SMACNA Duct Construction

ALTERNATIVE SUPPORT TO RISER REINFORCEMENT ABOVE FLOOR

HANGER ROD BETWEEN RISER SUPPORT & RISER REINFORCING

RISER REINFORCING (FOR DUAL DUTY) FASTENERS * FIG. B * MINIMUM NUMBER OF FASTENERS ON EACH OF TWO SUPPORT BARS LARGEST DUCT DIM.

MINIMUM NUMBER OF FASTENERS 2 3 Largest duct dim. Divided by 8

16” and down 17” - 24” over 24”

Locate a fastener within 2” of the duct edges. Locate others at evenly spaced intervals. See Table 4-4 on page 4.16.

SUGGESTED SIZING FOR SUPPORT OF 12 FT. OF DUCT

DUCT JOINT

2”

ANGLE

DUCT SIZE

ANGLE

36” x 18”

1 1/2” x 1 1/2” x 1/8”

48” x 24”

1 1/2” x 1 1/2” x 1/8”

60” x 30”

1 1/2” x 1 1/2” x 3/16”

60” x 60”

1 1/2” x 1 1/2” x 1/4” or 2” x 2” x 1/8”

FIG. A

3” MAX. OVER 60” - INCREASE ANGLE SIZE AS DISTANCE REQUIRED FOR SPACE & DUCT SIZE TO SUPPORT

SUPPORT RISERS SO THAT THEY ARE IN TENSION

FIGURE 4-7 RISER SUPPORTS - FROM FLOOR

4.14

HVAC Duct Construction Standards Metal and Flexible S Second Edition

FIG. A - SUGGESTED SIZING

Y

DUCT SIZE

BAND

457 x 300 mm 610 x 508 mm

38.1 x 1.61 mm 25 x 3.2 mm

X TABLE 4-4

Y

ALLOWABLE

FASTENER

ANCHOR FIG. A SHOWS SUPPLEMENTAL FASTENER LOCATIONS

DUCT GAGE

LOAD PER FASTENER*

0.48, 0.58 mm 0.70, 1.00 mm 1.31, 1.61 mm

11.3 KG 16 KG 23 KG

* WELD, BOLT OR NO. 8 SCREW (MIN.) DEVIATION PERMITTED BY OTHER ANALYSIS. X = 25 mm, Y = 51 mm; ADD OTHERS TO ACCOMODATE LOAD. MINIMUM OF 3 ON 610 mm WIDTH AND UP. ADD ALONG SIDES NEAREST ANCHORS.

Y

X

(HANGER)

Y

ANCHOR SEE KNEE BRACKET TABLES IN THE ROUND INDUSTRIAL STDS. FIG. B - SUGGESTED SIZING

ANCHOR FIG. B

NOTES:

DUCT SIZE

ANGLE

762 x 305 mm 914 x 457 mm 1067 x 610 mm 1219 x 914 mm

25 x 25 x 3.2 mm 25 x 25 x 3.2 mm 31.8 x 31.8 x 3.2 mm 31.8 x 31.8 x 3.2 mm

1. BRACKETS ARE SIZED FOR 3.7 M OF DUCT, MAXIMUM. 2. LOCATE DUCTS AGAINST WALL OR MAXIMUM OF 51 mm AWAY FROM WALL. 3. EACH WALL ANCHOR SHALL SATISFY THE FOLLOWING CRITERIA UNLESS OTHER ANALYSIS IS MADE: A. TENSILE LOAD = 3/8 x DUCT WEIGHT; SAFETY FACTOR 4. B. SHEAR LOAD x 1/2 x DUCT WEIGHT; SAFETY FACTOR 4.

FIGURE 4-8M SUPPORT FROM WALL

HVAC Duct Construction Standards Metal and Flexible • Second Edition

4.17