Fire Technology
Subtitle
The Significant parts of the BCA that are concerned with building fire safety. Section A General Provisions A3 Classifications of buildings and structures. Section C Fire Resistance. C1 Fire Resistance and Stability. C2 Compartmentation and Seperation. C3 protection on Openings. Secton D Access and Egress. D1 Provision of Escape. D2 Construction of exits. Section E Services and equipment. E1 Fire Fighting Equipment. E2 Smoke and hazard management. E3 Lift Insulations. E4 Emergency Lighting, Exit Signs and Warning systems. SA BCA Appendix. Part E and G SAE1.3 Fire Hydrants SAE1.4 Fire Hose reels. SAG5.3 Construction in bushfire zones Building Classifications as defined within the BCA A3.2 A building or part of a building is determined by the purpose for which it is designed, constructed or adapted to be used. The classifications are classes 1 - 10. A few examples.
Class 3 a residential building, other than a building of Class 1 or 2,
which is a common place of long term or transient living for a number of
unrelated persons.
Class 5 an office building used for professional or commercial purposes, excluding buildings of Class 6, 7, 8 or 9.
Class 8 a laboratory, or a building in which a handicraft or process for the production, assembling, altering, repairing, packing, finishing, or cleaning of goods or produce is carried on for trade, sale, or gain.
The structure of the BCA comprises the following as shown in the Figure above Reference BCA General Provisions A0.1 - A0.10.
(a) The Objectives.
(b) The Functional Statements.
(c) The Performance Requirements with which all Building Solutions must comply. d) The Building SolutionA building solution will comply with the BCA if it satisfies the Performance requirements.
The Performance Requirements can be achieved by
1. Complying with the Deemed to Satisfy Provisions (DTS).
2. Formulating an Alternative Solution that must be assesed to one or more assessment methods, which is shown to be at least equilivant to the DTS or a combination of the two.
Legislation in South Australia.
Part 59 Log Book.
Ministers Specification SA76. Maintenance and testing of safety installations as listed below.
Schedule 3.1 Structural Fire Protection and Compartmentation,
Schedule 3.5 Fire Fighting Services, this includes Fire Hose Reels & Hydrants, Fire Extingushers, Sprinklers.
Schedule 3.6 Air Handling Systems.
Schedule 3.7 Automatic Fire Detection and Alarm Systems.
Schedule 3.8 Emergency Warning and Intercommunication Systems (EWIS)
Schedule 3.9 Lifts
Schedule 3.10 Emergency Power Supply.
Schedule 3.11 Interconnections - Fire Safety Systems.
Schedule 3.12 Access for Fire Appliances.
Schedule 3.13 Clearance for Large Isolate Buildings.
Schedule 3.15 Occupancy Hazard.
Schedule 3.15 Evacuation Procedures.
Development act 1993.
Advisory Notices SA. Development Act Advisory Notices (10/07 is an interesting read).
The approached methods of analysis as defined in the International Fire Engineering Guidelines (IFEG) determines the non - compliance issues, objectives and performance requirements. The IFEG guides you into several approaches and methods of analysis. Comparative or absolute. Qualitative or Quantitive. Deterministic or Probabilistic. A deterministic Comparative approach would be the preferred approach of analysis of fire safety. These approaches are used in helping the Fire Engineer to formulate his final conclusion in the Fire Engineering Brief (FEB).
COMPARATIVE or ABSOLUTE APPROACH.
We could say compare. A comparative approach is when the Fire Engineer compares Sub Systems in a simular building which is Deemed to Satisfy (DTS) as defined in the Building Code of Australia (BCA). This method of analysis would then involve the same calculations, models input data used originally. Using this information the Fire Engineer could then determine whether the solution would be better than or at least equal to DTS. An absolute approach is when an evaluation is carried out on an absolute basis. Any results from these tests are matched using the agreed acceptance criteria. This criteria does not compare with the DTS or any other prescriptive benchmark designs.
QUALITATIVE or QUANTITIVE APPROACH.
Qualitative analysis is very rarely used and is only normally considered in and FEB for a single non compliance issue. The IFEG recommends a "
An example of a qualitative approach. "A single escape route is appropriate to this escape height due to the protection offered by the escape stair, i.e. Building is sprinkler protected, and the stairs are open to the outside allowing passive smoke ventilation. Therefore the stair would not become smoke logged in the event of fire"
Quantitative approach is used for the majority of complex cases and non compliance issues. This system uses many analysis methods including but not restricted to, formulas, spread sheet calculations, statistical studies, Fire modelling, full scale test and computer simulation of people movements. Which ever method or methods that are used than shall be well documented, suitable for the task and have clearly defined limitations and assumptions Quantitive methods will also be supplied by additional qualitative arguments.
An example of a Quantitive approach.
This alternative solution involves the proposed reduction in Fire Resistance Level(FRL) associated with the Class 5 (Commercial) andClass 6 (Retail) parts of the redevelopment. For this alternative solution, It is proposed to undertake a Quantitative Analysis to determine what FRL is actually required to achieve compliance with the relevant Performance Requirements of the BCA. This will be done by calculating the equivalent heat exposure of a fire and considering the affect of a fire sprinkler system utilizing fast response sprinklers.
DETERMINISTIC or PROBILISTIC
Deterministic methods are used most commonly. They are better developed and less complex. The methods are based on scientific theories and verifiable by observation and experience. Normally the Deterministic methodogies will always give the same outcome. Any analyze using deterministic methods usually adopts a time line approach.
Probilistic This method of evaluation was developed by Beck and Yung in!994. A probilistic approach is used to assess the overall level of risk based on critical parameters. This method analyzes and combines several different scenarios to gain a complete Fire Engineering evaluation of a building design. Using a probilistic approach requires a large amount of statistical data and is very complex and time consuming. Validity is not always possible due to the complexities and use of the many fire statistics and experiments.