The canister shall receive 75 ±1 grams 6x16 mesh granular activated carbon. The moisture content of the carbon shall not exceed 3% of the weight.
The charcoal shall be held firmly in place by a stainless screen, which fits, snugly to the inside of the can. The fit should preclude loss of any of the 6 x16 mesh charcoal particles around the edge of the screen. The screen shall have a 4” outer diameter, a 0.016 wire diameter and provide an openness of 30 to 50%. The screen must be held in place by a removable, internally expandable 0.125” diameter ring, which fits, into the groove in the perimeter of the can. The ring and screen shall be of sufficient stiffness to hold the charcoal in place during shipping and handling, including dropping from heights of 3—4 feet onto a concrete floor. A piece of foam material sized to fit in the lid of the can (see attached drawing) shall be attached to the inner surface of the lid to help keep the screen and charcoal in place during shipping by placing slight pressure on the screen when the lid is on the can.
The charcoal must have low radioactivity content; specifically gamma emitters must be less than 0.2 picocuries per gram except for natural potassium-40.
The canister shall have a 4” diameter borosilicate glass fiber filter paper of 0.005 calipers with a basis weight of 22.9 gr/m2.
The canister shall contain a 4” diameter polyethylene barrier that is nominally 0.001 + 0.013 caliper. The membrane shall contain twenty 0.094” diameter holes, 5 holes symmetrically located per quadrant; 8 each at 0.67” from center and 12 each at 1.245” from center.
The finished canister may be identified unobtrusively with the manufacturer company name but not address or telephone number, (inclusion of these may confuse a homeowner where the canisters are placed in use in homes). The top of the can must be left unused since this is the location used by EPA for affixing an identification label.
Each individual canister shall be packaged in a cardboard, self-sealing box like the sample enclosed. This design is important to match existing Instruction sheets and to provide consistency in the program.

F&J - Model R40VDB -Charcoal Canister for Radon Testing

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