The accuracy of weighing devices in laboratories and production can become less reliable over time, substantially affecting a company’s business success. Inconsistent product quality, reputational damage, and financial and legal consequences can all stem from uncalibrated devices and a lack of routine testing.
Calibration of your weighing devices is needed to maintain accuracy and avoid the consequences of inaccurate measurements. Routine testing of balances and scales between calibrations is necessary to maintain reliable results over time.
Only an onsite calibration in the environment where a balance or scale is used allows you to assess how reliable weighing results are. Our Accuracy Calibration Certificate (ACC) is a state-of-the-art calibration service. It offers various tolerance assessments to analyze your calibration results – giving you concrete results you can use.
USP Chapter 41 and Ph. Eur. Chapter 2.1.7. describe the importance not only of calibration but also of including a statement of measurement uncertainty. In combination with the Accuracy Calibration Certificate (ACC), our Pharmacopoeia certificates provide you with the physical evidence of compliance according to these important USP and Ph. Eur. Chapters.
Are you sure your balance or scale is performing as it should? Could you document its performance if you had to? In this video, we'll talk about the routine testing of your balance or scale. You'll learn what routine testing is, why it's necessary, and how to do it right. First, let's look at what routine testing actually is. Imagine your balance or scale is a car. As a responsible car owner, you have regularly scheduled service appointments with a mechanic to help keep your car running well. Are you sure your weighing equipment is performing as it should? Could you document it if you need to? In this video by METTLER TOLEDO, you will learn about the routine testing of balances or scales and the answers to common questions such as: What is routine testing? Why is it necessary? How can it be done correctly? Over time, the performance of your weighing device can change. By testing routinely, you can make sure your weighing results remain accurate. Learn more about how to perform successful routine testing. Click the link below to find out more about GWP-Verification: https://www.mt.com/global/en/home/library/laboratory-weighing/Good-Weighing-Practice/verification-of-good-weighing.html?cmp=smo_GLO_YT_LAB_OTH_Youtube_LAB_zs3Y0w0hh3w Over time, the performance of your weighing device can change due to environmental influences, wear and tear, and other damage that's not visible. Routine testing checks to ensure that the device continues to perform accurately enough based on your needs until your next calibration. What is the right way to test a weighing device? There are four pillars that influence the routine testing of any weighing device. They are test frequency, test methods, test weights, and test tolerances. User training is also a key factor and forms the basis for the success of your routine testing program. First, let's take a closer look at what test frequency entails. How often do you need to perform your tests? The frequency will increase depending on the risks that are a part of your weighing process and how those risks could affect results. If the risk to accuracy, your process, or your product quality is high, you will need to perform testing more frequently. The second pillar involves your test methods. To verify the performance of your weighing device, there are three different tests that need to be run. Sensitivity tests are quick and simple. Sensitivity is measured by comparing the indicated value to the reference weight value. This is performed by placing a calibrated test weight on your balance or scale. The repeatability test checks the ability of a balance or scale to supply the same result with repeated weighings using the same load under the same conditions. It's usually measured by 6 to 10 consecutive measurements. A standard deviation is then calculated. Repeatability tests are usually done less frequently than sensitivity tests. However, they are important, especially when measuring small samples. The eccentricity test checks the corners of your balance or scale. Is there a difference in the indicated weight depending on where you place the load on the weighing pan? For each of these three tests, we offer SOPs, standard operating procedures, that you can download for free. They guide you through each of these test methods in detail. You learn how to perform these tests and assess the results. Now, let's look at the third pillar, choosing and using correct test weights based on your device, your process, and standard operating procedures. Good weighing practice, Mettler Toledo's global weighing standard, specifies that you only need two test weights for the routine testing of a balance or scale. This reduced requirement can simplify and optimize your testing efforts, while saving you a considerable amount of time and money. A smaller weight is needed for repeatability tests, typically about 5% of your device's capacity, and a larger weight is needed for sensitivity and eccentricity tests. And finally, let's review test tolerances, the fourth pillar of an effective balance testing program. Routine testing tells you whether or not your balance or scale is performing accurately enough. To have a clear pass or fail result, you need to define testing tolerances. GWP offers three levels of performance verification based on the concept of tolerance. The first level, in green, means the device performs within your predefined tolerances. The second level is a warning limit. This indication in yellow means that the device is not out of tolerance yet, but the safety margin has decreased. The balance or scale can still be used, but Mettler Toledo should be contacted. The control limit in red specifies when the device is out of tolerance and no longer fit for purpose. In this case, the balance or scale must be taken out of operation. Contact Mettler Toledo for a calibration and to assess the next steps. Keep in mind that the results of your routine testing depend on proper user training. This essential component should also be documented for audit purposes. Congratulations! You're now familiar with the four pillars of a robust and effective routine testing program. If you need help determining your necessary test frequency, which tests you should perform, and which weights you should use, Good Weighing Practice offers the GWP Verification Service. This easy-to-apply service answers these questions for your specific case, based on your requirements and your assessed risk. On selected Mettler Toledo weighing devices, a routine testing program is pre-installed. For more information on whether these devices are right for your process, contact us. Thank you for watching. We hope we can support you as you work to achieve accurate weighing results.
How can you be sure your weighing results remain accurate between calibrations? Proper routine testing performed by the user gives you both peace of mind and the documentation you need.
However, to test your devices properly, test frequency, methods, weights and tolerances need to be defined.
Do you know how often your balances and scales need to be calibrated? Are you sure about the details of your routine testing plan?
Based on a risk assessment of your weighing process and performance, our GWP® Verification service provides you with a solid routine testing and calibration action plan.
Good Weighing Practice™ can help you ensure consistent quality, reduce costs, and create full compliance in any weighing process.
Find OIML or ASTM test weights ranging from 1 mg up to 5 tons in all accuracy classes with or without certificate to meet your testing needs.
Prevent failures and extend equipment lifetime with Preventive Maintenance.
To assess the performance of your balances and scales, an onsite calibration by a Service Technician must be performed.
Between regularly scheduled calibrations, routine testing of balances and scales should be performed by the user. To do so effectively, a routine testing plan must be defined that includes test frequency, methods, weights and tolerances.
