NBN EN ISO 9906:2012

ISO 9906:2012 specifies hydraulic performance tests for customers' acceptance of rotodynamic pumps (centrifugal, mixed flow and axial pumps). It is intended to be used for pump acceptance testing at pump test facilities, such as manufacturers' pump test facilities or laboratories. ISO 9906:2012 can be applied to pumps of any size and to any pumped liquids which behave as clean, cold water.
It specifies three levels of acceptance:

grades 1B, 1E and 1U with tighter tolerance;
grades 2B and 2U with broader tolerance;
grade 3B with even broader tolerance.

It applies either to a pump itself without any fittings or to a combination of a pump associated with all or part of its upstream and/or downstream fittings.