Re: Lead shielding installation techniques

[jthomas <jthomas@usuhs.mil>]

Eric Cowdrey wrote:

>I am interested in hearing about current techniques for installing lead 
>shielding and/or drywall in diagnostic x-ray facilities. I am particularly 
>interested in fastening techniques that may involve the penetration of the 
>sheeting material; specifically, how is the possibility of pin hole 
>radiation leaks around the fasteners avoided?

	In construction there are two methods used to shield Dx x-ray rooms.  In
the first the room walls are made of double studs (either steel or wood)
The lead sheathing is mounted between the double studs.  Lead sheets can be
overlapped by 2x the thickness of the sheet or I have seen that the sheets
are heat sealed / soldered along each seam.  The second method is shielding
with Gyp board that has the Pb glued to the back or in the center of the
board.  The sheets are mounted using standard dry wall screws (generally 2").

	In a Dx x-ray room there is not a constant long intensity exposure to any
wall so "pin hole" leaks are not detected.  Also, remember that the steel
or Aluminum screw is drilled into either a steel or wood stud.  The
attenuation of these also need to be considered.

	If the shielding is going into a Therapy room, the screws need to be
covered with Pb patches.  Rx room shielding will require substantially more
Pb than a Dx room.  


Jerry Thomas

 
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