medical vault, concrete rebar design

huangyhg

medical vault, concrete & rebar design
does anyone know the reinforcing requirements for concrete vaults used for sheilding medical equipment's radiation?
two foot thick walls are specified by the hospital for a high density radiation vault and up to 6' thick walls around a linear accelerator vault.
also, is there a special high density concrete that should be used for this application?
thanks,
wdm
depending on your location the hospital radiation protection officer should have gotten with the architect and specified a concrete mix to achieve his required shielding and the structural engineer should have called out the steel.  the density of concrete is very important in determining the thickness required for a given protection based on the source of the radiation.  the density is usually very high along with special aggregates at times.   
there are usually a lot of local standards (us) that have to taken care of in considering radiation protection where the public is involved.  

i've been involved in two "specialty" x-ray rooms for hospitals and for both, the owner's x-ray equipment supplier had a physicist design the protection scheme.  they both were on the second floor and had about 5' of concrete for the floor, along with a 6"-8" thick steel plate.  the walls were about 30" thick and had a lead lining(beto11 gets an attaboy for the pb symbol for lead <g>!) of a thichness specified by the physicist.
just designing and building the concrete formwork for the structural slab was a fun task!