NZ4202 - Unitec
NZ4202 - Unitec
NZ4202 - Unitec
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Issued June 1995 NZS 4202: 1 995<br />
All calculations are based on air stream size<br />
Surface area = P x L, where<br />
P = perimeter of largest end<br />
L = length of duct or fitting calculated as follows:<br />
Spring line<br />
STRAIGHT<br />
DUCT<br />
150 mrnj<br />
Extent of splitter or damper<br />
L=L1tL2<br />
JUNCTION<br />
O<br />
91<br />
(No splitter]<br />
L=L1 t L2<br />
JUNCTION<br />
I<br />
(Intersection of<br />
straight ducts<br />
without splitters<br />
or dampers)<br />
(Any angle up to<br />
and including 90")<br />
Measure as straight ducts<br />
STRAIGHT<br />
DUCT<br />
TAP IN<br />
V<br />
Spring line<br />
L=L1 t L2<br />
BEND*<br />
H<br />
L=L1<br />
TRANSITION<br />
Spring line<br />
Extent of splitter or damper<br />
L.LltL2<br />
JUNCTION<br />
Dimensions are to spring line of branch<br />
L =Li t L2<br />
JUNCTION<br />
--`,,``,,,,,,``,``,`,,,`,,,`,-`-`,,`,,`,`,,`---<br />
(Any angle up to<br />
and including 90")<br />
L.Li+Li<br />
ELBOW*<br />
* If over 90" to be considered<br />
two bends - one 90; the other<br />
the remainder<br />
I<br />
L<br />
-i<br />
.A<br />
IL;i.l<br />
L=L -1 + L2 + L3<br />
JUNCTION<br />
Duct pieces not conforming with the above diagrams shall have the area calculated by applying the same principles.<br />
Lines in diagrams do not necessarily indicate the positions of joints in the ductwork. Splitters are not measured but are<br />
deemed to be covered by the foregoing formulae.<br />
Figure A l - Surface area of ductwork<br />
Copyright Standards New Zealand<br />
Provided by IHS under license with SNZ<br />
Document provided by IHS Licensee=<strong>Unitec</strong> Inst of Technology/5911177001,<br />
03/02/2005 18:31:52 MST Questions or comments about this message: please call<br />
the Document Policy Group at 303-397-2295.
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