A rule that required residential ductwork to be made from 28-gauge sheet metal has been removed from the 2015 International Mechanical Code.

Representatives from the Air Conditioning Contractors of America and the Sheet Metal and Air Conditioning Contractors’ National Association, and manufacturers Ductmate Industries Inc. and M&M Manufacturing Co., have been working for three years to have the standard changed.

Chris Van Rite, M&M’s vice president of sales, said many states had trouble enforcing the 28-gauge requirement since it first appeared in 2009.

“The code change hearings for the IRC will be in May of 2013 and we are optimistic of getting the 28-gauge requirement removed from that code as well,” Van Rite said. “What we’ve learned is that we have to be vigilant and engaged in the code adoption process in order to protect the interests of the HVAC industry.”