Rhode Island Journeyman Plumber Practice Exam

What is the minimum number of roof drains required on a roof under 10,000 square feet?

1. 2

2. 3

3. 4

4. 5

The correct answer is: 4

The minimum number of roof drains required for a roof under 10,000 square feet is two. This requirement is based on plumbing codes that dictate drainage systems must effectively handle stormwater to prevent flooding and structural damage. In this context, it’s essential to understand that proper drainage on roofs is critical in ensuring water does not pool and cause leaks or damage to the roofing structure. With roofs that are smaller in area, like those under 10,000 square feet, having at least two drains allows for adequate water flow management, especially during heavy rainfall. More than two drains could lead to unnecessary complexity and expense without significantly improving drainage efficacy for this specific area size. Hence, the minimum standard established is two drains. Having three, four, or five drains would exceed the minimum requirement and might be considered for specific drainage issues, building designs, or local codes, but they are not necessary under standard circumstances for this roof size.