Benson Town Office/Museum 1. HVAC: Replace the existing oil boiler with heat pumps cooling and heating systems as recommended by engineering design and/or the installer. Replace the current fossil fuel HVAC system by a heat pump system. Perform commercial load calculation in accordance with the current version of ANSI/ACCA Manual N (Commercial Load Calculation) or equivalent using interior design temperatures of 75 degrees for cooling and 70 degrees for heating. Room by room load calculations will be performed when installing a new duct system or in retro-commissioning projects. Select commercial equipment in accordance with the current version of ANSI/ACCA Manual CS (Commercial Applications, Systems and Equipment) or equivalent. Select cooling equipment capable of meeting the sensible and latent load of the building that is not sized more than 115% of total load or next available size. Select heating equipment of the lowest capacity required to meet the design heating load and provide the air movement required by any air conditioning equipment installed. Select system that is ENERGY STAR® certified or equivalent. Select outdoor units that are corrosion-protected for marine climate zones. Demolish existing HVAC units. Procure and install new like-for-like high efficiency Heat Pump units (SEER 15). If on the roof, reuse existing curbs on the roof, provide curb adapter if necessary. Install new disconnect switch and conduit to the new units in accordance with NFPA 70. Locate unit to provide clearance on all sides and top according to manufacturer specifications and service access according to applicable code. Situate outdoor unit on a non-wicking equipment pad.Install exterior ductwork using rigid, corrosion-resistant metal insulated to a minimum of R-12. Test and balance all modified systems. Perform duct leak remediation as required per SMACNA standards. Install smoke detector if required by local State Code. Connect new HVAC equipment to new Thermostat. Commission equipment and controls. Install smoke detectors inside the supply duct plenum of systems that move more than 2,500 cubic feet per minute (CFM) in accordance with the applicable building code. 2. Perform air sealing and add insulation as recommended by the engineering design and/or the installer. Perform activities to control external air leakage into the building: • Weatherstripping: Place weatherstripping around all openings including access to attic areas and crawl spaces. Where external vents are used – such as for a clothes dryer – select vent covers that are as airtight as possible. Apply weatherstripping snugly against both surfaces. The material should compress when the window or door is shut. Choose the appropriate door sweeps and thresholds for the bottom of the doors. Weatherstrip the entire door jamb. Apply one continuous strip along each side. Ensure the weatherstripping meets tightly at the corners. Use a thickness that causes the weatherstripping to press tightly between the door and the door jamb when the door closes without making it difficult to shut. • Caulking: Replace all caulking on windows. Most caulk is designed to fill a joint that is no more than ½-inch deep and ½-inch wide, although products called elastomeric caulks can fill larger gaps. Joints that are the correct width, but too deep, such as the gap between a window frame and the rough opening, can be packed with backer rod or stuffed with fiberglass insulation first and the remaining space filled with caulk. For larger gaps, expanding foam is an effective sealant. Dispensed from canisters through a gun, foam will fill gaps up to a couple of inches wide. However, larger gaps may need to be covered with a scrap of solid wood or OSB first and then foam applied in the remaining gaps. Install mastic on electrical boxes, wired penetrations and unused knockouts. Window and door frames should be sealed to the wall frames with caulk, foam or flexible tape depending on the size of the gap. Casement and awning windows are preferable from an air leakage standpoint because the sash presses against the gasket when closed. When possible locate attic hatches and crawl space access doors in places where they will not penetrate the air barrier. For example, the attic hatch can often be located in a garage or gable end wall. Crawl space access can be placed in an outside wall below the level of the insulated floor. Install insulation in the attic space. Ensure space can be safely insulated. Verify that installation area is intact, able to support insulation weight, and air sealed. Remove any existing insulation or vapor barrier materials from the installation area that are installed improperly. Select insulation materials that have a flame spread and smoke development index of 25/450 or less when tested in accordance with ASTM E84 or UL 723. Install insulation to prescribed R-value (R-49) in every joist bay in full contact with the air barrier and all sides of the cavity without gaps, voids, compressions, or misalignments. If using batt insulation, install it in contact with the conditioned space.
