If openings of required size are not possible on horizontal ducts, how often should openings be provided for thorough cleaning?

The requirement for openings on horizontal ducts is essential for ensuring proper access for thorough cleaning and maintenance. According to the NFPA 96 standard, when openings of the required size cannot be provided, the guidelines specify that cleanouts should be placed at intervals that facilitate effective cleaning without compromising the performance of the ventilation system.

In this case, providing an opening every 12 feet is aligned with best practices for maintaining cleanliness in the ductwork. This distance allows for adequate access to ensure that grease and other accumulations can be managed effectively, reducing the risk of fire hazards associated with built-up grease in the ducts. By stipulating openings at this interval, the NFPA 96 promotes safety, operational efficiency, and compliance with fire safety codes in commercial cooking environments.

The other distances mentioned might not ensure the same level of cleanliness and accessibility, highlighting the significance of the 12-foot interval as a balanced approach to duct maintenance under challenging installation circumstances.