Historical
ANSI Z21.13b-2007/CSA 4.9b-2007
Addenda 2 to ANSI Z21.13-2004/CSA 4.9-2004, Gas-Fired Low Pressure Steam and Hot Water Boilers
Details test and examination criteria for Category I, Category II, Category III and Category IV low-pressure steam and hot water boilers for use with natural, manufactured and mixed gases, liquefied petroleum gases and LP gas-air mixtures. A boiler is defined in the standard as a boiler operating at or below the following pressures or temperatures: steam heating boiler - 15 psi (103.42 kPa) steam pressure; hot water heating or supply boiler - 160 psi (1.10 MPa) water pressure, 250°F (121°C) water temperature.
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