How many safety valves are required on a miniature boiler?

In miniature boilers, which are typically defined as those with a maximum allowable working pressure (MAWP) of 15 psi or less, the requirement for safety valves is generally simplified. For such boilers, the regulation stipulates that only one safety valve is necessary. This safety valve serves to protect the boiler from overpressure conditions by releasing excess steam if the pressure exceeds the set limit.

The rationale behind having just one safety valve is that miniature boilers operate at relatively low pressures compared to larger installations, and the risk of catastrophic failure is significantly reduced. Additionally, having a single safety valve simplifies the design and maintenance of the boiler while still ensuring adequate safety measures are in place to prevent dangerous pressure build-up.

In contrast, larger boilers typically require multiple safety valves because they operate at higher pressures and present a greater risk if not properly managed. This distinction in requirements helps ensure that safety standards are appropriate to the scale and operational characteristics of the equipment in use.