25
S
EARCH
HEADS
R
Ordinary strength signals
Ordinary strength signals are obtained when the head is accurately aligned with the middle of a
side. Only this type of signal is suitable for measuring depth of cover.
Figure 17. Ordinary strength signals from middle of one side of a loop
11 SEARCH HEADS
Four types of search head are available for your Covermeter; Standard, Narrow Pitch, Deep Cover
and Borehole Probe. To order any of these search heads see “Accessories” on page 33.
All search heads are fully interchangeable. Changing from one type of search head to another is
quick and easy; simply switch off the Covermeter, swap search heads, switch on again and zero
the Covermeter.
Figure 18. Search head search fields
Use the
Narrow Pitch
search head when the reinforcement bars are close together, i.e. when the
pitch of the reinforcement bars is narrow.
Use the
Deep Cover
head to measure depth of cover over reinforcement bars deep within the
structure. Because the Deep Cover search head only resolves bars if they are adequately spaced
(centre-to-centre pitch more than about 1½ times their cover), for covers shallower than 70 mm, the
Standard search head should be used in preference.
Narrow Pitch
Standard
Deep Cover
Borehole Probe
331.book Page 25 Thursday, March 12, 2009 9:51 PM
