Unless otherwise specified, longitudinal laps on jacketing should be in what position?

• A. 12 o'clock to 1 o'clock
• B. 9 o'clock to 10 o'clock
• C. 6 o'clock to 7 o'clock
• D. 3 o'clock to 4 o'clock

Answer: (D)

The main idea is to place the longitudinal lap where it’s least likely to let water get into the jacket and where sealing and inspection are easiest. Putting the seam on the side of the pipe, around the 3 to 4 o’clock position, keeps the lap away from direct rain impact and reduces the chance that water will run down into the seam or pool at the joint. A top (12 o’clock) seam is more exposed to rain washing into the lap, while a bottom (6 o’clock) seam can collect water and debris, promoting moisture entry. A side position is generally preferred because it’s easier to seal and inspect and it minimizes weathering effects. So, 3 to 4 o’clock is the standard choice unless the project specifies a different orientation.