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Checking Line and Grade
The grade readings must be taked from the same relative position in the pipe.
The illustration shows the readings being taken from the invert of the pipe.
Determine the actual grade of the pipe
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Subtract distance "B" from distance "A" to determine the "rise" of the pipe.
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Measure the horizontal distance "C" of the pipe.
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Divide the rise distance (A-B) by the horizontal distance (C), and then multiply
this value by 100 to determine the percent of grade.
Compare the measured grade to the grade dialed in the Piper
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Compare the measured grade to the grade shown in the display of the Piper.
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If they are equal, the pipe is at the proper grade.
•
If they are not equal, repeat the procedure to ensure that a mistake was not
made. If they are still not equal, check the accuracy of the Piper and the instru-
ment being used.
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