At what pressure is the safety valve in the air compressor tank set to open?

Answer: C — 150 psi

The safety valve in the air compressor tank is designed to open at a pressure that ensures safety and prevents over-pressurization of the tank. Commonly, this safety valve is typically set to open at 150 psi. This setting allows the valve to release air when the pressure within the tank exceeds this threshold, thereby preventing potential damage to the compressor or even catastrophic failure of the tank due to excessive pressure. Considering that air tanks can be subject to varying operational pressures, setting the safety valve to open at 150 psi strikes a balance between allowing normal operation and providing a safety mechanism. Other pressures listed, such as 100 psi, 120 psi, or 180 psi, either do not align with standard safety practices for air compressor systems or could allow for unsafe conditions if the operating pressures get too close to the tank’s maximum capacity.