ISO (International Organization for Standardization) is the world’s largest body for developing and publishing international standards. There are three ISO standards inherent in compressed air testing and quality: the ISO8573 series, the ISO12500 series, and the ISO7183 series. The most widely used is the ISO8573 series and, in particular, ISO8573-1:2010.
ISO8573 is the group of international standards inherent in the quality (or purity) of compressed air. The standard consists of nine parts. ISO8573-1 (Part 1), the most widely used, is inherent in the classification of compressed air quality. Parts 2 through 9 specify the test methods to be adopted for a range of contaminants.
Here we will discuss six essential factors to consider when using the ISO8573 Part 1 series to optimize the effectiveness and efficiency of air treatment in your industrial production facility.
1. Understanding of air purity classification tables.
ISO8573-1 includes air purity classification tables, which specify the minimum air purity required at each point of use depending on the type of contaminant to be removed: solid particulate, water, and total oil (see Figure 1). The table allows for:
- Specify the amount of contaminants allowed at a given point of use.
- Identify the most appropriate compressed air equipment to meet the desired level of purity.
- Classify, by testing, the actual purity of compressed air at points of use before and after the installation of compressed air treatment equipment.
Figure 1. ISO8573-1 Combined Table
2. How to specify air purity by classes.
In the ISO8573-1 table, contaminants in compressed air are grouped under the headings of solid particulate matter, water and total oil. There are different gradations for each contaminant indicated, and this is to make it easier to choose the most appropriate combination of levels based on the individual user’s use. These combinations are called “purity classes.” If ISO8573-1 is used to define the required air purity, the following requirements should be followed:
- State the standard (ISO8573-1).
- Specify the year (revision) stated.
- Specify the required purity classes (separating them with colons). Example: ISO8573-1:2010 [A:B:C:].
- A = particle purity class; B = moisture (vapor) and water purity class in the liquid state; C = total oil purity class (aerosol, liquid and vapor).
The following is an example of an air purity specification:
ISO 8573-1:2010 Class 1:2:1
Based on the indications provided in Figure 1, this air purity specification would indicate that Class 1 particulate levels do not exceed 20,000 particles between 0.1 and 0.5 microns in size, with additional levels for what concerns particles of different sizes; Class 2 water levels indicate that the pressure dew point (PDO) is at -40 °C; Class 3 total oil refers to an amount of total oil that does not exceed 0.01 mg.
3. Facts and legends about the ISO8573-1 Class 0 standard
ISO8573-1 was updated in 2010 with the introduction of Class 0 for the three contaminants (see Figure 2). Class 0 was introduced as a “customizable” specification that users and equipment manufacturers could use to identify a specific air quality, which is more stringent than Class 1. This has given rise to misinterpretations or actual legends. Here are some of them:
- Class 0 compressed air is totally free of contaminants.
- Class 0 refers only to oil contamination.
- A Class 0 compressor ensures oil-free compressed air.
- The value of class 0 oil contamination is 0 mg/m3.
Important facts that need to be kept in mind:
- Class 0 does not indicate the total absence of contaminants.
- Class 0 does not indicate that the compressed air is oil-free.
- A Class 0 compressor does not guarantee oil-free compressed air.
- Class 0 does not refer exclusively to oil contamination.
- A Class 0 specification implies greater “cleanliness” than a Class 1 specification for what concerns the same contaminant.
Figure 2. Classification table of 2010 (combined)
4. Which revision of ISO8573-1 should be used?
When specifying or updating a new system, among the three revisions of the standard (1991, 2001 and 2010) the 2010 revision should be used. However, if an earlier version has always been used to specify purity levels, it is permissible to continue to use it, paying attention to the fact that varying contamination levels require different purity equipment.
Parker, for example, offers a range of purification equipment that allows the user to specify compressed air quality for any application, from
general-purpose main ring protection
, up to
critical clean dry air systems
(CDA) at the point of use. Parker boasts complete range of purification equipment capable of fully meeting system requirements and ensuring minimal investment and operating costs. Figure 3 provides an overview of the Parker purification equipment required to meet or exceed the classes in ISO8573-1:2010.
Figure 3. Overview of Parker purification equipment that meets or exceeds the classes in ISO8573-1:2010
5. Simple guidelines for selecting purification equipment
The quality of compressed air needed for the specific system should be identified. Each point in the system may require a different quality, depending on the application. Refer to your supplier for the quality classes illustrated in ISO8573-1.
- Clearly indicate to suppliers that ISO8573-1:2010 is the version of the standard being addressed.
- Ensure that the equipment chosen provides air quality in accordance with ISO8573-1:2010.
- Regarding coalescing filters, confirm that they have been tested in accordance with ISO12500-1 and ISO8573-4.
- Theoretically, a supplier should ensure third-party certification of product performance.
- A supplier should produce a written guarantee on the quality of the air delivered.
- Installation of non-lubricated compressors requires the same precautions regarding filtration as oil-lubricated compressors.
- Make sure that pressure losses are specified as “saturated.”
- Checking the inherent characteristics of filter clogging is useful in calculating energy costs.
- Ascertain the total cost of ownership of the purification equipment, thus not limiting it to only the initial purchase cost.
6. Cost-effective system design
To optimize the return on the investment made for the purification equipment, it is recommended that the compressed air to be distributed in the compressor room be subjected to treatment in order to meet the plant’s extensive needs. Purification at the point of use should be performed with special attention to the air quality required by each individual application. This approach ensures that the air is not overtreated and provides the most cost-effective solution for obtaining high-quality compressed air. Figure 4 shows an example of general-purpose air with oil-free air for critical applications.
Figure 4. General purpose air with oil-free air for critical applications
This article was written by Mark White, Applications Manager for Compressed Air Processing,
Parker Gas Separation and Filtration Division EMEA
Related Content
Is Your Compressed Air Purity Validated?
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Compressed Air Treatment Solutions for Today’s Manufacturing Plants
Why Are Coalescing Filters Installed in Pairs?
Why You Need a Maintenance Plan for Manufacturing Equipment
ISO (International Organization for Standardization) is the world’s largest body for developing and publishing international standards. There are three ISO standards inherent in compressed air testing and quality: the ISO8573 series, the ISO12500 series, and the ISO7183 series. The most widely used is the ISO8573 series and, in particular, ISO8573-1:2010.
ISO8573 is the group of international standards inherent in the quality (or purity) of compressed air. The standard consists of nine parts. ISO8573-1 (Part 1), the most widely used, is inherent in the classification of compressed air quality. Parts 2 through 9 specify the test methods to be adopted for a range of contaminants.
Here we will discuss six essential factors to consider when using the ISO8573 Part 1 series to optimize the effectiveness and efficiency of air treatment in your industrial production facility.
To discover some cost-effective system design examples and get comprehensive information on ISO8573, including detailed tables on applications, download the full whitepaper.
1. Understanding of air purity classification tables.
ISO8573-1 includes air purity classification tables, which specify the minimum air purity required at each point of use depending on the type of contaminant to be removed: solid particulate, water, and total oil (see Figure 1). The table allows for:
Specify the amount of contaminants allowed at a given point of use.
Identify the most appropriate compressed air equipment to meet the desired level of purity.
Classify, by testing, the actual purity of compressed air at points of use before and after the installation of compressed air treatment equipment.
Figure 1. ISO8573-1 Combined Table
2. How to specify air purity by classes.
In the ISO8573-1 table, contaminants in compressed air are grouped under the headings of solid particulate matter, water and total oil. There are different gradations for each contaminant indicated, and this is to make it easier to choose the most appropriate combination of levels based on the individual user’s use. These combinations are called “purity classes.” If ISO8573-1 is used to define the required air purity, the following requirements should be followed:
State the standard (ISO8573-1).
Specify the year (revision) stated.
Specify the required purity classes (separating them with colons). Example: ISO8573-1:2010 [A:B:C:].
A = particle purity class; B = moisture (vapor) and water purity class in the liquid state; C = total oil purity class (aerosol, liquid and vapor).
The following is an example of an air purity specification:
ISO 8573-1:2010 Class 1:2:1
Based on the indications provided in Figure 1, this air purity specification would indicate that Class 1 particulate levels do not exceed 20,000 particles between 0.1 and 0.5 microns in size, with additional levels for what concerns particles of different sizes; Class 2 water levels indicate that the pressure dew point (PDO) is at -40 °C; Class 3 total oil refers to an amount of total oil that does not exceed 0.01 mg.
3. Facts and legends about the ISO8573-1 Class 0 standard
ISO8573-1 was updated in 2010 with the introduction of Class 0 for the three contaminants (see Figure 2). Class 0 was introduced as a “customizable” specification that users and equipment manufacturers could use to identify a specific air quality, which is more stringent than Class 1. This has given rise to misinterpretations or actual legends. Here are some of them:
Class 0 compressed air is totally free of contaminants.
Class 0 refers only to oil contamination.
A Class 0 compressor ensures oil-free compressed air.
The value of class 0 oil contamination is 0 mg/m3.
Important facts that need to be kept in mind:
Class 0 does not indicate the total absence of contaminants.
Class 0 does not indicate that the compressed air is oil-free.
A Class 0 compressor does not guarantee oil-free compressed air.
Class 0 does not refer exclusively to oil contamination.
A Class 0 specification implies greater “cleanliness” than a Class 1 specification with regard to the same contaminant.
Figure 2. Classification table of 2010 (combined)
4. Which revision of ISO8573-1 should be used?
When specifying or updating a new system, among the three revisions of the standard (1991, 2001 and 2010) the 2010 revision should be used. However, if an earlier version has always been used to specify purity levels, it is permissible to continue to use it, paying attention to the fact that varying contamination levels require different purity equipment.
Parker, for example, offers a range of purification equipment that allows the user to specify compressed air quality for any application, from general-purpose main loop protection to critical clean dry air (CDA) systems at the point of use. Parker boasts complete range of purification equipment capable of fully meeting system requirements and ensuring minimal investment and operating costs. Figure 3 provides an overview of the Parker purification equipment required to meet or exceed the classes in ISO8573-1:2010.
Figure 3. Overview of Parker purification equipment that meets or exceeds the classes in ISO8573-1:2010
5. Simple guidelines for selecting purification equipment
The quality of compressed air needed for the specific system should be identified. Each point in the system may require a different quality, depending on the application. Refer to your supplier for the quality classes illustrated in ISO8573-1.
Clearly indicate to suppliers that ISO8573-1:2010 is the version of the standard being addressed.
Ensure that the equipment chosen provides air quality in accordance with ISO8573-1:2010.
Regarding coalescing filters, confirm that they have been tested in accordance with ISO12500-1 and ISO8573-4.
Theoretically, a supplier should ensure third-party certification of product performance.
A supplier should produce a written guarantee on the quality of the air delivered.
Installation of non-lubricated compressors requires the same precautions regarding filtration as oil-lubricated compressors.
Make sure that pressure losses are specified as “saturated.”
Checking the inherent characteristics of filter clogging is useful in calculating energy costs.
Ascertain the total cost of ownership of the purification equipment, thus not limiting it to only the initial purchase cost.
6. Cost-effective system design
In order to optimize the return on the investment made for the purification equipment, it is recommended that the compressed air to be distributed in the compressor room be subjected to treatment in order to meet the extensive needs of the plant. Purification at the point of use should be performed with special attention to the air quality required by each individual application. This approach ensures that the air is not overtreated and provides the most cost-effective solution for obtaining high-quality compressed air. Figure 4 shows an example of general-purpose air with oil-free air for critical applications.
Figure 4. General purpose air with oil-free air for critical applications
To discover some cost-effective system design examples and get comprehensive information on ISO8573, including detailed tables on applications, download the full whitepaper.
This article was written by Mark White, applications manager for compressed air processing, Parker Gas Separation and Filtration Division EMEA
Related Content
Is Your Compressed Air Purity Validated?
How Oil Vapour in Ambient Air Affects Compressed Air Quality
Compressed Air Treatment Solutions for Today’s Manufacturing Plants
Why Are Coalescing Filters Installed in Pairs?
Why You Need a Maintenance Plan for Manufacturing EquipmentParker Hannifin | Parker Hannifin