If you thought that you could rely on the manufacturer’s specification to compare the accuracy of water level data loggers, think again. A comprehensive research paper testing the performance of 14 leading brands has highlighted a large range of inconsistencies. Peter Dumble, Technical Director at Waterra In-Situ, reflects on the report.
The 2011 paper by Sorenson and Butcher of the British Geological Survey “Water Level Monitoring Pressure Transducers – A Need for Industry-Wide Standards” (Posted from Ground Water Monitoring & Remediation with permission of the National Ground Water Association. Copyright 2011) has highlighted some key issues for everybody involved in ground water and surface water level monitoring.
The paper looks at the results of comprehensive laboratory and field tests on 14 leading brands of pressure-transducer based water level logging devices, and the results are troubling.
We fully support the paper’s call for industry wide standards for both calibration and specification. Hydrogeologists, geotechnical consultants and environmental consultants need to be able to make their choice of equipment based on actual performance and the real capability, not on untested supplier aspirations. Monitoring organisations and field engineers should be able to trust the measurements they are receiving, especially as the trend for reductions in the number of site visits accelerates.
At Waterra In-Situ we are proud to be judged on performance. All of our water level and water quality monitoring equipment is precision engineered and features solid titanium housings and a choice of both ceramic and titanium sensors for sustainable long term deployment. Level sensors are calibrated across their full operating temperature and pressure range to ensure that they conform fully to their stated accuracy. Factory calibration is conducted to fully traceable external national standards (NIST - National Institute of Standards and Technology).
As a result we are confident that we state the accuracy specifications of our loggers, that's what you will get in the real world.
To find out more about the testing and calibration of the Waterra In-Situ range contact our support team on +44 (0) 121 733 7743 or email sales@waterra-in-situ.com.
There is more information on the accuracy and calibration of our loggers on the website and we have a one day data loggers training course on March 28th 2012 that focuses on improving the accuracy of water level measurement.
 |
| Peter Dumble, Technical Director, Waterra In-Situ |
The paper looks at the results of comprehensive laboratory and field tests on 14 leading brands of pressure-transducer based water level logging devices, and the results are troubling.
- In laboratory tests poor temperature compensation was a particularly significant issue, with 5 sensors showing substandard performance.
- In field tests variations in pressure recording during extreme temperatures or rapid temperature changes were also outside of the stated ranges for several sensors. The authors highlighted two factors as causes of inaccuracy:
- Sensor design and the efficacy of correction algorithms
- Lack of thoroughness by manufacturers in instrument calibration - Field testing also exposed the problem of drift, with sensor accuracy deteriorating over time. One high pressure sensor drifted by up to 181mm. The paper comments that drift “may be the key accuracy determinant during long term water level monitoring”.
We fully support the paper’s call for industry wide standards for both calibration and specification. Hydrogeologists, geotechnical consultants and environmental consultants need to be able to make their choice of equipment based on actual performance and the real capability, not on untested supplier aspirations. Monitoring organisations and field engineers should be able to trust the measurements they are receiving, especially as the trend for reductions in the number of site visits accelerates.
At Waterra In-Situ we are proud to be judged on performance. All of our water level and water quality monitoring equipment is precision engineered and features solid titanium housings and a choice of both ceramic and titanium sensors for sustainable long term deployment. Level sensors are calibrated across their full operating temperature and pressure range to ensure that they conform fully to their stated accuracy. Factory calibration is conducted to fully traceable external national standards (NIST - National Institute of Standards and Technology).
As a result we are confident that we state the accuracy specifications of our loggers, that's what you will get in the real world.
To find out more about the testing and calibration of the Waterra In-Situ range contact our support team on +44 (0) 121 733 7743 or email sales@waterra-in-situ.com.
There is more information on the accuracy and calibration of our loggers on the website and we have a one day data loggers training course on March 28th 2012 that focuses on improving the accuracy of water level measurement.
0 comments:
Post a Comment