What is SRM 2806?

SRM 2806 is a particle counter calibrant for liquid suspensions and required reference material for ISO 11171:2010 Hydraulic fluid power—Calibration of automatic particle counters for liquids. Industries impacted by SRM 2806 include the hydraulics industry, aerospace, automotive, ship, petroleum and lubricant, gas, power generation, filter manufacturers and the military.

In 2015, NIST (National Institute of Standards and Technology) released the current batch of SRM 2806 calibration fluid for optical particle counters, identified as SRM 2806b. Users of SRM 2806b calibrate their particle counters using cumulative size distribution aligned with ISO 11171:2010. It’s important to note that SRM 2806b has considerably higher certified values than those of previous batches (SRM2806 and SRM2806a).

Although more accurately certified than previous batches of calibration fluid, SRM 2806b has generated challenges with particle count data not altogether dissimilar to those in 1998 when ISO MTD replaced ACFTD as the source of particulates in calibration fluids.