PPE for buildings

Shortly after the start of the weekly Friday meeting of the executive council in the boardroom on the top floor of the Muschdoller Bank headquarters in downtown Boston, the urgent wail and flashing yellow lights of a sensor alarm by a ventilator grate in the elevator lobby interrupts an accounts payable presentation, indicating the presence of a toxic chemical in the building.

Penny Nichols, the most junior executive, who also serves as boardroom marshal, knows the drill, because she was recently rehearsed by the corporate emergency planning and response team.

She dashes for an 8-foot walnut cupboard against the wall, twists a chrome handle and pulls the front of the cabinet out across the room until a clear plastic expandable shelter housed inside is fully extended. She then opens the shelter entry, directs the nine other vice presidents inside, seals the entry behind her and activates the filtration system. Such is life for Muschdoller Bank executives in the Age of Terrorism.

Options and threats
Muschdoller Bank of Boston doesn’t exist, of course, but the shelter, called an Expandable Cabinet Shelter, is real.

According to the manufacturer,  Collective Protection Inc. of Baltimore www.collectiveprotectioninc.com, it’s impermeable to chemical warfare agents, bacteria and viruses; can be located in boardroom, bedroom or airport executive lounge (anywhere you can fit an armoire-sized cabinet); and, depending on model and optional accessories, can house six to 36 occupants, for several days if necessary. Extended stays require several optional features, not the least of which is a chemical toilet, survival rations and a high-speed Internet connection.

This sort of sheltering in place is just one answer to the collective-protection problem. Plenty of more sophisticated solutions exist in a range of technologies designed to protect building occupants from a chemical or biological weapons attack.

“The need to control our indoor environment is more critical now than ever,” says Steve Slayzak, a project manager at the National Renewable Energy Laboratory, Golden, Colo.

“While our homes and buildings are built ever tighter for maximum energy efficiency, terrorist attack by weaponized airborne agents is a credible threat. Buildings and their HVAC systems are effective means of delivery of deadly airborne agents.”

Collective protection exists to counter these attacks.

Collective protection
Collective protection is a mature military building (and ship) protection concept that’s beginning to emerge more and more in civilian homeland protection circles. It’s essentially just personal protective equipment for the insides of buildings, technologies that perform the same function for structures that PPE does for individuals.

At one end of the technology range are low-cost, low-end solutions such as sheltering in place based on a warning of an impending attack or creating temporary safe rooms using expedient colpro equipment. One step-up is filtration systems that scrub the air. At the top end are protection systems that integrate passive measures such as filtration with automated active building responses that are initiated when an attack is detected.

Automated response includes machine-to-machine technologies that enable computers, sensors and actuators to communicate with one another, take measurements and make decisions, usually without human intervention. An example might be automatically shutting down fans and all operable dampers to prevent dangerous agents from migrating through a building’s air-distribution system.

There is a significant cost-performance trade-off in these systems.

“The low-end solutions have as their primary advantage low cost, but may only address a portion of the threat spectrum,” says Jim Risser, associate manager for infrastructure assessment at Battelle, a global science and technology enterprise that develops and commercializes technology and manages laboratories for customers www.battelle.com.

“The high-end systems address a broad range of threat agents and a variety of release scenarios. However, they currently suffer from costs that can be prohibitive to some prospective users.”

Battelle and others are working to reduce costs in this space, to make colpro technologies accessible to a broader range of clients.

Lockheed Martin’s Building Protection System, for instance, ranges from simple procedural changes to full-scale dynamic, reconfigurable building-wide sensor networks tailored to individual customers’ needs. By modifying and augmenting the existing building infrastructure, the Building Protection System can greatly reduce the effectiveness of an NBC attack through the use of commercial-off-the-shelf hardware and software. Customers can use their existing HVAC infrastructure and update it with emerging chemical and biological sensors.

Risser says interest in applying advanced building protection systems continues to grow in the civilian sector.

“Currently, the leading areas are medical facilities and transportation centers: airports, railway and subway stations,” he says. “We expect that efforts to protect arenas and assembly areas with large populations will begin to increase rapidly in the near future.”
 
Air supply
Since chemical and bio-aerosol threats could be launched through HVAC systems, air supply protection is probably the most critical aspect of collective protection.

nrel, for instance, is developing a unique HVAC dehumidifier that provides a dual-use (chem-bio) filtration. The technology is based on desiccants, materials that naturally attract moisture from gases and liquids. The desiccant material becomes saturated as moisture is absorbed or collects on the surface, but when heated, the desiccant dries out (regenerates) and can be used again. The Department of Defense has identified these features as important to the next generation of colpro air filters.

“This new functionality enables chem-bio agent deactivation strategies that were previously unavailable,” Slayzak says.

Sorption-based air-conditioning technologies address design needs for adequate ventilation, waste-energy recycling, and thermal and chemical indoor air quality, as well as homeland security. It can be a tricky equilibrium to maintain.

HVAC systems have to strike a balance between energy use, indoor environmental quality and security functions. Probably the least expensive way to achieve this balance is by combining colpro filtration with existing HVAC systems, but there are limitations.

“Typically, HVAC units cannot handle the additional cooling/heating loads placed on them by collective protection demand,” says engineer Carl S. Pates of New World Associates, Fredericksburg, Va. www.newworldassociates.com

The AirePod CBR Filter System is a fully packaged air-handling system with integrated CBR filtration and can be attached to a building's existing HVAC system. The inlet plenum is at right, and the outlet plenum, with the filter housings (in blue), is at left.

“Standard HVAC systems are not designed for higher pressures, plus they all have significant leaks.”

Modular systems like New World's AirePod cbr Filter System come pre-packaged with integrated CBR filtration, for creating colpro environments. Users can simply duct-tape the AirePod’s ventilation outlet to a building intake and connect it to ac power. It can operate in stand-alone mode or be connected to existing building management systems for integrated control. Its modular design offers significant savings of time and integration expense over custom filtration systems, according to New World.

The civilian market
So far, these collective protection technologies haven’t penetrated far into the civilian sector. Today’s security paradigm still consists of interior smoke alarms, a string of closed circuit television cameras and a uniformed guard sitting at a security console in the lobby checking employee badges.

“Very little is being done in general in buildings, other than those at high risk,” says engineer Larry Spielvogel, chair of the Presidential Ad Hoc Committee on Homeland Security for the American Society of Heating, Refrigerating and Air-Conditioning Engineers.

Spielvogel says ASHRAE’s approach looks primarily at two factors. One is multiple-benefit solutions to more readily justify implementation measures. Multiple-benefit solutions provide both everyday improvements and greater protection against bio-chem attacks.

“Better quality air filtration is one example,” Spielvogel says.

The other factor is resilience to all types of incidents, including natural and accidental events in addition to intentional malice. Resilience provides benefits both for natural and accidental incidents as well as intentional incidents, but not necessarily everyday benefits.

As an example, on-site water storage provides benefits for loss of water supply for all types of incidents, but not everyday benefits, Spielvogel says.

“This allows limited but more widespread protection than against intentional incidents alone, but adopts those measures that are more likely to be used,” Spielvogel says. “Even measures in high-risk buildings are limited by the lack of reasonable, affordable and reliable sensor technology.”

Nevertheless, companies in this space are beginning to see interest from the civilian market for these types of colpro technologies, driving improvements in sensor technology.

“For instance, banking and financial institutions, as well as the transportation sector, have begun to see the importance of chemical detection in an attempt to protect their assets,” says Susan Cooper-Curcio, director of marketing at Smiths Detection, Pine Brook, N.J. www.smithsdetection.com.

Some sensors, like Smiths’ Centurion, are already installed in some federal and commercial buildings as an early warning mechanism for detecting chemical warfare agents and toxic industrial chemicals. (The company declined to name specific installations.)

The Centurion detector is based on ion mobility spectrometry, a powerful analytical tool that permits detection and identification of a wide variety of chemical substances that, in this case, has been optimized for the detection of CWAs and TICs. This unit can detect and identify the most common cwas (sarin, phosgene, ricin, soman and others), plus 16 common tics (bisphenol A, phthalates, perchlorate and others), most of which are classified as high threats on the Justice Department’s Toxic Industrial Material List.

Currently, no single measurement technique is able to analyze for all known tics.

“Analyzing for tics is advantageous, since TICs are becoming much more of a threat than CWAs because they are more easily obtainable,” says Cooper-Curcio.

The Department of Transportation estimates that hazmat traffic levels in the u.s. now exceed 800,000 shipments per day and result in the transport of more than 3.1 billion tons of hazardous materials annually, making the tic threat a serious one. Chemical plants, pipelines, storage facilities, railroads and trucks are all possible sources from which toxic industrial compounds could be released, or obtained for use by terrorists.

Sensor technologies
Ion mobility spectrometry is a mature technology, having been around for over 20 years. A number of firms market products worldwide using the same principle for narcotics and explosive detection.

The cost for IMS sensors for collective protection varies widely depending on the size of the building, air-handling systems and reporting requirements.

A number of other sensor technologies also exist. One, called surface acoustic wave, creates extremely sensitive gravimetric detectors that can be coated with a film to collect chemical species of interest. Some sensor systems based on this technology can detect trace amounts of airborne contaminants on the parts-per-billion level.

Chemiresistor gas sensors use another technology. These are large arrays of chemical sensors with responses interpreted using a pattern-recognition algorithm that can discriminate a variety of chemicals. Chemiresistors, which change resistance when exposed to a gas or vapor, are low-cost devices that can be easily implemented in a sensor array. These devices consist of interwoven electrodes coated with a conducting polymer film.

One approach to realizing a miniaturized, low-cost sensor system is to construct on-chip acoustic sensors and combine these with on-chip control electronics. A novel integrated micro­sensor being developed at Sandia National Laboratories will enable increased sensitivity for trace detection and identification of a variety of chemical species. The sensor combines saw technology with microelectronics to produce a monolithic, compact, low-power integrated circuit microsensor.

Sandia believes the combination of low power, compact size, high sensitivity and robustness of integrated high-frequency saw sensors makes them ideal candidates for applications requiring miniaturized and portable trace chemical detection capabilities, particularly for in-situ monitoring.

Building water purity is not overlooked in collective protection. Electrochemically-based chemical sensors responsive to electrochemical reactions are being developed to detect a wide range of chemicals in water. These sensors consist of highly ordered arrays of nanometer-sized dots (electrodes) that detect trace (parts per million to parts per billion) levels of waterborne contaminants.

Federal advances
Whatever the method, collective protection technologies are currently more likely to appear in new federal buildings than anywhere else.

In the normal construction sequence, the basic structure is erected, then occupants design their own subdivided spaces. Some new government buildings, however, like the Jacksonville, Fla., federal courthouse, are planned down to the chair rails, making it simpler for designers to implement detailed security features using a concept known as a “total construction perspective.”

At the Jacksonville courthouse, door placement, corridor layouts, ventilation systems, and even key and lock coordination were considered in advance and handled according to strict government guidelines, says Brian Murray, project director for Skanska usa, one of the project architects.

Some existing federal structures are also getting a retrospective collective protection treatment. For instance, parts of the Pentagon has been outfitted with an anti-terror air filtration system called the Advanced UV System, designed to protect the interior of a building against biological attacks and also to create safe zones within the building. The installation is part of a Department of Defense program called the Collective Protection Technology Readiness Evaluation.

The AUVs technology, from Novatron Inc. of San Diego www.novatroninc.com, involved installing intense ultraviolet air-sterilization equipment in the building’s HVAC system to kill microorganisms in flowing air. Novatron president and CEO Richard Clark says this system is capable of protecting Pentagon employees against anthrax, ricin, small pox, and even the flu and common cold. The Defense Advanced Research Projects Agency provided Novatron with $4.5 million in grant funding as part of DARPA’s Immune Building Technology Development Program to develop the system.

“While Novatron now has a firm foothold in the defense industry, its future may well include markets outside the defense market,” says Suzanne Finch, director of marketing for the Department of Defense–supported Center for Commercialization of Advanced Technology, a program providing funding and business commercialization services for small businesses to help them through the technology-transfer process.

A promising future
While collective protection in the civilian sector is largely in its infancy, there’s plenty of promise in its future. Ongoing efforts at cost reduction for high-end systems should help ease the current financial burden.

From a technology standpoint, improvements in biological and chemical detectors are needed to further improve system performance and help reduce costs.

“New detectors are likely to become available in the next five years and beyond that will address various detection issues including improved sensitivity, a broader range of agents detected, lower false alarm rates, and significantly lower cost,” Risser says. He also expects development of filtration systems that can capture a wider range of tics.

Other experts see an integration of existing technologies as methods harden.

“Since every technology has advantages and disadvantages, in five years we are likely to see a combination of technologies, where one technology would be used as the primary source and the other used as a secondary confirmation,” says Cooper-Curcio. This idea could see a marriage of ims and saw or even two ims detectors in the same device.
Combining technologies will solve a major flaw in most current systems, the false alarm.
“The combination of technologies will successfully minimize the nuisance alarm,” Cooper-Curcio says.

In the future, she says, chemical detectors will become more frequent in buildings and be built into each building’s structure.