IAPMO Introduces WDC-Pro to Streamline Multi-Family Design

IAPMO has launched WDC-Pro, a web-based tool designed to improve the efficiency and accuracy of water pipe sizing for multi-family, high-rise and residential buildings.

Building on the success of the original IAPMO Water Demand Calculator, WDC-Pro streamlines complex calculations, particularly for multi-family applications, reducing design time by 50% or more while optimizing pipe sizing to reduce construction costs and enhance water efficiency. This reduces calculation time from six hours to just two or three for large-scale projects.

The primary benefit of WDC-Pro is that it uses templates to compute the instantaneous water demand expected during the period of peak indoor water use in multi-family buildings such as apartments and condominium complexes. The user provides the number and flow rate for each type of indoor fixture in the residential building. WDC-Pro summarizes the input data and returns an estimate of the corresponding 99th percentile of the instantaneous water demand.

The traditional method for sizing plumbing pipes, developed in the 1940s, assumes simultaneous use of all fixtures — an outdated approach that leads to oversized pipes, increased costs, and unnecessary water waste. The Water Demand Calculator methodology, now expanded with WDC-Pro, uses modern water usage data to determine the right pipe sizes, reducing material costs and water stagnation risks linked to biofilm growth and Legionella bacteria.