Why Use a 17025 Certified Viscosity Standard? Viscosity varies with temperature and using calibration oils that are certified at that specific temperature are recommended for peak viscometer performance.
Cosmetics, Food, Paint, Pharma, Personal Care, and a host of other product manufacturers all run daily viscosity tests on a large variety of their products. Viscosity is measured in R&D, during production, and in final product QC. The products measured can vary in viscosity. For example, a food manufacturer might need to test relatively thin, low viscosity salad dressing, as well as higher viscosity ketchup with shear thinning flow behavior.
When using a viscometer to test substances of varying viscosities it is important to ensure that your viscometer is calibrated in the viscosity range of the products that you are testing. Modern rotational viscometers like the BYK byko-visc RT series enable the user to verify the calibration, as well as to calibrate their instrument on site using ISO 17025 certified standard oils.
QC Labs and the Rotational Viscometer - The most popular viscometer in QC labs is the rotational viscometer. These instruments can measure in a broad viscosity range, from less than 5 to over 100,000,00 centipoise, depending on choice of viscometer and spindle. Labs that need to test a variety of products daily prefer these instruments as they allow them to test a large range of products with a single viscometer. Due to the extreme viscosity range available, and to achieve accurate, repeatable results, the chosen viscometer should be calibrated in the viscosity range of the products to be tested. ISO 17025 certified oils are available from Gardco that cover the entire available viscosity range, making regular calibration simple and inexpensive.
Certified Oils for Viscosity Measurement Performance - Because viscosity varies with temperature, calibration oils are certified at specific temperatures that are listed on the certificate. Most oils are certified at 25Â°C, but oils certified at higher temperatures are also available. Some oils are certified at multiple temperatures as well. It is important to note that the temperature of the calibration oil as well as the spindle should be maintained at the certification temperature when calibrating. This can be accomplished by using a circulating water bath or other accessory that allows temperature stability. To ensure accurate calibration, the use of two or three oils with differing viscosity values is suggested. Ideally one should be below the viscosity of your products, and one should be above. BYK standard oils do not change viscosity with time or shear. All oils are certified to have a minimum 1-year shelf life, if they are not contaminated and are stored with the cap attached securely. Assuming this, the oils can be confidently used up until the expiration date printed on the certificate.
Calibration oils relevant to the viscosity of the products to be measured should be purchased with every viscometer to ensure accurate readings, as well as to comply with ISO 17025 and other quality systems, standards, and requirements.