Airports in a Post-9/11 World

Of all the businesses impacted by the stunning terrorist attacks of Sept. 11, 2001, commercial aviation may have been hit the hardest. Since that ill-fated date, billions of dollars in terminal and runway improvements have been put on hold, including major projects in Miami, San Francisco, Denver, Seattle, Las Vegas, Boston, Houston and now Chicago.

Indeed, as the fallout from Sept. 11 has settled, the long-term impact on the airline industry has become manifest: a drastic drop in air passenger traffic. Commercial traffic, in fact, is down 12% to date, compared with the same period in 2001. A slow recovery seems inevitable considering these economic indicators: the American Stock Exchange airline index dropped 33% in the second quarter of this year, and global financial firm J.P. Morgan and Company estimates the airline industry as a whole will lose $4.7 billion by the end of 2002.

Airport work, however, is proceeding. But instead of large-scale expansions, airports and airlines are busy implementing security measures mandated by the new Transportation Security Administration (TSA).

New York, Los Angeles, Orlando and San Francisco are among the cities taking the initiative by engaging consultants to master plan for the installation of baggage, employee and passenger screening equipment, amid other security improvements.

In assessing the big security picture, baggage screening poses the most significant mechanical, electrical and structural challenges. Simply put, baggage screening is more complex than employee or passenger screening, largely due to the number of bags involved. Additionally, the situation is complicated by a federal mandate for airports to have 100% baggage screening in place by the end of the year.

In the effort to meet the government's deadline, many airports are turning to a promising solution: explosive-detection systems (EDS). The technology—which is somewhat similar to the X-ray machines used in the current passenger screening process—uses sharper X-ray projection and high-resolution computed tomography (CT) technology to scan luggage, according to manufacturers.

The technology also offers a number of additional features, manufacturers say, such as the ability to make quick and accurate alarm/clear decisions while a bag is still in the system.

However, mandatory deployment of this equipment is expensive—each unit can cost millions of dollars—and meeting TSA's deadlines remains a strain for many of the nation's 429 airports.

To help ease the pressure, TSA has agreed to allow a hybrid solution. This alternative still requires the installation of some EDS machines, but allows the overall baggage-screening process to be augmented with a similar, but less expensive technology—explosive trace detection (ETD). These hand-held devices detect explosives by testing a sample obtained by running a wand over open baggage. Although ETD screening is more time-consuming and manpower-intensive, the technology is effective, more readily available and generally easier to implement.

Such hybrid schemes, however, are likely short-term fixes, as ETD equipment, eventually, will likely be replaced by automated EDS machines integrated into the baggage conveyer system. Some long-term plans also suggest screening be done off-site, for example, at hotels. Ultimately, the trade-off between the cost of facility modification vs. manpower logistics has to be analyzed. Regardless of the number of EDS installed, it takes creative solutions to incorporate any EDS equipment into existing facilities. The sheer bulk of the machines, which are the size of a minivan and can weigh more than 17,000 lbs., requires very specific structural preparations, as well as electrical and HVAC requirements.

From an M/E engineering perspective, integrating EDS equipment into an existing system requires that designers establish new levels for functional systems reliability and passenger/personnel comfort.

For instance, each EDS unit needs up to 30 kVA. Medium to large terminal facilities may require between 15 and 40 EDS units to meet demand. Though ETD equipment requires much less electrical power—only about 500 watts—these same terminal facilities could require more than 100 ETD units.

This is exactly the case that's happening in one screening solution currently underway in an existing airport upgrade project. The plan called for ETD technology to serve every two ticket-counter positions, with a select number of EDS units checking bags that failed ETD inspection.

Because engineers might encounter such variables, the electrical system must be carefully evaluated to be certain that sufficient capacity is available. Additionally, failure analysis should be performed to limit the quantity of EDS and ETD units that might fail with the loss of a key component such as a transformer, breaker or feeder.

Furthermore, the electrical design should also accommodate any inherent weaknesses in the building's normal electrical service. If power outages are common, the use of local or central UPS systems should be considered.

A second M/E engineering EDS key deals with increased HVAC loads. The specific challenge depends on the type of EDS selected. Some units include internal refrigeration systems and are therefore able to be placed in environments with wide-ranging temperature and humidity levels. Other units, however, are designed to be placed in a controlled environment and have very restrictive temperature and humidity requirements. Once this decision is made, the next consideration involves the location of screening personnel and passengers. Even if EDS equipment is self-cooled, the unit will likely reject up to 30 MBh of heat to the surrounding space. If screening personnel are going to be located at the unit, HVAC systems must be retrofitted to provide a greater level of comfort.

Another key HVAC challenge is the added heat load associated with the ETD equipment and the potential for higher levels of occupancy density in adjacent areas as people wait to drop off their luggage. Cooling system capacity may be insufficient, so outside air provisions should be verified.

As far as integrating the EDS with the existing baggage-handling system, special considerations are involved, including ensuring the compatibility of the computer software directing the sorting and screening systems, and the physical proximity of baggage sorting with respect to passenger ticketing.

Security at our nation's airports continues to evolve. Major hubs are implementing security measures at a good pace. But even as sophisticated baggage-screening systems continue to be implemented, they are only one piece of the puzzle, albeit a large one. Perimeter security and access control will be necessary at many facilities (see "Biometrics Already in Action," opposite).

New recommendations from the Center for Disease Control and Prevention, issued in May 2002, also address ways that buildings should be designed to limit their vulnerability to chemical, biological and radiological attacks. Future HVAC systems will need to consider these suggestions for improved air filtration, fully ducted return air systems and specialized control sequences in the event of an attack.

Furthermore, some airports are conducting blast analyses to determine the threat associated with various locations of parked vehicles.

Additionally, as TSA continues to deploy federal screeners and streamline the process, engineers will likely see considerable adjustments in the locations and quantities of other kinds of screening equipment (see "A Peek At Things to Come," p. 32). The density of occupancy and the bulk heat rejection from equipment will likely result in HVAC system augmentation. We may also see specialized explosion-proof rooms and/or buildings at airports to accommodate bags that fail the various scanning tests.

And as noted, many airports are likely to consider installing automated baggage systems in order to provide long-term baggage-screening solutions that are less space-intensive and more seamless to the passenger. These systems will use EDS units to detect explosives as the bag travels from the ticket counter to the gate. Although the exact protocol as to how TSA wants bags to go through the screening process has not been finalized, several airports are already committed to such an inline process.

Finally, automated baggage systems will assist with another key development in the future—common use terminal equipment (CUTE). By installing automated baggage handling systems, airport operators can build in the ability to send bags from any ticket counter or curbside to any gate. This gives the airport the ability to shift gates on demand during the day.

Those airports that consider the use of automated baggage handling with inline EDS will encounter many interesting challenges such as phasing construction of the baggage systems in operational terminal facilities. Electrical power distribution and emergency shutdown systems will also require a great deal of coordination.

Despite these challenges, the use of automated baggage handling and CUTE systems will likely shape terminal baggage and passenger handling facilities in the future.

Nearly a year after the tragic events of Sept. 11, 2001, the world of aviation facility design is changing before our eyes. The move toward improved security will touch most aspects of the existing and future terminal designs. Our challenge is to understand why these changes are taking place and to help facilitate them for the benefit of the traveling public.