Desi sign gn Pri rinc ncip iple les s of Fir ire e Dete tect ctio ion n An A nd All ar A arm m Sy Sys s t em ems s for Buildings
COURSE TARGET •
Dates of changes
•
Life an and Pr Property Ca Categories
•
Design process
•
Manual call points
•
Detectors area of coverage
•
Sounders an and no noise le levels
•
Zone size
•
Tec Te chn hno olo log gy of system com omp ponen entts
•
Cable requirements
•
Standby supply
•
False alarm management
•
The Th e rol role e of of th the Re Resp spo onsi sib ble Person.
Some standards updates…
• BS5839 – pt1 1988 • WAS WITH THD DRAWN ON 15 JULY 2003 • FROM 15/7/2003. • ALL ALL SER SERVI VICI CING NG,, DES DESIG IGNS NS AN AND D INS INSTA TALL LLAT ATIO IONS NS WILL BE TO THE NEW BS 5839-pt1,-8,:2002
Why has the standard been updated? •
The cur The curre rent nt ed edit itio ion n of of BS BS 583 5839 9 par partt 1 was was wr writ itte ten n in in 198 1988. 8. Si Sinc nce e th then en there have been: – Changes in technology – Changes in custom and practise
•
The new The new sta stand ndar ard d take takes s the the abo above ve int into o acco accoun untt as we wellll as recommendations found in the European standard BS EN 54, 1-14.
Categories of Life and Property Systems •
M - Manual call points
•
L5 - (could follow a risk assessment).
•
L4 - Principle escape routes
•
L3 - Escape routes and areas leading onto escape routes
•
L2 - Defined areas (Hazards / areas of high risk)
•
L1 – All areas
•
P1 - System installed in all areas of the building few sounders
•
P1M - As P1 but with sounders throughout
•
P2 - System installed in defined parts of the building few sounders.
•
P2M - As P2 but with sounders throughout.
Consultation •
Consult the fire authorities – Special risks, uncertainties – E.g. connection to remote manned centre, delays etc
•
Input from interested parties: – Building control officers – Insurers / owners
Property
– Consultant / architect
and or l ife
– Occupiers
protection
– Service contractor
BS5839 PT 1 2002 Fire Alarm Design • • • • • • • • • • • • • • • •
The process of designing a system is to define the following – Detection zones Communication with the fire brigade Audible / Visual alarm signals DDA Staged alarms Manual call point locations Types of detectors Location of detection and area of coverage Considerations to design out False Alarms Control and indicating equipment Network systems Power supplies Interfacing to plant – lift shutdown, Air Con, etc Electrical safety User responsibility and customer training.
MANUAL CALL POINTS •
Breaking frangible element operates switch
•
Located so clearly visible, on the way out
•
All the call points must be similar – do not mix hammer and thumb push types
•
Use plastic element (not glass) in food prep areas
•
If necessary, use drip proof, waterproof or hazardous area types
•
Some shops do not have public call points
Call points
(sec 20.2c)
•
MCPs should be sited at all exits to the open air regardless of it being a designated Fire Exit or not.
•
1 - 4 story high, accommodation blocks, MCPs sited on landing or stairs adjacent to landing.
•
In buildings with multi-stories / and or phased evacuations, MCP’s should not be sited on stairways, therefore site MCP's on landing to stairs only.
SITING manual call points Escape route 1st floor Landing
Ground floor
Stairwell Final exit to open air
Choosing the point Detector •
Heat: Few false alarms. Less sensitive than smoke detectors and not for use on escape routes. Ideal for kitchens and boiler houses. The rate of rise is the most sensitive.
•
Smoke, Ionisation: sensitive to initial stages of fire. (ionisation devices being phased out)
•
Smoke, Optical: sensitive to larger particles from smouldering fires. Immune to wind speed.
•
Combined optical and heat: can be as sensitive to initial fires as the ionisation detector.
Choosing the point detector •
Kitchens – fixed temperature is best RoR may be too sensitive
•
Loading bays – lorry fumes may cause alarms overhead heaters may cause alarms in cold weather, RoR should be used
•
Smoking rooms RoR should be used
•
Kitchens – keep smoke detectors approx 7.5 mtr away from door.
•
Keep ionisation detectors away from high air flow fans = faults occur
•
Optical smoke is best for most locations escape routes, open office areas etc,
•
Flame detectors are good for generator / gas installations etc
•
But beware of welding and friendly flames will cause false alarms.
COVERAGE for point detectors •
Spacings specified in BS 5839 part 1
•
For detectors mounted on flat horizontal ceilings limits are based on:
•
–
100sq m for smoke detectors
–
50sq m for heat detectors
Any point in a room to a detector should be less than: – 7.5m for smoke detectors – 5.3m for heat detectors
SMOKE DETECTOR: spacing OPEN AREA
7.5m
5.3m
10.6m
area 10.6 x 10.6 = 112sq m (approx. 100sq m)
HEAT DETECTOR: spacing OPEN AREA
5.3m
3.8m
7.5m
area 7.5 x 7.5 = 56.3sq m (approx. 50sq m)
Heat detection is not allowed in cor ridors If t hey are used as escape routes, this is
SMOKE DETECTOR:
spacing in narrow escape routes
CORRIDOR 2m WIDE
9m 2m in room smoke detection on ceiling or above door L3 ONLY
17.9m Note: detectors should be on the centre in this calculation
Sec.13.5.3.
DETECTORS: distance from ceiling spreading •
Smoke detectors: – 25mm min, 600mm max
•
Heat detectors:
14 deg
– 25mm min, 150mm max
Ceiling / slab min Lintel / girder detector
max
DETECTORS: near isolated obstructions
• Detectors not less than 2 x depth of isolated obstruction ceiling
• Example: luminaire • CCTV, Projector, • Emergency light.
P
2XP
luminaire
Sound Levels
Sec 16.1-2
•
Generally sound pressure levels should be no less then 65 dB.
•
However at specific points of limited extent within any area, sound pressure levels of 60 dB are acceptable.
•
Examples of such areas include: – Staircases, small enclosed spaces, cellular offices. – Enclosure that are no more than approximately 60m² in area.
Sound loss over distance
100dB
94dB
88dB
82dB
1mtr
2mtr
4mtr
8mtr
Note – 1. As you double the distance you loose 6 dB. 2. Sound levels differ in HTM 82 STANDARDS
ALARMS: sound levels. Sleeping risk
125dB(A)
95dB(A) 85dB(A)
8 MT 75dB(A)
30dB(A) = LOSS THROUGH FIRE DOOR 20dB(A) = LOSS THROUGH NORMAL DOOR
Z3
ZONE AREAS Z2
• 2000sq m per zone - maximum area
Z1
• Generally, one zone limited to one storey
• For small buildings less than 300sq m – can be all one zone irrespective of storeys
Total floor area 300sq m all one zone
TECHNOLOGY : standard - non addressable
z1 Z1 Conventional panel (P)
z2 Z2
Z3 z3
TECHNOLOGY: Analogue addressable panel
1
Addressable panel
2
7 18
8 17
4
3
6 I/F
10 11
9 16
5
15
14
I/F 19
Exact location of f ire, with options t o alter the parameters of the detection sensitivit y, time delays. This system is more often specified for
12 I/F 13
SITING the fire alarm panel • Availability to staff • Away from unauthorised access/tampering • Availability to the fire brigade • Near to adequate lighting • In area of low fire risk • In a relatively quiet area.
Cabling
‘STANDARD’ fire resistant cable should be used in buildings that require single phased evacuation (soft skin i.e.: FP200, Fire tuff.) ‘ENHANCED’ fire resistant cable should be used in buildings requiring phased evacuation e.g. high rise buildings i.e.: (MICC).
• • • •
Fix using metal clips or metal trays and trunking Mechanical protection MICC or armoured self-protected Protect other cables if vulnerable, below 2m height. All cables linking manual call points detectors and ins power to the control p
l should be fire resistant cable
STANDBY BATTERIES
Category M and L • Standby period 24 hour +30 mins alarm load.
Category P • Standby period 24 hour longer than the time the building is unoccupied or a max of 72 hours which ever is the less.
False Alarm Management and USER RESPONSIBILITIES BS5839 pt1, 2002 sec3&7.
CATEGORIES OF FALSE ALARM
• Four False alarm categories: •
1. Equipment false alarms – Faults in equipment
•
2. Unwanted alarms (equipment works perfectly) – Fire-like phenomena, e.g. smoking, burning toast, hot work, building work
•
3. Malicious false alarms
•
4. False alarms with good intent.
ACCEPTABLE RATE OF FALSE ALARMS
• • • • • •
Any false alarm is undesirable BS5839 Pt1 1988 rate now unacceptable Complete elimination impossible RP to monitor periodically & action to reduce Many factors may give rise to false alarm Proportional to qty devices fitted, higher if mainly smoke detectors. Filtering may reduce • Manual & Heat detectors – few false alarms • Possible future action by fire authority
CAUSES OF FALSE ALARMS •
fumes
•
incense
•
steam
•
candles
•
tobacco smoke;
•
electromagnetic interference
•
dust
•
high humidity
•
insects
•
aerosol spray
•
water ingress
•
high air velocities
•
temperature changes
•
hot work
•
accidental damage
•
bonfires
MAINTENANCE and the LAW •
Fire Precautions (Workplace) Regulations require a system of maintenance
•
Systems with no battery backup are not legal – The service provider should advise users to replace urgently
•
Failure to keep the fire detection and alarms in good working order is a criminal offence
•
Arranging a suitable system of maintenance is so easy to do, that neglecting to do it is blatant flouting of the law.
The Health and Safety (signs & signals regulations) (1996) •
This regulation requires that fire warning systems shall be provided with a guaranteed emergency supply in the event of a power cut.
•
This means that systems not having standby power supply (battery back up) are no longer legal.
•
This is also a law, failure to comply being an offence.
•
Ref clause 46.2.b.4 – THE H&S.S.S REGS 1996.
MAINTENANCE - Routine Testing Responsible Person •
Routine testing and inspection – user or RP
•
Weekly operate MCP – Occupants report any poor audibility – Different MCP each week, recorded in log book – If 150 MCP, then 150 weeks for RP to test all
•
Monthly attention by user or RP – Generator if part of standby power supply – Visual inspection of vented battery – If RP is not trained for this – Competent person monthly visit.
MAINTENANCE - CP Inspection and servicing • Periodic servicing - Competent Person • 3 monthly inspect and top up vented cells • Periodic inspection – based on risk assessment, may be up to 6 months • Annual test now “generally test all over a 12 month period” • Maintenance Engineer to issue servicing certificate if tests acceptable.
USER RESPONSIBILITIES •
Log book updated correctly
•
Check cie at least every 24 hours
•
Arrange for maintenance by CP
•
Train other occupants, fire alarm and procedures
•
Limit false alarms
•
MCP and detectors not obstructed
•
Action on any relevant changes in the building
•
Hold small quantity of spare parts
•
Action following Pre Alarms
Zero Maintenance – the RISK Risk of no maintenance Eventually fire alarm will stop working
The fire alarm will give false alarms
Alarm may be delayed - loss of life
Continual false alarms will make people complacent
Brigade may not be called - Loss of property
In a genuine emergency People may not evacuate.
IF THE FIRE ALARM DOES NOT WORK, THE PREMISES MAY NOT BE SAFE, AS A PLACE OF WORK
Hazards of a zero maintenance fire alarm •
Regular Recalibration of specialist gas type detectors, 5-15 years
•
External circuit fault – may happen any time
•
Standby batteries – life 4 years is normal
•
Contamination of devices from dirty / harsh environments
•
Damaged detectors undetected
•
Alterations to building – may happen any time.
Responsible persons duties •
Supervise the system
•
Training of all users
•
Liaison with building engineers
•
Authorisation of work on the system
•
Ensuring detectors are unobstructed
•
Clear access to control panel
•
Control of keys or access codes disks etc
•
Identify persistent false alarms – details entered in log book
•
Identify any changes in working processes – false alarm issues
•
Identify areas of risk for shutting down in a fire condition.
Reducing automatic false alarms •
Responsible person requires a permit to work for contractors
•
Contractors sign a book make a method statement including how they can reduce false alarms
•
IE:- hot works, carpet cleaning, drilling, cutting bricks, plastering, paint stripping, washing down etc
•
All the above helps avoid false alarms and real fires
•
Training for staff.
Routine testing by the responsible person Daily attention – clause 47.2 – user responsibilities •
Check panel shows normal if not enter in log book – action taken
•
Check lob book to ensure previous faults have been actioned
Weekly attention•
Activate one different MCP and confirm the sounder audibility and operation – results entered in the log book.
•
No time limit if you have 50 MCP’s then it will take 50 weeks.
FILTERING OUT FALSE ALARMS •
Investigate delay
allows inspection before automatically transmitting the
Activation of single smoke det Seek and find e.g. 5 mins
*
signal to the ARC.
False alarm found And cancelled
5 mins times out
Coincedence detection may be required to
Real fire Operate MCP
Override the investigation delay.
*
Coincedence Detector = override
ALWAYS CONSULT THE FIRE AUTHORITIES BEFORE
EVACUATE
Schematic for design against false alarms SELECT the AREA Consider proposed protection For this area Identify circumstances, processes and actions with Potential to cause false alarms Identify means by which proposed system will minimise false alarms Identify likely frequency of false alarms Is this frequency acceptable ?
yes
no Formal proposals for further “ special” Measures to minimize false alarms or their effects
no yes no
Is this frequency now acceptable ?
yes Are the “special” measures detrimental to The system objectives ?
no
Are the “special” measures acceptable to the interested parties?
yes Proceed to Next area.
CERTIFICATION •
In triplicate, all certs must signed by the person directly responsible
•
Design Certificate
•
Installation Certificate
•
Commissioning certificate
•
Acceptance Certificate
•
Verification certificate (optional)
•
Maintenance Certificate.
SUMMARY •
Designers – Now have clearer recommendations from BS5839 on being flexible to design out false alarms.
•
Installers more pragmatic - call points H = 1.4m+/-0.2m
•
Commissioning – more knowledge / training
•
Service organisations – details how to limit agreed quantities of false alarms.
•
LPC1014 / BAFE 203 third party accreditation or registered installers
•
Users – legal obligation on user and guidance / employer for service.
SUMMARY OF FALSE ALARM MANAGEMENT •
Consultation with all parties
• Appoint a responsible person -
RP
•
Supervise painting, decorating, hot work
•
Record and compensate for any change of use
•
Keep fire alarm logbook up to date
•
Agree an acceptable rate of false alarms (e.g. less than 1 false alarm per 100 detectors per annum) in a clean environment ***
•
Ensure service and maintenance carried out
•
If no effort to limit – system is not compliant
*** NOTE:- In a factory 1FA / 75 detectors is more realistic.
