What is the DFU value as a load factor for a commercial automatic clothes washer?

The DFU, or Drainage Fixture Unit, value is a critical aspect of plumbing design, particularly when calculating the demand on a drainage system. For a commercial automatic clothes washer, a DFU value of 3 is established based on the anticipated load that such appliances place on the plumbing system.

This value takes into account not only the volume of water used by the clothes washer but also the frequency and duration of its operation. By assigning a DFU value of 3, plumbing codes recognize the typical discharge characteristics of a commercial clothes washer, allowing for proper sizing of drainage pipes and ensuring the system can handle peak loads without backing up or overloading.

In contrast, values like 1, 2, or 4 do not appropriately reflect the operational characteristics of a commercial automatic clothes washer and could lead to inadequate system planning, which might result in plumbing issues under maximum operational loads. Thus, using a DFU value of 3 provides a balanced and code-compliant approach to plumbing design for these appliances.