**4. Discussion**

**Figure 12.** Error in water meter measuring at Qn flow during water flow shorter than the time for which the meter

The minimum time at which measuring errors undoubtedly are within the permitted limit is

Qt 5 Qn 2

Qt 9 Qn 2.5

Qt 60 Qn 6

**Reading Dis- Minimum time accuracy charge (minutes)** 2.5 centilitres Qmin 3

1 decilitre Qmin 5

1 litre Qmin 36

**Table 3.** Minimum calibrated flow duration time in the function of reading accuracy.

was calibrated (4 min.) in the function of water meter reading accuracy.

144 Water Supply System Analysis - Selected Topics

defined for the calibrated flows of the water meter as follows:

Measurement results confirm and specify the conclusions of tests made in Udine in relation to the contribution of UFR to water meter operation: a) that the most significant contribution is at flow, when water meter propeller is steady (specifically for Qa), and b) that this contri‐ bution is decreasing from flow Qa towards flow Qmin.

The same conclusion is valid for test results on the UFR contribution at parts of the water supply network. Providing similar water consumption during testings on the test rig with‐ out UFR and with UFR enabled specifying the results.

In the case, when consumption time was shorter than the time the meter was calibrated for, the range of the meter measuring error exceeded the range of permitted errors.


**Table 4.** Error ranges of water meter measuring for calibrated discharges in the function of water meter reading accuracy (class B, rated diameter of 20 mm and discharge of Qn=1.5 m3/h), for a duration of 0.5 minutes flow.

It means that during consumption shorter than the time the water meter was calibrated for, measuring by the meter is unreliable in 95% of the consumption shorter than 1 minute. Dur‐ ing a discharge of 0.5 minutes, the error may be even 277.4%.

In order to improve water consumption measuring in households, it is necessary to provide conditions for measuring consumption at flow lower than Qmin and duration shorter than the time the meter has been calibrated for. Such conditions may be created in supply pipe‐ lines with water storage tanks in households. Only such systems are appropriate in which all the water needed in a household flows through this storage tank [19].

The UFR should be installed on the outlet pipe from the tank to the household. Signalising the start of the UFR's operation may initiate works on eliminating water losses due to leak‐ age on the tap, bathroom battery and the flushing cistern. This way, the use of UFR would serve to protect the interest of the households.

Recently, it has been a frequent practice, that a water meter is installed on the inlet pipe of the storage tank near the building [10, 20-25]. Such water meters provide the opportunity to ensure a minimum period of time, at which water meter measurement error surely stays within the permitted error limit.

**•** to provide that measuring errors of calibrated flows be lower than the permitted ones, the minimum time for measuring these flows is 5 minutes (for water meter reading accuracy of 2.5 centilitres), 9 minutes (for water meter reading accuracy of 1 decilitre), or 60 mi‐

Error in Water Meter Measuring Due to Shorter Flow and Consumption Shorter Than the Time...

http://dx.doi.org/10.5772/51046

147

Since it concerns 95% of water consumption measurement, such testings are necessary for all

[1] Hovanj, L. (2010). Minimum Time Period Between Reading off Flow Meters (Mini‐ malno vreme između dva očitavanja vodomera). *Zbornik radova Građevinskog fakulteta*

[2] Hovány, L. (2011). UFR Suppored Water Meter (Impulzust keltő szeleppel kiegészí‐

[3] Hovány, L. (2011). The Contribution of UFR in Measuring Water Volume by Water Meter in a Single Household. *In: EXPRES 2011. 3rd IEEE International Symposium on Exploitation of Renewable Energy Sources*, Procedings, March 11-12, Subotica, Serbia,

[4] Davidesko, A. (2007). UFR- an innovative solution for water meter under registra‐ tion. *In: Proceeding of the Water Loss 2007 Conference*, September 23-26. Bucharest, Ro‐

[5] Fantozzi, M. Reduction of customer meter under-registration by optimal economic replacement based on meter accuracy testing programme and Unmeasured Flow Re‐ ducers. http://www.studiomarcofantozzi.it/Aprile09/Fantozzi%20AppLosses

[6] Yaniv, S. (2009). Reduction of Apparent Losses Using the UFR (Unmeasured-Flow Reducer). Case Studies. *In: Efficient 2009 Conference*, October 25-29, Sydney, Australia, 1-8, http://www.arivalves.com/PDF/UFR/Reductions%20of%20Apparent%20Loss‐

mania, 704-709, http://waterloss2007.com/pdf\_vortraege/Mittwoch/B9-3.pdf.

nutes (for water meter reading accuracy of 1 litre).

Address all correspondence to: hovanyl@gf.uns.ac.rs

*u Subotici*, 19(1), 105-113.

Faculty of Civil Engineering Subotica, Republic of Serbia

tett vízmérő). *Hidrológiai Közlöny*, 91(2), 23-26.

%20WL09%20Paper%20V11%20250209.pdf.

**Author details**

Dr. Lajos Hovany\*

**References**

75-78.

es.pdf.

types of water meters used in the supply networks of this country.

By solving water quality problems in these storage tanks, the above mentioned conditions will, first and foremost, be provided in settlements already having such water supply net‐ works in place, e.g. in settlements without continuous potable water supply (e.g. in Mozam‐ bique, Yemen, Jordanian, Lebanon, Palestine, on the Mediterranean in Europe) and in water supply networks designed in the XIXth century (e.g. the UK) [21, 23, 26-30].
