Tank-wagon with expired inspection, damaged lining and a seized valve
At a private siding, a tank-wagon is being prepared for top-loading with UN 1789 HYDROCHLORIC ACID, Class 8, PG II. The tank plate shows “next periodic inspection due 2024”; the current date is 2026. The tank is mild steel with a rubber lining. The lining inspection report from 2023 records “lining damaged at manhole”. The loading supervisor plans to load 28,000 L. The wagon’s bottom outlet valve is seized open and cannot be closed. The loading arm is not bonded to the wagon, and the site procedure requires bonding. The supervisor says hydrochloric acid “does not burn, so bonding is unnecessary”. The train is waiting; the shipper wants the wagon loaded within the hour. The tank-wagon has no current test certificate in the cab.
1. Which defects make the tank-wagon unfit for this load? Explain the risk, not just the rule.
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The tank-wagon is unfit for several independent reasons. The periodic inspection was due in 2024 and it is now 2026, so the tank is outside its inspection regime and there is no current test certificate. The rubber lining is recorded as damaged at the manhole; hydrochloric acid will attack mild steel where the lining is breached, causing loss of containment and possibly hydrogen generation. The bottom outlet valve is seized open, so the tank cannot be isolated if the loading line fails or the tank is overfilled. The absence of a current certificate means the operator cannot show that the tank is fit for purpose.
The bonding point is secondary but still relevant: the site procedure requires bonding, and acid attack on steel can generate hydrogen. Even if the supervisor believes acid “does not burn”, the procedure exists to control static and reaction hazards. The primary decision is that the tank-wagon must not be loaded.
2. What loading controls and checks must be completed before any transfer?
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Before any transfer, the tank-wagon must be replaced or brought back into a fit state: valid periodic inspection and test certificate, lining repaired and verified, and the bottom outlet valve repaired so it can be closed and locked. The tank material and lining must be suitable for hydrochloric acid. The loading team must verify the tank is empty, clean and not overfilled, and that the correct filling limit for the tank is known.
The site must complete its pre-loading checklist: trained personnel, correct PPE, spill kit, emergency shower and eye wash, communication with the train crew, and a written loading procedure. Bonding must be connected where the site procedure requires it. The loading arm and hose must be inspected, and the tank must be earthed or bonded as required. No transfer should start until the supervisor and a competent person have signed off the tank and the loading setup.
3. What should be recorded and reported, and who should be informed?
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Record the rejection in the loading log, the tank-wagon number, the defects found, the date and time, and the names of the persons informed. The DGSA should record it as a compliance finding and check whether the same tank-wagon or operator has been used for other loads. Management should be informed because the defect involves an expired inspection and a damaged lining, not just a minor loading delay.
The consignor and tank-wagon owner must be told that the wagon is rejected and why. Maintenance should receive the valve and lining defects. If the shipper pressures the terminal to load anyway, escalate to the terminal manager and, if necessary, the competent authority. The corrective action should be closed only when valid certification, a repaired lining and a functioning valve have been verified.