In Massachusetts plumbing code, what is the primary consideration for sizing drainage piping?

In the context of the Massachusetts plumbing code, the number of fixtures served is the primary consideration for sizing drainage piping. When determining the appropriate size for drainage pipes, it is essential to account for the cumulative flow from all the fixtures connected to the system. Each fixture contributes to the overall demand on the drainage system, so understanding how many fixtures will discharge into the system helps ensure that the pipes can handle the necessary flow without causing backups or inadequate drainage.

Additional factors, like the length of the pipe, type of fluid, and gravity flow, are relevant but secondary to the primary consideration of the number of fixtures. These factors can influence the system's performance and may necessitate adjustments to pipe size or configuration, but they do not serve as the foundation for sizing decisions in the way that the number of fixtures does. This prioritization helps maintain effective drainage performance across a plumbing system, ensuring it functions efficiently under expected conditions.