Safe Handling of Tank Containers - ITCO

ICHCA International Safety Panel Briefing Pamphlet No 30
A6.2.4 In Service
It is possible that the seal will be compacted during transport; this could be
caused by vibration or the properties of the seal material. Should this
happen then there is a risk that the seal will be broken thus increasing the
risk of the cargo or its vapours escaping. If this should happen then the
swing bolts should be re-tightened.
A6.2.5 Maintenance
A6.2.5.1 Once per year the manway lid mechanism and dimensions should be
checked as follow:
A6.3 Safety
Manway lid and neck ring thicknesses
The actual thickness shall remain over the minimum calculation
thickness after potential corrosion. The values shown below are
typical:
Minimum manway lid thickness: 4.4 mm (5 mm at time of delivery)
Minimum neckring thickness: 7.5 mm (8 mm at time of delivery)
Welding visual check
No crack should show on swing bolts bracket attachments, fillets and
on the circular weld between collar and neckring
Seal tightness check
Replace gasket if necessary
Swing bolt threads check
Replace the swing bolts if the threads are scratched or elongated
Pressure test inspection
According to tank standards requirements
A6.3.1 All valves, ports and access lids must be properly closed once filling has
been completed.
A6.3.2 Manway lids are a major cause of leaks due to improper fitting of the seal,
incorrectly tightening swing bolts or swing bolts that have loosened during
transport. The structure of a tank container can survive a drop from height,
but if it lands upside down and the manway lid is not tightened correctly
there will be a serious risk of the cargo escaping.
A6.3.3 If there is any doubt about the integrity of any closure then the shipper
should be informed immediately.
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