scope:

This Code applies to all air heaters used in industrial application, e.g., air heaters servicing steam generators and industrial furnaces. This specifically includes

(a) combustion gas-to-air heat exchanger including air heaters with multisection air streams

(b) air preheater coils utilizing noncondensing (single phase) steam, water, or other hot fluids

This Code does not cover direct-fired air heaters or gas-to-gas heat exchangers. In the latter application, this Code may be used to determine both the thermal and pressure drop performance, while alternate methods of leakage measurement should be agreed upon between the parties. This Code also does not cover heat exchangers where the heating fluid is condensed while passing through the heater.

Air heaters in parallel shall be tested individually (wherever possible) for purposes of checking actual performance.