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Viscosity Standards FAQ
All Your Questions About Viscosity Standards – Answered by Lab Unlimited
Brookfield Viscosity Standards are essential for maintaining accurate, reliable, and traceable viscosity measurements.
Below, you’ll find expert answers to the most common questions about viscosity standards, calibration, and instrument verification.
- Why do I need a viscosity standard?
- How often do I need to replace my viscosity standard?
- How many viscosity standards do I need?
- What are the different types of viscosity standards?
- Should I use silicone oil or mineral oil?
- How to Select a CAP Fluid?
- How do I store and handle viscosity standards?
- How often should I calibrate my viscosity measurement instrument using a viscosity standard?
- What Is the difference between calibration and verification?
- Can I use a viscosity standard with a different temperature or viscosity range than my sample?
- My fluid's viscosity is not on your list. What should I do?
- What is a viscal kit?
- Where can I view the full range of viscosity standards?
Why do I need a viscosity standard?
Viscosity standards are reference fluids with known viscosity values used to check the accuracy and performance of viscometers and rheometers.
They provide a constant, traceable viscosity value at a defined temperature (typically 25 °C), ensuring calibration verification that meets ISO, ASTM, and other quality system requirements.
All AMETEK Brookfield viscosity standards are certified to be accurate within ±1.0 % of the stated viscosity value and are traceable to the U.S. National Institute of Standards and Technology (NIST).
Special-order silicone fluids are also available with specified viscosity values between 10 °C and 80 °C.
How often do I need to replace my viscosity standard?
For optimum performance, viscosity standards should be replaced annually.
egular checks should also be carried out to ensure that the fluids have not degraded or become contaminated.
lowing this schedule ensures reliable measurements and compliance with calibration standards.
How many viscosity standards do I need?
The number of standards required depends on:
- The number of instruments and measurement ranges used.
- The required accuracy and frequency of verification.
It is recommended to have
Secondary check standards may also be used between formal calibrations to detect drift or performance changes.
What are the different types of viscosity standards?
Brookfield offers two primary categories of standards:
- Silicone Viscosity Standards – Newtonian fluids with excellent temperature stability, ideal for most rotational viscometers.
- Range: 5 cP to 100,000 cP at 25 °C
- Supplied in 1 L bottles (≤ 12,500 cP) or 0.5 L bottles (> 12,500 cP).
- Accuracy: ±1 %.
- Oil Viscosity Standards – Recommended for applications that cannot use silicone, such as the paint and coatings industry.
- Suitable for cone/plate, CAP, and Krebs viscometers.
- Accuracy: ±1 %.
- Excellent for shear rates above 500 s-¹.
High-Temperature Silicone Fluids and Special-Order Blends are also available for extended ranges or custom applications.
Should I use silicone or mineral oil viscosity standards?
This depends on your product and process requirements:
- Silicone fluids are preferred for most applications because they are less sensitive to temperature changes and completely Newtonian.
- Mineral oils are used when silicone contamination must be avoided (e.g. in the paint and coatings industry).
Recommendations:
- Silicone: Regular viscometers, Small Sample Adaptors, and UL Adaptors.
- High-Temperature Silicone (HT): For Thermosel accessories and controllers.
- Mineral Oil: For CAP Series and KU-3 viscometers or cone/plate systems.
How to Select a CAP Fluid?
CAP Viscosity Standards are specifically designed for cone/plate viscometers such as the Brookfield CAP 1000 and CAP 2000 series. Selecting the correct CAP fluid ensures accurate results and traceability.
Follow these guidelines:
- Choose a CAP fluid with a viscosity value close to your sample’s expected viscosity at the test temperature.
- Verify the temperature range of the CAP standard — common options include 25 °C, 50 °C, and 100 °C.
- Always use CAP Mineral Oil Standards for CAP cone/plate systems (avoid silicone oils to prevent contamination).
- Store CAP fluids in their original containers, tightly sealed, and avoid repeated heating cycles.
- Replace annually or if fluid shows signs of contamination or viscosity drift.
How do I store and handle viscosity standards?
Store viscosity standards in their original containers, away from light, moisture, and extreme temperatures.
Before testing:
- Allow the standard to equilibrate to the test temperature.
- Gently mix to ensure uniformity.
- Avoid contamination by using clean tools and containers.
How often should I calibrate my viscosity measurement instrument using a viscosity standard?
Calibration frequency depends on the instrument’s use and accuracy requirements:
- At least once per year (or as defined in your quality policy).
- After any repairs or mechanical shock.
- Whenever verification fails.
In addition, verification checks using viscosity standards should be performed monthly, weekly, or before critical measurements.
What is the difference between calibration and verification?
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Calibration |
Verification |
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Calibration ensures traceable accuracy, while verification ensures consistent performance between calibrations.
Can I use a viscosity standard with a different temperature or viscosity range than my sample?
For best results, always use a standard that matches or closely approximates your sample’s viscosity and temperature range.
Using a mismatched standard can introduce error or require calibration adjustments.
If unsure, contact our technical team for guidance on the most appropriate viscosity standard for your application.
My fluid's viscosity is not on your list. What should I do?
Brookfield viscosity standards are Newtonian, meaning their viscosity does not change with shear rate.
This makes them ideal for calibration, even if your own sample is non-Newtonian.
In most cases, you do not need a custom blend, as verification at one range ensures accuracy across the entire instrument range.
However, special-order blends (5 – 60,000 cP at 10 – 80 °C, within ±2 %) are available on request.
What is a viscal kit?
A VisCal Kit is a convenient package that includes everything you need to verify your viscometer’s calibration.
Standard VisCal Kit contents:
- 600 mL beaker
- 1 L of silicone viscosity standard (5 – 12,500 cP)
- Dispersing bottle and Trapper cleaning agent (US only)
Plastic VisCal Kit:
- Includes a 600 mL plastic beaker and a metal lid for anchoring the temperature bath.
- Ideal for glass-free environments such as safety-critical labs.
Where can I view the full range of viscosity standards?
Our full range can be viewed on the Viscosity Standards section of our website. If you have a need that is not covered in this range, please contact our Sales Team. You can see the full Brookfield Ametek Viscometer range on our website, as well.
Also, be sure to check out our article on how Viscosity Standards Help to Avoid Production Downtimes.
Check Out the Viscosity Standards! |
Where Can I See a Full List of Available Viscosity Standards?
Our full range can be viewed on the Viscosity Standards section of our website. If you have a need that is not covered in this range, please contact our Sales Team. You can see the full Brookfield Ametek Viscometer range on our website, as well.
Also, be sure to check out our article on how Viscosity Standards Help to Avoid Production Downtimes.
Check Out the Viscosity Standards! |
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Contact our team for technical support, guidance, or to explore our full range of Brookfield AMETEK instruments and viscosity standards.