Originally posted by AlaskaFranke
reply to post by lilwolf
I would be interested in reading your thoughts on Long Term Shelter. I am presently "tinkering" with a carbon activated, sand/gravel air filtration
unit, using a store bought HEPA ionizing fan. Hey-it fits perfectly inside of a 5-gallon bucket.
The only thing that I'm a little unsure of, is how to to build a decent blast valve to protect from over-pressure. I would hate to drop a big check
on this, at least at the present time.
Shelter is made from a 8' x 20' steel shipping container, reinforced on the the roof with 12" x 12" x 12' pressure treated timbers, then covered
with 5 feet of packed earth.
The sides are equally protected, but I use 12,000 year old Pet-Moss to add as an insulating barrier, in order to minimize frost heave, and ice
swelling on the sides. Peet Moss, even when its well below zero outside, will maintain (about) a 53 to 58 degree core temperature. I've dug into it,
and was surprised that even when the first few feet were frozen almost solid, and covered in several feet of snow, the inside was warm enough to keep
the chill off my hands.
What part of the world are you loacted in...?
The shelter units we bought and buried are from radius international... and it came with a blast over pressure valve setup made by CPI, inc.
from the site:
We offer heavy duty blast valves with prefilter to protect the interior of a shelter from blast waves caused by outside explosions. A prefilter, with
an efficiency of ~ 90%, is fully integrated. Normally, the valve is open and it closes up in case of an outside explosion. CPI produces different
types of blast valves to withstand different levels of blast waves: 3, 11, 40, 60bar and even higher reflected pressure.
Features:
Double-action valve (protects against explosive and implosive waves)
Maintenance-free
Resistant against high temperatures and corrosion
All steel parts are phosphate treated and finished with a powder coating
www.collectiveprotectioninc.com...
It works pretty good and seems to meet everything we needed....
Also on the subject of where you dug into...I have spent time in North Alaska and what you have done is exactly the way some of the shelters up there
are dug in.... some military sites up there (wink) are built this way with the sea trains.... all underground....
BTW... I live in Southern Idaho..... but the shelter is about 28 miles due north , and built into a mountain side.... fresh water from underground
wells , and totally air filtered.
If interested I can eventually bring you out here and show you the entire set up... it might give you a good many ideas for yours.
My hard drive was chock full of them. 
