7/28/2019 Ut Rule of Thumb

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RULE OF THUMBULTRASONIC

To find a Depth , given a reading in a screen or the BPL by approximation:

On the Half skip area:

On the full skip area:

D

D

RADIOGRAPHY:

The intensity of radiation is inversely proportional to the SFD.

Inverse Square Law: I x D = I x D

When the distance is doubled increased the exposure time by 4 times.

When the distance is reduced to half of its original distance, the exposure time will reduce

to of the its original exposure time.

Time x Dist. = Time x Dist.

RADIOGRAPHY: Safe Distance

Safe Distance=26 Curies

Safe Distance= Ci x 37 x130

7.5

Exact formula

By

Approximation

For 70: D= BPL 3

For 60: D=BPL 2For 45 D= BPL 1.4

For 70: D= 2T-(BPL 3)

For 60: D= 2T-(BPL 2)For 45 D=2T- (BPL 1.4)

60 Probe

More sounds reflected back to the probe producesHigh signal on the screen.

Less signal reflected back to the probe produces

small echo on the screen.

70 Probe

Si nal not reflected

Reflected si nal

Root Check Technique:A s much as possible a 60 probe is not use for a root check because even a good root bead will produced a high

signal which will be easily mistaken for a root defect.

A 70 is a better option because a good root bead will produced only a small echo, which means a root defect thatproduces a high signal like lack of root penetration will be easily identified.See sketch below.

Edmundo T. Botor Jr.Senior CSWIP 3.2 No.3147-2

PCN Level 2 No.207763