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The Elcometer 331 Mk 2 Top TH Model Concrete Cover Meters (gauge part number W331TH-2) is a hand-held covermeter that locates reinforcement bars in concrete, measures the depth of cover over them, determines their orientation and diameter, and assesses the potential for corrosion using a half-cell. Insufficient cover or corroding rebar shortens the service life of a concrete structure, so being able to map both cover depth and corrosion risk on site informs maintenance, repair and inspection decisions before damage becomes structural.
The Elcometer 331 Mk2 Top TH Model Concrete Cover Meter works by detecting the steel beneath the surface through interchangeable search heads, with the tone increasing as the head approaches a bar and signal-strength shown on a bar display. Cover is read in millimetres or inches on a backlit graphical screen that also shows statistics, batch data and graph plots. The half-cell function reads in millivolts to indicate where corrosion is most likely. Memory holds up to 240,000 readings in linear or grid batches, and data can be output via RS232 directly to a printer or PC for use with EDTS Excel link or Covermaster software. The IP65-rated waterproof case suits use in harsh site conditions, and Autosize and Orthogonal modes estimate bar diameter.
It can be used in accordance with standards including ACI 318, ASTM C876, BS 1881:201 and :204, BS 8110, DIN 1045 and EC 2, which cover cover measurement and half-cell corrosion assessment of reinforced concrete. Search heads, borehole probes and copper or silver half-cell kits are ordered separately. Used in concrete testing, structural inspection and civil engineering, the Elcometer 331 Mk2 Top TH Model Concrete Cover Meter is supplied by BAMR, South Africa's authorised Elcometer distributor.
Elcometer 331 Mk2 Top TH Model Concrete Cover Meters
The Elcometer 331 Mk 2 Top TH Model Concrete Cover Meters is an easy to use gauge that not only quickly and accurately identifies the location, orientation, depth and diameter of rebar, but also the potential for corrosion. Designed to meet IP65 this all-in-one rugged waterproof gauge can be used in the harshest of environments.
- Fast and accurate Locate and determine orientation of rebar quickly, easily and accurately.
- Corrosion check Check for potential corrosion of rebar using the same gauge.
- Large memory Holds up to 240,000 readings in linear or grid batches.
- Large, easy to read backlit display Graphical display clearly shows statistics, batches, graph plots and numerical readings
- Interchangeable search heads and Half-Cell kits
Elcometer 331 Models
• = available / compatible with that option or model
| Description | B | BH | SH | TH | THD |
|---|---|---|---|---|---|
| Covermeter / Rebar location | • | • | • | • | • |
| Half Cell measurement | • | • | • | • | |
| Rebar orientation | • | • | • | • | • |
| Depth of cover | • | • | • | • | • |
| Large cover (thickness) reading mm or inches | • | • | • | • | • |
| Large graphics display with backlight | • | • | • | • | • |
| Multiple language menu structure | • | • | • | • | • |
| signal strength bar | • | • | • | • | • |
| Interchangeable heads with LED & keypad | • | • | • | • | • |
| User selectable bar range sizes & numbers | • | • | • | • | • |
| Rugged waterproof case (IP65) | • | • | • | • | • |
| Adjustable beep volume & earphone socket | • | • | • | • | • |
| Measurement sound modes | • | • | • | • | • |
| Locate (tone increases as head approaches rebar) | • | • | • | • | • |
| Under Cover (tone only sound for low cover) | • | • | • | • | • |
| Maxpip (tone only as head passes rebar centre) | • | • | • | • | • |
| Half Cell capability | • | • | • | • | |
| Large half cell reading mV | • | • | • | • | |
| Autosize mode bar diameter determination | • | • | • | ||
| Orthogonal mode bar diameter determination | • | • | • | ||
| RS232 Output – direct to printer or PC | • | • | • | ||
| EDTS Excel link software | • | • | • | ||
| Covermaster software | • | • | • | ||
| Statistics | • | • | • | ||
| Minimum & maximum cover limits | • | • | • | ||
| Date & time | • | • | • | ||
| Memory | • | • | • | ||
| Linear batch memory | No Memory | No Memory | 10 Linear batches of 1,000 readings each | Up to 200 batches of 1,000 readings | Up to 200 batches of 1,000 readings |
| Grid batch memory | Up to 240,000 readings | Up to 240,000 readings | |||
| User certified batch size | • | • | |||
| Graphics Plot | • | • | |||
| Threshold plot | • | • |
- Stainless Steel measurement mode
- •
- Bar dimension range
- Click on the Bar Dimension Tab at the top for a range of Bar Dimensions
- Rechargeable power supply
- 7.4V lithium ion battery pack provides up to 32 hours of continuous use (20 hrs if backlight is on). Rechargeable in 4 hours either inside or outside the gauge using an external charger.
- Maximum operating temperature
- 50°C
- Unit dimensions
- 230 x 130 x 125mm
- Unit weight
- 1.54kg
- W331B-2
- Elcometer 3312 Model B Covermeter (Supplied complete with Standard Search Head)
- W331BH-2
- Elcometer 3312 Model BH Covermeter with Half Cell (Order search heads or Half-Cell probes separately)
- W331SH-2
- Elcometer 3312 Model SH Covermeter with Half Cell (Order search heads or Half-Cell probes separately)
- W331TH-2
- Elcometer 3312 Model TH Covermeter with Half Cell (Order search heads or Half-Cell probes separately)
- Elcometer 331 2 Model B Covermeter (Supplied complete with Standard Search Head)
- W331B-2
- Elcometer 331 2 Model BH Covermeter with Half Cell (Order search heads or Half-Cell probe...
- W331BH–2
- Elcometer 331 2 Model SH Covermeter with Half Cell (Order search heads or Half-Cell probe...
- W331SH–2
- Elcometer 331 2 Model TH Covermeter with Half Cell (Order search heads or Half-Cell probe...
- W331TH–2
- Elcometer 331 2 Model THD Covermeter with Half Cell (Order search heads or Half-Cell prob...
- W331THD-2
- Elcometer 331 2 Standard Search Head
- TW33119124-1A
- Elcometer 331 2 Narrow Pitch Seach Head
- TW33119124-2A
- Elcometer 331 2 Deep Cover Search Head
- TW33119171A
- Elcometer 331 2 Borehole Probe 0 -40cm
- TW33119223-1A
- Elcometer 331 2 Borehole Probe 0 - 100cm
- TW33119223-2A
- Elcometer 331 2 Borehole Probe 0 - 16″
- TW33119223-3A
- Elcometer 331 2 Borehole Probe 0 40″
- TW33119223-4A
- Elcometer 331 2 Half Cell Probe Kit Cu/CuSO 4 (Cannot be used with Model B)
- TW331CUKIT
- Elcometer 331 2 Half Cell Probe Kit Ag/AgCl (Cannot be used with Model B)
- TW331AGKIT
- Elcometer 331 2 Half Cell Probe Cu/CuSO 4 (Cannot be used with Model B)
- TW33119688-1
- Elcometer 331 2 Half Cell Probe Ag/AgCl (Cannot be used with Model B)
- TW33119688-2
- Elcometer 331 2 High Tensile and Stainless Steel Dual search head (Can only be used with...
- TW33120014D
- Search Head Option A
- TW33119683
- Search Head Option B
- TW33119218
- Search Head Option C
- TW33119222
Specifications
Elcometer 331 Models
• = available / compatible with that option or model
| Description | B | BH | SH | TH | THD |
|---|---|---|---|---|---|
| Covermeter / Rebar location | • | • | • | • | • |
| Half Cell measurement | • | • | • | • | |
| Rebar orientation | • | • | • | • | • |
| Depth of cover | • | • | • | • | • |
| Large cover (thickness) reading mm or inches | • | • | • | • | • |
| Large graphics display with backlight | • | • | • | • | • |
| Multiple language menu structure | • | • | • | • | • |
| signal strength bar | • | • | • | • | • |
| Interchangeable heads with LED & keypad | • | • | • | • | • |
| User selectable bar range sizes & numbers | • | • | • | • | • |
| Rugged waterproof case (IP65) | • | • | • | • | • |
| Adjustable beep volume & earphone socket | • | • | • | • | • |
| Measurement sound modes | • | • | • | • | • |
| Locate (tone increases as head approaches rebar) | • | • | • | • | • |
| Under Cover (tone only sound for low cover) | • | • | • | • | • |
| Maxpip (tone only as head passes rebar centre) | • | • | • | • | • |
| Half Cell capability | • | • | • | • | |
| Large half cell reading mV | • | • | • | • | |
| Autosize mode bar diameter determination | • | • | • | ||
| Orthogonal mode bar diameter determination | • | • | • | ||
| RS232 Output – direct to printer or PC | • | • | • | ||
| EDTS Excel link software | • | • | • | ||
| Covermaster software | • | • | • | ||
| Statistics | • | • | • | ||
| Minimum & maximum cover limits | • | • | • | ||
| Date & time | • | • | • | ||
| Memory | • | • | • | ||
| Linear batch memory | No Memory | No Memory | 10 Linear batches of 1,000 readings each | Up to 200 batches of 1,000 readings | Up to 200 batches of 1,000 readings |
| Grid batch memory | Up to 240,000 readings | Up to 240,000 readings | |||
| User certified batch size | • | • | |||
| Graphics Plot | • | • | |||
| Threshold plot | • | • |
- Stainless Steel measurement mode
- •
- Bar dimension range
- Click on the Bar Dimension Tab at the top for a range of Bar Dimensions
- Rechargeable power supply
- 7.4V lithium ion battery pack provides up to 32 hours of continuous use (20 hrs if backlight is on). Rechargeable in 4 hours either inside or outside the gauge using an external charger.
- Maximum operating temperature
- 50°C
- Unit dimensions
- 230 x 130 x 125mm
- Unit weight
- 1.54kg
- W331B-2
- Elcometer 3312 Model B Covermeter (Supplied complete with Standard Search Head)
- W331BH-2
- Elcometer 3312 Model BH Covermeter with Half Cell (Order search heads or Half-Cell probes separately)
- W331SH-2
- Elcometer 3312 Model SH Covermeter with Half Cell (Order search heads or Half-Cell probes separately)
- W331TH-2
- Elcometer 3312 Model TH Covermeter with Half Cell (Order search heads or Half-Cell probes separately)
- Elcometer 331 2 Model B Covermeter (Supplied complete with Standard Search Head)
- W331B-2
- Elcometer 331 2 Model BH Covermeter with Half Cell (Order search heads or Half-Cell probe...
- W331BH–2
- Elcometer 331 2 Model SH Covermeter with Half Cell (Order search heads or Half-Cell probe...
- W331SH–2
- Elcometer 331 2 Model TH Covermeter with Half Cell (Order search heads or Half-Cell probe...
- W331TH–2
- Elcometer 331 2 Model THD Covermeter with Half Cell (Order search heads or Half-Cell prob...
- W331THD-2
- Elcometer 331 2 Standard Search Head
- TW33119124-1A
- Elcometer 331 2 Narrow Pitch Seach Head
- TW33119124-2A
- Elcometer 331 2 Deep Cover Search Head
- TW33119171A
- Elcometer 331 2 Borehole Probe 0 -40cm
- TW33119223-1A
- Elcometer 331 2 Borehole Probe 0 - 100cm
- TW33119223-2A
- Elcometer 331 2 Borehole Probe 0 - 16″
- TW33119223-3A
- Elcometer 331 2 Borehole Probe 0 40″
- TW33119223-4A
- Elcometer 331 2 Half Cell Probe Kit Cu/CuSO 4 (Cannot be used with Model B)
- TW331CUKIT
- Elcometer 331 2 Half Cell Probe Kit Ag/AgCl (Cannot be used with Model B)
- TW331AGKIT
- Elcometer 331 2 Half Cell Probe Cu/CuSO 4 (Cannot be used with Model B)
- TW33119688-1
- Elcometer 331 2 Half Cell Probe Ag/AgCl (Cannot be used with Model B)
- TW33119688-2
- Elcometer 331 2 High Tensile and Stainless Steel Dual search head (Can only be used with...
- TW33120014D
- Search Head Option A
- TW33119683
- Search Head Option B
- TW33119218
- Search Head Option C
- TW33119222
Standards
Standards
Accessories
Accessories
| Standard Search HeadDesign to meet most of your measurement requirements. | |
| Range | 40mm bar - 15mm to 95mm8mm bar - 8mm to 70mm |
| Dimensions | 155 x 88 x 42mm |
| Sensing area | 120 x 60mm |
| Narrow Pitch Search HeadAccurately measures the cover thickness when the gaps (pitch) between each of the rebars are close together. | |
| Range | 40mm bar - 8mm to 80mm8mm bar - 5mm to 60mm |
| Dimensions | 155 x 88 x 42mm |
| Sensing area | 120 x 60mm |
| Deep Cover Search HeadThe ideal search head for accurately measuring rebars that are deep within the structure. | |
| Range | 40mm bar - 35mm to 180mm8mm bar - 25mm to 160mm |
| Dimensions | 170 x 94 x 54mm |
| Sensing area | 160 x 80mm |
| Dual Search Head for high tensile and stainless steelsThe search head specifically designed to locate high tensile and stainless steel. | |
| Range | 40mm bar - 35mm to 180mm8mm bar - 25mm to 160mm |
| Dimensions | 170 x 94 x 54mm |
| Sensing area | 160 x 80mm |
| Borehole ProbeThe solution for locating tendon ducts and multiple layers of rebar lying deep within the concrete. | |
| Metric | Imperial |
| TW33119223-1A Short | TW33119223-3A Short |
| TW33119223-2A Long | TW33119223-4A Long |
| Measurement depth | Short Probe: 0 - 40cmLong Probe: 0 - 100cm |
| Approximate detection ranges | Tendon duct (70mm): up to 90mm |
| Half-Cell KitConsisting of either a copper electrode in a copper sulphate solution or a silver electrode in a sodium chloride solution, each half cell is a sealed unit - no need to mix chemicals. Supplied with a 25m / 80′ cable, every half-cell probe is guaranteed for 5 years. | |
| Copper/Copper Sulphate | TW331CUKIT |
| Silver/Silver Chloride | TW331AGKIT |
| Extension Cable 100m / 325ftThe extension cable for use with the half-cell kits gives the flexibility to take readings in difficult to reach areas. |
| Verification BlockThe verification block allows the user to check the calibration of their gauge in order to ensure maximum measurement accuracy. |
| Extension Arm KitThis kit allows the user to scan bridge decks and floor areas using the hand-held search heads from a standing position. Both the standard or narrow pitch search head can be attached to the extension arm. |
Bar Diameter
Bar Diameter
| Metric · Bar Size | Metric · Diam. (mm) | US Bar · Bar Size | US Bar · Diam. (Inch) | ASTM/Canadian · Bar Size | ASTM/Canadian · Diam. (mm² ) | Japanese · Bar Size | Japanese · Diam. (mm) |
|---|---|---|---|---|---|---|---|
| 5 | 5 | #2 | 0.25 | 10M | 100 | 6 | 6 |
| 5.5 | 5.5 | #3 | 0.375 | 15M | 200 | 10 | 10 |
| 6 | 6 | #4 | 0.5 | 20M | 300 | 13 | 13 |
| 7 | 7 | #5 | 0.625 | 25M | 500 | 16 | 16 |
| 8 | 8 | #6 | 0.75 | 30M | 700 | 19 | 19 |
| 9 | 9 | #7 | 0.875 | 35M | 1000 | 22 | 22 |
| 10 | 10 | #8 | 1 | 45M | 1500 | 25 | 25 |
| 11 | 11 | #9 | 1.125 | 55M | 2500 | 29 | 29 |
| 12 | 12 | #10 | 1.25 | 32 | 32 | ||
| 14 | 14 | #11 | 1.375 | 35 | 35 | ||
| 16 | 16 | #12 | 1.5 | 38 | 38 | ||
| 18 | 18 | #13 | 1.625 | 41 | 41 | ||
| 20 | 20 | #14 | 1.75 | 44 | 44 | ||
| 22 | 22 | #15 | 1.875 | 48 | 48 | ||
| 25 | 25 | #16 | 2 | 51 | 51 | ||
| 28 | 28 | #18 | 2.25 | 57 | 57 | ||
| 32 | 32 | ||||||
| 36 | 36 | ||||||
| 40 | 40 | ||||||
| 44 | 44 | ||||||
| 50 | 50 |
Frequently asked questions
What measurements does the 331 Mk2 TH model provide?
The gauge identifies rebar location, orientation, and diameter, measures concrete cover depth, and identifies the potential for corrosion. The large backlit display shows all readings in millimetres or inches.
What battery life and charging time should I expect in the field?
The 7.4V lithium ion battery provides 32 hours of continuous use, or 20 hours with the backlight on. Full recharge takes 4 hours via the external charger, which works inside or outside the gauge.
Can I use the 331 Mk2 TH in wet and harsh site conditions?
Yes. The gauge is IP65-rated for full waterproofing and designed for rugged use in harsh environments. It operates reliably up to a maximum of 50°C.
What bar diameters and sizing standards does it detect?
The meter covers metric (5mm to 50mm), US (#2 to #18), ASTM/Canadian (10M to 55M), and Japanese (6mm to 57mm) bar sizes. Select your bar range in the menu before measurement.
How much measurement data can the TH model store?
The TH holds up to 200 linear batches of 1,000 readings each, allowing you to organise surveys by site, level, or structural zone.
What search heads are available for different applications?
The standard search head works for general rebar detection. Narrow pitch and deep cover variants are available separately for closely-spaced bars or greater depths. Borehole probes (0 to 40cm, 0 to 100cm, 0 to 16 inches, or 0 to 40 inches) can be ordered separately.
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Tell us about your application and we will send a quote with lead time and accessories.