The choices are direct reading or 3-15 psig receivers. The 3-15 psig receiver pressure gauges are used in the transmission of 3-15 psig pneumatic signals. This type of pneumatic signal is rarely used right now but still used in the place where no electric signal allowed (4-20mA etc). The 3-15 psig receiver pressure gauges is design so that the minimum scale is 3 psi and the maximum scale is 15 psi to simply indicate the pressure in the transmission line.
The direct reading pressure gauges are the gauge that completely different from receiver gauges. In the direct reading pressure gauges, the minimum scale must be a zero (atmospheric pressure) and the maximum shall be as per pressure gauge range.
For example, pressure gauges have a range from 0 to 700 psig, and then the gauge shall have the scale from 0 to 700 psig. This type of gauges is used to know the pressure of a process system what ever its shows (not fixed between 3 – 15 psig).
The exception from this direct reading type is the gauge that has a suppressed range. Gauges that have suppressed range mean that gauge minimum indicating pressure is not zero. It could be anything except zero.
Most of the end user avoids using this suppressed range because to simply see whether the instrument is on good condition or not someone must supply a pressure as indicated in the minimum indication. On the other hand the normal gauges, we just simply put it on the atmospheric pressure and see whether it point out to the zero scale or not.
The default choice shall be direct reading instead of 3-15 psig receivers because this type of gauges (receiver type) is rarely used in the present offshore application.