HVAC Duct Supports
Wind Load Rated @
120 MPH
Non-penetrating concrete base with rubber pad
prevents roof leaks
Pre-engineered to comply with wind loading
building code requirements
12 GA. pre-galvanized (ASTM A653) and hotdipped galvanized (ASTM A123) standard finishes
Adjustable height
Made in the USA
Diversfied Fall Protection
24400 Sperry Drive Cleveland, OH 44145 (440) 348-9460 www.unistrutohio.com
24400 Sperry Drive (440) 348-9460
Design Factors:
Based on new code requirements, Unistrut Service Company rooftop equipment supports are
designed specifically for each project & its location. The scope of these designs is outlined
below:
The snow loading is based on the geographical area and duct/pipe shape.
The wind loading is on the duct/pipe is determined in two (2) steps. First, basic wind pressure is determined
based on wind direction, exposure category, topographic factor and velocity pressure exposure coefficient. Then
the effective wind pressure on the duct/pipe is then calculated, based on the gust factor and net force
coefficient.
(Wind Loads act as a control over seismic loads) Basic Wind Speed, 3 Second Gust- 120 MPH (ASCE7-10)
Design Height- 15 feet. Building Classification Category- II. Wind Topographic Factor- 1.0. Exposure Category"D" . Wind Directionality Factor- 0.85 . Velocity Pressure Exposure Coefficient- 1.03
The seismic forces are also determined in two (2) steps. First, the basic design force is determined, based on
occupancy category, site soil class, building R-value, spectral acceleration from maps/USGS Website, maximum
considered earthquake, design base earthquake and period of vibration. Then the Base Shear for design of the
support force(s) is determined, based on the duct/pipe specific Seismic Response Coefficient.
Seismic Importance Factor- 1.0. Seismic Site Class- D. Seismic Design Category- A
Seismic Response Accelerations:
Short Period- Ss-0.153g
One Second Period S1-0.056g
Seismic Response Modification Coefficient R=3.0. Seismic Response Coefficient Cs-0.054 . Spectral Response
Coefficient Cs-0.054. Spectral Response Coefficients:
Short Period Sds- 0.163g
One Second Period Sd1- 0.089g
Rectangular/ Square Duct:
Quick reference:
Maximum Height of Duct from ground level: 60'
Maximum Wind Speed : 120 mph refer to Table #1
Maximum Wind Speed : 190 mph refer to Table #2
Note: Maximum Distance between supports is 5 feet.
Maximum height for Dimension C should include insulation if applicable
Table #1- 120 MPH max wind speed
Part #
Table #2- 190 MPH max wind speed
Part #
Table #1- 120 MPH max wind speed
Part #
Table #2- 190 MPH max wind speed
Part #
Round Duct:
Quick reference:
Maximum Height of Duct from ground level: 60'
Maximum Wind Speed: 120 mph refer to Table #1
Maximum Wind Speed: 190 mph refer to Table #2
Note: Maximum Distance between supports is 5 feet.
Maximum height for Dimension C should include insulation if applicable
Better HVAC Duct Supports By Design
Design Criteria:
Supports are designed in accordance with the following codes and
specifications:
International building code (IBC) 2015
American Institute of Steel Construction, April 14, 2010 (AISC 303-10)
Specification for Structural Steel Buildings, June 22, 2010 (AISC 360-10)
Minimum Design Loads for Buildings and Other Structures (ASCE7-05)
Minimum Design Loads for Buildings and Other Structures (ASCE7-10)
Ordering Information:
DS
01
Select Width
01=48"
02=54"
03=60"
04=66"
05=72"
PG
Select Finish
PG= Pre-Galvanized
HG= Hot Dipped Galvanized
PE Stamps
Available
Order Example: DS-01-PG is a 48" wide by 45 1/2" tall HVAC duct support with
pre-galvanized channel.
*Custom design orders are welcome.
Order Online at https://www.unistrutohio.com/rooftop-hvac-duct-supports
24400 Sperry Drive Cleveland, OH 44145 (440) 348-9460
www.unistrutohio.com