cOmpreSSed aIr
ISO 8573
When cOmpreSSed aIr qualIty cOuntS
Roy Brooks, technical development officer for the British Compressed Air Society (BCAS) outlines the basic principles of ISO 8573, the International Standard Relating to Compressed Air Purity (Quality) and explains why operators should consider all parts of a compressed air system during the specification process.
s many as 90 per cent of all industrial manufacturing sites rely on compressed air for some aspect of their operations, so ensuring a high-quality source of air at all times is vital for uptime and productivity. air quality is not just a requirement for hygiene
a
critical applications, such as in the food or beverage or pharmaceutical industry either – it should inform the equipment selection and testing methods for any compressed air installation.
WhICh COntAmInAnt? compressed air is not clean! In fact, it can contain up to ten different contaminants, which need to be treated correctly. these tend to be combined into three distinct
categories: particles (including viable and non-viable microbiological organisms), water and oil. ISO 8573- 1 refers to the main contaminants in this format. When selecting purification equipment, it is
important to note that contaminants will be in one of three different phases (states of matter). For example, water and oil in a compressed air system will be found in liquid form, as an aerosol (fine mist) and in a vapour (gaseous) phase and a different purification technology will be required depending upon the phase of the contaminant.
WhICh StAndARd? depending on the application, there are number of different compressed air standards and best practice guidelines which can be used to assist. ISO 8573 series is the most commonly used
standard for compressed air (excluding breathing air or medical air). It is made up of nine separate parts. part 1 refers to air purity (quality), while parts two to nine provide details on the equipment and methodology to be used to measure for different contaminants in a compressed air system (and meet the air purity (quality) classifications shown in part one).
ISO 8573-1 – InteRnAtIOnAl StAndARd RelAtIng tO COmPReSSed AIR PuRIty (QuAlIty) ISO 8573-1 provides guidance on specifying the air purity (quality) required for the entire compressed air system and/or for individual usage points, based upon application requirements. In addition, there are also specific
requirements for compressed air that comes in to direct or indirect contact with food or beverage products as well as the htm02-1 purity recommendation for medical and surgical air and htm2022 for dental air. Finally, BS en 12021:2014 is the specified standard for breathable air, indicating maximum permitted contaminant levels both in the uK and the eu.
SPeCIfyIng CORReCtly Whether designing new systems, or reviewing existing systems, the first step should be to define the precise compressed air purity (quality) requirements for the application. to achieve the degree of air purity (quality)
specified by ISO 8573-1, a careful approach to system design, commissioning and operation must be adopted. Best practice is to treat compressed air prior
to entry into the distribution system and at critical usage points and application, to ensure that contamination already in the distribution system is removed. purification equipment should ideally be
installed where the air is at the lowest possible temperature, i.e., downstream of air receivers, but also protected from freezing. point-of-use purification equipment should be installed as close as possible to the application. to allow correct sizing and selection of
purification equipment, operators should have the following operating parameters to hand:
the maximum compressed air flow rate into the filters/dryer
the maximum operating temperature into the filters/dryer
the maximum ambient air temperature where the equipment is to be installed
(required for some dryer technologies) the required dewpoint (dryers)
Individually, each of the primary operating
parameters can influence product sizing, however collectively they can have a major impact on product sizing and performance. many manufacturing plants only need a
proportion of the compressed air to be treated to a very high purity (quality). In these cases, excellent savings are achievable by treating all the generated air to the minimum acceptable level and improving the purity (quality) to the desired level at the usage point.
WhAt next? the specification of the most appropriate air treatment can be a complex task and this article only illustrates the basic principles. BcaS now offers an ISO 8573 blended learning
workshop. the course is aimed at typical industrial compressed air applications operating at low pressure, with a range between 7 bar g to 20 bar g and provides guidance on the differences between indicative testing and air quality verification. Follow the link to learn more about the course
www.bcas.org.uk/training/understanding- iso8573.aspx.
British Compressed Air Society (BCAS)
www.bcas.org.uk/airtreatment
28 aprIl 2021 | FactOry&handlInGSOlutIOnS
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54
