Which of the following is NOT a precaution under the gas piping test regulations?

Using oxygen as a test medium for gas piping is not appropriate and is thereby categorized as a precaution that should not be taken under the gas piping test regulations. Oxygen is a highly reactive gas that can create hazardous conditions when combined with flammable materials, such as natural gas. The regulations prioritize safety and effectiveness, and the use of nitrogen or other inert gases is recommended for testing purposes instead. These substances do not contribute to combustion and allow for accurate pressure testing of gas systems without introducing significant risks.

The other options reflect proper safety practices designed to minimize risks during the testing process. Disconnection of appliances ensures that they are not inadvertently affected or damaged during testing. Isolation of sections with blind flanges prevents gas from entering these areas, thus isolating portions of the piping system for accurate testing. Restricting the test pressure scale helps to conform to the system’s design specifications and prevents over-pressurization, an important safety consideration. All these actions contribute to a systematic approach to testing the integrity of gas piping.