Unions must be installed in a water supply system within what distance of regulating equipment?

Unions are essential components in plumbing systems as they facilitate easy disconnection and reconnection of pipes, especially around regulating equipment like valves and pressure regulators. The requirement to install unions within a specific distance of this equipment ensures that maintenance and repairs can be conducted efficiently without the need to dismantle extensive lengths of piping.

In this context, a distance of 12 inches is specified as the ideal length to ensure accessibility. This distance strikes a balance between structural integrity and ease of service. Having unions placed within 12 inches allows for sufficient room for tools and hands to maneuver when working on valves or other regulating devices, thus helping to prevent potential damage to the piping and ensure that any adjustments or replacements can be made without significant effort or alteration of the system.

Other distances mentioned would not provide the same level of accessibility or could potentially complicate repairs, making the specified 12-inch distance the most practical option.