Light weight deflectometer are measuring very precise and highly reliable test results, therefore they have to be re-calibrated every twelve months according to the international standard ASTM E2583-07 (American Society for Testing and Materials) independent of how often it was used in the last 12 month. Regular calibration will guarantee, that test results are always reliable and precise and that the equipment is working correctly. To do this annual service, owners have to resend the entire equipment to the manufacturer, because remote or online calibration is not possible. Winter time is perfect to do this required re-calibration because bad weather conditions are making the use of LWD nearly impossible during this period in most countries of the world. The lead time of calibration service depends mostly on the transport time, which is needed for shipment of the equipment to and from manufacturer and back to customer. Inside European Community it needs three weeks including transport time, calibration for overseas customers needs about four weeks depending on customs clearance. Sending back the equipment from overseas best to use a custom procedure to send equipment as temporary import to avoid custom fee. Proforma invoice issued by users has to be less than 1000 USD for temporary import. This makes custom clearance easier. As soon as the equipment has arrived in Germany, manufacturer will start the calibration process immediately .
The manufacturer is doing re-calibration of light weight deflectometer using three in house designed calibration systems, all accredited by BASt Germany (Bundesanstalt für Strassenwesen, a department of ministry of traffic of the German government), which guarantees that customers do not have to wait a long time for calibration service. The third calibration system was just accepted by BASt in the middle of February 2022. Calibration service means the calibration of the central geophone which calculates the deflection of the soil as well as the calibration of the two external geophones (if part of the equipment) and the calibration of the load cell which is measuring the load of the falling weight. The device works with a 10 kg falling weight and even with 15 kg and 20 kg if the user has purchased these options. Calibration service is according to the international standard ASTM E2583-07 and the manufacturer is following the strict rules of the German calibration standard TP BF-StB 8.4 in addition to make sure, that light weight deflectometer made in Germany will be very precise and reliable when doing compaction tests of soil in the field. After a successfully calibration, a label with the period of the valid calibration year will be attached on the equipment.
The service includes the check up of all functions of the device as well to make sure that the light weight deflectometer will work bug free at least till the next re-calibration after twelve more months. If dust or sand is in the device, the parts will be disassembled and cleaned carefully by technical staff. Before a necessary repair, the manufacturer will ask the owner to approve a commercial offer send via email where all repairs are explained and listed.
The manufacturer reminds all customers every year via email with a special calibration reminder service, that the calibration period of their equipment is expired.
