Table 2-2.Recommended Gauges for Sheet-Metal Duct Construction
and piping systems. These obstructions must be
avoided by fabricating the duct system to go around
the obstacles. Do NOT run obstructions through duct
systems because it creates turbulence that reduces the
efficiency of the system. When the obstruction is an
electrical obstruction, you should ensure all power is
off and safety checked. When running the duct
through an obstruction is absolutely unavoidable, the
turbulence can be reduced by enclosing the
obstruction in a streamlined collar (fig. 2-93).
Figure 2-93.Easement around an obstruction in ducts.
Most duct systems are connected to either a
create vibration should be made with heavy canvas, as
heating or a cooling system. These systems are
shown in figure 2-94.
general] y electric motor driven to move air through the
duct system. Therefore, all inlet and outlet duct
The most common method of making connections
connections to all fans or other equipment that may
between duct sections and fittings is the method of