UFAD System Construction Best Practices: Before RAF Installation
UFAD System Construction Best Practices: Before RAF Installation
1. Slab and Wall Sealing:
- All sheetrock walls and columns must be sealed to the slab using a durable, resilient, low-VOC caulk or fireproof sealing material suitable for the application. Use colored caulk instead of white or clear for easier inspection.
- Seal all vertical seams in drywall, including corners below the floor.
- Seal any through-slab, through-wall, or other penetrations in the slab or walls.
2. Conduit and Ductwork:
- Seal all conduits that terminate in the underfloor airway at the sheetrock and within the conduit itself. Use a removable sealing product for large conduits.
- Inspect ductwork to ensure air exits the end of the duct at 2000-2500 ft/min. and throws no more than 50 ft. to the furthest delivery point for cooling air.
- Seal around all four sides of duct penetrations, especially under the duct where it leaves the shaft.
3. Airway and Pressure Considerations:
- Check for major blockages in the underfloor supply airway, such as demising walls. Ensure they do not obstruct air travel to the perimeter.
- Use caution with air highways:
1. Verify air pressure drop calculations at full flow.
2. Consider temperature rise.
3. Check for leaks caused by wiring and conduit crossings. - Verify control wiring between floor boxes and thermostats.
- If two or more control dampers (or VFDs) control pressure in a large zone, ensure they use the same pressure reference or average the pressure references.
4. Material Suitability:
- Ensure all materials used underfloor are suitable for an environmental airway (e.g., plenum-rated Class A materials or as required by local codes).