The definition of Vacuum
For background information and to put the readings you see into context this part is provided as extra
material on different vacuum measurement units and its inter relations and conversion.
Source:
Convert from % Vacuum to Unit of Pressure
The % of vacuum is a relative value where pressure at
is the base value.
p
v%
= 100% - (p
v
/ p
atm
) 100%
(1)
where
p
v%
= vacuum (%)
p
v
= absolute pressure (psia, kPa, bar ..)
p
atm
= absolute presure at normal or standard conditions (psia, kPa, bar ..)
Table below refers to sea level
%
Vacuum
Torr
(mm
Mercury)
Micron
psia,
(lb/in
2
abs)
Inches
Mercury
Absolute
Inches
Mercury
Gauge
kPa
abs
0.0
760.0
760,000
14.7
29.92
0.00
101.4
1.3
750.0
750,000
14.5
29.5
0.42
99.9
1.9
735.6
735,600
14.2
28.9
1.02
97.7
7.9
700.0
700,000
13.5
27.6
2.32
93.5
21.0
600.0
600,000
11.6
23.6
6.32
79.9
34.0
500.0
500,000
9.7
19.7
10.22
66.7
47.0
400.0
400,000
7.7
15.7
14.22
53.2
50.0
380.0
380,000
7.3
15.0
14.92
50.8
61.0
300.0
300,000
5.8
11.8
18.12
40
74.0
200.0
200,000
3.9
7.85
22.07
26.6
87.0
100.0
100,000
1.93
3.94
25.98
13.3
88.0
90.0
90,000
1.74
3.54
26.38
12
89.5
80.0
80,000
1.55
3.15
26.77
10.7
90.8
70.0
70,000
1.35
2.76
27.16
9.3
92.1
60.0
60,000
1.16
2.36
27.56
8
93.0
51.7
51,700
1.00
2.03
27.89
6.9
93.5
50.0
50,000
0.97
1.97
27.95
6.7
94.8
40.0
40,000
0.77
1.57
28.35
5.3
96.1
30.0
30,000
0.58
1.18
28.74
4
96.6
25.4
25,400
0.49
1.00
28.92
3.4
97.4
20.0
20,000
0.39
0.785
29.14
2.7
98.7
10.0
10,000
0.193
0.394
29.53
1.3
99.0
7.6
7,600
0.147
0.299
29.62
1.0
99.87
1.0
1,000
0.01934
0.03937
29.88
0.13
99.90
0.75
750
0.0145
0.0295
29.89
0.1
99.99
0.10
100
0.00193
0.00394
29.916
0.013
99.999
0.01
10
0.000193
0.000394
29.9196
0.0013
100
0.00
0
0
0
29.92
0
Summary of Contents for Auto VH1
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