The Hotline Newsletter

New ANSI Standards for Make-Up Air Heaters Effective January 1, 2002

The American National Standards Institute (ANSI) has revised the Z83.4 and Z83.18 Standards for direct gas-fired make-up air heaters and industrial air heaters. This is both a BIG DEAL and very CONFUSING.
It's a BIG DEAL
Because the new standards go into effect in less than six months. They were revised to assure consumer safety and industry integrity. The new ANSI Standards now evaluate the burner's combustion performance at the extreme high/low limits of the heater's operating range as defined by not one, but two airflow switches, which now must be supplied with each unit. In addition, manufacturers will now be required to properly nameplate more complete information as to the actual certified capacities and inputs of the heaters to eliminate false claims of performance, such as maximum temperature rise and discharge temperature.

The process of developing these new standards started by combining the functions of all direct gas-fired heaters (make-up air heaters, door heaters and industrial air heaters) into a single standard due to similarity of design. However, the unique requirements applicable to non-recirculating and recirculating type equipment required the creation of two distinct standards, Z83.4 for non-recirculating and Z83.18 for recirculating heaters.

Cambridge Engineering manufactures only non-recirculating equipment. In fact, Cambridge was the first manufacturer to certify their Make-Up Air Heater product line to the industry's new, harmonized US/Canadian standard ANSI Z83.4/CSA 3.7-M99 which will be required for all similar non-recirculating equipment by January 1, 2002.

This is where it gets CONFUSING
The new more stringent, ANSI Standard Z83.18 for recirculating designs allows room contamination levels on heaters that recirculate to approach the maximum limits of 25 ppm for CO; 5000ppm for CO₂; and 3.0ppm for NO₂ set by the American Conference of Governmental Industrial Hygienists (ACGIH). Manufacturers of recirculating, direct gas-fired equipment (like 80/20 systems) will have problems getting their current designs certified prior to the existing deadline. This is due to a requirement of the new standard that reduces the discharge temperature of these designs as the percentage of recirculated room air is increased. A new control system will be required to meet the new standard and it is still not available.
With less than six months to go, engineers, contractors and local building code authorities have expressed concern. It now appears that many manufacturers of direct gas-fired make-up air heaters will not be able to ship their equipment with new CSA or ETL nameplates confirming that their heaters have been properly tested and certified to the new ANSI Z83 standards.

No one is quite sure what will happen next year when these new standards are to be implemented. However, one thing is for sure. Regardless of what happens, the Cambridge Make-Up Air Heater is already certified by CSA to the new standard.

Cambridge Engineering now offers an updated sample specification for our M-Series Make-Up Air Heater as a guide for engineers, mechanical contractors and local code authorities involved with specifying, buying or approving industrial make-up air systems. Using this sample specification will assure that direct gas-fired make-up air heating equipment installed in industrial manufacturing plants, warehouses or automobile/truck service areas will meet the requirements of the new ANSI Standard.