Pressure Gauge Range Selector
Pick a standard pressure gauge range so that normal pressure sits in the readable middle of the dial and maximum pressure stays within the EN 837 loading limits for steady or fluctuating service.
- Maximum allowed working pressure = 75 % of full scale (steady load)
- Smallest standard range with 8 bar ≤ 75 % of scale: 0 to 16 bar
Standard ranges compared
| Range | Normal pressure | Maximum pressure | Within limit |
|---|---|---|---|
| 0 to 10 bar | 60 % | 80 % | Too small |
| 0 to 16 bar | 38 % | 50 % | OK |
| 0 to 25 bar | 24 % | 32 % | OK |
| 0 to 40 bar | 15 % | 20 % | OK |
| 0 to 60 bar | 10 % | 13 % | OK |
How to Choose a Pressure Gauge Range
EN 837-2 recommends that the working pressure of a Bourdon tube gauge should not exceed 75 % of full scale for steady pressure, or two thirds of full scale for fluctuating pressure. This protects the measuring element from fatigue and keeps the pointer readable.
Fluctuating load: Pmax ≤ 0.67 × full scale
Standard metric ranges follow the series 1, 1.6, 2.5, 4, 6 multiplied by powers of ten (for example 0 to 10, 16, 25 bar).
Worked example
Normal pressure 6 bar, maximum 8 bar, steady load. 0 to 10 bar would put the maximum at 80 %, above the 75 % limit, so the right choice is 0 to 16 bar with normal pressure at 38 % and maximum at 50 % of scale.
Frequently Asked Questions
What percent of the range should a pressure gauge operate at?
Ideally normal pressure sits between about 25 % and 75 % of full scale, with maximum steady pressure no higher than 75 % (or 67 % for pulsating service).
What are standard pressure gauge ranges?
Metric ranges include 0 to 1, 1.6, 2.5, 4, 6, 10, 16, 25, 40, 60 and 100 bar. Common psi ranges include 0 to 15, 30, 60, 100, 160, 200, 300 and 600 psi.
Can I use a gauge above its full scale?
Most gauges withstand a short overload of 25 % or more without damage, but continuous use above full scale causes permanent set and inaccurate readings.
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