G½, BSPP and NPT: why the thread name matters

Identify the actual standard

A nominal half-inch designation does not describe every geometric detail. Check whether the connection is parallel or tapered and identify the specified standard. A partially engaging thread is not evidence of compatibility. For replacement work, obtain a drawing or verified connection code rather than estimating from a photograph.

Find the intended seal

Some parallel-thread arrangements seal at a gasket or defined face; others use a manufacturer-specific hygienic interface. Follow the instructions for the actual variant. Do not apply a generic instruction about thread tape to every hygienic or face-sealed connection.

The sensor, adapter and vessel connection can each introduce a different interface. List all of them on the quotation to avoid an incomplete package.

Check more than leakage

An adapter can change insertion depth, create a retention pocket or shift the sensing position. It also has its own pressure, temperature and material limits. Review the installed section before treating an adapter as a simple thread converter.

What to confirm for your application

• Thread standard and complete connection code
• Parallel or tapered form
• Seal type and permitted sealing practice
• Resulting insertion depth
• Adapter pressure and material limits