Procter Machine Guarding has produced a Whitepaper that explains the differences between BSI’s published document PD 5304:2014, Guidance on safe use of machinery, and the 2005 edition that is now superseded.
BSI has revised PD 5304 to reflect changes in legislation and machinery safety standards. Although much of the document remains substantially unchanged, there are numerous revisions in the new edition relating to risk assessments, guards, interlocking and control systems, and safety distances (reach distances). The Whitepaper provides a clause-by-clause analysis of the most important changes.
Unlike harmonised standards which support machine builders in conforming with the Essential Health and Safety Requirements (EHSRs) of the Machinery Directive when designing new machinery for the European market, BSI’s PD 5304 has the status of a Published Document, so compliance does not confer a presumption of conformity with the EHSRs. 
PD 5304:2014, which has evolved from CP 3004 (1964) through BS 5304 (1975) and PD 5304 (2000 and 2005), is published by BSI as a means of presenting practical measures and techniques that can be adopted by users of existing machinery for compliance with PUWER (the Provision and Use of Work Equipment Regulations 1998), as well as people modifying, refurbishing, upgrading or changing the use of machinery. 
The comprehensive guidance contained in the almost 200 pages of PD 5304 is intended to help protect machine users, including operatives and maintenance personnel.