Materials Other Than Reinforcing Bars - Elcometer Protovale CoverMaster CM52 Operating Instructions Manual

Method B for estimating bar size
This method is based on the recommendations of British Standard 4408:1:1969, repeated
in BS1881:204:1988.
insensitive to the diameter of the bar, and while this is a major operational advantage over
other types of instrument, the success of the BS method becomes very dependent on
accurate zeroing before every measurement.
1. Set the DIAM control to less than the estimated diameter of the bar.
2. Zero the instrument carefully on the CALibrate setting.
3. Switch to DEPth mode, make a depth measurement using the black face and
note the result.
4. Make a depth measurement using the white face and note the result.
5. Calculate the difference between the two results.
6. Advance the DIAM control one click and repeat steps 2-5.
7. Repeat until the diameter setting is found which gives the closest to 30mm
difference between measurements using the black and white faces.
8. Make all depth measurements using that setting and the black face of the search
head.
If no setting gives exactly 30mm difference, it may be necessary to make all
depth measurements twice, using the settings on either side of optimum and to
average each pair of results.
This method will be valid for cover depths between 30mm and 60mm. For cover depths
below 30mm, use the white face and insert an additional spacer of 15-20mm thickness.
Having found the best setting of the DIAM control, continue to use the white face and the
spacer, and remember to subtract the appropriate distance from all indicated depth
measurements.

5.10 Materials other than reinforcing bars

Steel pipes and conduit
With the DIAM control set to the outside diameter of the pipe, the CM52 CoverMaster will
operate exactly as with solid bars.
Nails and bolts
For ferrous objects lying end-on to the search coils, the search head of the CM52
CoverMaster gives two relatively weak signals, one from each loop, with a small dip
when the head is centred over the target (similar to Figure 8).
Protovale also manufacture instruments specifically for locating nails, bolts, wall-ties, etc.
The CM52 CoverMaster has been designed to be relatively
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