Have a Safe Flight
Fire professionals share the finer points of airport fire-protection design for these unique facilities. CSE: Given the unique nature of airports, what special fire-protection requirements do these facilities have? CASTELLANO: Today's airports incorporate large open areas, often atriums, to provide passengers with a sense of spacious surroundings and a welcoming environment to the arriving city.
Fire professionals share the finer points of airport fire-protection design for these unique facilities.
CSE: Given the unique nature of airports, what special fire-protection requirements do these facilities have?
CASTELLANO: Today's airports incorporate large open areas, often atriums, to provide passengers with a sense of spacious surroundings and a welcoming environment to the arriving city. Atriums, while desired by architects, owners and the general public, create a unique fire-protection challenge. An atrium is a large vertical opening between floors of a building that creates a path by which fire and smoke can travel. An engineering analysis is typically required by the relevant codes to determine the desired approach for the management of smoke movement.
MADDEN: Don't forget you're also combining high occupancies with the potential of a severe fire hazard because of fueled aircraft. That's why airport terminal buildings must be designed to provide for a fire-resistive separation between the building and adjacent aircraft. Such separations are made up of fire-rated construction assemblies, fire-barrier glazing systems or glazing systems protected by water-spray systems. Sprinkler protection, of course, should be provided throughout, including contiguous support/operations spaces. And regarding the latter, fueling ramp drainage is also necessary.
MARRION: I'd like to expand on the notion of large open spaces. These areas are also there to facilitate the free flow of passengers and intuitive wayfinding. Additionally, there is a clear trend toward creating multiple concourses, and therefore, rail stations are becoming necessary to move travelers between concourses. In and around these areas, there are also operations for security, retail and hotels, which at times, can conflict with the need for open space.
CSE: So how does this affect open space?
MARRION: The addition of these various occupancies presents challenges in terms of potentially higher fuel loads and possible high-rise code requirements. This all translates into the need for an integrated fire strategy that addresses code requirements for each occupancy, but also takes a holistic view, including an integrated evacuation plan, so that all strategies can function together.
CSE: On the subject of egress, you've got a wide variety of people using these facilities, ranging from infants to the elderly. There's also a wide-ranging occupancy level. How do you deal with these issues?
MARRION: It's critical to design good wayfinding, which, simultaneously, can benefit the evacuation strategy. One disadvantage of airports is that people usually have to evacuate to the apron level, which can be quite a dangerous place if not strictly controlled by management.
CSE: Since Sept. 11, 2001, it's safe to say that airport design has changed fundamentally. How have fire-protection requirements and expectations changed?
MADDEN: 9/11 pointed out the importance of looking beyond typical fire scenarios with regard to high-profile facilities such as airport terminal buildings. More of a systems approach to fire protection and life safety in such facilities needs to be taken, as opposed to just meeting minimum code requirements.
MARRION: Specifically, I'd note these challenges:
Reduced egress widths where security systems have been added, particularly at existing airports.
Higher occupant loads in various areas, due to heightened security procedures. This means exits and other facilities need to accommodate these larger numbers.
Exits discharging to the apron and secured areas must be reduced or eliminated.
Exits discharging from airside to landside must be reduced or eliminated.
An integrated evacuation plan that addresses all credible risks and threats is necessary.
Human behavior, including how people may respond during an incident—and respond to directions—must be appropriately addressed.
Development and implementation of a detailed fire-safety management program is necessary.
Blast analysis must be incorporated into the design.
MACDONALD: I'd add that fire personnel are also more aware of security and are concerned with potential scenarios in which terrorists might, for example, use the fire-alarm system to gain access to secure areas through the use of alarm activation to release locked doors.
CSE: When security and fire protection requirements conflict—for example, the need for emergency evacuation/egress into secured areas—how do you resolve this?
CASTELLANO: Fire protection and security will almost always have areas of conflict throughout the course of design of an airport terminal building. A key way to resolve these issues is communication between the fire-protection and security design professionals, or better yet, a company that has both professionals on staff. Another key is continuously meeting with all the main decision makers so that all the conflicting areas of design can be identified and resolved.
MADDEN: Exiting into a secured area has been common in airport terminal design in the past, and will continue in future terminals. As Mr. Marrion mentioned earlier, one of the challenges is providing for adequate exiting capacity when adding new security barriers and screening stations in existing terminal facilities. In new facilities, these conflicts can be more easily identified, planned for and worked through by the multi-discipline team.
MARRION: Other strategies I'd recommend include:
The use of horizontal exits to provide egress to adjacent safe areas.
Maintaining a separation between airside and landside as much as possible.
Working closely with the airport authority, security consultant, threat/risk consultant and local emergency responders to develop an integrated solution.
The avoidance of evacuating into secure areas, if possible.
Synchronizing egress with the natural movement through the airport.
CSE: What other notable operations trends do engineers need to be aware of?
CASTELLANO: The installation of new FAA-mandated security baggage screening equipment requires the use of pre-action fire sprinkler systems.
MARRION: Along a similar line, there's a general need to maximize business continuity and minimize operational disruption. If an airport is closed for business—no matter how long—it tends to adversely upset aircraft movements, which have a ripple effect locally, nationally and around the world.
Establishing objectives with the stakeholders early on is quite important. For example, airports often have airside and landside areas positioned on top of each other with staircases serving both areas. This can introduce security issues as landside and airside occupants become mixed during an evacuation.This can be controlled using either phased evacuation and management to direct landside and airside to different areas, or evacuating all occupants together for reprocessing upon re-entry into the building. The latter is typically easier from a design perspective, but not as good from a business continuity angle.
MACDONALD: On the subject of evacuation, be aware that commanding the attention of the traveling public when an alarm condition occurs is big. The general public tends to be indifferent and insensitive to fire alarms. This has created a strong need for intelligible, real-time voice announcements by fire-fighting personnel.
CASTELLANO: Maintenance is also a key issue, specifically, minimizing the impact one's design has on future maintenance requirements. This can be accomplished by minimizing the complexity of the initial system design and by the designer having knowledge of the required maintenance procedures so that his or her design will facilitate access to the equipment for future maintenance.
CSE: Please describe any newer technology that is now being implemented, or considered, for airport fire-protection schemes.
MARRION: To Mr. Castellano's point, some of the systems and features now being implemented include intelligible fire-alarm systems; integration of fire-alarm systems with PA systems; and localized smoke-management systems to limit smoke spread from the area of origin and help limit business interruption, as well as limit the areas that need to be evacuated. Also, smoke detection via CCTV is being looked at for some large open areas, as is infrared detection.
MADDEN: The cameras being installed for security monitoring provide more options for detecting and reacting to emergencies and hazardous conditions, as well as act as a tool for use during emergency response. Evolving smoke-detection technologies, in general, also offer more flexibility in system design and installation, along with more sensitive, discriminating detection capabilities. Earlier, someone mentioned preaction systems, and I think evolving sprinkler technologies are providing more flexibility with sprinkler protection for the large open spaces we discussed earlier. Addressable fire-alarm and detection-system equipment is also more flexible with regard to system installation, as well as for ongoing maintenance and modifications.
CSE: In general, what is particularly challenging when coordinating with other M/E/P engineers on airport projects, and what are some suggestions for how to deal with this?
MARRION: Biggest challenges include:
Coordination between disciplines with regard to fire and life-safety systems to help ensure they are coordinated and integrated to function together.
Dealing with landside and airside breaches, and coordinating fire/security design and management systems.
Designing flexibility for future use and expansion.
Providing exit stairways in certain areas, as baggage processing gets in the way at lower levels.
Dealing with issues with respect to interconnection of levels. For example, baggage handling needs to be open to baggage claim, which is open to ticketing, which is open to departure, which may be open to another rail or garage level above. While openness enhances movement through airports, it also enhances movement of smoke.
CASTELLANO: Solutions to improve communication, especially with out-of-state consultants, can include video conferencing or the use of secure FTP sites to post drawings.
MARRION: I find that multi-disciplinary workshops on fire safety during the design process are a great way of communicating the strategy, particularly if the strategy is complex. The fire strategy can also help define zones so that they are coordinated across disciplines for the various systems, both horizontal and vertically.
CSE: How do you deal with the fact that airport project plans and requirements tend to change over time?
CASTELLANO: By the sheer nature of their operations, airport terminal buildings will more often than not see changes that affect systems design. Incorporating flexibility into the initial design is key for a good design professional. One suggestion is exceeding the code to provide a safer environment for the occupant, as it can result in meeting the requirements of future code changes.
MARRION: The fire strategy should be flexible enough to enable some change without a large overhaul of the design. As plans change, the same concepts from the strategy can then be applied relatively easily. It is also important to monitor work that goes on, i.e., periodic inspections, to ensure compliance.
Airports often have their own maintenance staff and inspectors, who should be brought into the process early for their input, as well as to familiarize them with the strategy so they can incorporate it into future modifications and maintenance.
Airports also need to be designed with flexibility for future use in mind. However, it may be hard to convince the stakeholders that the additional cost involved is necessary during the design phase.
Finally, I'd say a management plan needs be developed that requires a review of any changes to the airport by a qualified fire engineer who has a full understanding of the original fire strategy. Both the original and up-to-date fire strategies need to be made available to the building manager and other relevant stakeholders, and should remain on site for future reference. In addition, this management plan should include periodic inspections by a qualified person to review the fire/life safety strategy and ensure that it continues to be implemented.
Joe Castellano , P.E. , Engineering Manager, The RJA Group, Atlanta
Christoper Marrion , P.E. , Associate Principal, Fire Strategist, New York
Michael J. Madden , P.E. , Principal Gage-Babcock & Assocs., La Palma, Calif.
John J. MacDonald , P.E. , Partner TMP, Consulting Engineers, Boston