A Short Guide to Industrial Viscosity Standards
Viscosity is a very important property for many materials. Fuels, lubricants, medicines, and paints all rely on having the right viscosity to perform properly. For oils and lubricants, the degradation of materials and changing viscosity parameters can lead to costly equipment failures.1
There are a number of different test types and equipment that can be used to evaluate the viscosity of materials reliably and accurately, including viscometers and rheometers.2 But how can we evaluate if a piece of equipment is delivering the correct data, and whether the data obtained is meaningful?
The answer to achieving the best quality viscosity measurements lies in viscosity standards. Measurement standards are a straightforward and highly efficient way to calibrate and/or verify instruments, and to make sure that your measurements are as good as they can be.
What are viscosity standards?
A viscosity standard is a reference material designed for the exact calibration and/or verification of viscosity instruments. When using a viscosity standard, measuring equipment should be able to return viscosity data in line with the certified values at a given temperature, and taking into account any test method precision and acceptability criteria.
Certified viscosity standards will also have traceability in terms of their calibration, as well as a quoted expanded uncertainty relating to the certified values on the accompanying certificate. Traceability and uncertainty are important requirements with any reference material for compliance with different international standards and methodologies.
An expert reference standards company can provide a number of different standard types, as it is important that the correct reference standard is used with the right measurement type. LGC Standards is therefore able to supply you with a large number of viscosity standards, and examples of our ranges, together with their applications, are given below.
How can standards help you?
Standards are a vitally important part of any measurement, as having known samples with known certified values is the only way to truly confirm if an instrument is measuring as expected.
One of the advantages of using standards is that they not only improve confidence in measurement quality, but also help improve overall efficiency. Using standards as part of measurement procedures and protocols means that it is immediately obvious if there are any problems with instrumentation, methodology, or operator performance - meaning that valuable time is not wasted with unnecessary troubleshooting.
Buying certified reference standards with full traceability from an expert partner like LGC is one way to ensure that you obtain maximum efficiency and benefit from your use of reference standards.
LGC Standards offers a wide variety of certified viscosity standards for the calibration and verification of glass capillary viscometers, auto viscometers, rotational viscometers, flow cups and other viscosity measuring equipment.
All viscosity standards are traceable to the primary standard of pure water, having a Kinematic Viscosity of 1.0034 mm2/s at 20 °C, as adopted by National Metrology Laboratories such as NIST and national standard bodies like ASTM, IP and ISO.
All certification is carried out in accordance with ISO 17025 and ISO 17034 accreditations. Examples of the viscosity standards available are given below, together with their applications (please note this is not an exhaustive list).
· General purpose viscosity standards are certified at temperatures between 20 and 100 °C using ASTM D2162, the primary method for the certification of oil-based viscosity standards. They offer the customer a comprehensive range of certified viscosity values within the temperature range, which can be used in a number of applications / industries.
· Cold Cranking Simulator (CCS) viscosity standards are manufactured and certified for use with ASTM D5293, the Standard Test Method for Apparent Viscosity of Engine Oils and Base Stocks Between –10 °C and –35 °C Using Cold-Cranking Simulator. They are also applicable to other low temperature test requirements.3
· Low temperature viscosity standards certified at different temperatures from 0 to -40 °C, are applicable for use in many low temperature applications - particularly, but not solely, in the petroleum industry. Application examples include the viscosity of aviation fuel at -20 °C and viscosity of lubricants at low temperature by rotational viscometer.
· High temperature viscosity standards certified at temperatures between 100 and 150 °C, which are intended for those applications where verification of viscometer performance is required at such temperatures.
· Rotational viscosity standardsare intended for the calibration / verification of rotational viscometers, and supplied in two matrices: a silicone fluid matrix (certified at 20 and 25 °C) and an oil matrix (certified between 20 and 25 °C, at 0.5 °C intervals).
· Medical viscosity standards certified at 25 and 37 °C are intended for clinical viscometers - such as those used for measuring the viscosity of blood plasma, and in other pharmaceutical applications.4
· Cone and Plate and Flow Cup viscosity standards are certified at temperatures between 20 and 25 °C, and are intended for use with viscometers found in the paint, coating and varnish industries.
LGC Standards – your ideal certified reference materials partner
For over 30 years, LGC Standards has been at the forefront of the development and production of certified reference materials for industrial applications. Certified reference materials are an excellent way of achieving operational savings and improving quality control in your processes, and LGC Standards is the ideal reference materials partner to support your business goals.
References and Further Reading
1. Wakiru, J. M., Pintelon, L., Muchiri, P. N., & Chemweno, P. K. (2019). A review on lubricant condition monitoring information analysis for maintenance decision support. Mechanical Systems and Signal Processing, 118, 108–132. https://doi.org/10.1016/j.ymssp.2018.08.039
2. Gupta, S., Wang, W. S., & Vanapalli, S. A. (2016). Microfluidic viscometers for shear rheology of complex fluids and biofluids. Biomicrofluidics, 10(4). https://doi.org/10.1063/1.4955123
3. Myshkin, N. K., Markova, L. V., Myshkin, N. K., & Markova, L. V. (2018). Oil viscosity monitoring. On-line Condition Monitoring in Industrial Lubrication and Tribology, 31-59. https://doi.org/10.1007/978-3-319-61134-1_2
4. Marapureddy, S. G., & Thareja, P. (2020). Structure and rheology of hydrogels: applications in drug delivery. Biointerface Engineering: Prospects in Medical Diagnostics and Drug Delivery, 75-99. https://doi.org/10.1007/978-981-15-4790-4_4