In my recent blog series, I’ve banged the drum a lot about the ramifications of getting the wrong meters installed. If you’re looking to get meters installed and haven’t read that article, I strongly suggest you do so as a starting point to avoid the common pitfalls that contractors make, mistakes that end up costing them an obscene amount of money in the long run. While that provides a basic education, you might still have questions about your specific situation and the type of meters to avoid. Things can get technical, so my best advice is to request a call back from an MWA metering expert to ease your concerns. But as a reference point here are some guidelines for common meter types.
The main problem with installing water meters is the misunderstanding of MID certification. This isn’t as complicated as it sounds. Your consultant might specify, for example, a water meter that is ‘MID Certified’. This is ideal, as MID certification means the meter has passed a standardised European assessment, but it isn’t all of the information you need. You should also be aware of the ‘MID Ratio’, which indicates the accurate flow range of the meter. The higher the number, the greater the accurate range. As a point of comparison, the minimum ratio used by UK water companies is R400.
Meters with low MID ratios are often more sensitive, so incorrect installation will result in inaccurate readings or the meters stopping at certain flow rates. Single-jet and multi-jet meters have relatively low ratios, so take more care with these. Note that for this reason UK water companies do not use multi-jet meters.
The key thing to understand with gas meters is pressure drop. In any pipe carrying fluids, the pressure of the fluid will naturally decrease the further along the pipe it gets. This is a result of friction. In an ideal world, this pressure drop will be as low as possible, so that less energy is required to bring the fluid up to adequate pressure later on in the network. Your meter also needs a minimum low pressure drop that satisfies the safety standard ‘IGEM UP/2’.
With this in mind, some consultants may advise getting a meter far larger than necessary, which is a cheap way to lower friction and therefore lower pressure drop. But you should never do this. It only results in the meter being inaccurate, or unable to record consumption at all. The only way to ensure it will be accurate and functional for its entire lifespan is to choose a suitable size for the flow rate it will be dealing with.
There has been a tendency in the UK to incorrectly install heat (thermal) meters based on old paddle wheel water meters. In mainland Europe this is not the case, and I’m not sure where this practice has come from. In any case, doing so results in premature failure of the metering system and should be avoided.
To ensure you’re installing a modern and correct thermal meter, it should be based on either Solid State Ultrasonic or Vortex Shredding technology. These meters should ideally be supplied by a single manufacturer and certified to MID Class II.
Don’t worry yourself over what meters to avoid, just call
As you can probably tell by that headache developing, correct meter installation is a minefield. The information here is a collation of over 20 years of technical knowledge, and is only a fraction of what’s taken into account when suggesting a new metering system. It doesn’t delve either into other types of meters, such as electric and oil meters. Rather than go it alone, contact one of our experts at MWA Technology and we’ll do the hard work for you. We provide technical advice as well as comprehensive onsite support for the entire project. Call a friendly human on +44(0)121 327 7771.
Martin Wardell, Chairman and Managing Director of MWA Technology – Connect with Martin on LinkedIn.