Metal Duct
6YkVciV\Zhd[bZiVaYjXi^h^ihXdcYjXi^k^in!Z[[^" X^ZcXn! VcY i]Vi ^i YdZh cdi Xdcig^WjiZ id hiVi^X ZaZXig^XVaX]Vg\ZWj^aY"je#=dlZkZg!hiVi^XX]Vg\" Zh VgZ hi^aa egdYjXZY l]Zc Yjhi eVgi^XaZh hig^`Z di]Zg Yjhi eVgi^XaZh Vh i]Zn bdkZ i]gdj\] i]Z YjXi# H^cXZ bZiVa YjXi ^h V XdcYjXidg! ^i XVc WZ \gdjcYZYfj^iZZVh^anidY^hh^eViZVcnhiVi^XZaZX" ig^XVaX]Vg\Zh#
Figure 41. :mVbeaZhd[bZiVae^eZVcY
XdbedcZcih#
I]ZgZVgZVcjbWZgd[dei^dchl]Zc^iXdbZhid bZiVaYjXi!WjibZiVaYjXii]Vi^hheZX^VaanbVcj" [VXijgZY [dg Yjhi XdaaZXi^dc ^h i]Z WZhi X]d^XZ# L]Zc hZaZXi^c\ ndjg bZiVa YjXi! X]ddhZ ]^\] fjVa^in bZiVa YjXi l^i] hbddi] lZaYZY ^ciZgcVa hZVbh i]Vi l^aa b^c^b^oZ V^g[adl gZh^hiVcXZ# I]^h ineZ d[ YjXi jhjVaan XdccZXih id di]Zg YjXih dg ZaWdlh l^i] V h^beaZ! hZa["hZVa^c\ XaVbe! ^h kZgn fj^X` VcY ZVhn id VhhZbWaZ! VcY XVc WZ gZVY^anY^hbVciaZYVcYgZ"^chiVaaZY#I]^h^hZheZ" X^Vaan^bedgiVci^[ndjZkZgcZZYidX]Vc\Zi]^c\h VgdjcY^cndjgh]dedgVYYbdgZiddah#
6kd^Y^c[Zg^dgbZiVaYjXii]VigZfj^gZhndjidXji^i idaZc\i]VcYhcVe^iid\Zi]Zg#I]^hineZd[YjXi^h i^bZXdchjb^c\id^chiVaaWZXVjhZ^igZfj^gZhndj idhZVaVaai]ZhZVbhl^i]h^a^XdcZVcYhXgZli]Z XdbedcZcihdci]ZZcYhl^i]h]ZZibZiVahXgZlh# 6cdi]ZgY^hVYkVciV\Z^hi]Zgdj\]^ciZgcVahZVbh VcYXg^beZYZcYhi]VijcVkd^YVWan^cXgZVhZhiVi^X egZhhjgZadhh#
"'+"
Flexible Duct
;aZm^WaZ ]dhZ ^h \ZcZgVaan jhZY [dg h]dgi gjch! hbVaah]dehVcYVig^\^YYjXi"id"iddaXdccZXi^dch# I]ZgZ VgZ bVcn Y^[[ZgZci ineZh d[ [aZm ]dhZ dc i]Z bVg`Zi idYVn# I]ZhZ VgZ bVcj[VXijgZY [gdb bViZg^Vah hjX] Vh edanZi]naZcZ! EK8! Xadi] ]dhZ Y^eeZY^cgjWWZgVcYZkZcbZiVa!^cXajY^c\hiZZa VcYVajb^cjb#
I]ZhjeZg^dgX]d^XZ]ZgZ^hbZiVa[aZm]dhZi]Vi^h YZh^\cZYidWZ[aZm^WaZ!nZiWZVhhbddi]Vhedh" h^WaZidgZYjXZhiVi^XegZhhjgZadhh#
Figure 42. :mVbeaZd[[aZm^WaZbZiVaYjXi#
I]ZgZVgZVahdbVcn`^cYhd[ejgZeaVhi^X[aZm^WaZ ]dhZ!hjX]Vhcdc"eZg[dgViZYYgV^cV\ZineZ]dhZ VcY YgnZg kZci ]dhZ# 9gV^cV\Z ineZ ]dhZ! l]^aZ WZ^c\ ZXdcdb^XVa! YdZh cdi fj^iZ ]VkZ i]Z [aZm" ^W^a^ingZfj^gZY[dgYjhiXdaaZXi^dc#I]Z^ch^YZd[i]Z YjXi^hVahdYZZeanXdggj\ViZYVcYXVc^cXgZVhZ i]ZhiVi^XegZhhjgZadhhWnVhbjX]Vh*%dkZg hbddi] lVaa YjXi# 9gnZg kZci ]dhZ! l]^aZ WZ^c\ XdbeaZiZan [aZm^WaZ! ^h cdc"gZh^hiVci id VWgVh^dc VcY ]Vh V iZcYZcXn id XdaaVehZ ^c V cZ\Vi^kZ egZhhjgZhnhiZb#LZ9DCDIgZXdbbZcYjh^c\ YgnZgkZci]dhZ^cndjgYjhiXdaaZXi^dchnhiZb#
>[jh^c\[aZm"]dhZ!ndjh]djaYX]ddhZdcZd[i]Z bVcnineZhi]ViVgZYZh^\cZYheZX^[^XVaan[dgi]Z bdkZbZci d[ hda^Y eVgi^XaZh! ^#Z# Yjhi! \gV^ch! VcY eaVhi^Xh# =dlZkZg! i]Z Xdhi d[ heZX^[^XVaan YZh^\cZY [aZm^WaZ YjXi XVc kVgn \gZVian# <g^ooan d[[ZghedanZi]naZcZ]dhZ!l]^X]^hlZaahj^iZY[dg i]ZgZbdkVad[eVgi^XjaViZbViiZg!ZheZX^VaanhVl" Yjhi! h^cXZ ^i ^h YjgVWaZ VcY XdbeaZiZan [aZm^WaZ# EdanZi]naZcZ ^h Vahd kZgn ZXdcdb^XVa VcY VkV^a" VWaZ^cVl^YZkVg^Zind[Y^VbZiZghVcYaZc\i]h[dg bdhiVeea^XVi^dch#