Lead Lined Doors for CT & X-Ray Rooms

Why lead doors leak

A shielded room is only as good as its weakest path. Walls get lead lined carefully, the viewing window is specified in lead glass, the shielding calculation is done properly — and then the door is handed to a general carpenter, because it looks like a door.

It is not. It is a heavy, hinged radiation barrier that has to maintain continuous lead equivalence across a moving joint. The failures we find repeatedly are the same few:

• Lead sheet butted instead of lapped. Two sheets meeting edge to edge leave a straight-line gap at the seam. Lead must overlap by a proper margin so there is no path through the joint.
• The frame ignored. A perfectly shielded leaf in an unshielded frame simply moves the leakage path to the perimeter. Frame and architrave need shielding continuous with the wall lining.
• Hinges and hardware sized for a normal door. Lead is dense, and a lead lined leaf is far heavier than it looks. Under-specified hinges let the leaf drop within months, opening a gap along the top edge and binding at the bottom.
• No treatment at the threshold. The floor-to-leaf gap is a direct path if it is not addressed in the design.
• Fixings driven straight through the lead. Every unsealed penetration is a hole in the barrier.
• Nobody surveys it afterwards. The failure is invisible. Without a leakage survey, a leaking door looks exactly like a working one.

How RADbuild builds them

• Shielding calculation first. Lead equivalence is derived for the specific room, workload and occupancy of adjacent spaces, in line with AERB requirements — not taken from a standard thickness
• Correctly lapped lead sheet through the leaf, with overlaps at every joint so no straight-line path exists
• Shielded frame continuous with the wall lining, so the perimeter is not the weak point
• Hinges, closers and hardware sized for the real leaf weight, so the door still seals in year five
• Sealed door-to-frame and threshold interfaces
• Lead glass viewing panels set with shielded margins
• Leakage survey and certification on completion, with recorded values handed over

Doors are one part of the shielded envelope

We deliver the door as part of the whole barrier, because splitting them across vendors is how gaps appear at the interfaces:

• Lead lining to walls, and where required ceiling and floor
• Lead glass viewing windows
• Shielded service penetrations — conduit, cable and duct routes through shielded walls
• Control room and console area shielding
• AERB layout and shielding documentation support

Retrofit and remediation

If an existing room has failed a survey, or you suspect a door is leaking, the fix is not automatically a new door. We survey to locate the actual leakage path, then remediate — which may mean reworking the frame, replacing hardware, correcting joints, or replacing the leaf. Then we re-survey and certify.

This work also comes up on pre-owned equipment installations and on rooms being re-purposed for a different modality, where the original shielding was calculated for a different workload entirely.