Is it true that we test pressures of pipelines carrying oil should be pressure tested with the pressure = 1.25 of the design pressures or 1.5 of design pressures?

For pipelines carrying oil (liquid hydrocarbons), the primary industry standard for design and testing is often ASME B31.4, "Pipeline Transportation Systems for Liquids and Slurries."

According to ASME B31.4, the hydrostatic test pressure for liquid pipelines should be at least 1.25 times the maximum operating pressure (MOP) or design pressure at any point along the test section. This ensures a safety margin and verifies the pipeline's integrity under stress higher than its normal operating conditions.

While 1.25 times the design pressure is the common minimum requirement for liquid pipelines, a multiplier of 1.5 times the design pressure is typically specified for gas pipelines (e.g., under ASME B31.8) or for specific components and higher-risk scenarios.

Therefore, for pipelines carrying oil, the test pressure is generally 1.25 times the design pressure.

The final answer is $\boxed{\text{True, the test pressure for pipelines carrying oil is typically 1.25 times the design pressure, as per standards like ASME B31.4.}}$