CISPR 11 is a widely used international standard for electromagnetic compatibility within Europe for electromagnetic emissions or disturbances from Industrial, Scientific and Medical, ISM, Equipment. CISPR 11 is maintained by CISPR: the International Special Committee on Radio Interference.
CISPR 11 applies to a very wide variety of equipment including everything from Wi-Fi systems, and microwaves through to arc welders, all of which fall into the industrial, scientific and medical category that can use the ISM license free bands like 2.4 GHz.
Compliance with CISPR 11 gives a partial presumption of conformity with the European EMC Directive, 2004/108/EC.
The CENELEC equivalent of CISPR 11, EN 55011 is an emission only standard covering radiated and conducted emissions. Most products will also require assessment to immunity standards, such as: EN 61326-1: Electrical equipment for measurement, control and laboratory use; or EN 61000-6-2: Generic Standards Immunity for industrial environments.