ISO 4406:2017 pdf download

ISO 4406:2017 pdf download.Hydraulic fluid power — Fluids — Method for coding the level of contamination by solid particles
1 Scope
This document specifies the code to be used in defining the quantity of solid particles in the fluid used in a given hydraulic fluid power system.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 4407, Hydraulic fluid power — Fluid contamination — Determination of particulate contamination by the counting method using an optical microscope
ISO 11171, Hydraulic fluid power — Calibration of automatic particle counters for liquids
ISO 11500, Hydraulic fluid power — Determination of the particulate contamination level of a liquid sample by automatic particle counting using the light-extinction principle
3 Code definition
3.1 General
The purpose of this code is to simplify the reporting of particle count data by converting the numbers of particles into broad classes or codes, where an increase in one code is generally a doubling of the contamination level. The original code, in accordance with the first edition of this document, stated the reporting at two sizes ≥ 5 µm and ≥ 15 µm. The sizes in this document account for the use of a different calibration standard for optical automatic particle counters (APCs). The reported sizes are ≥ 4 µm(c), ≥ 6 µm(c) and ≥ 14 µm(c), the last two of these being equivalent to the 5 µm and 15 µm particle sizes obtained using the ISO 4402:1991 1) method of calibrating APCs. Throughout this document the use of µm(c) means that particle size measurements are carried out using an automatic particle counter that has been calibrated in accordance with ISO 11171.Measurement of particles using an optical microscope as specified in ISO 4407 establishes the size of a particle as being equal to its longest dimension, whereas an automatic particle counter derives the size of an equivalent particle from its cross-sectional area, a value different in most cases from that determined using a microscope. The particle sizes to be reported for measurement by microscope ≥ 5 µm and ≥ 15 µm are unchanged from those specified in the first edition of this document. CAUTION — Particle counts are affected by a variety of factors. These factors include procurement of sample, particle counting accuracy and the sample container (where used), and its cleanliness. Proper care should be taken during sample procurement to ensure that the sample obtained is representative of the fluid circulation in the system.