In-service water tank inspection
Fire water tanks remain among the least inspected pieces of equipment on industrial sites. Yet their failure directly compromises safety and operational continuity. Our in-service inspection methodology makes it possible to characterize the condition of tank bottoms without draining and without interrupting the fire protection function.
A critical blind spot in your integrity strategies
On most industrial sites, the situation is recurring:
- Tanks operated for 30 to 70 years
- No intrusive inspection performed since commissioning
- No reliable data on the condition of the bottoms
Because they contain water, these pieces of equipment are often considered non-critical.
In reality, they directly determine your fire response capability.
An underestimated technical issue
Water tank bottoms present specific constraints that make conventional inspection ineffective:
Sediments
Accumulation of up to 1 meter observed on site
Corrosion
Corrosion mechanisms under invisible deposits
Access
Impossible to access during operation without draining
UT methods
Conventional ultrasonic methods cannot be applied
In practice, inspections are absent, partial or unusable from an integrity perspective — leaving the site without real visibility on the reliability of its fire protection capacity.
A methodology dedicated to in-service inspection
Our approach is based on three principles that radically distinguish in-service inspection from traditional methods:
- Access to critical areas under real operating conditions
- Large-scale acquisition of measured data, not estimation
- Direct usability for structural integrity assessment
A data-driven inspection
We carry out large-scale acquisition campaigns: 500,000+ UT thickness measurements per standard bottom, geolocated across the entire tank, with correlated high-resolution visual inspections.
This makes possible: complete mapping of the bottom condition, identification of degradation mechanisms, detection of corrosion under deposits otherwise invisible, and robust assessment of remaining service life.
You move from structural uncertainty to measured knowledge of your asset.
Field data observed on site
These data are not theoretical. They come from real interventions on operating industrial sites.
Removing the sediment barrier
The presence of deposits is the main obstacle to bottom inspection. Our intervention includes a preliminary clearing phase:
- Controlled displacement of sediments
- Targeted suction of critical areas
- Clearing of measurement surfaces
Direct effects. Access to historically inaccessible areas, more reliable ultrasonic measurements, clearing of water wells, and improvement of effective fire protection capacity. Inspection becomes possible — and operational performance is partly restored at the same time.
Inspection workflow
Deployment
System setup in an in-service tank.
Acquisition
Immersed inspection and continuous UT acquisition.
Processing
Structuring and correlation of collected data.
Report
Integrity analysis and generation of the final deliverable.
A complete chain, from measurement to decision.
Real case — Industrial fire water tank
45-year-old tank — no previous inspection
Context
Fire water tank in service for 45 years, with no usable previous inspection.
Issue
Heavy sediment accumulation (~80 cm), conventional inspection impossible, total uncertainty about the bottom condition.
Intervention
In-service inspection without draining, sediment displacement, acquisition of 520,000 UT measurements.
Results
Complete bottom mapping, identification of localized corrosion areas, validation of continued operation with targeted monitoring.
Decision made on measured data, without operational interruption.
Example deliverable
What you concretely receive:
- High-resolution thickness mapping
- Precise localization of critical areas
- Analysis of degradation mechanisms
- Remaining service life estimation
- Integrity recommendations
Data directly usable by your inspection and integrity teams.
What you secure, what you avoid
- Complete tank draining
- Construction of temporary storage
- Operational shutdown
- Human exposure in confined spaces
- Real availability of your fire protection capacity
- Control of a structural risk previously poorly characterized
- Your operating and maintenance decisions
- A monitored asset, no longer a blind asset
Compliance and integration
The inspections performed are compatible with recognized industrial standards:
API 653
Appendix G — tank bottom inspection
Inspection services
Results can be integrated into your existing programs
Industrial references
Demanding industrial environments, with strong operational constraints — where every intervention must be technically flawless and operationally transparent.
Frequently asked technical questions
Can measurements be taken through sediments?
No. Sediments are moved or suctioned to access the metal surface before UT measurement.
What is the measurement accuracy?
Ultrasonic measurements are performed after clearing the surfaces, ensuring accuracy in line with industrial standards.
What bottom coverage is achieved?
Coverage is comprehensive, with measurement density enabling complete bottom mapping.
Does the inspection impact operations?
No. The inspection is performed without interrupting the fire protection function.
From an uncharacterized asset to a monitored asset — without draining, without shutdown, without human exposure.
An inspection to assess on your site?
Let’s discuss your operational constraints, assess feasibility, and access detailed real-world cases.