Upload
samirsoubra
View
71
Download
4
Tags:
Embed Size (px)
Citation preview
Pioneering fire protection through innovation and
professionalism
BS 9999 in relation to changes in fire legislation
Bill ParlorTechnical Officer, Association for Specialist Fire Protection
BS 9999: 2008
• Code of practice for fire safety in the design, management and use of buildings
• Title excludes construction• Replaces DD 9999• Takes new fire legislation into account• Includes findings from BDAG the Buildings Disaster Assessment Group
BS 9999: What is it?
• A prescriptive code of practice for fire safety design beyond the limits of Approved Document B.
• It is NOT a fire engineering guide, although it uses fire engineering principles to formulate the guidance provided
• Conceived in 1997 to publish in 2002• Sits between AD/B and FSE• Replaces/updates most of BS 5588:
Fire precautions in the design, construction and use of buildings, except Part 1 for residential buildings
Technical guidance at 3 levels
• General approach• Applicable to the majority of buildings• Government guidance, Approved Document B
• Advanced approach• BS 9999, a flexible and transparent approach• Structured approach to risk based design based on FSE
• Fire safety engineering• BS 7974 with supporting Published Documents• FSE may be the only practical approach for some large and
complex buildings, and for buildings containing different uses.
A basis for greater confidence?
• Approved Document B has served us well in the past
• Are the provisions in AD/B overly conservative?• Do they require a new approach?
• BS 9999 replaces most of BS 5588• But Approved Document B still references BS 5588
Positioning of BS 9999
• BSI suggest that• BS 9999 provides an advanced approach to fire
safety, and• It promotes a more flexible approach to fire safety
design through use of structured risk-based design where designers can take account of varying human factors
• But also suggest that• Individual recommendations applied in isolation
might give little or no benefit, and might even
reduce the level of fire safety. Strong words!
Replacement of BS 5588?
• It 1997, BSI FSH14 steering panel identified a number of problems with the existing BS 5588 series, including
• Incomplete coverage of aspects, systems and /or occupancies• Duplication of text in the various sections• Variations in wording• Variations of guidance within BSI documents, and with
other national guidance documents
First thoughts for the new code ?
• A code based on functional requirements rather than occupancies and 4 functional areas were identified
• Means of escape• Construction• Access and facilities for fire fighting• Management of fire safety
• Subsequently, BSI FSH14 steering group realised that more work was needed, to absorb new changes to fire safety law and re-issue of AD-B
BS 9999: Original format
• Based on occupancy risk profile• Risk category, fire load density, fire growth potential
• Fire safety management as a critical feature• Section 5 is about designing so that buildings can be managed• Section 9 is about managing occupied buildings
• NOTE that Paragraph numbers do not match ‘section numbers’
• Travel time for means of escape• Travel distance, occupant numbers
• Construction • Added guidance takes account of ventilation, fire suppression
systems, etc
BS 9999 today: Nine sections
1 General2 Risk profiles and assessing risk3 Ensuring effective fire protection4 Managing fire safety5 Designing means of escape6 Access and facilities for fire fighting7 Designing the building structure: Load bearing
and non load bearing elementsSections 30 – 38: pages 149 - 238
8 Special risk protection9. Managing occupied buildings
BS 9999: 460 pages
460 pages may be too big to manage! Introduction starts on page 21 9 main sections in 234 pages Plus 26 annexes in another 205 pages, such as
Business continuity Atria, theatres and cinemas, shops Commissioning and handover of smoke control
systems Inspection and maintenance of fire safety installations
for ducts.
Fire risks – Table 1
RISK ASSESSMENTS & RISK PROFILES OF• the occupants, the property and business continuity• the use of the building• the risks associated with its use• The likelihood of a fire occurring• the likely severity and potential spread of fire growth
• Tables helps the risk to be assessed by determining occupancy, travel distance, exit capacities, etc
• Five different occupant categories are considered
NOTE: This risk assessment is not designed to satisfy the fire risk assessment requirements of any fire safety related legislation!
Risk profile per building – Table 4
Occupancy Fire growth Risk characteristic rate profile
u
A 1 Slow A1
Occupants who are awake 2 Medium A2
And familiar with the building 3 Fast A3
4 Ultra fast A4 unacceptable in BS 9999
B 1 Slow B1
Occupants who are awake and 2 Medium B2
Unfamiliar with the building 3 Fast B3
4Ultra fast B4
C
Occupants who are likely to 1 Slow C1
be asleep 2 Medium C2
3 Fast C3 unacceptable
4 Ultra fast C4 unacceptable
Occupancies C, D and E
• C Occupants likely to be asleep• Ci long term individual occupancy• Cii long term manage doccupancy• Ciii short term occupancy [in hotels]
• D Occupants receiving medical care• E Occupants in transit
[railway stations, airports]
Fire growth rate KJ/s3
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
slow medium fast ultra fastBank hall Cardboard
boxes
Plastic
products
Expanded
Cellular plastics
Sprinklers & risk 6.5
• If sprinklers are installed, the fire growth rate can be reduced by one level in Tables 4, 12 and 13, subject to defined limits.• Does this assumes that sprinklers can react to quell an ultra fast
fire?
• Only sprinklers designed and installed in accordance with BS EN 12845 and BS 5306-2 can be used to reduce the fire resistance periods in Tables 25 and 26
Detection and alarm systems
• Each risk profile is associated with minimum acceptable types of alarm and detection systems, Types available M, L1, L2, L3 ( BS 5839-1).
• These may permit extensions or reductions to the travel distance or door widths, but there are limits on the extent of changes permitted.
• Some may argue that some of the tables are merely guidance and should not be taken to literally, but the document is said to be prescriptive!
Design so that a building can be builtand managed
• Innovative solutions rely on all fire precautions functioning and the effective interaction of passive/active defences
• Clear need for competent products and competent installers• Do recognise that BCO’s rarely inspect work on site!• Need for reliable commissioning and maintenance• Do fire safety engineers ever go to site?
• What about product life cycle, periodic inspections, durability and planned replacement
THREE Management levels: Table 6
• 1 = highest and best level• 2 = normally acceptable level• 3 = basic level of management [not acceptable]
• Enforcers (in design phase) may decide that Level 3 (in use phase) is never enough to meet legislative requirements! Level 1 requires individual Level 1 for all management factorsLevel 2 requires individual Level 2 for all management factors
Details of management factor levels
Planning for changes in risk profile 8.3.2 Resources and authority 8.3.3 Staffing levels & ratio to occupants 8.3.4 Fire training 8.3.5 Work control and repairs 8.3.6 Communications 8.3.7 Maintenance and testing 8.3.8 Liaison with fire service 8.3.9 Contingency planning 8.3.10
Example of Building management factor
WORK CONTROL• Level 1 developed proactively with clear lines of
responsibility; a permit system; logging and audit processes and routine checking and supervision.
Should anticipate required changes to fire safety strategy
• Level 2 Identifies and reacts to any changes and work required on site; temporary abnormalities, clear lines of
responsibility; a permit system; logging and audit processes.
• Level 3 A level 3 work control system is reactive to work required on site, and is unlikely to meet legislative
duties.
Management of premises
Management is covered in two sectionsDESIGN STAGE
○ The occupancy profile is needed at an early stage, with clear determination of the ‘quality/level of management’ of fire safety to be expected when occupied
OCCUPANCY STAGE○ Covers all aspects of management of fire safety in an
occupied building, up to demolition of the building
Occupant response and travel time
ignition alarmTenability
Threatens life
SMOKE KILLS
Time to
alarmPre-movement time
ALLOWABLE
TRAVEL TIME
ASET available safe escape time
Management controlled?
FIRE Travel startsDIE OR
SURVIVE
Getting out
• TOTAL EVACUATION• Phased procedure
• Do occupants understand/believe the fire escape strategy?• Often used in high rise premises [ Since all floors are fire resisting]
• Simultaneous procedure• Single or two staged evacuation
• Decided by psychological response?
• PROGRESSIVE EVACUATION• Initially to a place of relative safety?
• To an adjoining fire compartment• No fire compartments mean no choices exist
• Followed by managed escape?
• Human behaviour?• Only depends on the visibility of the fire or smoke!
Travel distances
• BS 9999 Table 12 provides maximum travel distances when minimum fire protection measures are provided
Risk profile Fire 2-way distance 1- way distance
A1 slow 65m 26mA2 medium 55m 22mA3 fast 45m 18mA4 ultra fast 30m 14m
NOTE 1 - Reduce distances by 25% if alcohol is available.
NOTE Fitting sprinklers to A3 risk could allow 1 way distance to be increased from 18m to 22m
Means of escape
• Egress design values/person allow change to various width factors depending on the risk profile of the occupants [change of use?]
• Travel distances can be extended by 10 – 25% if smoke ventilation exists, or if high ceilings are used [assumes good order]
• Corridor widths shall be the same as the door width in the corridor, or 1200mm [but can be reduced if no wheelchair users ‘are expected’ or where areas are ‘just used for maintenance’]
• All smoke vents should be at least 3m from an escape route [no wind expected?]
BS 9999 and Refuges (Annex G)
• A refuge is a location where people whose abilities or impairments might cause delayed evacuation can await assistance with the next part of their escape.
• It must be a place of relative safety.• Refuges are temporary waiting areas during planned evacuation.• Consideration should be given to the likely number and size of
refuges, and to allow for bigger powered wheelchairs• 1200mm wide corridors allow turning through 180 degrees.
• Refuges are not to be used as a place to leave disabled people to await rescue by the fire service
Fire resistance
• The purpose of structural fire resistance is threefold• Minimise risk to occupants• Reduce risk to fire-fighters coming in to search• Reduce danger to persons in the vicinity of the building
• Apply to load bearing structure, if required• Non load bearing elements enclosing escape routes
Fire resistance: Tables 24, 25, 26
• Determine FR values as required from Table 24
• Table 25 gives FR values based on fuel load density, assuming an unventilated fire, with and without sprinklers
• Table 26 gives FR values provided that the ventilation conditions given in Table 27 can be met.• Including non-standard REI figures of 15, 45, 75, 105 minutes
• Fire loads are built into Tables 25, 26 and reflect the typical risk profiles provided in Table 5
Ventilation conditions: Tables 26 and 27
• Occupancy characteristics• Use of building
• Ventilation parameter• As minimum ventilation area as a percentage of floor area
• Typically 2.5 to 10%
• As height of opening as fraction of compartment height• Typically 0.3 to 0.9/1.0
Maximum size of compartments
RISK PROFILE SINGLE STOREY MULTISTOREY
FLOOR AREA TOP FLOOR HEIGHT MAX FLOOR AREA
A1 No limit no limit No limit
A2 No limit less than 30m no limit
over 30m n/a
A3 No limit less than 18m 14 000 sqm
18 to 30m 4 000 sqm
A4 20 000 sqm less than 18m 20 000 sqm
over 18m n/a
Trade off’s with sprinklers
• BS 9999 does not require sprinklers to be mandatory in any buildings.• It is suggested that sprinklers should be installed in buildings
over 30m high
• BS 9999 generally allows more attractive trade off for automatic sprinkler installation and automatic fire detection, than are generally available through Approved Document B.• Has the evidence been provided for this step?
Ups and downs1Steel industry guidance SN36 on BS 9999
• A two storey office building with ground floor area less than 1000m2 will see the required fire resistance drop from 30 minutes to 15 minutes.
• Most hot rolled steel structural sections will achieve 15 minutes without fire protection, so that no additional fire protection will be required.
Ups and downs 2Steel industry guidance SN36
• An open plan office building between 30 to 60 metres high will see a reduction in AD/B requirements • from 120 minutes with sprinklers, to 90 minutes without
sprinklers; and 60 minutes with sprinklers
• A department store without sprinklers, between 11- 18m high will see an increase from 60 to 75 minutes.• But there is no 75 minute period of classification available in
BS EN Classification systems
Change of use of buildings; 48.3
• Should be taken into account at design stage [clause 10] and used as a basis for fire safety documentation • Fire safety manual – Clause 9 / Annex H
• Generally, the fire safety documentation needs to be re-assessed if the use of the building is changed. • Who will be liable all the fire safety provisions?
Personal observations 1
• Which issues are most critical for a successful fire safety strategy?
• Will fire investigators consider the fire strategy and the construction? • Critical lessons are being missed.• Feedback is vital
Personal observations 2
• Will fire fighters know which code was used for the design when they’re about to tackle a fire incident, and will it affect their decisions?
• How can we know what level of tenability is acceptable when fire fighters leave the safety of the fire lobby?
Buildings are getting higher! Buildings have fewer windows that open!
Personal observations 3
• Will escaping occupants care a hoot about the design method? Should they care?
• Escaping occupants and fire fighters will care that the fire safety measures are properly specified and properly installed, and do their job!• Will they be happy with 1st party certification?• Will they be happy that untrained or poorly trained
installers have been selected on price for the critical installation.
• ITS HIGH TIME WE JOINED IT ALL UP!
Meeting legal liabilities? – 3 elements
• Appoint competent designers and competent installers• especially for specialist fire protection works• CDM Regulations 2007
• Contractors must provide building users with fire safety information at handover• Building Regulation 16B and Approved Doc B appendix G
• Building users must make and maintain a risk assessment• Regulatory Reform (Fire safety) Order 2005
John Ruskin – philosopher and poet‘Nothing really changes’
It is unwise to pay too much, But it is worse to pay too little.When you pay too much, all you lose is money, that is all.
When you pay too little, you sometimes lose everythingBecause the thing you bought was incapableOf doing the thing it was bought to do.
The common law of business prohibits paying a littleAnd getting a lot – it can’t be done.
If you do deal with the lowest bidder, it is well to addSomething for the risk you run, and if you do that,You will have enough to pay for something better