Airport fire safety design poses unique challenges for the fire protection engineer. There are few other building types whose dominant focus is a full operations cycle involving large numbers of public occupants as well as a complex support system to enable the building function (retail, baggage handling, security, and so on). To enable this interaction, architecture becomes key in creating tall, open front-of-house spaces and enabling high-frequency operations back-of-house—all in a specific departures and arrivals cycle running in parallel. This remains true regardless of the geographic location. This article presents a fire safety design approach, using the fire protection engineering process outlined in BS 7974,1 to highlight the key items that can create a practical airport terminal fire safety design.

Over the years, the fire protection engineer has played a role in airport design—seen as an enabler of the operational and design features. Success relies on integration with the other design team members and stakeholders. With operational requirements and signature architecture forming a fundamental basis of the project, close communication with the airport operator, their fire safety management team, as well as the architect, from the very conceptual stages, have proven to be fundamental to the successful design and implementation of an airport terminal fire safety design.

The fire protection engineer has a substantial role from concept stages, right through to design, quantifying the agreed principles and being part of the specification stage and onwards to construction and design compliance on-site. For airports (like many other complex buildings and one could suggest, in fact, any building), a robust strategy for commissioning the fire and life safety systems and inspecting the key elements for completeness, as well as participating in the training and handover of a functioning fire strategy, is increasingly a required part of the fire protection engineer's role.

A recent project at Dublin Airport (Terminal 2) in Ireland illustrates pertinent fire safety issues relating to the design and, ultimately, the successful delivery of an airport terminal.

Terminal 2 is located to the east of the existing Terminal 1. The building consists of a seven-story main terminal building of approximately 70,000 m2 and a three story Pier E building of approximately 20,000 m2 in area. The state-of-the-art terminal is capable of handling up to 15 million passengers per year. At its peak, Terminal 2 was the largest construction project in the state and employed up to 2,600 workers on-site. Importantly, the terminal was built in a live airport environment creating substantial logistics re-alignment on the site to enable continuity of operations.

The initial fire strategy concept began in 2006, culminating in completion of the final as-built fire strategy revisions in 2012.

Irish legislation, until recent amendments were introduced, required that site works could not commence without prior approval of fire safety design in the form of an approved "Fire Safety Certificate” from the fire authority. Revised certificates were subsequently required in order to reflect the as-built form. A change control method was adopted so that the fire protection engineer could review changes as they arose and subsequently address them with the fire authority. Such changes included architectural design development and modifications arising from on-site constructability issues.

Figure 1. QDR Process


Airports, due to their design, necessitate the adoption of a fire protection engineered approach as opposed to following the recommendations of prescriptive guidance. BS 7974 provides a basic framework for the application of fire safety engineering and is similar in that regard to the processes set out in other contemporary performance-based design guides such as that developed by SFPE.2 This approach is illustrated in Figure 1.

The guidance recommends four main steps in the process:

  1. Qualitative design review (QDR)
  2. Quantitative analysis of design
  3. Assessment against criteria
  4. Reporting and presentation of results

While all of these stages are important in developing a robust strategy, it is during the QDR stage where the parameters that can create a successful fire safety design are created. If the key items are not known or identified during the QDR, the remainder of the process will suffer. The remainder of this discussion will use the challenges met during the design and construction of Terminal 2 as an example of items that should be identified and addressed during the QDR stage.


BS 7974 identifies the main stages in the QDR process as the following:

  1. Review of architectural design and occupant characteristics,
  2. Establish fire safety objectives,
  3. Identify fire hazards and possible consequences,
  4. Establish trial fire safety designs,
  5. Identify acceptance criteria and methods of analysis,
  6. Establish fire scenarios for analysis.
Storage Concept Design Construction
Client (including client bodies such as security, retail, customs, etc.) Understand operational goals & agree on business continuity objectives. Communicate concept fire strategy. Communicate detailed fire strategy and any operational implications. Clearly outline fire safety management requirements. Hold workshops with client bodies as required. Close collaboration during Operational Readiness Activation Transition (ORAT) phase to understand client needs. Provide for the safety of occupants within the building prior to completion. Advise on legislative health & safety implications.
Architect Understand architectural aspirations & communicate concept fire strategy. Communicate detailed fire strategy & hold design workshops to develop integrated solutions. Illustrate fire strategy on drawings. Agreement of construction details. Approving benchmark construction details and assisting with site inspections. Assistance with problems encountered on-site.
Mechanical, Electrical & Plumbing (MEP) Understand concept MEP strategy & communicate concept life safety systems strategy. Communicate detailed fire strategy & hold design workshops to develop integrated solutions. Assist and witness systems commissioning. Assist with site inspections.
Dublin Fire Brigade Agree on main fire strategy principles. Hold meetings and workshops as necessary to agree on detailed strategy. Gain formal strategy approval. Additional approvals if required.
Insurer Understand main insurance objectives. Communication and agreement of detailed strategy. Verify that insurance goals are maintained.
Construction Manager     Impart fire strategy principles and importance of quality during construction. Regular liaison to prioritize areas of work depending on client needs (e.g., ORAT). Assisting with construction quality assurance.
Main Contractor     Agree on benchmark details. Close liaison to agree on solutions to problems encountered during construction.

Table 1. QDR Team Members and Responsibilities

The team formulated to carry out this process is key to the success of the final fire safety design and is discussed below.

The QDR Team

Through design and delivery of the T2 project, the interaction between the various teams and people involved was found to be fundamental to proper design and delivery. Table 1 illustrates the relevant teams and their importance at each stage.

Review of Architectural Design, Occupant Characteristics & Fire Hazards
BS 7974 advises that the following be considered in relation to the architectural design and occupant characteristics of the building: building structure and layout, use(s) and contents of the building, fire service access to the building, occupants, ventilation systems, unusual fire hazards, planning constraints and client requirements, including possible future options.

The Building, its Uses and Hazards
Passenger experience is key to the architectural design aspirations behind an airport. The fire strategy must facilitate this process. The resultant architectural design typically consists of large and high, open spaces front-of-house for the public, with little or no physical separation between each area to allow a smooth transition for passengers from function to function (check in, security, retail, departure; and the reverse function of arrivals, immigration, baggage pickup, retail, arrivals and onwards travel). Physical separation is required to separate back-of-house from front-of-house.

Security and immigration create spaces where a single direction of forward travel must occur, and mixing of occupants at dif ferent stages in their journey must be prevented. The most important "line” in the airport terminal is the landside to airside line. This can be physical in parts (particularly through back-of-house) but front-of-house this tends to be a mix of physical barriers and staff-controlled processing lines. The evacuation strategy must accommodate this, and prevent mixing of processed and unprocessed passengers, as well as a major reprocessing of passengers in the event of an evacuation.

Front-of-house consists of large, high, open spaces, which may also be subdivided from an evacuation perspective to control safe escape and minimize interruption. In the absence of a physical subdivision, the role of active smoke control systems and fire hazard and control strategies becomes central to the fire safety design.

The identification of fire hazards and how they are mitigated are therefore central to the fire safety design. Terminal 2's high-volume, open plan, front-of-house areas relied on a strategy that was based on either suppression or the creation of maximum permitted fuel load sizes and locations in areas where smoke from a fire could rise directly from a fire to the ceiling above (ranging from 10-40 m in height).

The airside environment of an airport is a highly controlled area, with all staff and tenants operating under strict procedures and everyone (including members of the public) being limited in terms of the items they can transfer across the airside/ landside line. It is unusual to have a public building where the fire load can be so well defined.

One area of an airport terminal that requires detailed consideration is the baggage handling area. This is where luggage is either sent to the planes from the check-in desks or received from the planes and sent to the baggage reclaim carousels. It generally consists of a large volume with many baggage conveyors, sorters, platforms, walkways, open stairs and mezzanines. Challenges encountered in this area include: treatment of connections to steel work, appropriate means of escape signage in a highly complex environment, maintaining compartmentation between the handling hall and other parts of the terminal, and providing acceptable travel distances for the trained staff occupying the space.

Unusual fire loads need to be envisaged during the QDR also, specifically in areas with high ceilings (i.e., >10-15 m), such as Christmas trees or marketing promotion stands (e.g., cars on display). As always, the flexibility of retail requirements needs to be considered, as unrealistic fuel load controls from a fire strategy will cause implementation problems and an unrealistic and potentially unsafe approach as a basis for a fire strategy. That is why the retail team was constantly involved in fire strategy decision making. For implementation, a set of fuel load drawings were created and approved under the process with Dublin Fire Brigade, which illustrated to the client what type of fuel load could be located in each area and which areas had to be sterile.

The strategy adopted for each area was:

  • Back-of-house areas. There was a need for all back-of-house areas to be physically separated from the remainder of the building for security purposes; therefore, traditional compartmentation was adopted.
  • Retail areas. A cabin concept approach was adopted based on automatic sprinkler protection and localized smoke control designed to prevent smoke spilling to other areas.
  • Front-of-house areas underneath mezzanines were provided with sprinkler protection, and smoke control was provided underneath the floor slab to limit smoke spread to other levels.
  • Front-of-house areas not directly below a floor slab in which smoke from a fire could rise to roof level were subject to fuel load control limits, depending on the maximum size of fire that could be expected either due to an open retail kiosk or luggage fire.

Figure 2. Cabin Concept

The cabin concept approach referenced above relates to a method commonly adopted in large - volume buildings in which the fire load is located within cabin-like structures. A retail unit within a shopping center or airport is a prime example.

The approach is based on the provision of a ceiling void that acts as a smoke reservoir, as shown in Figure 2. The provision of automatic sprinkler protection limits the fire size and volume of smoke produced. Smoke extraction is designed to limit any spread out of the cabin. The cabin concept is a useful approach in buildings in which, allowing smoke to flow up to the roof, would result in significant extraction rates. Other benefits include limiting smoke spread (and, therefore, business disruption) to the fire unit and the maintaining of an open-unit frontage.

Fire Service Access
In large terminal buildings, the fire service typically wants to be able to arrive at a single control point to receive a briefing from airport staff and assess the situation before deciding the next steps. From there, they need to be able to access the fire floor within a protected route and get within a reasonable distance of the fire with an adequate supply of water. The means in which they cross the airside/landside line is, therefore, an important consideration.

Terminal 2 was provided with a fire control center within which it was possible to receive live information from the life safety systems, including the CCTV cameras. The control center was separated from the remainder of the terminal with 120-minute fire resisting construction and had dedicated access direct to open air. From the fire control center, the fire brigade could access a total of eight ventilated firefighting shafts with dry mains provided therein. There were also two specific fire service cross-over points within the building through which firefighters only could pass the airside/ landside line as well as two external routes. One external route was a passenger gate in the airside/landside fence near the building perimeter while the other was a manned vehicle gate that allowed access to the apron.

The fire control center was provided with control panels for each smoke zone and evacuation area, which allows for full control of evacuation of the affected area. The evacuation can be phased on an automatic or manual basis, or the decision can be taken to simultaneously evacuate the entire terminal from the control room if considered necessary. In addition, a microphone is provided with which direct announcements can be given to occupants.

Dublin Airport has an airport fire brigade who are the first-responders in any incident. Dublin Fire Brigade are secondary responders following a confirmed fire, and there is an agreed approach between each in terms of overall command and the protocol to be followed in an emergency fire situation.

The Occupants
The occupants of an airport terminal are of a broad range of nationalities, mobility abilities, family groups, single travelers, and a wide range of familiarity of travel. All are focused on either departing a flight, or obtaining their luggage on arrival and getting home. Their behavior is key to a successful evacuation strategy.

With such focus on their process, and at peak times in many airports such high numbers of occupants present, the standard total evacuation policy in most buildings can be unrealistic and even unsafe. A phased approach, where a limited number of evacuation zones actually evacuate in a fire, is preferred. This requires that remaining building zones be safe to occupy.

Prescriptive codes assume floor space factors, and resulting exit width provisions. For airports, the occupancy is far more complex, and subject to detailed quantifying by the airport planning team. The fire protection engineer can, therefore, use passenger numbers that are based on the flow of people through the terminal as dictated by the scheduled arrival and departure of flights. The number of support staff supporting the airport services, as well as airline staff, must also be incorporated, and these too are subject to peak flows in a working day.

The type of people within the building and their probable response upon hearing an evacuation message is another factor that the design must take into account, especially if an ASET (available safe egress time) vs. RSET (required safe egress time) assessment is being undertaken. PD 7974-63 describes items that will have an impact on the pre-movement time of occupants, which include security restrictions, the possession of luggage, presence of family groups and language barriers.

Another consideration that was taken within the T2 strategy was the possibility of a relatively large number of mobility-impaired persons being present within the terminal. This is due to potential religious groups travelling to Lourdes in Europe, where one party may require assistance at times for up to 130 persons, or sporting events for disabled participants. Additional overflow disabled refuge areas were provided for within the design to help cater for such a scenario and specific staff procedures put in place.

Key to all of the above is a competent trained fire safety team, and credible reliance on this is key to a successful airport fire design. In the absence of such competence, far less reliance on management must occur.

Client Requirements & Future Flexibility
In an airport, one of the main client requirements is that the building operates as smoothly as possible. When dealing with a terminal building, this means that passengers are processed without delay and security lines are maintained. This was a fundamental challenge within the strategy, and meant that numerous lines throughout the terminal could not be crossed, even in an emergency situation.

An area that deserves detailed consideration is the route the airside/landside line takes through the building. The airside/landside line is the main security line through which all people and objects must pass. Once on the airside (i.e., the departure side) side of this line, a passenger or object has been security cleared and is assumed to be fit for flight. This line may be formed by solid walls, partial walls, doors or simply a space occupied by staff and an x-ray machine. The position of this line needs to be understood fully as it can affect what happens in an emergency situation, including direction of escape, signage and zoning of fire safety systems.

Separating the building into different evacuation areas allowed this challenge to be overcome, and created a solution where occupants do not pass from airside to landside or vice versa in an emergency situation. All escape routes are designed independently of one another. It was another key client requirement that the building could be evacuated as an "all out” function if required, which was also achieved within the design.

Airports are similar to shopping centers in that they are constantly undergoing change due to the large number of third-party organizations and tenant areas within the building. Flexibility was built into the T2 strategy in a number of areas. In addition to conservative figures being assumed for the occupancy of each area, a strategy was developed that negated the need for the provision of fire dampers within air-conditioning ductwork, which passed between retail units.

The strategy for the omission of dampers from the ductwork between the retail units was based on testing undertaken for the Hong Kong International Airport, which showed that smoke within a unit designed in accordance with the cabin concept typically does not exceed 80°C. In addition, the ambient air supply was maintained to provide a positive air pressure within the ductwork, thereby reducing the likelihood of smoke ingress and spread. It should be noted that a fire damper was provided where the ductwork left the retail area.

Another important stage in the project is Operational Readiness Activation Transition (ORAT). A period within which a series of User Acceptance Tests (UATs) are undertaken, the ORAT phase allows end-user groups to conduct their own sets of tests and scenarios in order to build confidence and satisfy themselves that systems are operating as expected. On Terminal 2, this posed a unique challenge as, due to the construction program, beneficial access had to be given to the ORAT team while construction was being completed. It was necessary to provide adequate levels of safety for these occupants under the Irish Safety, Health and Welfare at Work Act. To do so, an ORAT temporary fire strategy was put in place so that appropriate levels of safety were maintained. The ORAT fire strategy, which evolved on a daily basis depending on the construction work taking place that day, entailed:

  • Prioritization of work in certain areas to facilitate the temporary fire strategy,
  • Induction sessions for all RAT staff on fire safety procedures on site,
  • Putting in place a number of fire marshals whose sole duties were to enforce the agreed interim fire strategy and to lead the ORAT staff out of the building in the event of a fire,
  • Identification and signage of appropriate escape routes remote from construction works,
  • The provision of a temporary wireless fire detection and alarm system while the final building systems were being commissioned.

Way-finding trials were also held before the building was fully completed, as part of the ORAT process, which involved multiple events with many (4,000+) members of the public (including mobility-impaired persons and children) being processed through the airport as if they were departing or arriving. Again, a specific fire strategy had to be developed and implemented to ensure participants' welfare.

Fire Safety Objectives & Acceptance Criteria
At the start of the process, the fire safety goals and objectives were discussed in detail with the client and the approving authority, which allowed a set of acceptance criteria to be established before fire strategy work commenced.

Life Safety
It was the duty of Dublin Fire Brigade(the approving authority) to verify that adequate levels of life safety were being met in accordance with the Irish Building Regulations.

The Second Schedule of Part B (Fire Safety) of the Building Regulations4 requires that adequate levels of life safety be achieved in new buildings by complying with five main functional requirements:

  • B1 – Providing adequate means of escape measures. This goal was achieved by carrying out an ASET vs. RSET assessment to demonstrate that untenable conditions would not occur in the time required for occupants to escape.
  • B2 – Limiting the potential for fire spread within the building over surface linings, which was achieved by following prescriptive guidance.
  • B3 – Limiting the potential for fire spread within the building by limiting compartment sizes and providing proper compartment construction. Smoke extraction, suppression, fuel load control and active fire safety systems were used to achieve this goal.
  • B4 – Limiting the potential for external fire spread.
  • B5 – Providing adequate access and facilities for the fire service. This was achieved by the provision of dedicated and protected access routes, building suppression systems and active ventilation.

Business Continuity
Airports operate on a continual basis and are a critical piece of infrastructure. Therefore, large-scale evacuations or disruption of passenger processing in a terminal is catastrophic for the airlines and the terminal operator for commercial and reputational reasons. Business continuity goals were, therefore, established during the concept stage with the client.

The strategy was the protection of sensitive areas or areas of high fire hazard while also providing a response that was in proportion to the event. The philosophy adopted was based on minimizing nuisance alarms by adopting a two-stage cause and effect, which meant that only an evacuation would be automatically instigated following a second activation of a smoke detector. Aspirating smoke detection was also utilized in the baggage handling hall to avoid unnecessary nuisance alarms and implications for the baggage handling system.

If a fire did occur, it was limited as much as possible by the control of fuel load, either by management controlling the size of retail kiosks, etc., or by suppression in the form of sprinklers or gaseous suppression. Disruption was limited by evacuating only those areas needing to be evacuated, while maintaining passenger segregation.

In the unlikely event that a large incident did occur, it was still feasible to initiate a full and simultaneous evacuation of the terminal.

Barbara Lane, William Ward and John Noone are with Arup.


  1. Application of Fire Safety Engineering Principles to the Design of Buildings – Code of Practice, British Standards Institution, London, 2001.
  2. Engineering Guide - Performance-Based Fire Protection, National Fire Protection Association, Quincy, MA, 2007.
  3. The Application of Fire Safety Engineering Principles to Fire Safety Design of Buildings – Part 6: Human Factors: Life Safety Strategies – Occupant Evacuation, Behaviour and Condition, British Standards Institution, London, 2004.
  4. Technical Guidance Document B – Fire Safety, Department of the Environment, Heritage and Local Government, Dublin, 2006.