The Singapore Fire safety Engineering Guidelines (SFEG)

Transcription

1 The Singapore Fire safety Engineering Guidelines (SFEG) Nicholas Lee Senior Consultant (Performance-Based) Fire Safety & Shelter Department Singapore Civil Defence Force Introduction The fire safety standards for buildings in Singapore are governed by the Code of Practice for Fire Precautions in Buildings commonly known as the Fire Code. The Fire Code is used by Qualified Persons (QPs) in design of fire safety works in buildings. Fire safety works that are designed in accordance with the prescribed requirements in the Fire Code are known as prescriptive-based fire safety design. In July 2004, the Singapore Civil Defence Force (SCDF) offered the building industry an alternative approach to designing fire safety works in buildings i.e. one that is based on fire engineering principles. Such an approach is also commonly known as performance-based (PB) fire safety engineering design, where only Fire Safety Engineers (FSEs) who are registered with the SCDF can undertake such designs. Prior to launching Singapore s PB guidelines, there were several international fire safety engineering guidelines 1 that an FSE can refer to when embarking on PB fire safety engineering design. However, these are generic and do not contain critical design input and output parameters such as design methodology, assumptions, acceptance criteria, design fire sizes, software modelling tools to be used and type of output data required. There is thus the need for FSEs to frequently consult SCDF on these parameters prior to embarking on any detailed PB fire safety engineering design. This takes up much time for both the FSEs and SCDF. SCDF has thus developed a set of local fire engineering guidelines for reference by the FSEs to facilitate their work in PB fire safety engineering design. The Performance-Based Plan Approval Process For projects embarking on the PB approach (See Annex A for the flowchart for Singapore s PB plan approval process), the FSE prepares the Fire Safety Engineering Design Brief (FEDB) to be submitted to SCDF for in-principle approval of the proposed fire safety engineering approach, methodology, software, tools, etc. The FSE would consult SCDF on the FEDB proposal before formal submission to SCDF is made. 1 These guidelines are reference documents that state design principles and design objectives. Some examples used by FSEs include the SFPE Engineering Guide to Performance-Based Fire Protection, BS7974: Application of Fire Safety Engineering principles to the Design of Buildings, ISO 13387: Application of the Fire Performance Concepts to Design Objectives and the International Fire Engineering Guidelines.

2 The FEDB will be assessed by our SCDF officers 2. Upon the in-principle approval of the FEDB, the FSE can proceed to prepare the Fire Safety Engineering Report (FER) which documents the results of the fire engineering study and the Operations and Maintenance (O&M) Manual which summarizes all the performance-based issues for the building owner to address in planning his fire protection maintenance regime. After the preparation of the above reports by the FSE, an independent peer reviewer, who is also a registered FSE with SCDF, would be engaged to assess the above reports and ensure that the PB solution is incorporated in the Building and M&E Plans. The peer reviewer will then prepare a report for his assessment in a Peer Reviewer s Report. The project Qualified Person (QP) is required to collate all the above reports for plan submission to SCDF. All performance-based plan submissions are audited by SCDF. Upon completion of the fire safety works, the owner is required to engage a Registered Inspector (RI) who must be a FSE to inspect the performance-based aspect of the fire safety works. This is over and above the RI (Architecture) and RI (M&E) 3 that are required for most new buildings. The Need For The SFEG The need for drafting the SFEG is discussed below. Extensive consultation As highlighted in the earlier paragraph, the set of international fire safety guidelines currently adopted are generic and lack critical design information. This results in extensive consultation sessions where the design parameters and methodologies are discussed. The requirements are verbalised during the consultation sessions and documented in the individual fire safety reports. These requirements however are not available in any common reference documents that FSEs can refer to. Hence, these design parameters and methodologies need to be documented to reduce consultation with SCDF and to improve transparency and consistency. To provide guidance FSEs that specialise in certain type of projects (e.g. industrial projects) would also benefit if they take on PB projects of other nature/purpose groups as there would be a set of guidelines that provides critical design input parameters. 2 SCDF officers assessing PB fire safety engineering design all possess Masters Degrees in fire safety engineering in addition to possessing a basic engineering or technical degree. 3 A RI is a person who is registered under the Fire Safety Act to be qualified and competent to inspect fire safety works in buildings that were submitted by the QPs to ascertain the degree of compliance of fire safety requirements.

3 Maturity of the PB fire safety approach in Singapore When performance-based fire safety design was first introduced to the industry in July 2004, FSEs had adopted the approaches found in international fire engineering guidelines as templates in drafting their reports and presenting their analysis/results. The PB fire safety approach here has since matured and now has the depth and capacity to draft our own fire safety engineering guidelines to better reflect the local PB fire safety landscape. Clarity on critical design parameters. The SFEG documents the basic design fundamentals and design input and output parameters when embarking on a PB fire safety engineering design approach. FSEs will therefore be informed of what assumptions/inputs can and cannot be adopted in the design process and what output results to be shown in the FER. This includes design fire scenarios, determination of fire sizes, soot yield values, smoke temperature readings, etc. Stakeholders Involvement SCDF did not embark on this journey alone. A PB Code Review Committee was formed in May 2013 to develop the SFEG. This committee was chaired by the Director of the Fire Safety and Shelter Department (FSSD) and comprises FSSD officers, FSEs representing the various institutions 4 and active FSEs participating in their individual capacity. Guiding principles in drafting the SFEG The principal considerations adopted when drafting Singapore s PB guidelines were as follows: The SFEG should be aligned with international best practices. Methodologies to be adopted to address deviations should be congruent with existing international fire safety engineering guidelines. While PB fire safety engineering design can generally be classified into deterministic or probabilistic analysis of fire scenarios, the latter is not considered in this SFEG as FSEs have been adopting deterministic approach in their PB fire safety engineering designs. As far as possible, the SFEG should be applicable and relevant to all PB fire safety engineering design approaches, which are methodologies adopted by FSEs to justify that their design can still meet relevant life safety criteria. The methodologies in the SFEG would need to be congruent with the performance-based root and sub-objectives listed in the Fire Code. 4 The committee comprises the Institute of Engineers, Singapore (IES), Institution of Fire Engineers (IFE), Singapore, Association of Consulting Engineers, Singapore (ACES) and the Society of Fire Protection Engineers Singapore Chapter (SFPE).

4 Seeking Consultation and Comments Before launch, the SFEG was tabled at the fire safety policy discussion platform (SCDF Fire Safety Standing Committee) and technical discussion platforms (Fire Code Review Committee) for deliberation. Members from both these platforms are made up of SCDF officers and members representing the various professional institutions. As part of soliciting industry feedback, the SFEG was also circulated to all SCDF registered FSEs for public comments. Structure of the Singapore Fire Safety Engineering Guidelines The SFEG is categorised into two main parts, namely (i) Design fundamentals and assumptions such as what design fires to adopt and where to measure tenability limits and (ii) methods of assessment of common deviations from fire code requirements. These common deviations are selected based on the PB submissions to SCDF in the past 10 years. Part 1 Fundamentals and design assumptions The main items discussed are: Fire scenarios: The fire scenarios represent the worst-case credible fire risks that the design would need to cater for. Available Safe Egress Time (ASET): This is the calculated time interval between the time of ignition of a fire and the time at which conditions become such that the occupant is estimated to be incapacitated (ie, unable to take effective action to escape to a place of safety). Required Safe Egress Time (RSET): Time required for escape. This is the calculated time period required for an individual occupant to travel from their location at the time of ignition to a place of safety. Marked-up drawings: This section captures the details needed to be marked up on plans to be used for presentation purposes. Examples of details include design fire size/location, location of vent openings, table of deviations, etc. Operations & Maintenance (O&M) Manual: The O&M Manual is prepared by the FSE for the building owner. It documents the deviations addressed in the performance-based studies and specifies the limitations that the building owner must take note of in future additions and alterations to the building Peer Reviewer: Due to the complexity of fire safety issues involved, an independent 3 rd party checker (also a registered FSE) is required to review all performance based projects. The SFEG stipulates the role of the peer reviewer and the sensitivity studies he/she must carry out. Registered Inspector (R.I.): In addition to the R.I. (Architecture) and R.I. (M&E), all performance-based projects would require a R.I. (FSE) at the Temporary Fire Permit (TFP) and/or Fire Safety Certificate (FSC) stage. His focus would be on the performance-based aspects of the design and whether or not all the performance based provisions operate as specified.

5 Part 2 Method of assessment for common deviations This section discusses the recommended methods of assessment for common deviations. FSEs may propose other methods to assess the deviations which SCDF would consider based on the merits of the case. The list of common deviations below is not exhaustive and would be updated as and when other common deviations comes to fore. The list of common deviations from the prescribed requirements are: a) Enlarged smoke reservoir size b) Enlarged fire compartments c) Extended 2-way travel distance or excessive occupant loading d) Internal discharge of exit staircases e) Insufficient set-back distances to prevent fire spread between buildings. f) Reduced fire-resistance rating to element of structures g) Benefits Of The SFEG With greater clarity and transparency, FSEs would have more certainty at the conceptual design stage of the project and this would lead to faster plans preparation and reduce the number of consultations needed. The SFEG can be used by both new and existing FSEs as a guide on (i) fundamental design assumptions/parameters for a performance-based analysis and (ii) methodologies on how common deviations are justified. If the FSE is appointed as a peer reviewer, this role as the independent checker is also more clearly defined as the SFEG specifies the scope of the peer reviewer study, the stages of peer reviewer involvement and the modelling required for sensitivity analysis. The building industry can also rely on the SFEG at the conceptual design stage to better appreciate design limitations, especially if there are many deviations from the fire code. The SFEG also lists down the critical fire safety provisions that form part of the PB fire safety engineering design that should be included in the building plan submissions. This ensures that the design proposed by the FSE is communicated to the QPs and that these details are documented accordingly in the building plans that are submitted. The SFEG also serves as a reference for SCDF officers who are newly assigned to undertake performance-based fire safety engineering responsibility. This would shorten the induction time as the new officer would require less guidance to actively and confidently engage FSEs. Conclusion The SFEG is a crucial reference document that will provide greater clarity at the FEDB stage by specifying acceptance criteria and input parameters that can be adopted for most performancebased designs. This facilitates the role of all relevant parties i.e. FSEs in preparing the PB fire safety plans, peer reviewers in checking the plans and SCDF in approving the plans, and taken together, leads to faster approval of PB fire safety plans.

6 Singapore s Performance-Based Plan Approval Process. Annex A