1.3. Maximum flowrate (Qmax)
The maximum flowrate, Qmax, is the highest flowrate at which the meter must be able to function over limited periods without damage, and without exceeding the maximum permissible errors and the maximum permissible value for loss of pressure.
1.4. Nominal flowrate (Qn)
The nominal flowrate Qn, is equal to half the maximum flowrate, Qmax. It is expressed in cubic metres per hour and is used to designate the meter.
At the nominal flowrate, Qn, the meter must be able to function in normal use, i.e., in continuous and intermittent operating conditions, without the maximum permissible errors being exceeded.
1.5. Minimum flowrate (Qmin)
The minimum flowrate, Qmin, is the flowrate above which the maximum permissible errors must not be exceeded, and is fixed as a function of Qn.
1.6. Flowrate range
The flowrate range of the meter is bounded by the maximum and minimum flowrates, Qmax and Qmin. It is divided into two regions, termed upper and lower, with different maximum permissible errors.
1.7. Transitional flowrate (Qt)
The transitional flowrate, Qt, is the flowrate which divides the upper and lower regions of the flowrate range and the flowrate at which the maximum permissible errors become discontinuous.
