Correct Pressure Gauge range 1

[Iomcube]

Say a vessel's operating pressure is 12 barg & its design pressure is 27 barg. A PSV on it has a set pressure of 25.4 barg.

Now I want to install a pressure gauge on it; what is the range I should select? Any standards or guidelines?

 

[mk3223]

May refer to ASME B40.100 for the recommendation of the pressure gauge selection to meet the operation requirement, i.e. range, accuracy, etc.

 

[LittleInch]

https://www.industrialcontrolsonline.com/informationcenter/selecting-a-pressure-gauge-in-7-steps/

Why not use a pressure indicating transmitter?

How accurate do you need it to be?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[danw2]

The rule is that overpressuring a mechanical gauge exceeds the pressure element's elasticity and 'stretches' the element creating a permanent offset and probably a gain error. It does, but there's a small margin of overpressure beyond the maximum scale value that does not affect the gauge..

Standard gauge ranges are 0-16, 0-25 and 0-40 bar.

The 0-25 bar range puts the normal operating pressure at mid scale which is the perfect condition under which to run a pressure gauge.

Proof Pressure is a rating which is the maximum pressure a gauge can withstand without evidence of change in accuracy.

Proof pressures per ASME B40.100 (except retard and differential pressure gauges) ranges up to 1000psi have a proof pressure of 130% of span. (25 bar is roughly 375 psig).

So the 25.4 relief pressure is less than 2% just beyond the maximum scale value, well within the 130% proof pressure rating.

 

[Iomcube]

Thanks for your comments guys

 

[LittleInch]

The other thing you need to be careful of though is that gauges often come with end stops - some visible, some not.

So you can't see if in fact the pressure is higher than your max range by a quick visual glance... so in the case above a 0-25 will simply stop reading / indicating at around 24-25 bar.

I don't think that is good practice myself.

Neither really are over range protectors which do a similar function.

Ever thought of a battery powered pressure guage?

https://www.omega.co.uk/pptst/DPG-108.html

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[danw2]

The use of a zero stop pin on non-compound range gauges is nearly universal.

The use of a maximum (overpressure) stop pin is far less common, but the ones I've seen are positioned beyond the 100% scale position to allow for some overrange pressure above the scale maximum.