How far apart should duct hangers be?
How far apart should duct hangers be?
But the underlying “common sense” behind those recommendations is pretty simple: have no more than two duct joints between supports. That explains the 8 to 10 feet apart recommendation when you are installing 4 and 5 foot joints of rectangular duct.
What is SMACNA standard?
SMACNA standards help contractors reduce costs, anticipate technical requirements, and increase productivity and efficiency. SMACNA standards and manuals address all facets of the sheet metal industry, from duct construction and installation to air pollution control, energy recovery, and roofing.
Is standard for ducting?
This standard covers materials and constructional requirements of air ducts used for air conditioning and ventilation system (including gas exhausting system). The standards listed at Annex A contain provisions, which through reference in this text, constitute provisions of this stidard.
What are duct hangers?
Duct Hangers are designed to pull rectangular trunk duct work up tight to the bottom of joists. They can be easily assembled on the floor prior to hanging. These hangers can be attached to wood or metal framing with a maximum 10 foot interval.
How often does ductwork need to be supported?
every once 4 feet
Supports should be installed at least every once 4 feet. The maximum allowable sag in flexible duct is one-half inch per foot. (Source: Calcs Plus.) Place supports at each connection between flex duct and rigid metal duct.
What is the maximum length of flexible duct?
Flexible air connectors which are listed to UL 181 are allowed by the standard in lengths up to 14 feet. This product is specifically evaluated for the maximum length up to 14 feet, and the manufacturer’s installation instructions are reviewed to ensure proper installation up to this length.
How many chapters are there in Smacna?
There are nearly 100 local SMACNA Chapters across the United States, Canada, Brazil, and Australia that represent signatory sheet metal and HVAC contractors. Membership in a local chapter automatically extends your membership to SMACNA.
How do you screw ductwork together?
Attaching HVAC Ducts
- Push the ducts together firmly.
- Insert 1/2-inch self-tapping sheet metal screws through metal ducts where the ends come together.
- Staple fiberglass ducts together with a staple gun and 1/2-inch staples.
- Attach flexible HVAC ducts with plastic or metal duct bands or straps.
How do you connect ductwork together?
How to Connect Duct Work
- Step 1: Crimp One End. Select standard duct pieces for the connection that have crimped and uncrimped ends.
- Step 2: Insert Duct Into Next Piece. Insert the crimped end of the round duct into the uncrimped end of the next round duct.
- Step 3: Tape the Seams.
- Step 4: Screw the Pieces Together.
How do you measure insulated ducts?
Measure the diameter of the duct then divide it by 2 to get the radius. Square the radius then multiply the radius by Pi, or 3.14. This will give you square inches of the duct. Divide that total by 144 to get square feet of the actual duct.
How do you secure ducting?
Attach flexible HVAC ducts with plastic or metal duct bands or straps. If the flexible ducts have vertical runs, screw in three sheet metal screws around the diameter of the duct directly below the duct straps. For extra durability, brush on mastic over the screwed-down seam.
What should the spacing be between duct hangers?
The often cited reference for hanger requirements is SMACNA HVAC Duct Construction Standards. Hanger spacing in SMACNA is either every 4’, 5’, 8’ or 10’. Its best to use hanger spacing of 8’ or 10’ to maximize the span between hangers and reduce the amount of time for installing hangers.
What are the gauges for SMACNA ductwork?
In general, the current SMACNA (2005) gauges are suitable for spans up to 30 feet; however, the more stringent ductwork support guidelines must be followed. The current version for SMACNA RIDCS is the 2nd edition (1999) which made a decision (outlined in section 5.3.1) to require 22 gauge minimum.
How big does ductwork support need to be?
In addition, a variety of options are offered for the ductwork support which are more stringent than the SMACNA (2005) requirements. In general, the current SMACNA (2005) gauges are suitable for spans up to 30 feet; however, the more stringent ductwork support guidelines must be followed.
What are the standards for duct work in HVAC?
If the designer does not designate pressure class for duct construction on the contract drawings, the basis of compliance with the SMACNA HVAC Duct Construction Standards is as follows: 2” (500 Pa) w.g. for all ducts between the supply fan and variable volume control boxes and 1” (250 Pa) w.g. for all other ducts of any application.