Concrete block thickness matters more than I thought for radiation shielding

I was reading some old FEMA pamphlets from the 80s I found at a garage sale in Denton last spring. Turns out a standard 8 inch concrete block with hollow cores only stops about half the gamma radiation they claim. You need at least 12 inches of solid concrete or fill those cores with sand or rebar grout. I had been planning my shelter walls based on those basic cinder blocks. Now I gotta rethink the whole layout. Has anyone else had to redo their wall plans after checking the real numbers?

3 comments

3 Comments

jamieb807d ago

Man that reminds me of when I was helping my uncle pour a slab for his workshop back in 07. He was dead set on using those 8 inch blocks cause they were cheap and he found a pallet on Craigslist. We got to talking with this old timer at the lumber yard who used to work at Los Alamos back in the day. He laughed and said those hollow blocks are basically just fancy egg crates when it comes to stopping radiation. Said you might as well stack up phone books for all the good they do. Ended up filling all the cores with a dry sand and pea gravel mix which was a whole weekend project by itself. But that sand made a huge difference according to the Geiger counter my uncle borrowed from a buddy at the university.

calebc407d ago

That old timer knew what he was talking about, you see that kinda REAL wisdom popping up everywhere if you listen. @jamieb80

the_olivia7d ago

Oh man that totally tracks @jamieb80! I helped my dad do something similar with his storm shelter back in 09 and yeah those hollow blocks are basically just for looks until you fill em up.