OIML R49 Water Meters for Cold Drinking Water and Hot Water

The “OIML R49 Water meters for cold drinking water and hot water” standard developed by the International Organization of Legal Metrology (OIML) consists of the following subsections:

• The standard “OIML R 49-1 Part 1: Metrological and technical requirements” describes the metrological and technical requirements for water meters for cold potable water and hot water flowing through a completely filled, closed channel. These water meters include devices that indicate the integrated volume. In addition to water meters based on mechanical principles, this standard applies to devices based on electrical or electronic principles and mechanical principles that include electronic devices used to measure the volume of cold potable water and hot water. This standard also applies to electronic auxiliary devices. Auxiliary devices are optional. However, it is possible that national or regional regulations make certain auxiliary devices mandatory in connection with the use of water meters.

For the purposes of this standard, the following terms and definitions apply to the water meter and its components:

• A water meter is a device designed to continuously measure, memorize and display the volume of water passing through a measuring transducer under measuring conditions. A water meter includes at least a measuring transducer, a calculator (including adjustment or correction devices, if any) and an indicating device.
• The measuring transducer is the part of the measuring device that contains the sensor and converts the water flow rate or volume to be measured into signals transmitted to the calculator. The measuring transducer can operate autonomously or use an external power source and can be based on a mechanical, electrical or electronic principle.
• A sensor is a meter element that is directly affected by a phenomenon, object, or substance that carries a quantity to be measured. For a water meter, the sensor may be a disk, piston, wheel, or turbine element, the electrodes on an electromagnetic meter, or some other element. The element senses the flow rate or volume of water passing through the meter.
• The calculator is the part of the measuring device that converts the output signals from the measuring transducers and possibly associated measuring devices and, if appropriate, stores the results in memory until they are used. The gear is considered the calculator in a mechanical measuring device. The calculator can communicate with auxiliary devices in both directions.
• The adjusting device is a part of the meter that allows the error curve of the meter to be shifted parallel to itself, usually to fit within the envelope of maximum allowable errors.
• A correction device is a device connected to or incorporated in a measuring device for automatic correction of water volume under measuring conditions. It works by taking into account the flow rate or properties of the water to be measured and predetermined calibration curves. The properties of the water, such as temperature and pressure, can be measured using associated measuring devices or stored in a memory in the measuring device.
• An auxiliary device is a device designed to perform a specific function directly related to the processing, transmission or display of measured values. The main auxiliary devices are: zeroing device, price indicating device, repeating display device, printing device, memory device, tariff controller, presetting device, self-service device, flow sensor motion detector (to detect the movement of the flow sensor before it is clearly visible on the display device), remote reading device (may be permanently included or temporarily attached). Depending on national legislation, auxiliary devices may be subject to statutory metrological control.

The performance tests described in this standard for all water meters are:

• Static pressure test
• Determining the effect of internal errors (indicators) and meter direction
• Water temperature test
• Water pressure test
• Flow reversal test
• Pressure loss test
• Flow disturbance tests
• Endurance tests

The performance tests described in this standard for electronic water meters and mechanical meters equipped with electronic devices are:

• Dry heat (non-condensing)
• Cold
• Moist heat, cyclic (condensing)
• Power voltage change
• Vibration (random)
• Mechanical shock
• Short-term power drops
• explosions
• Electrostatic discharge
• Electromagnetic susceptibility

Our organization, which has been trying to support businesses from every sector with its testing, measurement, analysis and evaluation studies carried out in a wide range for years, has a strong staff that closely follows the developments in the world in the field of science and technology and constantly improves itself. In this context, testing services in accordance with the "OIML R49 Water meters for cold drinking water and hot water" standard are also provided to businesses.