Occupational monitoring with the European Standard EN 13826 peak flow meter
A new PEF Meter manufactured to the new European Standard EN 13826 will be available from 1st Sept 2004. This will replace the Wright PEF. There could be differences of up to 30% in the readings.
Could you advise on how we proceed re our occupational monitoring.
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The original (round metal) Wright peak flow meter was calibrated against an accurate pneumotachograph using a steady flow of air. This was found to produce different results when the air flow had a fast acceleration and slower deceleration as in a maximum exhalation. The development of accurate computer controlled pumps allowed the accurate calibration of peak flow meters. The original Wright was fond to overestimate the PEF in the midrange by up to 80litres/min, and to underestimate over avout 650. This results in a reduced diurnal variation by on average 4%, but does not alter the sensitivity of the Oasys analysis. The Oasys programme allows you to linearise non-linear Mini-Wright meters (click the linearise button). Much of the world has been using linear meters for some time. They have been delayed in the UK as the disposable meters are prescribable on the drug tarif, and for a meter to qualify it had to reproduce the original Wright calibration. The way foreward is linear meters, unfortunately they are a bit more difficult to read due to the closeness of the line markings at some points on the scale (the markings are not evenly spaced). It is important to use a single meter throughout the period of a record in an individual, and to record which scale is being used. If you are concerned about the diurnal variation and magnitude of the difference between work and rest, then linearise all non-linearised meters. Oasys copes well with both scales. Turbine and infra-red meters have always been designed to be linear.
1.Miller MR, Dickinson SA, Hitchings DJ. The accuracy of portable peak flow meters. Thorax 1992;47:904-9.
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If Mini-Wright peak flow meters are being used, then it is possible to provide an approximate value for the new "EU" (or EN 13826) scale reading at http://www.peakflow.com
Other brands of peak flow meters may have needed to have their design changed to ensure they meet the new EN13826 standard, so check with the manufacturer of the meters you use before using the above converter.
To avoid confusion, PEF readings should now have either "EU" or "Wright" noted with the reading e.g.
PEF 440 L/min (Wright)
PEF 387 L/min (EU) or (EN13826)
By the way, the above readings are for exactly the same peak flow, just measured on different scale Mini-Wrights.
Hard copy of the conversions from Wright to EU scale will be available from Clement Clarke.
Jon Bell
Clement Clarke International Ltd
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This page is out of date.
EN13826 is superceded by ISO 23747:2007.
Since the life of a mechanical PFM is 3 years, there should be no 'Wright' scale devices out there, they should all be to the ISO standard now.
(Why ever call it EU? EN maybe until 2007)
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Why are you using 6-year old mechanical peak flow meters? These are hardly likely to be accurate now no matter which scale is stuck onto them. You will know from the annual calibration certificate for each of these measuring devices how they compare to the flow measurement traceable reference device.
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So to make this clear for data entry staff:
When using the Oasys program the user is required to choose the Meter Type. Using a Mini-Wright Peak Flow Meter with an 'EU' / ISO 23747 marked scale, should one choose 'Mini-Wright Linear' or 'Mini-Wright Non Linear'?
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Hi,
When using a mini-wright with an EU scale (as all should be now), you need to choose 'mini-wright linear' as the meter type.
many thanks
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