Created by Ana Valverde – Hidroconta

 

Water meters play an important role in the water network, and choosing the ideal metering solutions for your specific needs can be challenging.

To help minimize the guesswork and get your solution operating at the highest level, try to solve the issues below, to ensure you identify the perfect meter for your network.

A water flow meter is a metrological instrument specifically designed to measure the volumetric or mass flow rate of water. There are, as you may already know if you are reading this article, hundreds of water meters on the market with wide range of typologies, prices, applications and capabilities. A wise choice of water meter can help you to save money and  energy, assets optimisation…. It is therefore not a petty matter!

The key to choosing a water meter is to fully understand your specific requirements and goals. For that purpose, a comprehensive understanding of the performance and data capabilities expected will ensure that you acquire the technology that best suits your needs.

Your choice should be based on both technological and economic criteria. With the aim of helping our customers and friends, I have developed the following guidelines to assist you in your water meter choice. as a first approach to the water meter choice.

Which issues should we consider for a first?

Let’s see how one or several of the following aspects will influence your decision:

Usage

The intended use of the water meter is the first basic question to be answered because it will determine its building materials, its technology, its communication capabilities, etc….

  • For Irrigation? Industrial use? Domestic use?
  • For billing control?
  • To encourage water conservation?
  • For chemical dosing processes?
  • For general reports?
  • For water saving purposes?
  • Leakage detection?
  • Etc…

The legal requirements

For both irrigation and domestic use, water meters, as a metrological instrument is under strict legal controls. Therefore, you need to be sure to install a meter that complies with the local legal legislation.

For example, in Spain irrigation meters are subjected to legal regulations, requires that the meter have and specific certification (emeñe)

For domestic use these certifications are even more important.

Low Flow Sensibility and accuracy

When purchasing a water meter, it will be necessary to choose the metrological working range. This parameter does not define the accuracy of the water meter but the lower flow sensibility.

The metrological working range is defined by the Ratio (This value is the relation between Working flow / Minimum flow).

The higher the “R” Ratio, the greater sensitivity the meter has for measuring low flow rates.

The standard values of the R ratios in water meter are the following*:

  • R40, R50, R63, R80, R100, R125, R160, R 200, R250, R315, R400, R500, R630, R800 y R1000.

(*This list can be extended in some serials. Be aware that this this nomenclature is replacing the old metrological classes A, B, and C)

And remember that a meter will only be accurate if the environmental conditions meet all the manufacturer’s requirements of flow profile, installation, temperature, flow range, vibration etc.

Water Source and quality

Where you are sourcing water from will have a bearing on the water quality (silt, weed etc.), range of flow rates and pressure, so it must be taken into account whether the source is a river, surface water, groundwater, or open channel or pressurised pipe water.

For example, a meter with no moving parts will be recommended for watercourse with dirt (ultrasonic or electromagnetic technologies).

To be considered as well is the presence of any potential contaminants.

Head (Pressure)

  1. How much pressure is in there where you want to measure?
  2. Do water levels fluctuate during a season?

Remember the pipe must run full to provide an accurate measurement.

Flow Range

What is the flow range of your abstraction  or net throughout the year?

The working flows of a water meters are defined as follow:

  • Q1 Minimum flow rate
  • Q2 Transitional flow rate
  • Q3 Permanent flow rate (working flow)
  • Q4 Overload flow rate

Make sure that the maximum flow that will pass through the meter never exceeds Q3.

Most water meters have a minimum flow (Q1), below which they cannot provide an accurate reading.

If you choose a large meter, you may lose accuracy at the lower end of the flow range.

Meters that continually operated on the overload flow range (Q4) have a shorter life span and less accuracy.

Size your meter appropriately for the flow you intend to measure.

Installation

Each kind of water meter has different installation requirements that could directly affect your choice. The distances upstream and downstream will highly affect the installation costs as well.

The location of the meter will determine then the technology to be used too (next to the pumping station, before an elbow, before a regulation valve…)

Access to Power

When selecting meters for remote locations consider whether they can run accurately on solar power, batteries or if they even need power at all. There may also be a requirement if you decide to ha a telemetry unit.

Longevity

Consider the average operating life before an overhaul is required.

This will depend on the meter type and the context it is used in.

The meter’s life span can differ depending on the technology.

As an example, legally, domestic water meters in Spain should be changed every 12 years. This should be taken into account when choosing the meter.

Communications

This requirement is key when choosing a water meter (pulse output, remote reading, smart metering…)

Would you connect the meter to a PLC? Shall the meter communicate with an existing SCADA system? Where is the control room located? Do I want to control the consumption by using any device on the cloud?

Cost

Generally, the more accurate and reliable a water meter is, the more expensive it is.

However, the purchase price should not be yours is not the only cost factor you need to consider. Count as well the cost of installation, maintenance, data collection, calibration and longevity costs.

These are most of the issues that must be answered and that and that will help you to make the right choice. In case of doubt, you can always ask to the experts who will advise and guide you through the process.

I hope you found this article useful. Please contact me for any further information or share any constructive feedback.

I hope you found this article useful. Please contact me for any further information or share any constructive feedback.