HVAC Duct stiffening

[sk90]

Can anyone suggest some links on HVAC duct beading, Cross breaking,pleating and bead stiffening?
what are the disadvantages ? Why is it that some specifications do not allow the above? Instead external stiffeners are recommended

Regards
SK

 

[Istre]

Regarding why some ducts require external stiffening, there could be a number of reasons. One is that heavier gauges of metal just don't lend themselves to easy cross-breaking or beading. Another is that ducts of larger cross-sections may just have dimensions that are so large that a cross-break or bead won't support the metal's own weight. Also, there may be absolutely no good technical reason why the cross-break or bead is taboo; it could just be the whim of the architect or engineer that designed the HVAC system.

Some sites I'd suggest looking into for more information would be ASHRAE's website and SMACNA's website. Both of these should have some information on ducting that might be able to give you more concrete answers than I'm able to.

 

[jherbert]

hi,

reduces chances for grease (in kitchen exhaust app.), water ponding (Legionella), dust & mould (IAQ), etc. etc accumulating in horz. duct.

As Istre mentioned above, as duct sizes increase the
plate thickness and mass increases. I would also
check DW 143 (issued from UK).

my 2 cents.

cheers.

 

[sk90]

Thanks members