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BAA Developing a Coherent Approach to Fire Safety Design

Posted: 26 May 2009 | John Boyce MSc(Eng) MSc (Struct E) BSc(Hons) CEng MIFireE MBEng MRICS, Head of Fire Safety Heathrow Airport and Gary Moorshead, Chief Fire Officer BAA | No comments yet

This is the first in a series of articles which describes some of the fundamental initiatives BAA have developed to ensure fire safety design is an integral part of the design process resulting in fire strategies that meets our operational and business requirements across our airports.

This is the first in a series of articles which describes some of the fundamental initiatives BAA have developed to ensure fire safety design is an integral part of the design process resulting in fire strategies that meets our operational and business requirements across our airports.

The layout of terminal facilities are designed and developed around processing operations as such the layout of facilities is largely pre determined by processes required to get passengers to and from aircrafts.

Airport Terminals are characterized by large undivided spaces with little physical separation between functional areas. Such design features could potentially make the facility very sensitive to a fire due to the potential for smoke spread throughout the concourse areas.

Establishing Fire Safety Objectives

The approach to fire safety design must be considered in the context of the overall fire safety objectives.
For BAA these fire safety objectives are detailed in the Master Fire Safety Plan (MFSP) and relate to:

  • Life Safety
  • Property protection
  • Business continuity (operational and commercial continuity)
  • Corporate image
  • Insurance requirements.

The purpose of the MFSP is:

  • To provide a cohesive framework for the development of fire safety strategies across the airport
  • To ensure fire safety objectives are aligned to the business and operational aspirations of our stakeholders
  • Set out what Fire Safety Plans (FSPs) are required and how they interact.
  • To provide a document which sets out those aspects of fire safety both technical and procedural which need to be considered and applied across the whole of the airport campus
  • To provide guidance to the project teams and designers on the preparation of subsequent FSPs
  • To ensure alignment with existing operating protocols.
  • To provide a document which can be used in negotiation with the statutory authorities and which can be agreed by them as the common basis for fire safety, in conjunction with the FSP’s it shall provide a formal record of the fire safety arrangements across the airport campus.

The Master Fire Safety Plan (MFSP) requires the following FSPs to be developed:

  • Building Fire Safety Plans (BFSPs): Describes the measures including active and passive fire systems within the facility required to meet the objectives detailed in the MFSP and will be the principal document used to demonstrate the design meets the functional requirements of the Building Regulations.
  • Construction Phase Fire Safety Plans (CFSPs): It is essential to ensure that fire safety is managed during the construction phasing in terms of reducing fires during construction
  • Operational Fire Safety Plans (OFSP’s): It is important to ensure that the BFSP is developed within the context of how the facility is operated and managed. The OFSPs describe the fire safety management processes within the facility such as operational response to an incident, evacuation principles and zoning etc.
  • Retail Fire Safety Plan: The retail strategy defines the types of retail which can be provided in the different areas of the terminal. The fire strategy must be developed in order to facilitate as much retail flexibility as practically possible within the constraints of the building design and to ensure an integrated solution with other services whilst achieving retailing aspirations.
  • Fire Alarms (User Requirements Document): This document describes the user requirements of the fire alarm system in supporting the fire safety objectives contained in this document. The URD outlines at a strategic level how the system should operate and how it must support the operational and business continuity aspirations of Stakeholders.

The MFSP is the principal document which sets out fire safety objectives which is fundamental in ensuring that the right fire safety solutions are developed not only with respect to life safety but also business continuity and operational protection which are seen as primary objectives in any terminal fire strategy.

The development of these FSPs is based on the procedure contained in the British Standard guidance on fire safety engineering (BS7974). The procedure contained in the British Standard has essentially five basic components as follows:

  • Stage l – Qualitative Design Review commonly referred to as a QDR.
  • Stage 2 – Quantitative Analysis
  • Stage 3 – Assessment Against Criteria
  • Stage 4 – Reporting
  • Stage 5 – Re-evaluation due to design changes.

The term QDR stands for a qualitative design review and provides a framework for developing a rational for development of a fire safety strategy. Such an approach is necessary especially where there is a need to consider a number of strategic fire safety objectives. Therefore there is the necessity for a robust means of managing and documenting the process of fire safety design to encompass the whole working life of the facility. Adopting a QDR approach will ensure that the fire safety measures are directly aligned to the high level fire safety objectives within the MFSP.

It is recognised that many stakeholders have valuable contributions to make within this process. In being a qualitative process it draws upon the experience and knowledge of stakeholders in order to develop and agree fire-safety objectives and appropriate inputs to any quantitative analysis and acceptance criteria.

Such an approach aims to ensure that all individual aspects of the design are considered in the context of fire safety objectives and the impact of proposed solutions is fully understood.

A typical example would include understanding of fire risks within a specific area of the terminal in terms of ignition sources, fire load and potential spread. It is very similar to a ‘hazard and operability’ (HAZOP) study as developed by the petrochemical and other high risk industries. A HAZOP study is a structured discussion of the hazards associated with the operation of a process and the measures required to reduce the risk from these hazards. The purpose of the QDR is to provide a similar structured discussion of fire safety and how it could affect the building or facility and to identify the key issues which are likely to determine the fire safety measures required.

Whilst the fire safety requirements relating to life safety are covered by the provision of the Building Regulations it is often the case that the measures provided to reduce operational disruption and maintain business continuity during an incident will afford a higher standard of fire safety than those required for life safety purposes.

Application of Fire Safety Engineering

Fire Safety engineering (FSE) can be defined as the application of scientific and engineering principles to fire safety design.

Due to the complex nature of terminal buildings following a traditional fire safety approach may result in solutions which are impractical to maintain and operate throughout the life of the facility .

A fire safety engineering approach that takes into account the total fire safety package can often provide a more fundamental and economical solution in comparison to the traditional prescriptive approach of following prescriptive standards as it consider the interaction of active passive and management systems in meeting fire safety objectives.

Whilst it is recognized that such an approach may not be appropriate in all cases it does provide a robust mechanism for assessing fire safety .Such an approach has the following benefits:

  • Provide the basis of a risk-based approach enabling both the design team and client to make an informed decision on fire safety matters.
  • Provide an opportunity for innovation.
  • Provide up front information to the client in relation to management
  • Provide a basis for the selection of active/passive fire systems.
  • Allow the safety levels for alternative design to be assessed
  • Provide a mechanism for the selection of solution in meeting fire safety objectives.

The application of fire safety engineering supports BAA approach to fire safety which is based around of six contributing tactics:

  • Prevention: reduce the probability of fire occurring. Employment of all proactive measures that control ignition hazards and storage of combustible elements. Fire safety management risk assessment and day to day supervision are key elements of fire prevention .The inclusion of fire prevention is one of the key tactics in supporting the on going process of risk assessment under the RRO.
  • Communication: utilising all communication options to ensure that all occupants receive the right information at the right time this also includes management response to a fire incident.
  • Escape : ensure all occupants are able to move to a place of safety before they are exposed to heat and smoke
  • Containment: ensuring that fire/smoke is contained therefore preventing the spread of smoke throughout the terminal thereby limiting the amount of smoke damage and associated operational downtime following an incident.
  • Extinguishment: ensuring that the fire can be controlled to reduce the amount of consequential damage to the facility.
  • Recovery: Despite all preventative measures it is not practical to reduce the probability of fire to zero. Therefore it is essential to have systems and processes in place that will reduce the operational downtime to a minimum following a fire.

For airport terminals common fire safety challenges relate to:

  • Extended travel distances
  • Large compartments
  • Fire Service Access
  • Reduction of operational disruption
  • Maintaining business continuity
  • Achieving a suitable degree of retail flexibility
  • Operational and process protocols
  • Insurer requirements.

These challenges are normally resolved by the introduction of both passive and active systems such as smoke control and sprinklers. The justification of design proposals is normally based on a combination of the following fire engineering methodologies:

  • Deterministic – the objective is to show that on the basis of a set of initial assumptions a defined set of conditions will not occur e.g. the smoke layer will not drop below a level of 3.0m. Disadvantages associated with this method of analysis is that it is very dependant on initial assumptions and provides no real measure of cost and benefit as it provides a simple yes/no answer.
  • Probabilistic – criteria set to ensure that the probability of a given event occurring is acceptably low. Although a valid method of analysis it is not often used as it does start to quantify the number of acceptable deaths per year. However it does have a number of distinct advantages which includes : provides data for cost benefit analysis and a numerical value of risk and can prove useful in providing comparison between dissimilar fire protection systems
  • Comparative – This is the most common form of analysis because it is often difficult to establish the level of safety in real or absolute terms whereas it is relatively straight forward to demonstrate that the proposed design achieves the same level of safety as a recognised prescriptive code. In the vast majority of cases comparative analysis may well involve a degree of probabilistic and deterministic analysis based on an agreed set of assumptions.

Managing fire safety is the whole process throughout the life of a building, starting with the initial design, which is intended both to minimize the incidence of fire and to ensure that, when a fire does occur, appropriate fire safety systems (including active, passive, and procedural systems) are in place and are fully functional. The management of fire safety is thus an essential element in averting disaster in the event of a fire hence in adopting a FSE approach it is essential that the principles assumptions are fully documented for the successful on going management of the facility. This statement is particularly relevant to airport terminals where the design of the facility is based around processing operations.

Whilst the application of FSE is a useful tool in addressing the design challenges of modern terminal design , for BAA is essential that any fire strategy must be developed in the context of the aim and objectives contained in the MFSP to ensure a coherent and consistent approach of solutions which are understood by the end users and is aligned to the established operational protocols associated with terminal facilities.

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