Requirements for use for trade
No person may use for trade a water meter for the supply of potable water to domestic premises in the temperature range from 0.1°C to and including 30°C (“a cold water meter”) unless—
(a) it is compliant with the essential requirements applicable to cold water meters (other than the provisions relating to maximum permissible errors);
(b) it operates within the maximum permissible errors set out in paragraph 3; and
(c) the requirements of paragraph 4 are complied with.
Maximum permissible error
(1) Where a cold-water meter is used for trade within a flowrate range set out in column 1 of the following Table, it must operate within the maximum permissible error specified for that flowrate range set out in column 2 of that Table.
(2) For the purposes of that Table—
(a) “Q 1 ” is the lowest flowrate at which the cold-water meter provides indications that satisfy the requirements concerning the maximum permissible errors;
(b) “Q 2 ” is the flowrate value occurring between the permanent and minimum flowrates, at which the flowrate range is divided into two zones, the upper zone and the lower zone, each zone having a characteristic maximum permissible error;
(c) “Q 3 ” is the permanent flowrate; and
(d) “Q 4 ” is the highest flowrate at which the cold-water meter operates in a satisfactory manner.
Maximum permissible error
(1) Where a cold water meter is marked with—
(a) a temperature range, it must not be used for trade in temperatures outside that range; or
(b) a flowrate range, it must not be used at a flowrate outside that range.
(2) Where a cold-water meter bears a mark which signifies the manner and purposes of use, it must not be used for trade in a manner or for a purpose which does not accord with that marking.
(3) A cold water meter must not be used for trade in circumstances—
(a) in which it may be prevented from operating consistently or accurately; or
(b) which are likely prematurely to degrade its metrological characteristics.
(4) A cold-water meter must not be used for trade unless, when adjusted, the calibration of the instrument is set as close to zero as practicable.
