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The IAQ Plan: An Underrated Essential Kit Brockles, TBE Engineered Air Balance Co., Inc. M aintaining proper indoor air quality (IAQ) during construction is becoming more important, particularly in healthcare and education facilities. The construction industry knows there can be an impact on a project schedule due to maintaining a higher level of air quality. What the industry still seems to be coming to terms with is that an IAQ Plan is nonetheless a critical component of the project. Unfortunately, the trades most affected by the IAQ Plan are often excluded from the creation of a project schedule. It is hard to believe there is a way to install and program the direct digital control systems and sequences of operation before half of an air handling unit system is energized, let alone completely tested, adjusted and balanced, and commissioned. Furthermore, owners and contractors can be so focused on the time required at the end of a project to get all the necessary tasks accomplished that properly maintaining good indoor air quality is essentially cast aside. On some sites, for example, return air systems are energized and started up the day before health department inspections or substantial completion. In other cases, efforts such as putting filters on return outlets, keeping the proper filtration at the air handing units, covering return air paths and keeping a job site clean are ignored when trades are on top of each other at the end of a project trying to complete their work. But ignoring the IAQ Plan can have consequences that negatively impact the project as well. For example, painters working in the final stages during the return air balance compromise the cleanliness of the return system. Moreover, various trades will undoubtedly create construction dust to complete their scheduled tasks, which obviously affects air quality. It would be better to complete 8 these activities before any of the return air balance work begins. It is also not uncommon to see filter media covering the return air grilles in the construction area with the adhesive side of the media facing the grille. When the filters get dirty, new ones are installed in the same way. At the end of the project when the filters are finally removed, there is a layer of adhesive left on the grilles from multiple filters. Remaining particles in the air then get stuck to the adhesive on the grille’s surface, which cause a buildup of dust and debris that affects IAQ. Another potential issue is that outside air is commonly used throughout a project in an effort to create positive pressure on the building. Air handling units with economizer packages are placed in 100% outside air operation to accomplish this. While this practice continually flushes the building of contaminants created during construction and prevents dust and debris from entering the facility, without utilizing the return ductwork to relieve the inside air to keep it clean, the building’s pressure becomes excessively positive. This can cause problems when buildings are turned over to the owner in phases. Let’s look at an example of this. Figures 1 and 2 show a three-story building with an atrium in the center. This atrium made all three floors common to one another. The owner planned to take over half of the first floor before the rest of the building was complete to use as an operating room suite. Operating suites are very pressure sensitive areas. The outside air serving the suite is controlled by tracking the return airflow at a specified amount below the supply airflow. The suite was set up as positive. Unfortunately, the rest of the building was still being served by 100% outside air with no pressure relief. The remaining portion that was under construction was positive relative to the operating suite during normal operation. Temporary walls and a vestibule had to be erected to prevent cross contamination between the construction area and the operating suite. Figure 1 Building without the roof Figure 2 Floor Plan To conclude, the important role IAQ plans play in the construction process should not be underestimated. Disregarding them can lead not only to compromised air quality but also to problematic scenarios for the building owner once he takes occupancy. TAB Journal Summer 2013

Table of Contents for the Digital Edition of TAB Journal Summer 2013

TAB Journal Summer 2013

TAB Journal Summer 2013 - (Page C1)
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