Overview
ISO 21018-1:2008 - Hydraulic fluid power - Monitoring the level of particulate contamination of the fluid - Part 1: General principles - establishes general principles, methods and selection guidance for monitoring particulate contamination in hydraulic systems. It is intended to help users choose and apply appropriate monitoring techniques for assessing fluid cleanliness, tracking flushing progress, and verifying support equipment or test rigs. The standard is also applicable to other liquids such as lubricants, fuels and process liquids.
Key topics and requirements
- Scope and purpose: Defines methods suitable for monitoring general cleanliness levels and progress during flushing operations; supports selection of monitors for specific applications.
- Sampling modes: Describes and differentiates off-line, on-line, in-line and suction (sip) sampling techniques and the precautions needed to obtain representative samples.
- Technique selection: Guidance on choosing monitoring methods based on intended use, required parameters and operating mode (e.g., portable workplace monitors vs. laboratory particle counters).
- Data types: Distinguishes qualitative (range-based, go/no-go) versus quantitative monitoring and notes that many workplace monitors are not direct substitutes for laboratory particle counters.
- Calibration & validation: Recommends calibration procedures, periodic verification and checks on data validity; highlights limits of traceability for workplace instruments.
- Health, safety & compatibility: Covers electrical, mechanical and process-liquid safety, handling volatile liquids and chemical compatibility; advises use of appropriate PPE and safe connections to pressurized lines.
- Operational controls: Addresses training, precision control, handling of gels/silt, and test reporting requirements.
Practical applications and users
ISO 21018-1 is useful for:
- Hydraulic system designers and maintenance engineers monitoring system fluid cleanliness and implementing contamination control programs.
- Service technicians and field personnel using portable monitors for go/no‑go checks or flushing verification.
- Test rig operators and commissioning teams validating cleanliness during assembly or maintenance.
- Quality and reliability engineers defining and enforcing Required Cleanliness Levels (RCLs) for components and systems.
- Industries using other liquids (lubricants, fuels, process fluids) where particulate monitoring is required.
Practical benefits include improved component life, reduced wear, validated flushing effectiveness and faster in-situ contamination detection.
Related standards
Relevant ISO documents referenced by ISO 21018-1:
These standards support implementation by covering sampling containers, extraction methods, terminology and calibration practices.
Open preview (PDF)Hydraulic fluid power — Monitoring the level of particulate contamination of the fluid — Part 1: General principles