Preparing to Traverse a Rectangular Duct
To do a proper airflow measurement (CFM) you should do traverse
readings to obtain the true average airflow through the duct. It is rec-
ommended to do at least 12 points of measurement. There are two
ways to perform this test using the DC580, Time Based Traverse and
Spot Based Traverse. Time based is typically easier but both are
explained in the next sections.
1. You will need to determine the easiest access to take your read-
ings. Normally it is best to enter from the side (Height) of the duct
since you will have to drill less holes, but you may have to drill from
the bottom (Width) of the duct. See below.
Ideal side to
enter the duct.
Not the ideal side to enter
the duct but may be neces-
sary
Choose one
side to enter
the duct.
13
