Duct & Stacks
Our custom-designed stacks are also available in a wide variety of diameters and lengths.
Ducts
FRP SYSTEMS manufactures ventilation or process ducting to meet your specifications and requirements. Ducting can be round or rectangular and be designed for vacuum service as required.
Stacks
FRP SYSTEMS can design and manufacture vent stacks to your required diameter, height and support arrangement. Each stack is designed specific to your needs including consideration for: Process conditions; Method of support; Free standing, guyed or cantilevered; Dynamic wind effects; Internal material buildup; Condensate; and Lightning protection.
Duct Dimensions
The following chart represents industry accepted specifications for fiberglass reinforced polyester round duct dimensions.
Reinforced-Polyester Round Duct Dimensions
I.D. |
Wall Thickness (min.) |
Allowable Vacuum (2)
|
Allowable Pressure (2) |
Nominal Flange Dia. (O.D.) |
Flange Thickness |
Bolt Circle Dia. |
Bolt Hole Dia. |
No. of Bolt Holes |
|---|---|---|---|---|---|---|---|---|
| In. | In. | In. of Water | In. of Water | In. | In. | In. | In. | |
| 2 | 1/8 | 405 | 750 | 6-3/8 | 1/4 | 5 | 7/16 | 4 |
| 3 | 1/8 | 405 | 500 | 7-3/8 | 1/4 | 6 | 7/16 | 4 |
| 4 | 1/8 | 210 | 410 | 8-3/8 | 1/4 | 7 | 7/16 | 4 |
| 6 | 1/8 | 64 | 350 | 10-3/8 | 1/4 | 9 | 7/16 | 8 |
| 8 | 1/8 | 30 | 180 | 12-3/8 | 1/4 | 11 | 7/16 | 8 |
| 10 | 1/8 | 16 | 340 | 14-3/8 | 3/8 | 13 | 7/16 | 12 |
| 12 | 1/8 | 9 | 280 | 16-3/8 | 3/8 | 15 | 7/16 | 12 |
| 14 | 1/8 | 7 | 220 | 18-3/8 | 3/8 | 17 | 7/16 | 12 |
| 16 | 1/8 | 6 | 290 | 20-3/8 | 1/2 | 19 | 7/16 | 16 |
| 18 | 1/8 | 5 | 240 | 22-3/8 | 1/2 | 21 | 7/16 | 16 |
| 20 | 1/8 | 5 | 190 | 24-3/8 | 1/2 | 23 | 7/16 | 20 |
| 24 | 3/16 | 9 | 140 | 28-3/8 | 1/2 | 27 | 7/16 | 20 |
| 30 | 3/16 | 7 | 100 | 34-3/8 | 1/2 | 33 | 7/16 | 28 |
| 36 | 3/16 | 5 | 70 | 40-3/8 | 1/2 | 39 | 7/16 | 32 |
| 42 | 1/4 | 10 | 120 | 46-3/8 | 5/8 | 45 | 7/16 | 36 |
| 48 | 1/4 | 9 | 100 | 54-3/8 | 5/8 | 52 | 9/16 | 44 |
| 54 | 1/4 | 7 | 80 | 60-3/8 | 5/8 | 58 | 9/16 | 44 |
| 60 | 1/4 | 6 | 60 | 66-3/8 | 5/8 | 64 | 9/16 | 52 |
(1) 5 to 1 design factor of safety. Also based on 10-foot lengths between stiffener rings for vacuum service.
(2) These ratings are suitable for use up to 180°F (82.2°C) in pressure service and ambient atmospheric temperatures on vacuum service. For ratings at higher temperatures, consult FRP SYSTEMS.
Sizes over 60″ dia. are custom designed to suit service requirements.