The current American National Standards Institute (ANSI) standard (Z83.6-1982) method determining total infrared heat output from commercial gas-fired infrared-wtube space beaters is not sufficiently broad to encompass all of the equipment currently in the marketplace. For example, long straight or U-shaped tubular heaters cannot be evaluated under the spherical grid approach specified in the standard. The grid size would be simply too large for practical use.

An approach to extending the procedure to other heaters has been developed through a literature survey and a laboratory evaluation. Current test procedures were evaluated along with instrumentation used to measure infrared heat rates. A procedure was developed for measuring total radiant output based on the use of a 180° view angle radiometer and a cylindrical grid surrounding the heater. The procedure was tested in the laboratory and found to perform satisfactorily. A total radiant output of 40,500 Btu/h was measured emanating from a straight tube heater of 104,000 Btu/h gross input. The measuring procedure developed includes several parameters that were carefully assessed and defined, specifically, radiometer window material, the need for radiometer water cooling, calibration techniques, and measurement of background radiation.

Units: I-P