Roladuct Spiral Flat-Oval duct is machine-formed from Roladuct Round Spiral Tubing. The flat-oval shape is specifically designed for low head room and restricted space locations which cannot accept round duct.
Spiral Flat-Oval Compared with Rectangular Duct
The Spiral Flat-Oval has considerably less flat surface than rectangular duct. If the springy structure of flat-oval is adequately dampered, it has less surface susceptible to vibration. Thus, properly designed flat-oval duct can be superior in performance to rectangular duct.
The characteristics of flat-oval duct parallel those of circularshaped duct closely enough that slip-joint couplings can be used. Slip-joint couplings provide easier sealing against air leaks at the joints, a significant improvement over other types of duct connections.
There is an unfortunate tendency to make a surface application of sealer over a joint and assume that this is a permanently satisfactory solution to the sealing problem. This is not the case, as surface-applied sealers are not a permanent seal. Roladuct research into materials and techniques for joint sealing has proved that the sealer must be protected by metal, such as within a slip-joint, in order to be considered a permanent seal.
The Spiral Flat-Oval coupling and joint permits the use of the same experience-proven materials and technique for sealing that have been so successful in circular duct joints.
Under certain size and pressure conditions, both flat-oval and rectangular duct must be braced and reinforced against deflection.
Flat-Oval Duct Design
The design of a duct system utilising flat-oval duct follows the same procedures used with rectangular duct.
- The system is first designed on the basis of circular duct.
- Where space limitations require the use of oval duct, the circular duct is converted to its equivalent Roladuct Spiral Flat-Oval duct by using the selection chart. This chart has been arranged in a manner that makes its uses similar to tables for rectangular duct and should be used in exactly the same way.
- Spiral Flat-Oval duct is made only in the sizes listed in selection chart. For maximum economy, select your flat-oval duct size from this table.
- For clarity, please identify flat-oval duct on your drawing by listing the minor x major axis dimensions followed by the symbol