A DISCUSSION ON THE SECURE STOWAGE OF PACKAGES

The meaning of ‘secure stowage of packages’ within the UK (and elsewhere) is not consistently understood.   There are obviously variations across industry with each organisations specialist preferring a particular method.  There are also variations in package stowage (or tie?downs) within package types, for example Type B package are routinely held rigidly in place by trunnions or lashings and chocks or occasionally more freely in a well area that the package can not topple or bounce out of.  There are greater variations across package types e.g. Type A or excepted packages in the medical sector are often freely placed in the boot of a car or a Type A nuclear density gauge may be loosely tied in the back of a van with rope.  Further variations can be found in the techniques used to demonstrate ‘secure stowage’ some form of dynamic or static stress analysis either by hand calculation or numerical analysis usually takes place.  Again, there are many variations as to what is a conservative analysis.  More variations in understanding occur across the modes where each mode has its own guidelines which may not always concur with the IAEA guidelines and are also enforced by different organisations.  Significant variations (or the risk of misunderstanding) can occur between the Design Safety Report, the Operating, Handling and Maintenance Instructions and the Local Work Instructions.  Finally two conditions must be considered for secure stowage: routine and normal; and under accident conditions the tie?down points, if they fail, must fail in such a way so as not to reduce the capacity of the package to meet the regulations.     The intention of the author is to explore these variables and produce guidance for industry on best practice and also to highlight areas that may still not be clear so that they may be resolved in the future