What organization rates the large pressurized cylinders in air conditioning systems that hold more than 15 psig internal pressure?

The American Society of Mechanical Engineers (ASME) is responsible for setting the standards and providing certifications for pressure vessels, including large pressurized cylinders used in air conditioning systems that hold more than 15 psig internal pressure. ASME's Boiler and Pressure Vessel Code establishes safety standards that manufacturers must adhere to when designing and fabricating these vessels, ensuring they can withstand the high pressures and temperatures they may encounter during operation.

Given this context, ASME's role is pivotal in promoting safety and reliability in the engineering of pressure vessels, making it essential for industries including HVAC to comply with these standards. Other organizations listed, while significant in their respective fields, do not specifically focus on the rating and standards for pressure vessels like ASME does. For instance, NIST deals more with measurement standards; EPA oversees environmental regulations; and OSHA is concerned with workplace safety and health standards rather than engineering specifications for equipment like pressure cylinders.