How close to the edges of the duct must horizontal cleanout openings be installed?

Horizontal cleanout openings in ducts are measured for their placement in relation to the edges of the duct. According to the Mechanical Code, these cleanouts must be installed no closer than 1 inch from the edge of the duct. This requirement is crucial for ensuring accessibility and functionality during maintenance and cleaning operations. Having a cleanout too close to the edge may hinder proper access for tools and reduce the effectiveness of cleaning, potentially leading to buildup that can affect system performance.

It's essential to adhere to this spacing guideline to ensure that the ductwork is not only compliant with code but also practical for maintenance tasks, thus promoting a more efficient HVAC system overall.