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A Snapshot Of A Changing Industry - Building Control & Homeland Security

Mike Schell
Director Sales & Marketing
AirTest Technologies 

In the near term, the homeland security threat to buildings will force the long anticipated integration of building control, fire and security system to truly act as a single, intelligent system in buildings.

The events of September 11, 2001 have started to drastically influence the way we design and operating buildings. The use of airborne chemical or biological agents by terrorists is increasingly becoming a domestic concern. Buildings and their associated ventilation systems can either be a perfect delivery mechanism for these deadly air contaminants or when systems are properly designed, they can ensure a haven of safety.

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It is important to note, I am not a WMD (weapons of mass destruction) expert, nor a biologist or a chemist. I have no military background or expertise in defense planning. I am an individual who has been involved in the sensor area of building control and indoor air quality for over 20 years. Like many of you I just understand how buildings work. What I will share in this article is some of the things I have learned from investigating this issue in the past year and a half. My intent is to provide a brief snapshot of what the near-term state-of-the-art is in protecting buildings. I will also provide a number of references should you like to further investigate these issues yourself.

Building Operation And Homeland Security

Believe it or not, it is the building operators, mechanical engineers and control contractors who are on the front line in defending against this threat. This is because building protection will ultimately involve many of the same disciplines and knowledge we apply today in our profession including: 

  • Understanding of basic building science principals including factors that affect pressurization, infiltration and air movement in buildings. 

  • Understanding of mechanical system operation and building, security and fire control methodologies. 

  • Understanding of how IAQ focused equipment such as filtration and UV lights will deal with these previously unanticipated threats. 

  • Understanding of sensor technology and factors that will have a bearing sampling effectiveness and efficiency.

Preparing for this potential threat will also force building owners to pay much more attention to the operating status of their building. This will ultimately improve the quality and safety of indoor environments in general. Hopefully, such attacks will not occur, but preparing for this possibility will benefit buildings and their occupants. We are also treading on some new challenging territory involving integration of new sensor technologies and integrating response and functionality of building systems for fire, security and building control. The functions have traditionally have operated autonomously.

What Is The Threat?

A recent conference I attended on homeland security issues divided the nature of the threat into four major classifications. 

In fact, at the conference, I witnessed a lengthy debate by a panel of defense experts who argued about which of these four threats was the most significant.

Well, I walked away from the debate convinced that the threat from each of these was equally as terrifying.

What Is The Risk?

contemporary The truth is we don't know what the real risk is. There is considerable debate right now regarding the likelihood of a chemical or biological attack versus other risks we face such as earthquakes, tornadoes or other catastrophes. Many experts also point out that it is likely that such an attack might directly affect a small number of people but could cause widespread panic.

As part of my research on the issue, I came across the recently published book, Germs… Biological Weapons and America's Secret War (Simon & Schuster 2002, ISBN 0-648-87158-0). It provides an incredible chronicle of the recent evolution of biological and chemical weapons. The book describes a number of recent events we probably all remember hearing about. Each at the time seemed an isolated incident. The shock for me was realizing how each of these events revealed a disturbing trend that has continued to the present day. Here are just of a few incidents described in the book:

The conclusions drawn in the book Germs is that the knowledge, techniques and materials to make harmful chemical and biological agents is much more available today than it was just a few years ago. Expertise is increasingly available. With the collapse of the Soviet Union, thousands of Soviet scientists skilled in chemical and biological warfare have found themselves unemployed or penniless. Many are suspected to be shopping their unique skills to the highest bidder. The worldwide use of modern pharmaceutical manufacturing techniques has also resulted in widespread dissemination of knowledge and techniques that previously were held by a few superpowers and required significant resources to develop.

The attractiveness of biological and chemical weapons to rogue states or terrorist organizations is that they are effectively the "poor man's atomic bomb". According to Soviet defector, Ken Albeck, head of the Soviet bio warfare program, "An expert could teach a terrorist group how to make a devastating germ weapon with a few handfuls of backyard dirt and some widely available laboratory equipment."

My reading of Germs tells me that the genie is out of the bottle, and it is unlikely we can put it back. The reality is that we will have to add the risk of exposure to chemical and biological agents, to all the other manmade and natural risks we face every day. Only time will tell how significant this new risk is. But those of us in the buildings and indoor air quality industries have to begin considering how to add these new risk variables to our professional capabilities.

Current Thinking On Building Protection

Obviously, we are dealing with a work in progress. One of the first organizations to jump into action to consider these new implications for building construction and operation was the American Society Of Heating, Refrigeration and Air-Conditioning Engineers. In 2001, soon after Sept. 11, a special study group was formed to consider health and safety implications of extraordinary events. Its first eight-page report, titled "Risk Management Guidance For Health & Safety Under Extraordinary Events," was released in January 2003. A full copy of the report is available from

The report makes a number of commonsense recommendations for building designers and operators and cautions about making drastic changes that may impact other aspects of building operation. The report represents the state of the art but acknowledges that there is much work to be done. A large portion of the report focuses on encouraging building owners to understand how their building operates and the implications for preventing the distribution of aerosols. Some of their recommendations include:

Importantly, the report also provides some guidance on what building owners should not do. The report suggests that no immediate changes should be made to existing building codes and standards until we know more. Also, it stresses that changes to buildings should not be made without consideration of maintenance cost, energy consumption, indoor air quality and site adaptability.

The report also talks about sensors. It states, "Sensors or other means of for warning are not presently available or are not reliable for many contaminants. Therefore strategies and other feedback control must be relied upon today." This means that the typical detect-and-respond model used in building control may not be available at this time.

Another good reference for building protection, one that deals more with the nuts and bolts issues of protecting buildings, was published by the Army Core of Engineers. Published in October 2001, the report is called "Protecting Buildings and Their Occupants from Airborne Hazards." Copies of this 25-page report are available at Included in the report are sections on: 

The U.S. Department of Defense has also been active in developing technologies for the protection of buildings. Taking a lead role in this effort has been the Immune Buildings Program operated by the Defense Advanced Research Project Agency (DARPA). This program has a multimillion-dollar research program facilitating the development of response methodologies, equipment and sensors to better "immunize" buildings from potential terrorist attacks. While primarily focused on military-related buildings, in most cases the knowledge and technology developed can be readily applied to commercial and public buildings.

Air filtration will play an important part in protecting buildings. The Centers for Disease Control have released a publication called "Guidance for Filtration and Air-Cleaning Systems to Protect Building Environments from Airborne Chemical, Biological, or Radiological Attacks." It is targeted at existing building owners and managers. Copies of the report can be found at

As ASHRAE observed, a big hole in developing a protective strategy for buildings is the lack of reliable detection methods for may of these new threats. New sensor technologies are needed to detect both chemical and biological agents.

Sensor For Chemical Agents

For chemical agents, that tend to be fast acting, a rapid measurement method is necessary to detect lethal doses that can be in the tens of parts per million. As lower concentrations can be measured, more advanced warning can be provided allowing more time to prepare and respond. Today, the state-of-the-art in chemical detectors is people as observed by security and traffic cameras. If people are observed to be falling or lying down, it can be the most obvious indicator of a lethal exposure.

Some equipment is available today for first responders to identify potential chemical threats. Most of this technology however, is not capable of cost effectively being operated on a continuous basis either because of consumable components or the need for highly trained maintenance and operation personnel. Response time is also an issue. Current devices may take a number of minutes (or hours) to provide a reliable indication of a harmful agent. The reality for building protection is that a fast response is critical if preventative action is going to be effective.

The good news is that while fast response chemical detection technology is not available today, the increased concern over homeland security is fostering a tremendous amount of product research and development in sensor technology. This includes the development inexpensive of micro-sensors, the size of a fingernail, that have capabilities of identifying a broad range of gases down to parts per billion levels. These sensors will not only change how we can protect buildings, but they will also open up a whole new methodology of identifying and controlling other indoor air contaminants. Prototypes of these sensor technologies are now being tested in real world applications and are probably less than two years from commercialization.

At the same time, the government is active in developing certification and testing methods for detection technologies to ensure that users fully understand the capabilities of these new sensor technologies.

Sensing For Biological Agents

Biological detection is very different from chemical agent detection in many ways. First, the time delay between exposure and observed symptoms can be significant. In the case of anthrax, it may take a few days for initial symptoms to appear after exposure. In many cases exposure to biological agents can be treated, but greater treatment success is linked to timely identification of the exposure and the people affected. Time is critical.

Second, the accurate analysis of biological materials is currently a laboratory intensive process that today, takes hours. The state-of-the-art of biological detection in the US today is targeted not to detect and prevent or interdict but rather to "detect and treat". Recent pilot programs at high profile public events, utilizing airborne sampling stations and mobile analysis laboratories work on an analytical timeline that can take a number of hours. However, if an exposure is detected, contingencies are in place to quickly identify where the exposure took place and which individuals likely need treatment. The most promising techniques used today for analysis involves liquid-based genetic testing, which potentially allows for significant differentiation between species and different strains of the similar biological material.

Third, the sampling of biological material involves collecting airborne samples and trapping a significant amount of the material to provide a good sample. Current sampling devices tend to be high maintenance and require professional handling.

There are pending sensor breakthroughs in this area as well. For example, systems are being developed that in real time, can detect unusual levels of particulates of a certain size that might correspond to a biological release. In some cases these systems use newly developed optical means to identify the presence of organic material that would further help differentiate viable biological material from harmless inert material.

If the optical system detects a potential biological exposure it immediately activates a sample collection system. A lab is also alerted to retrieve the sample and begin immediate analysis. In the case of a building application, this would allow for identification of an immediate exposure, activation of preventative measures (such as high efficiency filtration/UV light systems), and identification of areas and people exposed. As a result, timely treatment and decontamination can be undertaken if a harmful exposure has occurred. This methodology is currently being applied to mail sorting systems. In this case it allows for quick detection of a possible problem, and quarantine of a limited amount of suspect mail. This is especially important to organizations such as financial institutions, that are highly dependent on mail delivery.

Other Technologies

Control Solutions, Inc Other technologies on the horizon include low cost particulate sampling technologies called virtual impactors. These devices can differentiate and separate large proportions of specifically sized particulates from a large air stream and concentrate these particulates into a highly concentrated area for analysis. This offers a great advantage over the current air filter based particulate sampling technologies that are limited in sampling and airflow capacity, and require frequent replacement filter media.

Also on the horizon are inexpensive micro-fluidic analytical systems that in three to five years time may offer real-time lab analysis on a chip for biological materials. This technology will then enable real time detection of many biological threats. These devices will also have a significant impact on the medical field in general.


In my estimation, the risks related to biological and chemical attacks to buildings and their occupants are real. We all are on a learning curve when dealing with these new threats we face. Hopefully, this snapshot of how we are starting to approach homeland security in buildings has been useful to you in understanding how the way we design and operate buildings might change in the near future. In many cases, you may be on the front line of developing and applying solutions to these new risks.

Methodologies, technologies and systems including sensors are still a work-in-progress. However, these efforts to "Immunize" buildings from airborne threats will pay future dividends in providing buildings that are easier to operate, more comfortable, healthier and more energy efficient. As a sensor manufacturer I am excited about how some of the upcoming breakthroughs will enhance our ability to provide healthy and clean indoor environments, cost-effectively, and regardless of the homeland security risk.

From a sensor perspective, the buildings of the future will likely incorporate a broad-based sensor system designed to detect threats like smoke and fire as well as other airborne threats. In the near term, the homeland security threat to buildings will force the long anticipated integration of building control, fire and security system to truly act as a single, intelligent system in buildings.

Stay tuned, there is much more to come!

Reprinted with permission from the June 2003 edition of Indoor Environment Connections newspaper. 

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