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Airtight Buildings – When the cure can be worse than the disease

Older buildings were built to conform to a number of free-market ideas, like low cost-per-square-foot, competitive rental space, and basic by-low-sell-high economics.

I remember how the Arab oil embargo of 1973 changed how America would do business. For example, full-service gas stations became self-service almost overnight. I left the aerospace business in 1974 to start a new career in building controls.

Naturally, the federal government focused on a nationwide campaign to force us to use less motor fuel. The feds blackmailed states by threatening to withhold federal highway funds to create a national speed limit of 55 MPH. The lower speed limit naturally inspired motorists like me to purchase CB radios because those of us who live outside the Washington DC Beltway who lived in the wide open spaces of southwestern and western states basically would have gone out of business. The distance from my office to a customer in El Paso, Texas is 659 actual road miles. You see the problem.

The feds demanded tighter, more energy efficient buildings. We built them and – voila – a new set of problems arose: health issues due to tight building syndrome. Well, there was a ready-made federal bureaucracy that was signed into law by President Richard Nixon on December 2, 1970, called the Environmental Protection Agency. At this point, follow me on a tangent.

Here in the Great State of Texas, we have a bureaucracy called the Texas Commission on Environmental Quality (TCEQ). What is so significant about the difference between the name of the federal agency and our Texas agency?

Environmental Protection Agency – From whom or what is the agency protecting what or whom?

Texas Commission on Environmental Quality – Do you see it?

Let me break it down for you. The feds have a goal of protecting the environment from human activity, implying we humans are bad for the environment. Our TCEQ has a goal of assuring a quality environment for we the people of the Great State of Texas. Do you see the difference now?

On August 4, 1977, the federal Department of Energy (DOE) was enacted. At this point, please entertain my opinion: neither the EPA nor the DOE is a constitutional prerogative of the federal government. If not among the enumerated powers, all such governance is reserved for the states, as per the Tenth Amendment.

The environmentalist movement was around almost a century before the creation of the EPA and DOE. However, these two agencies gave the movement ‘statutory teeth’ and it is the idea of protecting the environment from people that drive federal regulations today. I now return regular programming from this tangent.

I leave a discussion the evolution of the American Society of Heating and Ventilating Engineers (ASHV) to our present-day American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) for another day, another topic.

The older buildings were not airtight. Infiltration and exfiltration were common to all buildings. Early interest was ventilation to manage odors (still got to do it) and carbon-dioxide (CO2) concentration (something we still do).

Medical experts discovered how diseases were affecting the occupants of buildings, so the ASHV adopted ventilation rate standards to address this issue. The outcome was greatly increased ventilation. Willis Carrier’s 1902 invention of air conditioning to control relative humidity in printing plant where he worked was the genesis of commercial air conditioning for human comfort. By 1954, the ASHV renamed itself ASHRAE thereby bringing engineered solutions to commercial airconditioning.

Present day energy codes dictate airtight structures with walls impermeable to moisture. This reverses the infiltration/exfiltration problem of older buildings while introducing new problems to new buildings. To be sure, contemporary so-called energy codes are driven by the same idea upon which the EPA was named: radical environmentalism. Due to little or no infiltration, HVAC systems must introduce more outdoor air and this process also introduces outdoor moisture the impermeable wraps prevent. Collectively, the two matters require new HVAC technologies that satisfy the ventilation requirements and also control humidity.

Due to little or no infiltration, HVAC systems must introduce more outdoor air and this process also introduces outdoor moisture the impermeable wraps prevent. Collectively, the two matters require new HVAC technologies that satisfy the ventilation requirements and also control humidity.

The cost for all the new apparatus mandated for new buildings has an obvious effect on total cost of ownership. True, over time there will be savings from energy efficiencies – if they actually work in a particular building. Meanwhile, the upfront high cost of “green” construction affects the cash flow of commercial rental properties and hence the resale value of the commercial building. The value of an office or medical building depends on the profitability of the property, not necessarily the location, location, location.

If you have an older building, should you just demolish it and replace it with a “green” building? Perhaps. Perhaps not.

We have developed techniques to minimize the effects of infiltration and exfiltration using existing HVAC systems by incorporating metrics (measuring stuff) and designing intelligent control systems to maintain those metrics. One cannot control what one does not measure.

One example is a six-story government office building built in 1979. The HVAC system featured approximately 250 high-pressure dual-duct terminals, two 100 HP cold-duct vaneaxial fans, one 75 HP hot-duct vaneaxial fan, and two 45 HP vaneaxial return-air fans. All five fans ran constant-volume and due to high infiltration and exfiltration operated 24/7/365. All HVAC controls were pneumatic.

After running the numbers, the retrofit plan was to convert all 250 dual-duct zones to variable-volume, install variable-frequency drives (VFD) on all fans but the hot-duct fan. The hot duct was needed only for one floor. Precision air-flow measuring stations on return-air fans and the two cold-duct fans, along with incorporation with demand-control ventilation and fan-tracking algorithms, dramatically reduced infiltration and exfiltration. Other benefits included the almost total elimination of hot-and-cold calls, and a reduction in electrical consumption by 50% – kWh, not dollars. Dollars were reduced more than 50% due to increases in electrical rates.

There are other issues like hardening a structure against fire hazards, but I limit the discussion to the above example to say, your older building may be a candidate for creative energy-saving solutions.

Initial site review in the Dallas/Fort Worth Metroplex is available for no charge. Out of town (greater than 60 miles from Rockwall) will be chargeable.

How can we help you?

John White

Rockwall Controls Company, Inc.

(972) 771-3514      office