This standard BS EN 50216-12:2011 Power transformer and reactor fittings is classified in these ICS categories:
29.180 Transformers. Reactors
EN 50216-12 deals with fans for oil-to-air coolers used for transformers as well as fans used for blowing out radiators. Only fans operating axially are dealt with in this standard specification.
This standard specification defines the dimensions and requirements for ensuring fan interchangeability and uniform fan assembly.