[Code of Federal Regulations] [Title 46, Volume 2] [Revised as of October 1, 2004] From the U.S. Government Printing Office via GPO Access [CITE: 46CFR53.05-2] [Page 137-138] TITLE 46--SHIPPING CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PART 53_HEATING BOILERS--Table of Contents Subpart 53.05_Pressure Relieving Devices (Article 4) Sec. 53.05-2 Relief valve requirements for hot water boilers (modifies HG-400.2). (a) The relief valve requirements for hot water boilers must be as indicated in article 4 of section IV of the ASME [[Page 138]] Code except as noted otherwise in this section. (b) Hot water heating boilers. Each hot water heating boiler must have at least one safety relief valve. (c) Hot water supply boilers. Each hot water supply boiler must have at least one safety relief valve and a temperature relief valve or a pressure-temperature relief valve. The valve temperature setting must not be more than 99 [deg]C (210 [deg]F).