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IT’S IN THE EYE OF THE INSPECTOR
Overview of visual inspection methods in four countries and lessons learned
ISFD4, Toronto6 May 2008
Jaap Flikweert
Background
Based on study for NL Research programme
‘Inspection of flood defences’ (VIW)(STOWA & Rijkswaterstaat)
Co-author: Gerard Moser
Sources: Personal involvement in NL & UK Literature study & interviews for FR & DE
Lay out of presentation
Why inspect?
Role of visual inspection
Local context
Methods
Conclusions on effective use of visual inspection
Asset management
Flood risk management Risk-based asset management
Balancing risk, cost and performance
Why inspect?
To measure deterioration
To steer intervention
To improve performance
To reduce risk
graphic: Advantica Ltd.
Asset Inspection
Parallel with human health
Asset inspection
Visual, intru
sive,
rem
oteJudgem
ent, guidance,
calculation
Traditio
n,
perform
ance based
Role of visual inspection
Drivers for developments: Defences protect more More complicated structures Professionalisation Technological development
Why still visual inspection? Use of local knowledge Cost Human factor Emergency staff available
Local context
Local context
Local contextNetherlands:
Flood risk dominant, defences vital, long history
Strict legal framework, flexible application
Focus on meeting standards
Assets managed by professionals
Germany (Federal waterways):
Flood risk significant, defences very important
Strict procedures
Focus on preventing damage
Assets managed by professionals
England:
Flood risk significant, increasing profile, defences locally important
Permissive powers, strict procedures
Focus on cost-effectiveness and risk
Assets managed by professionals
France:
Flood risk significant, defences locally important
Guidance
Focus on introducing defence management
Varying but improving quality of asset management
Scale of flood risk
Rules
Focus
Organi-sation
Methods
Long tradition of visual inspection
Recent years: less embedded in asset management
Methods
Why:Identify & repair small defectsLimited link with asset management under development
How:
No detailed rules, left to local judgementGuidance under development
Who:Operational staff
Recent development: training available
Methods
Focus on Federal waterways
Framework: DIN flood embankments Specific internal directive for inspection
Clear hierarchical structure: Inspector: inspect and inform Field officer: check, respond and inform Asset manager: check and respond
Indicators are asset specific & failure mode related
Methods
Why:Identify defects, prevent breach
How:
Detailed roles
Asset specific indicators
Who:
Specialist full-time inspectors
Backed by experts
Methods
Since mid 90s: Condition Assessment Manual:
Condition grade (1-5) Nationally consistent Indicator for performance
Developments: Improve link with failure
modes
Methods
Why:Keep track of deterioration
Measure maintenance quality
How:
Detailed prescribed roles
Systematic technical guidance
Who:
Operational staff with specific training
Methods
Longer tradition of dam management, but flood defence management just starting
Opportunity for integrated approach: Performance based Inspection embedded in asset management
Guide pratique (Cémagref): Procedures Set of forms
Methods
Why:Identify defences and determine starting point
Move toward keeping track of deterioration
How:
General guidance on approach
Can be applied to set local indicators
Who:
Variable, depends on asset management organisation
Conclusions
Each country / culture its own method
Visual inspection can have different purposes
General move toward performance based inspection
Specific role for visual inspection within overall inspection, given technological developments: Taking the pulse Trigger for expert inspection Input for modelling
