What is the correct graduation requirement for a pressure gauge on an ASME section IV steam boiler?

The correct requirement for the graduation of a pressure gauge on an ASME Section IV steam boiler is a specification that ensures operational reliability and safety. A gauge must be graduated to no less than 30 psi (200 kPa) and no more than 60 psi (414 kPa). This specification is designed to provide an accurate and usable reading range that is appropriate for typical operating pressures of low-pressure steam boilers, which helps in monitoring pressure effectively within safe limits.

This graduation range ensures that operators can easily read the pressure under normal operating conditions and also guards against potential overpressure situations that can occur during operation. Having this defined range is important for both safety and compliance with regulatory standards laid out by ASME, which aim to prevent accidents and maintain safe operational practices.