TSI Instruments AccuBalance 8370, Operation And Service Manual

Page: 49 / 58

41
Appendix A
Standard Flow vs. Actual Flow
Standard flow is defined as the volumetric flow rate of air at
"Standard" temperature and barometric pressure conditions of 70ºF
(21.1ºC) and 14.7 psia (760 mmHg). By contrast, actual flow is the
volumetric flow rate of air at local temperature and barometric
pressure conditions. It is common in ventilation test applications that
standard flow is the desired measurement parameter. The
A
CCU
B
ALANCE
automatically indicates standard flow readings. There
is therefore no need to apply a correction factor; however, if you wish
to convert standard flow readings to actual flow readings, you must
apply an air-density correction factor:
Actual Flow low
P
T
=
⎡
⎣⎢ ⎤
⎦⎥
+
⎡
⎣⎢ ⎤
⎦⎥
(Standard F )
act
act
14 7 460
530
.
where
P
T
act
act
=
=
.
Your air flow temperature in F.
Your local barometric pressure in psia
°
Or
Actual Flow low
P
T
t
=
⎡
⎣⎢ ⎤
⎦⎥
+
⎡
⎣⎢ ⎤
⎦⎥
(Standard F )
ac
act
760 27315
294 25
1
1
.
.
where
P
T
act
act
1
1
= .
=
Your air flow temperature in C.
Your local barometric pressure in mmHg
°