U.S. TAG Creates Video to Describe Possible Updates to ISO 11171

fluid power standardization

Work continues in the ISO Technical Committee 131 – Fluid power systems, Subcommittee 6 – Contamination Control and in the U.S. Technical Advisory Group (TAG) to this subcommittee to revise ISO 11171, Calibration of automatic particle counters for liquids. Round robin testing is being conducted in parallel with the revision to support NIST’s development of SRM 2806d as a consensus standard. Results will be included in the final draft. The TAG asked that a video be created to help answer questions and describe possible updates to ISO 11171. The following notable updates are being considered:

  • The current version of the revision to ISO 11171 denotes a single method of reporting particle size, µm(c).
  • The current version of the ISO 11171 revision specifies the way particle counter threshold settings for calibration are determined.
  • The constrained cubic spline method of interpolation is specified for interpolation of threshold voltage settings and particle size data for calibration purposes.
  • The current version of the revision specifies a minimum of 16 sizes to interpolate sizes/thresholds for primary and secondary calibrations. Three different calibration samples must be used. Together, these changes reduce the average error from 14% down to <1%, and maximum error from 52% down to ~1%.
  • A method of diluting calibration samples is defined to facilitate calibration of particle counters at sizes smaller than 4 µm(c).

NFPA would like to thank the co-project leaders Dr. Barry Verdegan from Cummins Filtration Inc. and Mr. Michael Schumacher from PAMAS for leading the work being done on this standard. We would also like to thank Bill Bars from Beckman Coulter Life Sciences for his work on the TAG and for volunteering to produce and star in this educational video.

Questions? Comments? Please contact Denise Husenica at dhusenica@nfpa.com.