What to check in an offline gas-plant calculator

Start with the question and the inputs

Before choosing a calculator, write down the question you are trying to answer. A hydrate estimate, a volume calculation, and a pressure-related check need different information. A familiar-looking number is not a substitute for checking that you selected the right tool.

Check the units and the meaning of each input. Gauge and absolute pressure are different quantities; a calculator should make its expected input clear. Use current, appropriate source data and your facility's approved methods rather than assumptions taken from an example screen.

• Does the tool state the units for every input and output?
• Does it name the calculation method and its assumptions?
• Can you distinguish the entered data from defaults or remembered values?

Read the method before relying on the result

Look for a named correlation or method, its source, its validity range, and any standing restrictions. A tool that displays a result outside its stated range should also make that warning visible. More decimal places do not remove uncertainty in the inputs or the method.

PlantHand includes a method sheet and validity warnings alongside its field estimates. Its hydrate-method screen, for example, identifies the Towler–Mokhatab gas-gravity correlation and states its assumptions. The product page shows the actual method sheet and a result with warnings.

Check what offline really includes

Try the tools you need before leaving a connected location. Check the calculator, the in-app explanation, and any saved inputs. A link to an external reference may still need a connection even when the calculation itself runs locally.

PlantHand's calculators and reference tools run on the device. Opening an external method citation in Safari requires network access. Review the tool list and screenshots to check whether it covers the work you have in mind.

Keep the approval boundary clear

An offline field estimate is not engineering design, a certified result, or permission to operate equipment. Verify results against facility-approved methods and never use the app as the sole basis for a safety-critical decision. This checklist helps you evaluate a calculator; it does not prescribe an operating procedure.