MWA Technology
MWA Technology Limited, Offices & Workshop,
2 Wharton Street Ind. Est., Birmingham, West Midlands, B7 5TR

+44 (0) 121 327 7771

Understanding WRAS & MID from MWA Technology

Understanding WRAS & MID

August 30, 2017

The meter found below is labelled an WRAS approved product. Any water meter, or fitting, can be submitted for UK WRAS approval, other European countries have their own approval organisation to certify that the meter or fitting is approved for use with potable water.


The major manufacturers of quality utility water meters, such as Itron & Elster, sell throughout Europe and their meters are approved for use with potable water by the local authorities. They do not label their meter WRAS as this only applies to the UK market. Their meters are WRAS approved and are listed on the WRAS website. The meters will also have the relevant approval for any other country to which they are supplied; Ireland, France, Germany etc. Clearly labeling a meter as WRAS approved product implies manufacture in a non-European, this could possibly be a far Eastern country!

Measurement Instruments Directive, MID

MID comprises of 2 parts – Type Approval & Production Quality Control System Assessment. No manufacturer is going to produce a sample meter which will fail type approval. Once approved the meter can be labelled MID accordingly but the question is whether the manufacturer has a strong and well maintained Quality Assurance system which is regularly assessed by a regulated body.

Let’s say a meter achieves MID certification from a Czech laboratory – which authority polices the production quality controls? Let’s also say our hypothetical meter is labelled as “Q3 4 R80H”. Q3 R80H means that the Q3:Q1 ratio of the accurate range of the meter from Q3 – continuous rating of the meter to Q1 – minimum accurate flow rate is Q3 of 4m3/h to Q1 (Qminimum accurate) of 50 litres per hour! Furthermore, the meter can only be installed in a horizontal line, as it’s marked “H”, with the index facing upwards. Had the meter been designed for both horizontal and vertical installation, the meter would have been marked R80H  R40V. R80 is a particularly low accurate range. R40 is much worse at low flow rates as the meter’s accuracy falls. Accurate low flow performance is extremely important for leak detection.

An Elster or Itron meter up to 40mm will generally have a much higher Q3:Q1 Ratio of a minimum of R180, and can be installed in any orientation. The maximum operating pressure is always stated and all meters produced by the leading manufacturers are pulse enabled.

Don’t let your lack of metering knowledge hold you back. Speak to a metering expert today on +44 (0)121 327 7771 or email info@mwatechnology.com. We are always happy to support you.

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