🔍 Key Concepts

• Bourdon tube-type pressure gage operation and what can damage it • How steam behaves when it cools in small piping (condensation) • Purpose of a pigtail/siphon loop ahead of a pressure gage on a steam line

💭 Think About

• Think about what part of the steam system would actually reach the delicate Bourdon tube if the pigtail is doing its job correctly. • Ask yourself: does the pigtail try to slow or divert the steam, or does it rely on a change of state (steam turning into water)? • Consider what medium (steam or water) is safer to have in direct contact with the pressure gage element.

✅ Before You Answer

• Verify how a siphon (pigtail) is installed: it forms a loop that traps liquid in front of the gage connection. • Confirm that in normal operation, the Bourdon tube should see pressure, but not the high temperature of live steam. • Eliminate any options that talk about velocity or bleeding off steam, and focus on what would form a protective barrier between hot steam and the gage.