The American Society for Heating, Refrigerating, and Air-Conditioning Engineers (http://www.ashrae.org), founded in 1894, is dedicated to providing safe, healthy, efficient and comfortable indoor environments. Measurements and controls play a key role in achieving these objectives.
In North America, larger non-residential buildings began using pneumatic feedback controllers in the 1940s. This practice expanded to encompass most commercial buildings by the early 1970s. A few buildings, all newly constructed with leading-edge functionality, installed minicomputers as centralized supervisory control systems. The primary economic driver for these systems was labor-savings as the centralized system allowed an operator to monitor variables and adjust setpoints on controllers scattered over many floors.
The Arab Oil Embargo of October 1973 and the attendant tripling of crude oil prices radically changed the economics of building operation. Energy became the major operating cost, and automatic energy management became an urgent requirement. After experimenting with minicomputer-based supervisory energy management systems, the building controls industry made the leap to microprocessor-based direct digital controls (DDC) in the late 1970s-early 1980s.
After a brief flirtation with the concept of a comprehensive "Intelligent Building" in the mid-1980s, the building controls industry focused on the traditional mechanical (HVAC) and electrical (lighting, alarms) functions. By the late 1990s, the integrated intelligent building concept became increasingly achievable and economically attractive. Communications technology, particularly in the area of wireless, and software tools were much advanced versus 10-15 years earlier.
The Continental Automated Buildings Assn. (
In response to the terrorist attacks of Sept. 11, 2001, ASHRAE formed a special Presidential Study Group to provide guidance to the buildings community. The groups first report, "Risk Management Guidance for Health and Safety under Extraordinary Incidents," was released in January 2002. This document recommends a set of common-sense precautions, such as securing mechanical equipment rooms, restricting access to fresh air intakes, and verifying that fresh air intake volumes and air filter efficiencies meet applicable codes. The report concludes with two steps that are specifically not recommended:
1. Any changes in building codes to address issues of health and safety under extraordinary incidents.
2. Requiring, or even recommending, that buildings be designed to enhance safety under extraordinary incidents without careful consideration of such parameters as initial and maintenance costs, energy consumption, indoor air quality, and site adaptability.
What not to do is further detailed to include:
1. Closing outdoor air dampers or otherwise blocking ventilation air paths.
2. Changing the designed airflow patterns or quantities.
3. Modifying the fire protection and life-safety systems without the approval of the local fire marshal. These admonitions should only be superceded under the written advice or direction of a registered professional engineer.
Commercial building security/life-safety is an $18 billion worldwide market, according to the Security Industry Annual Report 2002. Markets this size rarely turn on a dime. ASHRAE appears to be saying lets understand our current situation and take incremental steps that are clearly achievable while researching more venturesome initiatives.
It probably makes sense to heed this advice from professionals who have made this their lifes work and not be stampeded in unknown directions.
Terrence K. McMahon
McMahon Technology Associates
135 Fort Lee Road
Leonia, NJ 07605