April 2004
3-14
Surveying the Pipe (cont.)
Figure 3-14: Marking the 3 o’Clock Position
4. To find the coinciding point on the opposite site of the pipe
(180° away from each other), divide the measured
circumference by 2 an d measure this distance along the
circumferential lines from the zero point, as shown in Figure
3-15 below. Place marks on both sides of the circumferential
lines made with the layout tape and connect the marks.
Figure 3-15: Marking the 9 o’Clock Position
Make sure to take the 180° point measurement from both over the
top of the pipe and under the bottom of the pipe (on a horizon t al
pipe) to ensure reciprocity of the installation. Figure 3-16 on the
next page shows the appropriate way to measure the 180° point.