Product Description
Technical Specification
Instruction Manual
Data Sheet

Elcometer 331 Covermeters & Half-Cell Meters

An easy to use gauge that quickly and accurately locates/orientates reinforcement bars in concrete and measures the depth of cover over the rebar.

Designed to meet IP65 this rugged waterproof gauge can be used in the harshest of environments.

User Friendly

  • Easy to transport and store
  • Ergonomically shaped case for comfort
  • Single handed operation: All functions can be accessed & controlled through 4 simple keys/buttons


  • Locate and determine orientation of rebar quickly, easily & accurately
  • Up to 240,000 readings can be stored on the gauge for detailed reporting*
  • Memory and data logging with data output to PC or direct to printer*
  • Graph Plotting allows an immediate visual indication of results


  • Stainless Steel rebars can be located by the THD Model
  • Battery packs can be charged in the unit or externally. Additional batteries allow continued use


  • Specifically designed for use on-site
  • Rugged, waterproof IP65 case provides protection against the elements
  • Backlit screen for viewing in dark environments


  • Rebar locator, concrete covermeter and half-cell measurement all available in a single gauge - (selected models)
  • Intuitive menus enable each gauge to be used straight from the box


  • Links to Covermaster™ software
  • Ultimate data management tool to store cover & half cell readings and produce professional reports
  • On Screen graphic display provides visual assessment of readings allowing identification of areas of low concrete cover or potential areas of corrosion


screen 1 

Cover Display Screen

Alternative / Typical Data Review Screen View

  • Backlit screens for use in dark conditions
  • Easy to use menus, in multiple languages to enable access to all data needed whilst on site without constant reference to the instruction book
  • Alternative view shows the typical display when using the deep cover search head
  • Bar size and depth of cover can be input manually to suit specific requirements
  • Typical data review screen clearly displays where readings are below or above a user specified tolerance, where a reading has not been taken
  • Units of measurement can be displayed in mm or inches for cover, or mV for Half-Cell 
screen 2
screen 3

Half-Cell Mode

Typical Screen View

  • Elcometer 331 Model BH/SH/TH/THD can read both Cover and Half-Cell Values
  • Elcometer 331 Model B can read Cover Values only
  • Data logging information displayed on screen
  • Menu soft keys are visible in Elcometer 331 Model SH and TH


screen 4

Graphics Plot Mod

  • eHalf-Cell Mode - the gauge indicates the areas with the most potential for corrosion
  • Covermeter mode - the gauge indicates the depth of cover
  • Black indicates most potential for corrosion
  • White indicates least potential for corrosion with varying greyscale shade in between
  • Zoom feature allows the user to take a closer look at different areas that are of interest

Threshold View

  • Ideal method for a simple pass or fail analysis
  • Once the threshold value has been set, anything before the value is shown in black, while anything over the value is shown in white
screen 5
screen 6

Autosizing and Orthogonal Function

  • Autosizing automatically estimates the size of rebar and the depth of cover
  • If this estimated figure differs greatly from your expected rebar size or you do not know the expected rebar size, the orthogonal size function provides an accurate measurement of bar size
  • The step by step directions for orthogonal function on the covermeter make the accurate sizing of bars quick and easy
screen 7


Data Logging Feature

  • Simple Data Management on the Elcometer 331 Models SH, TH and THD
  • The Elcometer 331 Model SH can store up to 10 batches of 1,000 cover or half-cell readings, with batch statistics, ready for evaluation and report generation using Covermaster™ software package
  • The Elcometer 331 TH and THD models have user definable memory batches with either linear or grid batch data logging modes. (Linear batching is where data is stored in a batch one reading after another)
  • Grid batches allow data to be stored in a 'spreadsheet format' with each cell relating to the survey area typically mapped out on the structure prior to inspection. The grid batch feature facilitates fast surveying for both cover and half-cell readings. Problem areas that do not fall within specification can be immediately identified and marked directly on the concrete
  • Cover and half-cell readings can be recorded and 'overlaid' in each grid location

Powerful Statistics Feature

  • Continually calculates and displays the statistical analysis of readings as they are taken. So, while the covermeter is in use, you are always informed and know exactly how your site survey is progressing
  • Statistics values are also calculated for the readings within each batch and these values are stored in the batch along with all individual readings


Elcometer 331 Covermeter
Elcometer 331 Cover MeterElcometer 331 Half-Cell MeterElcometer 331 Half-Cell Meter Kit

Technical Specification

Product Features

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)


Large half cell reading mV


Automatic bar size estimate


Orthogonal bar size calculation


RS232 Output - direct to printer or PC


Covermaster software




Minimum & maximum cover limits


Date & Time




Linear batch memory


10 linear batches of

1,000 readings each

Up to 200 batches of

1000 readings#

Up to 200 batches of

1000 readings#

Grid batch memory


Up to 240,000


Up to 240,000


User certified batch size


Graphics plot


Threshold plot


Stainless steel measurement mode



# Linear batch mode: up to 200 batches of 1,000 readings each Grid batch mode: up to 1,000 batches, maximum number of readings: 240,000



Technical Specification

Part Number Description Certificate 


Elcometer Covermeter Model B  


Elcometer Covermeter and Half-Cell Meter Model BH o


Elcometer Covermeter and Half-Cell Meter Model SH o


Elcometer Covermeter and Half-Cell Meter Model TH o


Elcometer Covermeter and Half-Cell Meter Model THD o

Power supply

7.4V 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


Operating temperature

0 to 50°C (32 to 120°F)



230 x 130 x 125mm (9 x 5.1 x 4.9")



1.6kg (3.5lbs)


Packing List

Standard Items: Rechargeable battery pack & charger (UK, US & EU), earphone, shoulder strap, plastic carry case & operating instructions. 
Model B: Concrete Covermeter, standard search head & search head connecting cable.
Model BH, SH, TH & THD*: Concrete Covermeter with Half-Cell function & search head connecting cable. 
Model SH, TH & THD are also supplied with Covermaster™ software and PC cable. 


* Search Heads and Half-Cell Probes are not included as standard and must be ordered separately

o Optional Calibration Certificate available 


Elcometer 331  Search Heads & Half-Cell Probes

Part Number Description
TW33119124-1A Elcometer 3312 Standard Search Head
TW33119124-2A Elcometer 3312 Narrow Pitch Seach Head
TW33119171A Elcometer 3312 Deep Cover Search Head
TW33119223-1A Elcometer 3312 Borehole Probe 0 - 40cm
TW33119223-2A Elcometer 3312 Borehole Probe 0 - 100cm
TW33119223-3A Elcometer 3312 Borehole Probe 0 - 16"
TW33119223-4A Elcometer 3312 Borehole Probe 0 - 40"
TW331CUKIT Elcometer 3312 Half Cell Probe Kit Cu/CuSO4 (Cannot be used with Model B)
TW331AGKIT Elcometer 3312 Half Cell Probe Kit Ag/AgCl (Cannot be used with Model B)
TW33119688-1 Elcometer 3312 Half Cell Probe Cu/CuSO4 (Cannot be used with Model B)
TW33119688-2 Elcometer 3312 Half Cell Probe Ag/AgCl (Cannot be used with Model B)
TW33120014D Elcometer 3312 High Tensile and Stainless Steel Dual search head (Can only be used with the Model THD)



ACI 318, ASTM C876-91, BS1881:201, BS1881:204,  BS8110, CP 110,   DGZfP:B2, DGZfP:B3, DIN 1045, EC2, SIA 262, SS-EN 206, Concrete Society Technical Report 60, UNI 10174


Standards in grey have been superseded but are still recognised in some industries.


Standard Search Head     

Standard Search Head

Design to meet most of your measurement requirements.  

Part Number



40mm / 1.6" bar 15mm to 95mm / 0.6" to 3.75"

8mm / 0.3" bar 8mm to 70mm / 0.3" to 2.75"


155 x 88 x 42mm / 6.1 x 3.5 x 1.65"

Sensing area

120 x 60mm / 4.72 x 2.36"




Narrow Pitch Search Head    

Narrow Pitch Search Head


Accurately measures the cover thickness when the gaps (pitch) between each of the rebars are close together.

Part Number



40mm / 1.6" bar 8mm to 80mm / 0.3" to 3.1"

8mm / 0.3" bar 5mm to 60mm / 0.2" to 2.4"


155 x 88 x 42mm / 6.1 x 3.5 x 1.65"

Sensing area

120 x 60mm / 4.72 x 2.36"

Deep Cover Search Head    

Deep Cover Search Head


The ideal search head for accurately measuring rebars that are deep within the structure.

Part Number



40mm /1.6" bar 35mm to 180mm / 1.4" to 7"

8mm / 0.3" bar 25mm to 160mm / 1" to 6.3"


170 x 94 x 54mm / 6.7 x 3.7 x 2.1"

Sensing area

160 x 80mm / 6.3 x 3.15"

Dual Search Head     

Dual Search Head for high tensile and stainless steels


The search head specifically designed to locate high tensile and stainless steel.


Part Number



40mm /1.6" bar 35mm to 180mm / 1.4" to 7"

8mm / 0.3" bar 25mm to 160mm / 1" to 6.3"


170 x 94 x 54mm / 6.7 x 3.7 x 2.1"

Sensing area

160 x 80mm / 6.3 x 3.15"

Borehole Probe      

Borehole Probe


The solution for locating tendon ducts and multiple layers of rebar lying deep within the concrete.


Part Number




TW33119223-1A Short

TW33119223-3A Short

TW33119223-2A Long

TW33119223-4A Long

Measurement depth

Short Probe: 0 - 40cm / 0 - 16"

Long Probe: 0 - 100cm / 0 - 40"

Approximate detection ranges

Tendon duct (70mm/2.75" diameter): up to 90mm / 3.54"

Half-Cell Kit

Half-Cell Kit


Consisting 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.


Part Number

Copper/Copper Sulphate


Silver/Silver Chloride


Extension Cable

Extension Cable 100m / 325ft


The extension cable for use with the half-cell kits gives the flexibility to take readings in difficult to reach areas.


Part Number


Verification Block

Verification Block


The verification block allows the user to check the calibration of their gauge in order to ensure maximum measurement accuracy.

Part Number



Extension Arm Kit

Extension Arm Kit


This 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.

Part Number