How to Participate in an Interlaboratory Comparison (ILC) Easily

January 6, 2022

How to Participate in an Interlaboratory Comparison (ILC)

Many force calibration laboratories need help proving out their measurement capability. The ISO/IEC 17025:2005 listed interlaboratory comparisons (ILCs) in section 5.9.1. However, historically ILCs were not organized or completed because other less complicated methods were acceptable for monitoring the validity of the results.

The current ISO/IEC 17025:2017 standard still has the requirements of 5.9.1 in section 7.7.1 but it adds other quality control tools. The ISO/IEC 17025:2017 standard also made a significant change to ensure the validity of results and now mandates proficiency testing (PT) or interlaboratory comparisons (ILCs). Section 7.7.2 states, “The laboratory shall monitor its performance by comparison with results of other laboratories, where available and appropriate. This monitoring shall be planned and reviewed and shall include, but not be limited to, either or both of the following:

a) participation in proficiency testing;

Note ISO/IEC 17043 contains additional information on proficiency tests and proficiency testing providers. Proficiency testing providers that meet the requirements of ISO/IEC 17043 are considered to be competent.

b) participation in interlaboratory comparisons other than proficiency testing.” [1]

What is Proficiency Testing?

According to ISO/IEC 17043:2010, proficiency testing (PT) is the “evaluation of participant performance against pre-established criteria by means of interlaboratory comparisons.” [2]

What is Interlaboratory Comparison?

According to ISO/IEC 17043:2010, interlaboratory comparison (ILC), is the “organization, performance and evaluation of measurements or tests on the same or similar items by two or more laboratories in accordance with predetermined conditions.” [3]

How Morehouse Can Help You Satisfy Section 7.7.2 of ISO/IEC 17025:2017

Morehouse can help laboratories satisfy ISO/IEC 17025:2017, Section 7.7.2 with an ILC rental kit. Morehouse does not offer PT because it would be a conflict of interest. However, we have partnered with Sapphire Proficiency Testing. Contact Craig Glunt at 614-832-9142 or for more information.

Morehouse has two ILC rental kits available, one with a 100k load cell and one with a 25K load cell. They are calibrated per ASTM E74 in compression. The ASTM E74 standard is used to establish an expected performance for each load cell.

Interlaboratory Comparison Kit

Figure 1: ILC rental kit with 25K load cell and 4215 indicator

ILC Comparison Kit

Figure 2: ILC rental kit with 100k load cell and 4215 indicator

The ASTM E74 data is used in an uncertainty analysis to quantify the uncertainty of the system. After the ASTM calibration has been performed and uncertainties established, Morehouse will continually calibrate the load cell using our deadweight frames with a 10-pt calibration. This calibration serves as the short-term reference value. The ILC rental kit comes with adapters, a transportation case, cable, and 4215 indicator.

Once the end-user receives the ILC rental kit, they will perform their tests. If the rental kit will be used to help validate the system, then data will be sent with the system. If the end-user wants a formal report, then data will not be sent. Morehouse and the end-user will send data to a third-party PT provider like Sapphire Proficiency Testing.

Additional information and guidance on calculating uncertainties for force calibration can be found at

How an ILC Rental Kit Works

  1. We use deadweight primary standards known to be within 0.0025 % of applied force to calibrate the artifact. Next to a deadweight calibration by a National Metrology Institute such as NIST, this is the most accurate method to verify you are making measurements within your claimed CMC uncertainty parameter.

    Interlaboratory Comparison (ILC) Calibration of the Master Load Cell
    Figure 3: Morehouse 120,000 lbf deadweight machine

  2. We help control the drift and keep the uncertainties low. All instrumentation drifts over time. If a laboratory is trying to ensure the validity of their systems, then the closer the tests are to the calibration, the lower the uncertainty values become.
  3. We can help establish your CMC uncertainty parameter. The ILC is a great starting point for calculating your capability by comparing the Morehouse artifact against another artifact, preferably with a deadweight calibration performed. If done correctly, the comparison can be used to help establish your capability. The term for this is dissemination error.
  4. We will ship the rental kit with a “fresh” calibration. The calibration will be performed 1-2 days before shipment. This allows the end-user to validate their system and get up and running quickly.
  5. We have partnered with Sapphire Proficiency Testing to provide an independent third-party review of the data and issuance of a report. If this option is requested, the ILC will be blind and the cost will be higher because we will contract Sapphire Proficiency Testing to run the data.
  6. We allow for 21 days from shipment to return of equipment. This provides at least one week for you to make the measurements, assuming a worst-case scenario five-day shipment. We encourage anyone with a transit time longer than three days to opt for a 2nd-day shipment, which would allow two weeks for testing.

ILC Data Analysis

If you want to receive a formal report for the ILC, Morehouse has partnered with Sapphire Proficiency Testing to handle the data.

If a formal report is not needed, then Morehouse will send copies of the certificate along with the rental kit. Then you can keep the certificate and conduct your own ILC. In this case, Morehouse is not responsible for ensuring the validity of the results because we have sent the answers with the expectation that the end-user will use that data to improve their measurement process.

ILC Rental Kit Pricing

The 100K and 25K rental kits have the following options. To satisfy ISO/IEC 17025:2017 requirements, the end-user would need to choose option 3 or 4, or participate in a compliant Proficiency Test.

  1. Tension or compression calibration. The end-user receives a calibration report from Morehouse to validate their system. Price: $1,250
  2. Tension and compression calibration. The end-user receives a calibration report from Morehouse to validate their system. Price: $1,650
  3. Tension or compression calibration without the calibration data. Sapphire Proficiency Testing will handle the ILC data. Price: $1,650
  4. Tension and compression calibration without the calibration data. Sapphire Proficiency Testing will handle the ILC data. Price: $2,050
  5. Optional additional support from Morehouse via online meetings or calls to troubleshoot or help with measurements. Price: $150 per hour

Make Better Measurements

Morehouse wants to help you make better force measurements. Our goal is to provide a very low overall uncertainty for direct comparison. The low uncertainty allows for a more robust method to ensure laboratories meet their claimed CMC uncertainties. This service is offered to:

  1. help laboratories validate their CMC claims and make the necessary adjustments to their systems as needed
  2. satisfy the ILC requirement
  3. help calculate Repeatability and Reproducibility between technicians. More information on R & R can be found in this blog.


How to Participate in an Interlaboratory Comparison (ILC) Conclusion

I take great pride in our knowledgeable team at Morehouse, who will work with you to make sure your ILC needs are met. Learn more about our ILC rental kit.

We have been in business for over a century and focus on being the most recognized name in the force business. That vision comes from educating our customers on what matters most and having the proper discussions relating to force calibration concepts, equipment, and appropriate services.

Everything we do, we believe in changing how people think about force and torque calibration. We challenge the "just calibrate it" mentality by educating our customers on what matters, and what causes significant errors, and focus on reducing them. In addition, Morehouse makes simple-to-use calibration products. We build fantastic force equipment that is plumb, level, square, rigid and provide unparalleled calibration service with less than two-week lead times.

Contact us at 717-843-0081 to speak to a live person or email for more information.


  1. ISO/IEC 17025:2017
  2. ISO/IEC 17043:2010
  3. ISO/IEC 17043:2010

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