Sources of Contamination in Manufacturing
Compressor contamination can occur for many different reasons. This comprehensive webinar by our president Ruby Ochoa discusses compressor contamination and how it can occur. Manufacturers of food, pharmaceuticals, medical devices and much more will find many useful tips to avoiding contamination in this lesson. Feel free to contact us directly for your ISO 8573, SQF, BRC and BCAS compressed air testing needs.Compressor Contamination and How It Occurs
Intake Air
Intake Contamination may Include:
- Particles (viable & nonviable)
- Water Vapor
- Oil Vapor
- Gases
Compressor
Contaminants Created by the System Itself
- Wear Particles
- Intake Water can cause corrosion
- Damaging equipment
- Promote microbial growth
- Ruin the final product
Oil-free Compressors
- Can still have oil issues from oil introduced by the intake
Gases Possibly Created by the Compressor
- Carbon Monoxide
- Carbon Dioxide
- Gaseous Hydrocarbons
Human Error
Potential air quality problems can arise from misuse, mishandling, inattention to maintenance, and human error.
Distribution
New piping should be tested to assure that it has been properly purged of potential contaminants such as particulates, solders, or glues used during installation. Older piping can have an accumulation of water, rust, and oil. When connecting new piping to an older piping distribution system, the jarring of the old piping can cause particulates (such as rust, pipe scale, dirt, metal oxides, etc.) to be loosened and introduced into the new piping.
Storage receivers with excess water (vapor, liquid, or a mixture of oil and water) can become a breeding ground for microorganisms.
Remedies
A periodic air test program can provide critical information to monitor air quality degradation and help in the prevention of product contamination. The sampling plan should include sampling points, a statistically significant number of samples, and a frequency of sampling that will monitor all conditions that could affect the quality of air such as environmental conditions, maintenance schedules, and production activity. “The number of samples should be adequate to provide sufficient statistical confidence of quality.” [CGMP Guidance for Industry Process Validation: General Principles and Practices.]
Air Specifications
The tables below show the compressed air specifications as outlined by the BCAS and ISO 8573:2010. Many manufacturers establishing SOPs for compressed air used in the manufacturing process refer to these specifications to help establish their own guidelines.
BCAS Food and Beverage Grade Compressed Air |
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| ISO 8573-1:2010 Purity Class |
Particles (P) | Water | Oil | ||||
|---|---|---|---|---|---|---|---|
| By Particle Size (maximum number of particles per m3) |
Vapor Pressure Dewpoint | Aerosol & Vapor | |||||
| 0.1 µm < d ≤ 0.5 µm | 0.5 µm < d ≤ 1.0 µm | 1.0 µm < d ≤ 5.0 µm | °C | °F | mg/m3 | ||
| Direct Contact 2:2:1 |
400,000 | 6,000 | 100 | ≤ -40 | ≤ -40 | ≤ 0.01 | |
| Indirect Contact 2:4:2 |
400,000 | 6,000 | 100 | ≤ +3 | ≤ +37 | ≤ 0.1 | |
| Microbial Contaminants | Hazard analysis shall establish the risk of contamination by microbiological contaminants from compressed air. The level of control identified as being required over microbiological contaminants in the compressed air shall be detected using the test method specified in ISO 8573-7. | ||||||
| Footnotes | (P) Particle classes 1-5 may not be employed if particles >5 micron are present according to ISO 8573-1. | ||||||
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ISO 8573-1:2010 Compressed Air Contaminants and Purity Classes |
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| Class | Particles | Water | Oil | ||||||
|---|---|---|---|---|---|---|---|---|---|
| By Particle Size (maximum number of particles per m3) See Note 2 |
By Mass | Vapor Pressure Dewpoint | Liquid | Liquid, Aerosol, & Vapor See Note 1 |
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| 0.1 µm < d ≤ 0.5 µm | 0.5 µ m< d ≤ 1.0 µm | 1.0 µm < d ≤ 5.0 µm | mg/m3 | °C | °F | g/m3 | mg/m3 | ||
| 0 | As specified by the equipment user or supplier and more stringent than class 1 | ||||||||
| 1 | ≤ 20,000 | ≤ 400 | ≤ 10 | - | ≤ -70 | ≤ -94 | - | ≤ 0.01 | |
| 2 | ≤ 400,000 | ≤ 6,000 | ≤ 100 | - | ≤ -40 | ≤ -40 | - | ≤ 0.1 | |
| 3 | - | ≤ 90,000 | ≤ 1,000 | - | ≤ -20 | ≤ - 4 | - | ≤ 1 | |
| 4 | - | - | ≤ 10,000 | - | ≤ +3 | ≤ +37 | - | ≤ 5 | |
| 5 | - | - | ≤ 100,000 | - | ≤ +7 | ≤ +45 | - | - | |
| 6 | - | - | - | 0 – ≤ 5 | ≤ +10 | ≤ +50 | - | - | |
| 7 | - | - | - | 5 – ≤ 10 | - | - | ≤ 0.5 | - | |
| 8 | - | - | - | - | - | - | ≤ 5 | - | |
| 9 | - | - | - | - | - | - | ≤ 10 | - | |
| X | - | - | - | > 10 | - | - | > 10 | > 5 | |
| Microbiological Contaminants | Other Gaseous Contaminants | ||||||||
| No purity classes are identified | No purity classes are identified Gases mentioned are: CO, CO2, SO2, NOX, Hydrocarbons in the range of C1 to C5 |
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Note 1: ISO 8573 Oil includes aerosol, vapor in the range of C6+, and liquid oil. Liquid oil is typically sampled when wall flow is present, contamination is suspected, or results are greater than 5 mg/m3. Trace can provide a separate kit for liquid oil testing. Note 2: For Particle Class 0, 1, & 2 (0.1 - 0.5 µ range only), a laser particle counter with a high-pressure diffuser is required. Rental of this equipment is available on a reservation basis. Contact us for details. To qualify for Particle Classes 0 through 5, there can be no particles greater than 5µ present. In some cases, Trace uses alternative sampling techniques or analytical methods to those specified in ISO 8573, for details see Smith White Paper, 2012. |
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