*HomeMade Barometer For SafeRooms*
I remembered an old project I did from Boy scouts a long time ago that may help in accurately gauging the pressure in your saferoom.... a Home Made Barometer.
Take a large Mason jar and seal the opening with a balloon stretched over it snug, but not TOO tight (We used to use glass milk bottles, but who's seen those in a while? ;)
Glue a matchstick into the end of a drinking straw.
Glue the other end of the drinking straw to the center of the balloon (This is your "Pointer" and the matchstick is the "point"). The MatchStick is used as "Weight" on the end of the straw and, as noted above, as your pointer.
Make a cardboard chart showing Pressure.
Place the jar somewhere permanent like a counter top and place the cardboard "chart" on the wall in front of the "Pointer".
Turn on the local weather channel and find out what the barometer reading for your area is "right now" and mark it on the chart where the "pointer" (the straw with a matchstick tip)is pointing...
Over the next several days, find out what the barometer reading is from the local weather channel and mark those readings on your chart where the matchstick is pointing...
You can also use this in your saferoom to measure you positive pressure... simply mark on the chart the starting point, pressurize the room till you feel comfortable, and the matchstick tip should have risen some.. mark that spot as "goal pressure".
As the pressure inside the room builds, it pushes down on the top of the jar causing the balloon to sink in which makes the pointer glued to it rise..
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