Fluke 2470 User Manual
B-1
Appendix B
Equation A-4 — Air Density
Equation A-4 — Air Density
Air Density
(
AIR
P
) in units of g/cm
3
, is calculated as follows;
(
)
(
)
(
)
(
)
(
)
t
e
x
U
x
P
x
t
air
+
−
=
+
−
15
.
273
/
6
.
4990221
0004646
.
0
15
.
273
/
56
.
5315
ρ
where:
P
= Barometric Pressure, (mmHg)
t
= Air Temperature, (ºC)
U
= Relative Humidity, (%RH)
Nitrogen Density — English Units (0 to 1000 PSIG)
To calculate the density of Nitrogen at pressures from 0 psig to 1000 psig, use the following
equation;
(
) (
)
P
x
x
in
lbm
DENSITY
6
3
10
826
.
2
/
−
=
where;
PRESSURE
P
=
in psi absolute (if P is in gauge, convert it to an absolute value by
adding barometric pressure, e.g.
7
.
14
+
P
)
Nitrogen Density — English Units (1,000 to 15,000 PSIG)
To calculate the density of Nitrogen at pressures from 1,000 psig to 15,000, use the following
equation;
(
) (
) (
) (
)
2
11
6
4
3
10
9.46069
10
74396
.
2
10
37465
.
2
/
P
x
P
x
in
lbm
DENSITY
−
−
−
−
+
=
where;
PRESSURE
P
=
in psi absolute (if P is in gauge, convert it to an absolute value by
adding barometric pressure, e.g.
7
.
14
+
P
)