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
circular-shaped duct closely enough that slip-joint couplings
can be used. Slip-join 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 sealing has provided 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.
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