GE SF6, Instruction Manual

Page: 36 / 300

Description and operation
SF
6
gas monitoring
GE Information
07- 2016 L20- 001EN/08
4/6
Measuring density
Pressure units
D
The international unit pressure is the Pascal (Pa).
D
The practical unit is the bar (14.503 p.s.i.)
1 bar = 1,000 hPa
1 bar = 100 kPa
10 bar = 1 MPa
D
Standard atmospheric pressure is equal to 101.3 kPa at sea level and an
air temperature of 20

C (68

F).
Measuring density
When it is not possible to directly measure density, this may be checked
using an industrial pressure gauge capable of measuring the effective
pressure .
An effective pressure value corresponds to the rated density, determined
for normal atmospheric pressure (101.3 kPa) and an ambient temperature
of 20

C (68

F).
For each pressure reading (filling, inspection of densimeter thresholds...), the
rated effective pressure should be corrected according to the ambient tem-
perature and atmospheric pressure of the site at the time the reading is taken.
See the module “ Calculation of the SF
6
gas filling pressure to using the
pressure gauge (tool) ”.
The real pressure is therefore :
P
real
= P
rated effective in accordance with temperature
+
Δ
Pp
*
*
Δ
Pp : correction in accordance with atmospheric pressure .