1. Introduction
In modern manufacturing plants, compressed air is a critical resource. The quality of this air has a direct impact on the service life of pneumatic components, process stability and employee safety. Contaminants in compressed air lead to premature wear of seals, corrosion in valves and malfunctions in precision control systems. The DIN ISO 8573-1:2010 standard defines the requirements for the purity of compressed air to ensure a controlled and safe industrial environment. Compliance with this standard is not a mere recommendation, but a technical necessity for maintenance.
2. Scope
These guidelines apply to all industrial systems that use compressed air as an energy source or process medium. This particularly includes industries with high requirements for air purity, such as food production, the pharmaceutical industry, semiconductor production and general mechanical engineering with complex automation solutions. All components are affected, from the compressor to the end user (valves, cylinders, sensors).
3. Key requirements according to ISO 8573-1:2010
The standard classifies compressed air quality based on three main contaminants. The following table provides an overview of the purity classes.
| class | Particles (max. number per m³) | Pressure dew point (°C) | Total oil (mg/m³) |
|---|---|---|---|
| 1 | 0.1-0.5 µm: 20,000 / 0.5-1.0 µm: 400 / 1.0-5.0 µm: 10 | ≤ -70 | 0.01 |
| 2 | 0.1-0.5 µm: 400,000 / 0.5-1.0 µm: 6,000 / 1.0-5.0 µm: 100 | ≤ -40 | 0.1 |
| 3 | 0.1-0.5 µm: N/A / 0.5-1.0 µm: 90,000 / 1.0-5.0 µm: 1,000 | ≤ -20 | 1.0 |
| 4 | 0.1-0.5 µm: N/A / 0.5-1.0 µm: N/A / 1.0-5.0 µm: 10,000 | ≤ +3 | 5.0 |
4. Impact on maintenance
Compliance with the ISO 8573- classes requires systematic maintenance management. This includes:
- Regular monitoring of the pressure dew point to avoid corrosion caused by condensate.
- Checking the filter service life by measuring the differential pressure.
- Regular emptying of condensate separators to limit the oil concentration in the system.
- Documentation of maintenance activities as evidence for auditors.
5. Component requirements
Spare parts such as pneumatic valves, cylinders and measuring sensors require a defined input quality of the compressed air for reliable function. When selecting replacement parts, pay attention to specifications that are approved for the respective ISO class. In potentially explosive areas in accordance with the ATEX directive, care must also be taken to avoid electrostatic charges caused by dry air.
6. Maintenance Manager Compliance Checklist
- Is the required compressed air purity defined for each process area?
- Are all compressors certified for the required cleanliness class?
- Are all filter media designed for the specific load?
- Is the differential pressure on all filters continuously monitored?
- Is there a set maintenance plan for all filters and separators?
- Are condensate separators functional and maintained?
- Is the pressure dew point measured and recorded regularly?
- Are oil-water separators regularly checked and maintained?
- Are pipes free of corrosion and deposits?
- Are all withdrawal points labeled correctly?
- Are employees trained on the importance of air quality?
- Is there a protocol for deviations from target values?
- Is the effectiveness of the maintenance measures regularly audited?
- Are documents for the declaration of conformity archived?
- Is the procurement of spare parts focused on certified components?
- Is the system protected from condensation formation when it is at a standstill?
- Have pressure regulators been checked for correct function?
- Is air treatment reassessed before process changes?
- Are measuring instruments regularly calibrated?
- Is a risk analysis conducted for contamination-critical processes?
7. Common Compliance Mistakes
Auditors regularly identify deficiencies such as:
- Excessive change intervals for filter elements.
- Bypassing filter systems at high differential pressure.
- Lack of documentation of pressure dew point measurements.
- Use of sealing materials incompatible with existing air quality.
8. Consequences for non-compliance
Violations of the Industrial Safety Ordinance (BetrSichV) and internal security standards can have significant consequences:
- Operational interruptions: Due to failure of critical pneumatic components.
- Product liability: In the event of contamination of end products, e.g. in the food industry.
- Insurance protection: Insurance companies can reduce the benefits in the event of damage in the event of gross negligence (e.g. neglect of maintenance).
- Fines: For violations of state safety regulations by supervisory authorities.
9. Summary
Proactive monitoring and maintenance of the compressed air preparation is essential for reliable operation. The use of certified and compatible components reduces the risk of failures and ensures compliance with regulatory requirements. To obtain reliable and standard-compliant spare parts, visit the UNITEC-D E-Catalog.
10. References
DIN ISO 8573-1:2010: Compressed air - Part 1: Impurities and purity classes.
Industrial Safety Ordinance (BetrSichV).
VDMA standard sheets for compressed air preparation.
