What is the MAXIMUM spacing for double floor joists that are separated to allow installation of piping?

The maximum spacing for double floor joists that are separated to allow installation of piping is 4 feet on center. This guideline is crucial because it ensures that the structural integrity of the floor system is maintained while still allowing sufficient space for necessary mechanical installations, such as plumbing. By specifying a maximum spacing of 4 feet, it reduces the risk of sagging or excessive movement of the joists, which could occur if they are spaced too far apart.

In general construction practices, the spacing of structural components like joists is designed with load-bearing capacity in mind. Wider spacing could compromise the floor's ability to support weight, particularly when adding elements like piping and fixtures that contribute additional loads. Therefore, maintaining this maximum spacing helps uphold safety standards and building codes while facilitating the installation of essential service lines. The other spacing options would not meet the recommended standards for structural safety and function in this context.