BOILER CODES AND STANDARDS
Boilers must be installed and operated in accordance with applicable codes and standards. The local code authorities will refer to one or more of the following industry codes:
• American Society of Mechanical Engineers (ASME)
• American Gas Association (AGA)
• Hydronics Institute (HYDI)
• American Boiler Manufacturers’ Association (ABMA)
• Insurance-companies codes, such as that of Factory Mutual (FM), particularly with respect to burner systems.
• Underwriters’ Laboratories (UL) for certification of some of the control and safety devices, such as relief valves
The proposed design of the boiler system should be submitted to the owner’s insurance company to en- sure compliance with requirements.
Steam Pressure
Steam-pipe systems are categorized by the working pressure of the steam they supply. There are five steam systems:
• High-pressure system above 100 psig
• Medium-pressure system 100 psig to 15 psig
• Low-pressure system 15 psig to 0 psig
• Vapor systems subatmospheric pressures
• Vacuum systems subatmospheric pressures
Vapor systems use the condensing process to reach subatmospheric pressures. Vacuum systems need a mechanically operated vacuum pump to reach sub-atmospheric pressures.