This Standard covers the construction, and performance*, (See Part III, DEFINITIONS) for gas-fired appliances with inputs up to and including 400 o00 Btuh (117.23 kW)** to determine their suitability for use at high altitude. The appliances include furnaces, boilers, room heaters, unit heaters, water heaters and such other appliances where field conditions indicate the necessity of testing for high-altitude use (See Part III, DEFINITIONS). The test rate shall mean the appliance′s input at a datum of 600 feet (152 m) or 29.38 inches of mercury (99.2 kPa) pressure.

This Standard applies to appliances specified in 1.1.1 when for use over an altitude range of 2 000 - 4 500 feet (610 - 1370 m), or 0 - 4 500 feet (0 - 1370 m).

* NOTE:

At the option of the manufacturer, tests specified in Part II may be conducted at a high-altitude location.

** NOTE:

This input limitation reflects what is currently required by inspection authorities in high-altitude areas (i.e. appliances under 400 000 Btuh must meet the requirements of this Standard). Appliances with inputs in excess of 400 000 Btuh may still be reviewed for compliance with this Standard.