If you have a thermowell adjacent to the RTD you can insert a (calibrated) temperature probe and check they are reading within 0.5 degC of one another. As for the transmitter you can inject a resistance at 5 points across the range of the transmitter and measure the output which you compare...
I think rather than the standard, although it may be a useful reference, you require the calculation to determine the fuel gas density.
There are numerous resources online if you search for ISO 6976 calculation however http://www.sgc-valid8.com/ may prove useful.
Perhaps the meter can be reconfigured to output std volume?
Otherwise, you could convert your volume to mass using the density, then convert it again to std volume units using the std density. Quite messy though and unlikely to any reporting requirements.
In addition you should check the face of the orifice plate for contamination – lube oil, grease, dust, etc and any damage to the upstream face. You could also check the orientation of the plate, it’s not so uncommon to find a plate that has been installed the wrong way round. Quite often sites...
Apply for graduate schemes with the oil majors, or send in your CV/Resume - almost all large companys will have a job opportunity section/person to contact. Or you could try agencies that specialise in recruitment in the oil & gas industry. Oilcareers.com might be a useful website to get an...