What is the minimum grade required for conduit runs to ensure drainage into the manhole?

The minimum grade required for conduit runs to ensure proper drainage into the manhole is specified as no less than 3 inches for every 100 feet of run. This requirement ensures that there is adequate slope for the drainage to flow effectively, preventing pooling or blockage within the conduit. When maintaining such a gradient, it facilitates the movement of any water or debris that may enter the conduit, thereby ensuring that it can effectively reach the manhole and prevent any potential issues that could arise from stagnant water.

A slope of 3 inches per 100 feet translates to a 0.25% grade, which is critical for functionality in drainage systems, especially in underground utilities where proper flow is vital for maintaining operational integrity. The other options either overstate the necessary slope or do not provide an effective means of ensuring that water drains appropriately.