ICC Commercial Mechanical Practice Exam

What is the minimum sized pipe for drain pan lines used to carry condensate discharge from cooling coils and evaporators?

1. 1/4-inch internal diameter

2. 1/2-inch internal diameter

3. 3/4-inch internal diameter

4. 1-inch internal diameter

The correct answer is: 3/4-inch internal diameter

The minimum size of pipe for drain pan lines that carry condensate discharge from cooling coils and evaporators is established to ensure that the system can effectively handle water flow without causing blockages or inefficient drainage. In many building codes and mechanical standards, a 3/4-inch internal diameter pipe is commonly referenced as the minimum size for these applications. This size is important because it provides sufficient capacity to accommodate heavy condensate discharge during peak operation scenarios, minimizes the risk of backflow, and reduces the tendency for clogs or ice build-up that can occur with inadequate drainage. Choosing a pipe size that is too small could lead to overflow issues, inefficiency in the system, and potential damage to the building's structure or HVAC equipment. While larger diameters can be used in certain applications, the established minimum of 3/4 inch ensures a balance between effective fluid movement and practical installation considerations. The other options either do not meet the requirements for efficient drainage or may be more suited for specific situations rather than general use.