25 Novembre 2010
 Safe Maintenance through design
From machine engineering for safe maintenance to
maintenance engineering for safe machine
Workshop Maintenance – Bruxelles – Novembre 2010
Jean-Christophe.Blaise@inrs.fr
Maintenance & Design
 Contents
 From machine engineering…
> Regular and normative framework: main requirements and
recommendations
> Main issues (accidents analysis)
> Is « good » design enough?
 … to maintenance engineering
> More than a « simple intervention »: a complete process
 Conclusion
> Designer/ User Dialogue
> Training
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Machine engineering
 1.1.2. Principles of safety integration: Machinery must be designed and
constructed so that it is fitted for its function, and can be operated,
adjusted and maintained without putting persons at risk when these
operations are carried out
 1.6. MAINTENANCE –
> Adjustment and maintenance points must be located outside danger zones.
It must be possible to carry out adjustment, maintenance, repair, cleaning
and servicing operations while machinery is at a standstill
> If it cannot be satisfied for technical reasons, measures must be taken to
ensure that these operations can be carried out safely (see section 1.2.5)
> Machinery must be fitted with means to isolate it from all energy sources.
> Machinery must be so designed, constructed and equipped that the need
for operator intervention is limited.
> 1.6.5. Cleaning of internal parts
 1.7. INFORMATION - 1.7.4. Instructions
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Machine engineering
 1.7.4.2. Contents of the instructions - Each instruction manual must
contain:
> (e) the drawings, diagrams, descriptions and explanations necessary for the
use, maintenance and repair of the machinery and for checking its correct
functioning;
> (q) the operating method to be followed in the event of accident or
breakdown
> (r) the description of the adjustment and maintenance operations that
should be carried out by the user and the preventive maintenance
measures that should be observed;
> (s) instructions designed to enable adjustment and maintenance to be
carried out safely, including the protective measures that should be taken
during these operations;
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Machine engineering
 No specific safety of machinery standard relative to maintenance
(maintainability)
 EN ISO 14122: Permanent means of access to machinery
 EN 547-1: Human body measurements
 French standard: NF X 60-301 : Guide for taking into account criteria
for maintenability of durables for industrial and professionnal use
 EN 1037 – safety of machinery Prevention of unexpected start-up
 Reference standard on safety on machinery: EN ISO 12100
> Same recommendations than directive requirements
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Machine engineering
 3.3 maintainability (of a machine)
> ability of a machine to be maintained in a state which enables it to fulfill its
function under conditions of intended use, or restored into such a state, the
necessary actions (maintenance) being carried out according to specified
practices and using specified means
 4.11.9: Control mode for setting, teaching, process changeover, fault-
finding, cleaning or maintenance
 4.11.12 Provision of diagnostic systems to aid fault-finding
> Diagnostic systems to aid fault finding should be included in the control
system so that there is no need to disable any protective measure. NOTE
Such systems not only improve availability and maintainability of machinery;
they also reduce the exposure of maintenance staff to hazards.
 4.15 Limiting exposure to hazards through location of the setting and
maintenance points outside of danger zones
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Machine engineering
 Analysis of 93 accidents of « repair » - Main « direct » risk-factors
> Intervention when machine powered on: 76 % of accidents
•
•
•
machine fully operated : 40 %
machine automatically started up : 25 %
machine intentionally switched on : 25 %
> Statutory safety devices missing: 41 % of accidents
> Release of energy: 14 %
> Deactivation of safety devices: 11%
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EPICEA study
 OA Distribution/ EPICEA working phase
Working Phase
Reparing
30
Cleaning
30
Diagnosis
25
Testing
22
Jamming (Malfunction)
20
%
Lubrication
14
15
Inspection
9
10
8
Re-commissionning
5
5
5
3
3
Setting
2
Undetermined
0
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EPICEA study
 OA Distribution/ risks factors
Isolation/lock-out missing
Risks factors
Maintenability
Inadequate knowledge
35
Accessibility
31
Machine fully operates
30
Isolation/lock-out error
25
21
safety deactivation
Coactivity
20
%
14
14
Devices missing
12
15
12
9
10
9
Undetermined
8
7
Intentionnaly start up
7
4
2
5
Automatically start up
1
Isolated Work
0
Equipment availability
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Machine engineering
 Conclusion of OA analysis
 Intervention under energy
 Maintainability has to be improved
 Safety measures must be adapted to the intervention
 Integration at design stage to be prioritized
 It’s essential to identify intervention needs
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 Maintenance : high-risk activity?
Ensure
safety on
energies
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 Maintenance : high-risk activity?
Organize
the activity
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 Maintenance : high-risk activity?
Train
operators
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 Maintenance : In reality !
Analyze,
?
Estimate,
Prevent
Risks
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Maintenance Engineering
 Not only consider the intervention on machinery
 Before intervening
 After intervening
 Each maintenance stage contributes to safe operation performance on
work equipment
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Maintenance generic Chart
Process
25/10/2007
Sub-process
External entity
information
Trigger
Policy
Management
Assess need
Machine
Issue intervention request
Produce
Intervention request approved
Policy
Diagnose
Schedule
Observe symptoms and identify causes
Diagnostic report
Machine
Prepare/schedule
Identify intervention priorities
Equipment
Control
stocks
Prepare resources and
schedule actions
Actions to be performed
Equipment
Methods
Intervene on equipment
Isolate Equipment
Conduct tests
De-isolate Equipment
Perform work
Return to service
Personnel
Exploit
results
Actions performed
Human
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resources
REX
database
Gather Information
Draft report
Workshop
Maintenance
- Bruxelles
Store
information
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Conclusion
 Thinking aimed at designers
 A machine must be designed such that it can be safely maintained without
necessarily resorting to a maintenance operation under isolated conditions
 To optimize conditions under which a maintenance operation is performed
>
eliminate or limit it whenever possible through appropriate equipment design choices
>
integrate maintainability
>
analyze operating modes in relation to this maintenance operation based on zones,
durations and the work to be performed
>
analyze and assess risks for each operating mode,
>
derive safety measures appropriate to this operating mode,
>
knowing that each technical solution has its limits, derive compensatory measures, if
necessary,
 it is important to consider the consistency of adopted safety measures,
depending on the type of operation: a solution retained for a maintenance
operation can be incompatible with another operation.
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Conclusion
 Concerning designers: difficulties to forsee some « specific » modes:
process observation
 Concerning users: difficulties to anticipate some intervention:
breakdown, spare parts…
 Information have to be shared : dialogue - specification formalisation
 Operators training
> Before putting machine into service
> During the life of the machine (changes)
> drawings and diagrams available and up to date !.
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Safe maintenance is making progress
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