/test Non-routine attention New Code
1 = Design 2 = Installation 3 = Commissioning
4 = Acceptance (End User) 5 = Verification (optional) 6 = Servicing
Routine inspection/test Non-routine attention 7 = Modification
The revised Standard gives structure for:-
Relating to contract (who is responsible for what)
Reflecting Common Practice (installation vs commission)
Auditing the entire process (optional verification certificate) Variations and arbitrary figures
‘Deviation’ replaced by ‘Variation’
Variations listed on relevant certificate for agreement/action
Certain parts of the standard are expressed numerically but the values quoted are often arbitrary. Examples of these are:
1. Maximum zones size
2. Maximum area of protection disabled in the event of specified fault condition
3. Maximum travel distance to a MCP
4. Maximum area of coverage by a single automatic fire detector 5. Minimum sound pressure level
6. Minimum duration of standby power supply Levels of detection
The new standard uses “category” to define the level of detection instead of
“type” previously used in the old standard. “Type” will now be used to describe the principle of operation (e.g. conventional “type” system).
Current Code Types Manual = M
Property protection = P1 & P2 Life safety = L1, L2 & L3 New Code Categories Manual = M
Property protection = P1 & P2 (M) Life safety = L1, L2, L3, L4 & L5 (M)
Explanation of categories Category L5 (new) - (Bespoke)
Objective identified by risk assessment
Coverage may be higher or lower Than L2, L3 or L4 Category L4 (new) - (Escape Routes Only)
All escape stairways
All corridors
Any other areas forming part of the common escape route
Open plan office areas excluded - escape route dependent Category L3
Escape routes as L4
Rooms opening onto escape route - except rooms off corridors less than 4m long
Open plan office close to doorway leading to escape stairway or corridor greater than 4m
Category L2
Escape routes as L3
Rooms of high fire risk determined by risk assessment Category L1/P1
All rooms and areas except:
Toilets, showers and bathrooms (subject to RA)
Stairway and toilet lobbies
Small cupboards - (typically less than 1m2) Category P2
Clearly defined areas with physical barriers (areas to be defined by risk assessment)
Barriers need not have fire resistance Category P
Systems require automatic link unless premises continuously occupied
Detection required in room with ARC transmission equipment
All ARC communication cables to be fire resistant
Monitored cable between fire alarm panel & communicator
System fault monitoring Fault monitoring
Satisfied by use of BSEN54-2 & 4 control equipment System integrity
Single fault loses no more than 2000sqm or 1 floor and 5 devices on adjacent floors
Single open/short circuit fault to allow sounder near control panel to operate
2 sounder circuits required in large public areas
Circuits for remote PSU to be duplicated Definition of zones
Call points on landings of enclosed stairways to be part of zone for adjacent area
Single zone can extend from 2,000sqm to 10,000sqm if (was only 2000sqm):
1. It contains call points only 2. It is a single open plan area
Maximum zone search distance - 60 metres (was 30m)
Audibility levels for category M and L systems
Generally 65dB or 5dB above background noise level that last for more than 30 seconds. Running water is not included in this.
Levels can be reduced to 60dB in the following areas:
1. Stairways
2. Enclosures less than 60sqm 3. Points of limited extent
Installation of sounders
It is possible to comply with this standard by installing the sounders by the following two methods (although other arrangements are not precluded)
Wiring all alarms sounders within the building on a single sounder circuit, with a second circuit containing a single sounder in the vicinity of the control panel Wiring all the alarm sounders on a ring circuit capable of transmitting signal in either direction
In unoccupied premises any external sounders should silence automatically after 30 minutes. Radio sounders should silence automatically after 30 minutes.
Visual alarms
Used to supplement alarm sounders
Required when ambient noise levels exceed 90db.
2.1m mounting height
No closer than 150mm to ceiling
Fire alarm warning devices for people with impaired hearing Can Be:
1. Flashing beacon 2. Vibrating pad 3. Radio pager
Interconnecting cables and radio transmissions to be monitored for failure Installation of manual call points
3 second response
Located at all storey exits and final exits
45m travel distance measured along route that person would actually follow. If the final layout of the building is unknown the maximum straight- line distance should be 30 metres. These distances should be reduced to 25 and 16 respectively in the following circumstances:
1. Where a significant proportion of the occupants have a limited mobility and generally be the first person to operate the fire alarm system
2. Where the process in the area result in the likelihood of rapid fire development (e.g. highly flammable liquids or gases)
1.4m mounting height (note +/- 200mm)
Storey exit MCP part of the level’s zone (i.e. not the stairwell zone)
Sited in rooms of high fire hazard (e.g kitchens)
Use of hinged cover call point to be recorded as a variation
Selection of detectors
Heat detectors may be used in any area, other than the following:
1. Category P system where a small fire would cause unacceptable damage 2. Escape routes in category L systems (heat ok in rooms off)
3. Where smoke could present a threat to occupants before detected by people or heat detection
4. Areas in which heat detectors may false alarm
Smoke detectors may be used in any area, other than the following:
1. Where the fire hazard is presence of flammable liquids or gases that produce little smoke
2. Areas in which smoke detectors may false alarm
Protection of stairwells and riser/lift shafts that penetrate one or more ceilings
In enclosed stairways fire detectors should be sited at the top of the stairway and on each main landing.
With the exception of category L4, L5 and P2 systems fire detectors should be mounted within 1.5m of the penetration.
Protection of voids
Voids over 800mm to be protected if there is automatic detection in area below. Detection can excluded as variation if void is deemed to be low risk (subject to a Risk Assessment)
Voids less than 800mm generally do not require automatic detection unless:
1. Extensive spread of smoke or fire, particularly between rooms and compartments can take place before detection.
2. A Risk Assessment indicates that the fire risk is great enough to warrant additional detection.
General spacing of detectors
The horizontal distance between any point in a protected area and the detector nearest to that point should not exceed 7.5m for smoke detector and 5.3m for heat detector. Section 22.3 Note 2 details that if there is a facility for disabling the smoke element within a multi-sensor leaving only the heat element then the detectors should be spaced as a heat detector.
The standard now gives guidance of the spacing and siting of detectors on a horizontal ceiling comprising a series of small cells.
The standard now give guidance on spacing and siting of detectors on ceilings with cells formed by joists
A change to the standard on corridor detector spacing has been included in the new standard
Installation of fire alarm systems
The installation element only amounts to 2% of total standard. This is to reflect installer’s basic responsibility to install system to designer’s requirements and to follow good installation practice
Networked systems cable
‘Standard’ fire resisting cable (soft skin) may be used if:
1. The network is configured as a loop
&
2. Diverse routing of incoming & outgoing circuits
&
3. Short & open circuit protected
Otherwise ‘enhanced’ fire resisting cable (MICC) must be used Fire alarm cable recommendations
Enhanced fire resisting cables should generally be used if:
1. The building is unsprinklered with evacuation in 4 or more phases 2. The building is unsprinklered and is greater than 30 metres in height 3. The building is unsprinklered and the occupants will remain in the building
during the course of fire e.g. sheltered accommodation/hospitals 4. If it is decided as result of risk assessment
Installation of cable
Methods of cable support should withstand a similar temperature and duration to that of the cable. In effect this recommendation precludes the use of plastic clips, cable ties or trunking where these products are the sole means for support.
Other than in the case of joints within system components terminals used to joint cables should be constructed of materials that will withstand a similar temperature and duration to that of the cable
The standard recommends that all fire alarm cables should be coloured red
Limitation of false alarms
Design guidance to minimise false alarms. Systems above 50 detectors to be soak tested
False alarm categories include:
1. Unwanted alarms 2. Equipment false alarms 3. Malicious alarms
4. Good intent alarms
False alarm rates should be monitored and should trigger an investigation if they exceed recommended limits
Commissioning and handover
The commissioning engineer is responsible for getting the system to work.
It is generally not the responsibility of the commissioning engineer to verify compliance of design or installation.
The commissioning engineer should posses basic knowledge of sections 2,3 & 4 in order to comment on design.
Any variations to the standards should be documented & referred to designer for agreement or action.
System testing and maintenance Weekly test by user
MCP on rotational basis
50 MCP’s = 50 weeks. Previously 13 week cycle by zone Periodic Inspection
Frequency based on risk assessment
Typically between 3 and 6 months
Check panel and visually inspect building
Check false alarm log and action accordingly
