What is the maximum angle allowed for a field fabricated single mitre offset according to SMACNA standards?

The maximum angle allowed for a field fabricated single mitre offset, according to SMACNA (Sheet Metal and Air Conditioning Contractors' National Association) standards, is 15 degrees. This standard is established to ensure that the airflow is not excessively disrupted within ducts, which can happen if angles are too steep. A 15-degree angle strikes a balance between allowing for necessary directional changes in ductwork while minimizing the potential for turbulence and pressure loss.

For practical applications, maintaining this angle is vital for the efficiency and performance of HVAC systems. When fabricating ducts, adhering to this standard helps in creating a system that operates smoothly and effectively, contributing to energy efficiency and overall system performance. Thus, the guideline promotes the longevity of not just the ductwork but also the HVAC systems relying on that ducting.