| 5.3003.36a
Location: indoor (supply ducts) duct section located completely within the
thermal boundary
Thermal boundary
The separation between the interior and exterior environments of a building that slows heat flow
of the building | Duct material will be installed with an R-value compliant with code An appropriate
vapor retarder
Vapor retarder
A material that slows the passage of water vapor and contains a perm rating above 1
will be installed | Prevent condensation on the outside of the ductwork |
| 5.3003.36b
Location: outdoors duct section located outside of the
thermal boundary
Thermal boundary
The separation between the interior and exterior environments of a building that slows heat flow
of the building or in quasi-conditioned spaces | Duct material will be selected that meets the following criteria: - An insulation level compliant with code
- Permeability that prevents condensation
- Permeability that reduces heat loss or gain from the ductwork
| Prevent condensation on the outside of the ductwork Reduce thermal loss or gain from the ductwork |
| 5.3003.36c
Building cavities used as ductwork | When viable building cavities used as ductwork will be replaced with properly sized conventional duct material When replacement is not an option, building cavities used as ductwork will be sealed when accessible | Safeguard indoor environmental quality Maximize airflow Minimize energy use |
| 5.3003.36d
Fire rating | Ducts will be installed in accordance with the fire rating of local codes | Prevent a fire hazard |
| 5.3003.36e
Penetrations | Interior wall penetrations for ductwork will be sealed with a durable sealant (e.g., caulk, silicone, foam) Penetrations through fire walls and floors will be sealed with a fire-rated material | Prevent a fire hazard |
| 5.3003.36f
Support | Ductwork will be supported in a manner that does not constrict ductwork or duct insulation per
SMACNA
SMACNA
Sheet Metal and Air Conditioning Contractors' National Association, www.smacna.org
duct construction standards (
ADC
ADC
Air Diffusion Council, www.flexibleduct.org
for flexible duct or
NAIMA
NAIMA
North American Insulation Manufacturers Association, www.naima.org
for fiberglass duct) | Ensure ducts do not sag, bend, trap water, or experience diminished air flow |
| 5.3003.36g
Protection | Ducts will be routed such that service and repair to the building and its systems does not damage the ducts | Protect equipment from damage Ensure equipment operates as designed |
| 5.3003.36h
Fastening: metal to flexible duct | Flexible duct-to-metal connections will be fastened with tie bands using a
tie band
Tie band
A strap, often made of nylon, that mechanically squeezes a flexible duct to a fitting. Must have a minimum performance temperature rating of 165° (per UL 181A-type test) and a minimum tensile strength rating of 50 pounds
tensioning tool Beaded collars will be installed for all sheet metal to flexible duct connections Mastic will be applied to interior flex lining to metal connection Manufacturer specifications will be followed | Ensure duct connections are durable |
| 5.3003.36i
Fastening: metal to metal | Metal-to-metal connections will be fastened with equally spaced mechanical fasteners Gaps larger than 1/4" will be bridged with sheet metal Joints will be sealed with mastic Joints smaller than 1/4" will be sealed with
NFPA
NFPA
National Fire Protection Association, www.nfpa.org
90A and B approved sealant | Ensure duct connections are durable |
| 5.3003.36j
Fastening: duct board to metal | Duct board to metal connections will be fastened with mechanical fasteners Joints and connections will be sealed with
UL
UL
Underwriters Laboratories
181A listed tapes or mastics | Ensure duct connections are durable |
| 5.3003.36k
Fastening: boot to building connection | Boots will be fastened to the building with mechanical fasteners Connection will be sealed with mastic, caulk, or gaskets | Ensure duct connections are durable Properly seal the boots to minimize air leakage |
| 5.3003.36l
Terminations | Terminations capable of delivering air with proper speed and throw of 80-120% of the farthest wall, floor, or ceiling will be selected Selections will be based on
ANSI
ANSI
American National Standards Institute, www.ansi.org
/
ACCA
ACCA
Air Conditioning Contractors of America, www.acca.org
Manual T Air Distribution Basics | Deliver and properly mix air in the building |
| 5.3003.36m
Filtration | Filter bypasses will be eliminated Airtight filter slot covers will be installed to prevent return air leakage in combustion appliance zone Filters will be changed Filters with high static pressure drops will be avoided A visual inspection for excessive dust and debris will be performed, and ducts will be cleaned accordingly | Protect equipment from dirt and debris Allow for proper airflow |
| 5.3003.36n
External static pressure | Ductwork, filter, and other equipment will be installed so total external static pressure does not exceed manufacturer specifications | Ensure equipment operates as designed |
| 5.3003.36o
Air flow: cooling and heat pump systems | Measured air flow per ton will meet manufacturer specifications Airflow will be established in accordance with
ANSI
ANSI
American National Standards Institute, www.ansi.org
/
ACCA
ACCA
Air Conditioning Contractors of America, www.acca.org
5 QI
HVAC
HVAC
Heating, ventilation, and air conditioning
Quality Installation Specification and
ASHRAE
ASHRAE
American Society of Heating, Refrigerating and Air-Conditioning Engineers, www.ashrae.org
Standards | Ensure equipment operates as designed |
| 5.3003.36p
Temperature rise: heating-only systems | Temperature rise will be measured, and the result will be in accordance with manufacturer specifications | Ensure equipment operates as designed |
| 5.3003.36q
System protection during construction and renovation | Registers, grilles, and diffusers will be blocked, masked, or otherwise sealed with a durable material Use of system will not be allowed during renovation or construction Contractor and occupant will be educated on necessity of protecting the equipment | Protect equipment and occupants from debris in the system |
| 5.3003.36r
Room pressure balancing | An appropriate means of pressure balancing will be installed (e.g., transfer grilles, jumper ducts, individual room returns) Room-to-room pressure differences shall not exceed +/- 3 pascals with the air handler running | Ensure system has unrestricted airflow between supplies and returns Minimize
infiltration
Infiltration
The uncontrolled passage of outside air into a building through unintended leaks in the building envelope
and
exfiltration
Exfiltration
The uncontrolled passage of inside air out of a building through unintended leaks in the building envelope
caused by system Prevent interference with safe operation of combustion appliances |
| 5.3003.36s
Sealing: new ductwork | Total system leakage (including air handler) will not exceed 20% of designed system airflow (cubic feet per minute) when tested at 25 pascals For partial duct system replacement or improvement, existing ductwork specification will be applied | Minimize system air leakage |
| 5.3003.36t
Sealing: existing ductwork | Accessible joints, cracks, seams, holes, and penetrations will be sealed | Minimize system air leakage |
