Building America Industrialized Housing Partnership
TRIP REPORT
Habitat for Humanity of Calhoun County, AL
Energy Efficiency Possibilities During
2003 Jimmy Carter Work Project

DATE
March 26 and 27, 2002

ATTENDEES

Janet McIlvaine, David Beal - FSEC
Bill Wright, Executive Director, John Roberts, Construction Manager - Habitat for Humanity of Calhoun County, AL.
Dan Brundage - Habitat for Humanity International Green Team Volunteer

TRIP REPORT DISTRIBUTION LIST

George James, Keith Bennett - U.S. DOE
R. Vieira, S. Chandra, J. McIlvaine, D. Beal - FSEC
Bill Wright, E.D., John Roberts C.M. - Habitat for Humanity of Calhoun County, PO Box 1135, Anniston, AL. 36202
Dan Brundage - PO Box 453, Clayton GA. 30525
Nevil Eastwood, Director of Construction and Environmental Resources Department - Habitat for Humanity International, 121 Habitat St., Americas, GA. 31709

PURPOSE

The Habitat for Humanity of Calhoun County (HFH of CC) affiliate is participating in the 2003 Jimmy Carter Work Project (JCWP), an annual event, typically building 100 houses in one week. Calhoun County is one of three locations where the JCWP will be building houses in 2003. Calhoun county intends to build 50 houses during the JCWP.

The purpose of the Building America Industrialized Housing (BAIHP) team’s visit was to investigate how the affiliate builds their houses, and what could be done to improve their energy efficiency simply and inexpensively. Also on the agenda was a meeting with the affiliate’s decision makers to offer BAIHP assistance during the JCWP. Part of this effort included sharing information about the various resources available to them from Habitat for Humanity International (HFHI) and other affiliates and organizations that the BAIHP team has worked with.

TESTING AND OBSERVATIONS

The BAIHP team, accompanied by Dan Brundage, a volunteer with HFHI and John Roberts, Construction Manager for HFH of CC, visited two typical houses being built by the Calhoun county affiliate. Both houses were still under construction, one nearly finished, the other was dried in, but the interior was unfinished, and siding was not completed.

The nearly finished house had the duct work and unitary heating and cooling unit (package unit) installed. The package unit was located outside of the home, and the all-metal duct work was installed in the crawl space under the home. Duct work consisted of a panned floor return plenum (details below) attached to hard metal 12" pipe, and a supply duct of 12" square metal connected to 8" hard metal pipe run-outs to the registers (Figure 1).

A test was preformed using a duct blaster to yield the leakage rate of the duct system (cubic feet per minute of air leakage at 25 pascals (Pa) or CFM25). The total leakage from the duct system to the interior and exterior of the building (CFM25_total ) was measured. For a duct system to be considered to be “substantially leak free” by BAIHP, the CFM25_total must be a number that is less than 5% of the air handler fan flow. The test results for the 1064 ft² house was 225 CFM25_total. The package unit was a 2.5 ton model. Assuming 400 cfm per ton fan flow or 1000 cfm fan flow for a 2.5 ton unit, this leakage (225 CFM25_total) represents 22% of the fan flow. Using the desired criteria of 5% of fan flow, the target CFM25_total would be less than or equal to: (2.5 ton * 400 cfm/ton) * 0.05 = 50 CFM25_total.

Following the duct blaster test, a portable smoke generator was used to feed smoke into the duct work while the duct was pressurized. This helps to visualize where the duct was leaking. In this case, there was generalized smoke (Figure 2), indicating that there was small leakage throughout the duct system. One area that became obvious was the panned floor return plenum. A panned floor utilizes the framing of the floor as part of a duct, in this case the return plenum. This return used sheet metal (the pan) between three floor joists. An attempt to attach the metal to the floor joists was made using foil duct tape, which had already failed where attached to the wood (Figure 3). Foil duct tape also often fails when attached to metal unless the surface is scrupulously cleaned and the tape is applied according to the manufacture’s instructions.

The return plenum was the most obvious leak, so the team demonstrated a suitable repair (and installation technique) (Figure 4 and 5). This repair was made by removing the failed tape and replacing it with fiberglass mesh (adhesive drywall tape works well) and coating it with mastic. Mastic will stick to both wood and metal and makes a permeant, flexible seal.

A demonstration repair was also made to a joint in the return duct (Figure 6). This repair consisted of coating the joint with a layer of fiberglass mesh and mastic, again, making a permeant, flexible seal.

When visiting the second house we were able to observe details of the exterior air barrier and assess opportunities for air sealing of the buildings. The wall air barrier is approximately 3/8" thick extruded polystyrene. No sealing is attempted along the seams that occur when installing the board (Figure 7).

MEETING WITH EXECUTIVE DIRECTOR AND CONSTRUCTION MANAGER

HFH of CC Executive Director Bill Wright, their Construction Manager John Roberts, the HFHI green team volunteer Dan Brundage, and BAIHP team members Janet McIlvaine and David Beal, met to discuss test results and findings, various kinds of support available from BAIHP, HFHI , other HFH affiliates, and other organizations, and what the next steps should be. During the meeting Bill and John expressed great enthusiasm about the opportunities to build a better, more durable house that would be less expensive for their homeowners to live in. John was very impressed with the duct leakage demonstration, realizing that such high leakage represented money lost, in this case out the crawl space.

The BAIHP team has worked with dozens of affiliates, on three JCWP projects, and several smaller blitz builds. BAIHP offered assistance in energy related design, training for the heating and air conditioning contractors, and training for energy monitors during the blitz build. All of these offers of help were gladly accepted by the affiliate.

BAIHP has worked with a Construction Manager from the affiliate in the neighboring town of Birmingham, AL, who has worked on several JCWP blitz builds. He was contacted and he offered his support and knowledge, and was willing to travel to Anniston to meet with their Construction Manager. Dan Brundage, a volunteer for HFHI, has worked on five JCWP blitz builds, as well as doing energy audits and training for many affiliates in the southeast. He has many contacts among HFHI and affiliates in the region and was eager to assist the Anniston affiliate.

Executive Director Bill Wright invited BAIHP participation in the JCWP 2003. BAIHP recommended making duct system performance a focal point of the project. This idea met with the approval of Bill and John of HFH of CC. JCWPs attract volunteers from around the country, who take what they learn back to their affiliate. Duct leakage information and training efforts undertaken during JCWPs can have far reaching affects in HFH, fostering the adoption of tight duct construction in affiliates all over the country.

CONCLUSIONS AND NEXT STEPS

It was decided that the BAIHP team would take a typical house plan that HFH of CC is going to build for the JCWP and analyze it for potential energy improvements including: the discussed tight ducts specification, changing from double pane windows to double pane low-E windows, adding floor insulation, increasing wall insulation, and air sealing the home. These improvements and others will be discussed during our next meeting. Both the Construction Manager and Executive Director are eager to explore additional energy, indoor air quality, and durability issues.

To assist HFH of CC in pursuing their goal of building tight duct systems, BAIHP will work with HFH of CC’s mechanical contractors to identify major leakage factors and develop fabrication and installation techniques to overcome them. After successfully achieving “substantially leak free” ducts, the Construction Manager will write a specification and guide to be used by mechanical contractors participating in the JCWP 2003 build. These contractors will be recruited from neighboring counties.

BAIHP will also provide HFH of CC with contacts that have been established with other HFH affiliates and organizations that have worked in the past on other blitz builds. BAIHP training activities for volunteers during the JCWP 2003 will be coordinated with HFHI.

For questions or comments on this trip report, please contact Janet McIlvaine, BAIHP liaison for Habitat for Humanity at 321-638-1434 or via email at janet@fsec.ucf.edu, or the author, David Beal at 321-632-1433 or email to david@fsec.ucf.edu.

Figure 1 Supply (square) and return (round, towards back) duct work, with insulated run-out (foreground).	Figure 2 Smoke in the crawl space from duct smoke testing. Smoke from hard to specify leaks.
Figure 3 Failed duct tape attaching metal pan (top) to wooden floor joist.	Figure 4 Return plenum repair using mastic and fiberglass mesh
Figure 5 Return repair showing pan sealed at top, bottom and along sides. This needs to be done to entire plenum.	Figure 6 Duct repair with mastic
Figure 7 Exterior wall detail showing exterior insulation and window flashing.

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