Critical assessment of the technical standards and regulations about the energy isolation and unexpected start-up in machineries

Several international standards and regulations specify the practices and procedures necessary to remove the supply of energy and to disable machinery or equipment, thereby preventing the release of hazardous energy while employees perform servicing and maintenance activities. Among them, LockOut-TagOut (LOTO) is a common safety procedure used in industry to ensure that dangerous machineries are properly shut off and not able to be started up again prior to the completion of service or maintenance. Also, the essential health and safety requirement 1.6.3 of the Machinery Directive 2006/42/EC reports provisions about the isolation of energy sources. Despite all these documents address requirements to prevent unexpected machine start-ups to allow safe human interventions in hazardous zones, serious accidents continue to occur due to lapses and errors during these activities. Owing to these considerations, this paper compares standards and regulations dealing with unexpected machine start-ups and LOTO applications, discussing their strengths, weaknesses, and opportunities for improvements and making a comparison among the most relevant provisions. The aim is to critically discuss the most crucial requirements that users must follow when employees could be exposed to hazardous energy while servicing and maintaining equipment and machineries.