Aerosol consignment, heat and a defective extinguisher
Before departure on a hot July afternoon, a driver checks a vehicle loaded with 40 pallets of UN 1950 aerosols (division 2.1, 1 200 cartons) plus a small consignment of UN 1993 flammable liquid, n.o.s. (class 3, PG III, 4 × 25 litres). The vehicle has one 6 kg ABC extinguisher whose pressure gauge reads in the red, and one 2 kg dry powder extinguisher that is in the green. The driver's PPE consists of gloves and safety glasses; there is no eye wash and no face shield. The load is in a closed box body with no ventilation, and the driver plans to park in direct sun for a 3-hour lunch stop. The driver's ADR certificate covers packages.
1. What equipment deficiencies must be corrected before departure?
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The 6 kg extinguisher with a gauge in the red is not serviceable and must be replaced or recharged before departure; an extinguisher that cannot be relied on is worse than none because it creates false confidence. The 2 kg dry powder unit is serviceable but small, and the required complement for this vehicle and load must be checked against the ADR equipment table - typically at least one suitable extinguisher of adequate size for the engine/ cab and one for the load, with the correct minimum capacity. The PPE is also deficient: aerosols and flammable liquids demand protection against flash and splashes, so a face shield and eye wash should be added, and gloves should be checked as suitable for the substances. The driver should not sign for the vehicle until the extinguisher is corrected and the PPE completed.
2. What are the risks of the planned 3-hour sun parking, and what should the driver do instead?
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A closed box body in direct sun can reach temperatures well above ambient, and aerosols are pressure receptacles whose internal pressure rises with temperature; overheating can cause distortion, leakage or, in the worst case, rupture and projection of the can. The class 3 consignment adds a flammable liquid with its own vapour pressure. The driver should park in shade or under cover, avoid direct sun on the body, and keep the stop as short as possible; a 3-hour stop in full sun is a poor choice when a shaded or indoor option exists. The driver should also check that the aerosols are not stowed against the roof or in a way that blocks ventilation, and should not open the body in a way that creates a spark risk near the class 3 goods. If no shaded parking is available, the driver should move the stop or seek a covered site.
3. What supervision and documentation checks complete the pre-departure decision?
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The driver should confirm the transport document shows UN 1950, class 2.1, and the class 3 entry with PG III, the total quantities and the tunnel restriction codes, and that the vehicle carries the correct placards and orange plates for both classes. The driver should confirm the parking plan meets the supervision requirement for the quantity carried, and that the chosen stop is secure. The driver should record the extinguisher defect and its correction, and note the PPE added. If the extinguisher cannot be replaced before departure, the correct decision is to delay, not to depart with a defective unit. The driver should also confirm the emergency instructions in writing are in the cab and that the driver can explain the actions for a leaking or overheating aerosol.