Pollution
Humain
Environnement
Economique

An expert was dispatched by a certified body, accompanied by a colleague, to conduct a periodic re-certification inspection on an anti-pulsating air/water tank (pressure: 16 bar, volume: 8,000 litres) connected to an irrigation network.

To carry out the internal inspection, the device was prepared the previous Thursday by another employee. The preparation step involved bleeding air from the tank by removing an elbow on the water inlet and unscrewing the bolts securing the manhole cover. The employee was executing this sequence of tasks for the very first time; the extent of his training had consisted of verbal explanations from a co-worker present on the day of the accident.

At the time of the inspection, the manometer indicated a pressure of approx. 5 bar; in asserting that the manometer was inoperable, the employee along with the expert sought to lift the manhole cover using a hammer and large screwdriver.

The cover loosened and was blown off landing 30 m away. The employee’s left arm sustained a fracture.

The administrative agency overseeing pressurised equipment noted the noncompliance with safety guidelines issued by the body its expert staff had certified. In reality, these experts had not checked for the presence of pressure. The lack of appropriate technician training, combined with the operator’s failure to provide safety instructions relative to the pressure risk, the absence of a more senior employee during a preparation operation assigned to an employee with no experience and the excessive confidence displayed by the on-site team, are all to be included as causes of this accident.

The intense cold and damp weather during the week and weekend preceding the accident might explain why the cover remained stuck to the manhole flange even though the bolts had been removed and the pressure had only read around 5 bar.