Safe maintenance - basic rules and strategies

Transcription

1 The cycle of safe maintenance Safe maintenance - basic rules and strategies health and safety at work safety at maintenance work Reinhard Koerbler Austrian Workers Compensation Board, Vienna Example main switch locked out The cycle of safe maintenance health and safety at work safety by maintenance work safety at maintenance work Preserve or improve operating capability of machine or system Example revision sticker for cars Fatal accidents at maintenance work other 24 % 34 % transport 20 % production 22 % maintenance other objects falling down or falling over poisonings, burns injuries by machines falls from height 1

2 Servicing Delay of wear out cleaning lubrication adjusting Inspection Repair Assessment and rating of the present condition Defining the causes of wear out and finding necessary consequences for further operation measuring testing diagnosis restoration of proper function without any improvement exchange repair Improvement raising the safety level, without changing the original function raise wear resistance substitution of machine parts? Specifications in the operation manual according to EU machine directive assembly installation, starting up preparation for production proper handling use for production maintenance and repair de-assembly 2

3 technical personnel technical diagnosis procedure recognise changes at machine parts avoid unplanned break down maintenance as part of construction planning access to all parts of the system necessary easy exchange must be possible use of standardised system parts avoid dangerous parts or spots expected time of break down defined by knowledge and experience maintenance time in planned intervals, not depending on the real state of the machine part break down, damage or fire brigade strategy no maintenance works without break down maintenance works under time pressure possible effect on realization, safety and quality defining the state of the object by periodical inspection recognition of relevant changes implementation of measures This strategy is not always applicable, the state of wear and tear can not be defined exactly (e.g. in electrical systems). 3

4 heavy influence on productivity caused by drop out sand disturbances frequent tests ensure permanent quality definition of technical guidelines for maintenance and detailed instructions for work personnel sufficient number of qualified employees improved training qualification of experts better recognition of problem areas short time frame for maintenance high level of work safety Support by external companies possible Specific danger for personnel General strategies poor training unplanned according to a maintenance plan improvisation unknown conditions (space, heat) time pressure bypass at safety equipment after failure before failure carrying out the works poor information work at about dangerous operating substances machines poor preparation, ( and technical) performed after failure on schedule, without failure Rank 1: Lock Out - Tag Out Main switch locked out rank 1 electrical power supply locked out hydraulic, pneumatic, mechanical energy off no chemical emissions no additional hazards, heat, confined space etc. plus tag out against unplanned activation 4

5 Lockout system for maintenance workers Lockout station for maintenance workers right wrong personal lock for each maintenance worker personal key for each lock (plus one in spare) master key for head of maintenace Water supply locked out rank 1 Gas supply locked out rank 1 Flexible rope for multiple lock out rank 1 Lock out for power plug rank 1 5

6 Maintenance work tagged out rank 1 Restart procedure after maintenance works avctivation of all protection devices removing of all tag out signs removing of all lock out devices clearance by every involved worker definition of restart responsibility documentation of restart activity Rank 2: work on machines in operation Protection devices rank 2 only with protection devices separating: housing, grille or guard locally binding: dual hand operation, contact mat approach operated: light bar holding or fixing devices emergency off switch only - not permitted separating fixed movable not separating operated by contact operated without contact Separating protection device rank 2 Protection by light bar rank 2 6

7 Protection by contact mat rank 2 Protection by laser scanner rank 2 Rank 3: without standard protection devices Additional approval switch rank 3 only with additional special protection devices touching dangerous parts must be prevented reaching dangerous spots nearby prevented fast stop must be possible working without time pressure function 3-step3 approval switch Rank 4: without sufficient safety devices Detailed measures according to rank 4 + personnel measures must be taken to compensate insufficient technical devices evaluation of required measures for exceptional cases and detailed documentation in specific advices for maintenance work special qualification for maintenance workers recognition and prevention of risks special expert training on risks connected with work under defined special conditions additional qualified expert as supervisor needed 7