Prihoda Textile Air Dispersion Duct Sizing and Design Guidelines
Layout and System Recommendations
Match metal size to fabric inlet for a straight length of 3x diameter prior to fabric inlet when possible.
Use 1.5x dia radius elbows, laminar / smooth transitions whenever possible.
For best aesthetics use internal rings, track and tensioners.
When routing through structural members hold open components are mandatory.
Utilize a softstart or VFD w/ 30 sec ramp up if possible (especially if no hold open components, to prevent startup shock/popping).
- 1500fpm or less straight runs
- 1300fpm or less 90°’s , T’s or other fittings near fabric inlet
- 1000fpm or less sound sensitive
- 800fpm or less max for top inlet halfround
- negative pressure rectangular duct 1000fpm or less
Inlet Static Pressures
- .25″ w.c. minimum. Sound sensitive or very low pressure unit
- .50″ w.c. standard / typical
- .75″ w.c. high volume / high throw
- +1″ w.c. layout w/ many fittings or very long throw/high velocity required
- Rectangular duct for negative pressure .25”
5 - 10ft max
laminar, low throw, low velocity
(labs, kitchens, gun ranges, high comfort)
10 - 30ft
medium to long throw, high comfort
(pools, gyms, offices, classrooms, manufacturing)
30 - 100ft+
Longest throw with no linear deflection
(industrial, warehousing, air curtains, spot cooling)