The CM52 & CM9 CoverMasters^®
Protovale Cover Meters

The professional's cover meters

Millions are spent each year repairing concrete structures whose reinforcement bars have corroded due to inadequate cover. Any concrete surface, whether it's newly built or part of a long-standing structure, can be hiding a dangerous and costly time-bomb.

Protovale's cover meters have been designed in close cooperation with the construction industry to locate rebars quickly and precisely and measure concrete cover with unparalleled accuracy.

Our CoverMasters use an exclusive technology that delivers unvarying precision under all site conditions and in all types of concrete.

Both Protovale's CoverMasters give:

Rapid results

The loud audio signal helps locate rebars quickly and precisely. Scan large areas without constantly watching the meter.

Industry leading accuracy

The directional search head locates rebars, establishes their direction and measures cover with great precision even at very close centres.

Strength and reliability

Designed and built to withstand daily use in the toughest conditions. Thousands are in use in construction sites around the world. Weatherproof to IP54.

Versatility

The CM52 accepts a midget head for direct reading of cover under 30mm at very close centres. Ideal for checking pre-cast lintels and pipes.
The CM9 accepts a large head for reading of abnormally deep covers up to 200mm.

Parsons Brinckerhoff engineer using the CM9 CoverMaster

STATS Ltd using a Protovale CM52 in Warwickshire UK

The Protovale Advantage

All Protovale instruments are designed by the world's leading experts in the field of pulse induction technology. They use a unique system which is unaffected by moisture or temperature changes, making Protovale instruments remarkably stable in all site conditions.

Please contact us now for more information or a free demonstration

Protovale Oxford Ltd, Rectory Lane Trading Estate
Kingston Bagpuize, Abingdon OX13 5AS, England
Tel: +44 (0) 1865 821277, Fax: +44 (0) 1865 820573
email: info@protovale.co.uk

Both Protovale's CoverMasters have
better technology for better performance

Precision you can rely on in all conditions

Protovale's exclusive Pulse-Induction Eddy Current technology is uniquely stable and is immune to temperature variations, electrical interference, magnetic aggregates and the ionic effects of moisture in wet concrete.

Most other cover meters use magnetic search heads which are temperature sensitive and react unpredictably to nearby metal and magnetic aggregates.

Head and bar

"A rifle, not a shotgun"

Our cover meters have a very narrow search field which gives the strongest signal when the search head is lined up with the rebar, and the weakest signal when the search head is at right angles to the rebar.
This enables the operator to quickly locate rebars, quickly determine their orientation and obtain accurate cover readings even in congested situations.

Welded Mesh Fabric

The directional search head allows the "drilling safe spots" in welded mesh fabric to be located, and the cover to be measured accurately.

The truth is at the centre

We always quote the 'pitch' as the distance between bar centres. Some manufacturers make accuracy claims based on the 'spacing' between bars -- a smaller figure. Make sure you know which figure is being quoted!

Head/bar orientation

There is very little response at the sides of the search heads, so they remain accurate near scaffolding and metal window frames.
They also resolves cover in dense, complex rebar structures.

Standards conformance

Both CM52 and CM9 meet or exceed all requirements of: BS1881:204 and DGZfP:B2.
Conform to measuring requirements of: EC2, DIN1045, SIA62, and ACI318.

Maximum depth of cover and resolution

For parallel bars to be resolved by any cover meter, the pitch must be typically at least 1½ times their cover.

The above structure of bars might pose difficulties for some cover meters which cannot give accurate readings of cover in congested situations......
but as shown below, the CM52 remains accurate on this structure at even greater depths than the resolution example.

Standard head accuracy The CM9 can even improve on the CM52's excellent performance!

The Protovale CM52 CoverMaster

The CM52 is a reliable, easy-to-use cover meter suitable for most situations. If sizing of rebars is of little importance, eg. in new build or precast concrete situations, then this is the instrument for you.

Easy to use

Operated with three basic control knobs - which give a distinctive click for confidence - the CM52 can be mastered in minutes. An informative audio tone gets louder as it approaches the bar, quickly indicating depth of cover.

Bar Sizing

Measures cover to bars of unknown size.
A simple bar-sizing method requires just two measurements and a look-up graph. The resulting cover reading is always reliable.

Data-logging cover readings

The CM52 is fitted with an analogue output socket suitable for connecting to any commercially available data-logger. Please contact us if you intend using a data-logger.

Strong but lightweight

High impact ABS control unit in leather case with holster for the search head weighs less than 2kg. The search head itself weighs only 380grams.

The Standard Head

With the standard large head the CM52 can resolve bars and measure cover at closer pitches than any of its rivals with their large head, eg 50mm cover and 75mm pitch between centres (less than 60mm separation between bars). See diagram on previous page.

Measures depths of up to 100mm -- all that is required for reinforced concrete.

Tendon Duct Locator

Compatible with Protovale's tendon duct locator / borehole probe.

The Midget Head

for areas of low cover.

With the midget head the figures are scaled down dramatically to give accurate readings of cover under 30mm and at very close centres.

For example, T10 bars can be resolved and measured at 15mm cover at as little as 30mm centres (a mere 20mm separation between bars).

Midget head accuracy

Advantages of the Midget head

Accuracy of cover measurement between 6 and 30mm is ±1mm (half that required by BS1881:204).
Ideal for checking precast concrete units and reinforced cages in concrete pipes.
Exceptionally congested situations can be investigated with ease.
Castellated concrete surfaces can be surveyed as the small head will fit between sculpted reliefs.

I've tried other cover meters, but the Protovale is my favourite. It's accurate, robust and easy to use. The search range is focussed so there's no problem working near scaffolding, and the audio tone lets you concentrate on the area you're working on.

We've used Protovales for years, and the CM52 is a welcome addition to the range

Gareth Moorhead, Project Engineer,
Stats Consultancy Ltd

The CM9 The World's most intelligent cover meter

Protovale's CM9 CoverMaster is the first cover meter to give the position, direction, cover and diameter of reinforcing bars in concrete, all at the same time. The CM9 has the accuracy and reliability of the CM52 CoverMaster but even more time-saving features.

The cost of traffic management on motorways and major roads, and the expense of access equipment for testing buildings was a deciding influence in Protovale's decision to make the CM9 CoverMaster -- a cover meter that would be very fast and accurate to use in noisy, dark conditions, frequently with difficult access.

Fast and easy to use -- even in the dark

The ultra bright indicator light in the search head and the loud audio tones make bar location quick and accurate.

Thinks for itself

The CM9 gives correct readings of cover, no matter what bar diameter you select.

True one handed operation

The four control buttons are duplicated on the search head for one-handed operation. The search head clips onto the machine when not in use.

Accurate and Easy to use

The LCD screen has a back light and shows the cover readings in jumbo characters, operating instructions and short form prompts.

The CM52 measures bar diameter manually, but the CM9 has the added benefit of a microprocessor and can size bars automatically.

Two Automatic Bar-sizing modes

Mode 1 gives correct cover and estimates the bar diameter.
Mode 2 directly measures the diameter of a single bar.

Low cover mode

A very loud audio signal and brighter light immediately warns you of areas of low cover. Can be programmed to identify bars with less than the required cover.

Optional large head

Gives double the depth of the standard head
CM9 large head

With the CM9, you're going to get a pretty good picture every time. You can scan all sorts of structures and types of concrete and come out with accurate results.

You can trust its interpretation. It's precise and reliable

Roel van Es BSc(Hons), MCS, MICorr.
Company Engineer, Makers UK Ltd

Comparisons between the CM52 and CM9


Features	CM52	CM9
Stable in all site conditions
Rugged construction
Leather case
Holster for search head
Backlight for LCD display
Indicator light in search head
Loud audible tone
Depth of cover in mm
Bar sizing	manual	automatic
Accurate to BS1881:204
Low cover mode
Control buttons on the head
Rechargeable batteries
Additional optional head	midget	large
Optional Borehole probe
Output to data-logger
Carrying case

Performance	CM52	CM9
Standard Head Cover Range for ø40mm bar for ø8mm bar	25--100mm 25--100mm	15--95mm 5--70mm
Standard Head Accuracy up to 65mm 70mm and over	to BS1881:204 & DGZfP:B2 ±2mm ±3mm	to BS1881:204 & DGZfP:B2 ±2mm max (±1mm typ.) ±5% max (±3% typ.)
Standard Head Resolution (eg)	ø16 bars at 50mm cover, 75mm pitch (60mm separation)	ø10 bars at 30mm cover, 50mm pitch (40mm separation)
Midget Head Cover Range	6--50mm
Midget Head Accuracy	±1mm from 10mm to 30mm
Midget Head Resolution (eg)	ø10 bars at 15mm cover, 30mm pitch (20mm separation)
Large Head Cover Range		20mm (ø8) -- 180mm (ø40)
Bar Diameters encompassed	ø5--ø40 (11 values)	ø5--ø50 (21 values)
Bar-Sizing Cover to bars of unknown size Measurement of Diameter	Manual process, ±5% Manual estimate process	Automatic and instantaneous Automatic, ±15% of diameter

Characteristics and dimensions
Features	CM52	CM9

Display	4-digit LCD cover in mm (or signal mV).	2-line × 24-character LCD screen for menu, operating prompts, readings, and cover in jumbo-sized characters.
backlight for LCD	No.	Yes (with battery-saving time-out).
audible signal	Yes (built-in loudspeaker).	Yes (built-in loudspeaker).
visual signal	Analogue meter.	Bright LED on search head.
"low cover" warning	No.	Yes, user-programmable 10--75mm.

Controls	Three knobs: ON/OFF & set Zero, DIAMeter selection, CALibrate/DEPth Mode.	ON/OFF buttons, audio knob; plus four control buttons duplicated on standard search head.

Battery	NiCad rechargeable 8.4V	NiCad rechargeable 8.4V.
operating hours backlight off backlight on	13 hours minimum.	8--12 hours 6--9 hours.
Charger	External sealed module.	External sealed module.
input voltages	200--250V AC 3-pin UK or 2-pin Euro or 100--125V AC 2-pin.	200--250V AC 3-pin UK or 2-pin Euro or 100--125V AC 2-pin.
output current	140mA DC.	140mA DC.
recharge time	14--16 hours (eg overnight).	14--16 hours (eg overnight).

Connectors
Search Head	3-pin DIN41524 screw-locking.	8-pin DIN45326 screw-locking.
Phones	Standard 3.5mm stereo jack.	Standard 3.5mm stereo jack.
Charger	2.5mm coaxial dc.	2.5mm coaxial dc.
Data-Logger	3.5mm mono jack socket.

Variants available	CM42 reading in inches.	Text in most European languages.

Dimensions (mm)	CM52	CM9
Electronic unit with head & lead	(in leather case) 220 × 150 × 175, 2.3kg	247 × 127 × 174, 2.1kg
Standard Head overall sensing area	155 × 88 face × 42, 395g 120 × 60	140 × 63 face × 37, 285g 80 × 40
Additional Head overall sensing area	(Midget) 85 × 52 face × 45, 110g 60 × 30	(Large) 210 × 100 face × 52, 710g 160 × 80
Head Lead (coiled)	600 at rest, 1.8m extended, 140g	600 at rest, 1.8m extended, 165g
Battery charger	100 × 75 × 50, 230g	100 × 75 × 60, 230g

In carrying case with Large Head	520 × 370 × 125, 4.6kg	520 × 370 × 125, 4.3kg 4.98kg
Shipping Weight	5.1kg	4.76kg (with Large Head 5.5kg)

Talk to us

Protovale participates in industry and academic conferences around the world, analysing the technical issues associated with concrete cover inspection and explaining best practice.

We have worked with most of the leading consulting engineers in many countries and are always willing to share our experience with users.

Full support

Protovale offers its users support by
telephone +44 (0) 1865 821277,
fax +44 (0) 1865 820573
and email support@protovale.co.uk.

24-hour support on the web

Protovale's web site also provides updated product summaries, simple technical support and abstracts of technical papers on key issues relating to our instruments, and latest news flashes. Visit us on www.protovale.co.uk.

Full one year parts and labour warranty

Also available:
Rebar Plus bar locator, and Borehole Probe Tendon Duct Locator.

Request Information
Back to Home Page . . . . . . CM52 brochure

The CM52 & CM9 CoverMasters®

Protovale Cover Meters