Bottom Loading Tanker Trailers – ADR Approval (Requirements & Checklist)

Comprehensive guide to ADR approval for bottom loading tanker trailers: equipment list, overfill protection, vapour recovery, earthing, tests, and documentation checklist.

ADR Compliance Fuel & Chemical Transport
📅 Published on 2025-11-06 | ✍️ Semi Trailer News Editorial Desk

Image: Bottom loading manifold, overfill sensors and vapour recovery systems

🔹 What Is Bottom Loading?

Bottom loading fills tanker compartments from the ground using API couplers. It increases operator safety, reduces static electricity risk, and speeds up depot turnaround. ADR compliance requires **overfill protection**, **vapour recovery**, and proper **earthing systems**.

🔹 ADR Basics for Tanker Trailers

• Scope: ADR governs dangerous goods transport in Europe.
• Key areas: tank construction, fittings, safety systems, markings, testing and documentation.
• Main references: tank rules (6.8), vehicle safety (9.2), placarding, electrical safety, and test requirements.

✅ Equipment Checklist — Bottom Loading & ADR

• API bottom loading adapters: 4" dry-break, color-coded, dust caps.
• Overfill prevention: 2-wire or 5-wire probes + depot interface socket.
• Vapour recovery system: 4" line with check valve and flame arrestor (if required).
• Earthing system: certified earth point + continuity test label.
• Emergency valves: internal ESVs with pneumatic/manual actuation.
• Relief valves: PRV per compartment with certified set pressure.
• Safety equipment: extinguishers, chocks, spill kit, ADR signage.

🧰 Electrical & EX-Proof Requirements

• All hazardous-area components must be **ATEX/EX-certified**.
• 7/15-pin connectors sealed and protected against water ingress.
• Bonding straps on hose reels, pumps and valves.
• Grounding continuity between tank–frame–manifold must be documented.

🧪 Manufacturing Tests Required Before ADR Approval

• Hydrostatic or pneumatic pressure test.
• Leak test on all manlids, valves, and PRVs.
• Volume calibration (dip chart or digital gauge).
• Electrical continuity test with recorded results.
• EBS/ABS checks (roadworthiness requirement).

📄 Documentation Pack for Approval

• General arrangement drawings & material certificates.
• WPS/WPQR, welder qualifications, NDT reports.
• Pressure/leak test certificates.
• ATEX certificates, VR & overfill system declarations.
• Marking plate data + placards.
• Maintenance & inspection schedule.

🧾 Quick Operational Guide — Bottom Loading

1. Connect earthing clip first.
2. Select compartment & verify capacity.
3. Connect API coupler & overfill socket.
4. Open ESVs as per depot sequence.
5. Monitor overfill system during filling.
6. Disconnect & isolate — remove earthing last.

🗓 Periodic Inspections

Interval	Scope	Notes
Daily	Hoses, API seals, earthing point	Replace worn items immediately
Quarterly	Overfill probe test, VR check valves	Record results
Yearly	Leak test, continuity, extinguisher service	Update certificates
3–6 years	Internal/pressure test	Per ADR & national rules

⚠ Common Non-Conformities

• Incorrect PRV set pressure → recalibrate.
• Mismatched overfill wiring → align with gantry standard.
• Missing placards → apply UN numbers & hazard diamonds.
• Faulty earthing → restore grounding continuity.

Conclusion:
ADR approval for bottom loading tanker trailers becomes straightforward when equipment, testing, and documentation follow a clear sequence. A well-prepared tanker ensures safety, compliance, and long-term operational reliability.

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