3-7
April 2004

Performing a Pipe Survey (cont.)

4. Now measure the OD and the wall thickness at eight points
along the pipe circu mference at 45° intervals (shown in Figure
3-6 below), three tim es per point, and record the mean values.
Figure 3-6: Measuring the OD and Pipe Wall Thickness
5. Prepare the pipe for the dampening material by removing any
rust or loose paint and sanding down any rough spots in an
area 12 in. long around the circumference of the pipe. Take
care to preserve the original pipe curvature.
6. At the approximate location of each transducer, prepare an
area 100 mm (4 in.) lo ng by 5 0 mm (2 in. ) wide fo r CRV type
transducers and 100 mm wide for CRW type transducers.
Remove any paint or rust, and polish the cleared area, taking
care to preserve the original curvature of the pipe.
OD
1
OD
2
OD
3
OD
4
W
1
W
2
W
3
W
4
W
8
W
7
W
6
W
5