Corrosion challenges in storage tank and pipeline projects
Tank and pipeline corrosion is a “multi-driver” problem: chemistry, water, temperature cycling, and mechanical damage often act together.
Internal medium corrosion (oil / chemicals / water)
Internal surfaces see chemical exposure, water bottoms, microbial activity in some services, and temperature changes that can stress linings. Internal coating design is therefore dominated by chemical resistance, permeability, and adhesion under immersion/condensing conditions—very different from external atmospheric coating priorities.
External environment corrosion (soil / marine / industrial)
External tank shells and above-ground pipelines face wet/dry cycling, UV, coastal salts, and industrial pollutants. Buried pipelines add soil moisture, oxygen gradients, and mechanical stresses from backfill and handling.
Temperature & pressure variation (especially on pipelines)
Thermal cycling drives movement at supports and expansion joints; coatings fail first where movement and water traps combine (supports, clamps, guides, and low points).
Internal vs external coating requirements (do not mix them up)
A frequent RFQ mistake is treating “tank coating” as one scope line. Internal and external systems are fundamentally different.
Internal lining priorities (what the lining must do)
- Resist the stored medium (chemicals, hydrocarbons, produced water, additives).
- Minimize permeation and underfilm attack during long wet-time.
- Maintain adhesion under immersion or intermittent wetting.
- Allow inspectability and repair (spot repair rules).
External protection priorities (what outside coatings must do)
- Resist atmospheric corrosion and UV/weathering.
- Handle abrasion, impact, and maintenance damage.
- Stay repairable at welds, edges, and nozzle details.
- Maintain performance across temperature cycling and condensation.
Decision rule: If your internal media is uncertain, don’t “guess” a lining—ask the supplier for a media list review and lining recommendation with TDS/SDS and limitations stated.
Typical coating systems for storage tanks (what works where)
This section is about system direction—your final build-up should be confirmed by TDS/spec and the actual service conditions.
Epoxy lining systems (internal)
Best for: many internal tank services where chemical resistance and long wet-time adhesion are required.
What to specify: surface prep standard, lining DFT as ranges by coat, cure/return-to-service requirements, and holiday testing requirements for internal lining acceptance where applicable.
What buyers forget: internal lining failures are often caused by incomplete cure (rush to service), poor surface cleanliness, and sharp edges around welds/nozzles.
External high-build epoxy systems (shell, roof structure, externals)
Best for: barrier protection in industrial/coastal atmospheres when paired with an appropriate weathering topcoat strategy.
What to specify: zones (shell vs roof vs underside areas), detail stripe coats, DFT ranges, and repair procedure for erection damage.
Pipeline coating system design considerations (buried vs above-ground)
Buried pipelines (soil exposure + mechanical risk)
ISO 12944 includes Im3 for soil exposure (buried structures such as pipelines), which is a helpful reminder that “buried” is not the same as “outdoor atmospheric.”
Buried pipeline systems must also address:
- Mechanical protection during handling/backfilling.
- Compatibility with cathodic protection (CP) design and inspection practices.
What buyers forget: a coating that looks “tough” can still create CP shielding concerns if defects are hard to detect and repair, so QC and repairability matter as much as thickness.
Above-ground pipelines (UV + wet/dry cycling)
Above-ground lines behave like steel structures: UV/weathering, condensation at supports, and splash zones drive failures. Coating selection should focus on barrier build plus a durable finish, and it must define how clamps/support points will be treated.
Common coating failures in tank & pipeline projects (and why they happen)
Lining blistering (internal)
Often linked to contamination, moisture/osmotic effects, incomplete cure, or wrong lining choice for the medium. Prevention comes from strict surface prep acceptance, cure control, and lining selection based on service media.
External peeling (especially at details)
Typically caused by weak surface prep at edges/welds, poor stripe coat discipline, or exceeded recoat windows. This is preventable with hold points and detail-focused DFT checks.
Premature corrosion (buried and above-ground)
Usually driven by damaged coating during construction, missed holidays, or insufficient mechanical protection. A disciplined QC plan (including discontinuity/holiday detection where required) reduces “hidden defects” that become leaks later.
Step-by-step: how to specify the right system (EPC-ready)
Step 1: Split the scope into zones and write separate requirements
At minimum:
- Tank internal (lining)
- Tank external (atmospheric)
- Pipeline above-ground
- Pipeline buried (soil/CP interface)
Step 2: Define service inputs that change the recommendation
- Stored medium list (chemicals, water content, additives), temperature range, cleaning method.
- External environment: coastal distance, industrial fallout, UV exposure, insulation/condensation risk.
- Pipeline installation: trench/backfill type, handling method, CP design basis.
Step 3: Turn QC into deliverables (so pricing becomes comparable)
Require:
- Surface prep hold point and acceptance criteria.
- DFT ranges by layer (lining vs external).
- Repair procedure and re-inspection steps.
- Holiday testing requirement where applicable and reporting format.
Step 4: Compare quotes using the same assumptions
Ask suppliers to separate: material, application labor, access/mechanical protection, QC/inspection documentation.
Recommended coating solutions for tank & pipeline projects
If you want a system-oriented starting point for scope alignment (tanks + pipelines, internal + external), use Storage Tank & Pipeline Industrial Coatings to match your project type to a coating solution direction before finalizing the RFQ.
For teams also managing steel structures in the same facility (pipe racks, platforms, supports), it helps to keep coating system language consistent across packages (primer/barrier/topcoat logic): Steel Structure Coating System Guide.
Quality / inspection checklist (DFT, recoat, surface prep, holidays)
- Surface preparation: defined standard + acceptance criteria + documented hold point before lining/coating.
- DFT: verify by layer as ranges; add extra readings at welds, nozzles, edges, and supports.
- Recoat control: recoat windows and surface condition checks recorded to prevent intercoat delamination.
- Holiday testing: define method, timing, acceptance criteria, and repair/retest rules for linings and buried pipeline coatings where required.
- Handover dossier: batch traceability, QC reports, repair logs, and as-built coating map.
RFQ checklist
- Project country/region and environment (coastal/industrial/inland), plus asset zoning list
- Tank service: medium list, temperature range, cleaning method, return-to-service requirement
- Pipeline service: above-ground vs buried length, soil type, backfill method, CP requirement
- Substrate condition: new build vs maintenance; existing coating details (if any)
- Surface preparation method available and access constraints
- Documentation required: TDS/SDS, system recommendation, QC checklist, holiday test plan, repair procedure
Technical Note
Final system selection, DFT ranges, surface preparation level, and inspection acceptance criteria must be confirmed by the applicable TDS, project specification, and the exposure category logic used (e.g., ISO 12944 atmospheric vs immersion/soil categories).
CTA
Contact us for coating system recommendations for your storage tank or pipeline project—share your media list, temperature range, soil/coastal exposure, and CP requirements, and we will respond with a system recommendation plus TDS/SDS and QC deliverables via Contact.
