Heath Consultants Aqua-Scop - Manual (Page 30)

This gives two simultaneous equations:
IA XA - IB XB = O
XA + XB = X
O -IB
X 1 IBX
XA = ———— = ——————
IA -IB IA + IB
1 1
A O
1 X IAX
XB = ———— = ———————
IA -IB IA + IB
1 1
Example: Making contact measurements using the Magnet Attachment, we
check two hydrants separated by a distance of 70 yards. At hydrant A we
read .30 units and at hydrant B we read .90 units. We plot this graphically
by first laying off the X-axis as the total distance between hydrants, or
70 yards. We now mark off the value of intensity for hydrant A along the
positive Y-axis. LABEL THIS POINT B. At distance X from the origin,
draw a perpendicular. Starting at X and moving in the negative Y direction,
lay off the value of intensity for hydrant B. LABEL THIS POINT A. Draw
a straight line from point B to point A. Where this line intersects the X axis
is the point of leakage. Note the inversion of points A and B.
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