Engineered Systems - March 2008 - (Page 19)

CaseInPoint Anyone can claim to save you a lot. Construction of this high school required a temporary air management solution that would allow workers to apply finishes without having to fire up the permanent HVAC system. In order to place tile flooring, the concrete had to have moisture content below 5 lb of water per 1,000 sq ft. Temporary makeup air heaters provided just such a solution. dehumidifying, and air ﬁltration services. According to the Sheet Metal and Air Conditioning Contractors’ National Association (SMACNA), use of the permanent HVAC system in an attempt to dry wet surfaces, such as drying recently poured concrete ﬂoors or expediting the installation of carpet or wooden ﬂoors should not be permitted. Permanent HVAC systems typically are not designed or constructed to perform in such a manner. Such activities may result in subsequent IAQ problems associated with mold and other related airborne contaminants. Construction heaters are generally not intended to heat the space for worker comfort. The ﬁrst priority is to control the moisture resulting from construction processes such as concrete curing and ﬁreprooﬁng. Drying will require that the moisture be exhausted, either by inﬁltration or mechanical ventilation. That’s why, when opening this project for bid, Henry Bros. speciﬁcally requested makeup air heaters. Makeup air is air from the outdoors that is heated and then evenly distributed indoors in a controlled manner to replace the air that is being exhausted. This drier, tempered fresh air has the ability to absorb moisture, and ventilate the toxic fumes from the construction process. It provides lower relative humidity levels and dewpoint temperatures inside the building to prevent condensation and minimize the potential for mold. TEMP-AIR designed the IAQ proposal for this project for outdoor conditions of 10˚F with a desired inside temperature of 55˚. The school’s walls and roof were complete and in- sulated, but TEMP-AIR also recommended that the empty windows and doors be covered with a material suitable to retain heat. TEMP-AIR calculated fuel consumption for the six months of heating using project speciﬁc information and regional temperature data from the National Oceanographic and Atmospheric Administration (www. noaa.gov). Using that data, the estimated heating load for the entire space amounted to 11,895,001 Btuh based on maintaining at least 55° inside temperature and providing a mechanical ach of 0.47. In November 2007, TEMP-AIR delivered and installed a mixture of equipment from its THP Series makeup air heaters: • Seven THP-750, rated at 4,000 cfm of air with a variable gas-ﬁred burner • Six THP-1100, rated at 6,000 cfm of air with a variable gas-ﬁred burner • One THP-2000, rated at 11,000 cfm of air with a variable gas-ﬁred burner DROPPING THE POUNDS “The units were all located at the exterior of the building, which allowed us to install the ﬂoor ﬁnishes on the interior of vestibules and doorways without removing or relocating the units,” said John Tondelli, project manager for Henry Bros. According to Tondelli, prior to installation of the portable heating equipment, initial readings of the space were between 6 to7 lb of moisture/1,000 sq ft, well above their 5 lb requirement. Within a few weeks of running the TEMP-AIR equipment, readings dropped AERCO. The only manufacturer with UL-confirmed efficiency. Benchmark Boilers. Condensing is just part of the savings. Even before an independent third party confirmed the full- and part-load efficiency of our BMK2.0LN, we knew our unmatched 20:1 and 15:1 turndown would virtually eliminate cycling losses, minimize wear and tear, and improve temperature control. And with no need for primary pumps, three-way valves or extra heat exchangers, Benchmark boilers streamline system designs and reduce maintenance requirements. Plus, our flexible venting and air intake options also help lower project costs. To learn more visit www.aerco.com/bm4 Copyright 2008 AERCO International, Inc. Heat You Can Bank On FREE INFO: 72 w w w. esmag a zine . c o m ESM03084AeroV.indd 1 19 2/20/08 10:46:01 AM http://www.noaa.gov http://www.noaa.gov http://www.aerco.com/bm4 http://www.aerco.com/bm4 http://www.esmagazine.com

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Engineered Systems - March 2008 Contents Editor’s Note Back2Basics HVAC Challenge Case In Point Commissioning Building Automation Energy Wiz HVACR Designer Tips Application Checklist Exemplary Design = Elementary Success The Modern Unit Ventilator On A Mission VAV Systems And Green Design – Part II Issues & Events Products Glossary Classifieds Advertiser Index Tomorrow’s Engineer

Engineered Systems - March 2008

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