IEC 61167:2018 specifies the performance requirements for metal halide lamps for general lighting purposes.This fourth edition cancels and replaces the third edition published in 2015. This edition constitutes a technical revision.This edition includes the following significant technical changes with respect to the previous edition.a) A set of new lamp data sheets has been introduced for lamp types designed for replacing high pressure sodium lamps.b) A set of new lamp data sheets has been introduced for 4 200 K versions of 3 000 K lamp types already in the standard.c) A set of new lamp data sheets has been introduced for new lamp types where high frequency ignition data is important.d) Annex G has been revised to incorporate high frequency ignition. As a consequence of this change, all data sheets in the standard have been revised to a new format.e) A new informative Annex K has been introduced, giving recommended methods of making lamp temperature measurements.