CHESTERFIELD, MO — Cambridge Engineering, Inc., has announced the availability of a new sample specification guide for contractors, engineers, and local code authorities involved with specifying, buying, or approving makeup air heaters to be installed under the new harmonized U.S./Canadian standard. The guide covers its M-Series product line.

The American National Standards Institute (ANSI) has revised the Z83 standard for direct gas-fired makeup air heaters, and the new ANSI Standard Z83.4/CSA3.7 goes into effect on Jan. 1, 2002. As of the first of the year, units must carry new nameplates confirming they have been tested and certified to the new Z83.4 standard.

To ensure safety and product integrity, Cambridge says the standard now evaluates the burner’s combustion performance at the extreme high/low limits of the heater’s operating range as defined by two airflow switches which must be supplied with each unit. Another significant change is the requirement of a high gas pressure switch for applications where the gas supply pressure exceeds 14 in. wc. In addition, manufacturers will now be required to include on the nameplate more complete information as to the actual certified capacities and inputs of the heaters.