What is ISO 21501-2- Light scattering liquid-borne particle counter about?
ISO 21501-2 is a safety standard on single-particle light interaction methods.
ISO 21501-2 describes a calibration and verification method for a light scattering liquid-borne particle counter (LSLPC), which is used to measure the size and particle number concentration of particles suspended in the liquid. The light scattering method described in ISO 21501-2 is based on single-particle measurements. The typical size range of particles measured by this method is between 0,1 μm and 10 μm in particle size.
Note 1: ISO 21501-2 is applicable to instruments used for the evaluation of the cleanliness of pure water and chemicals, as well as the measurement of the number and size distribution of particles in various liquids. The measured particle size using the LSLPC depends on the refractive index of particles and medium; therefore, the measured particle size is equivalent to the calibration particles in pure water.
Note 2: The following are within the scope of ISO 21501-2:
- Size setting error
- Counting efficiency
- Size resolution
- False count
- Maximum particle number concentration
- Sampling flow rate error
- Sampling time error
- Sampling volume error
- Calibration interval
- Reporting results from tests and calibration
Who is ISO 21501-2- Light scattering liquid-borne particle counter for?
ISO 21501-2 on light scattering liquid-borne particle counter is relevant to:
- Manufacturers of precision machines
- Manufacturers of particle counters
- Electronic industries
- Pharmaceutical industries
- Medical personnel
Why should you use ISO 21501-2- Light scattering liquid-borne particle counter?
Monitoring particle contamination levels are required in various fields, e.g., in the electronic industry, in the pharmaceutical industry, in the manufacturing of precision machines, and in medical operations.
Particle counters are useful instruments for monitoring particle contamination in liquid. The purpose of ISO 21501-2 is to provide a calibration procedure and verification method for particle counters, to minimize the inaccuracy in the measurement result by a counter, as well as the differences in the results measured by different instruments.
Overall, ISO 21501-2 is useful as it assists the user in evaluating the counting efficiency of the LSLPC, that uses two populations of calibration particles.
What’s changed since the last update?
BS ISO 21501-2:2019 replaces the first edition (ISO 21501-2:2007), which has been technically revised. The main changes from the previous edition are as follows:
- Clause 4 for “Principle” and Clause 5 for “Basic configuration” have been added
- “Size calibration” and “verification of size setting” have been combined as “size setting error” in the requirements (Clause 6)
- “Test report” (3.11 in the previous edition) has been changed to 6.10 on “Reporting of test and calibration results”
- Information about uncertainties has been enriched and is now the subject of Annex D
