Oval Duct

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.

  1. The system is first designed on the basis of circular duct.
  2. 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.
  3. 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.
  4. For clarity, please identify flat-oval duct on your drawing by listing the minor x major axis dimensions followed by the symbol o.