What type of valve is used to relieve pressure in a pipeline, tank, or vessel?

A safety valve is specifically designed to protect equipment, such as pipelines, tanks, or vessels, from overpressure scenarios. Its primary function is to automatically open and release excess pressure when it reaches a predetermined limit, thereby preventing potential damage, explosions, or hazardous incidents. When the internal pressure exceeds this set threshold, the safety valve lifts its disc, allowing the pressurized fluid to escape, which reduces pressure within the system and protects the integrity of the equipment.

Control valves, while important for regulating flow and pressure within a system, do not primarily serve the purpose of relieving excess pressure. Butterfly valves are straightforward, quarter-turn valves typically used for on/off control or throttling flow but do not specifically address the need for pressure relief. Needle valves are designed for precise flow regulation but are not intended for high-pressure relief situations and lack the safety functionality of a safety valve. Thus, the safety valve is the most appropriate choice for the requirement stated in the question.