Who provides the x-ray shielding plan?

Key facts

Who calculates the shielding?

A qualified expert. North Carolina's rule says that before construction, the floor plans and equipment arrangement of every x-ray installation must be reviewed by a qualified expert. The facility gives the expert room dimensions, unit specs and the planned use. The expert works out the minimum construction materials needed to protect the operator, nearby patients and anyone outside the room (NC DHHS).

NCRP Report 177 gives guidance for "qualified experts conducting radiation protection surveys, equipment performance evaluations, and determining facility shielding and layout designs." It updates Report 145 on dental radiation safety (NCRP). NC directs dental designs to NCRP 177 (NC DHHS).

Not every state uses the same credential names. NC uses "Class III–Dental" providers for intraoral and panoramic units and treats extraoral units (ceph, tomography, dental CT) as medical units that may need more review (NC DHHS). South Carolina requires plans prepared and submitted by a registered vendor in Class III, IV, VII, VIII or IX, depending on application type (SC DES).

Which installations need a reviewed plan?

It depends on the state:

• North Carolina: every planned dental x-ray location, intraoral and panoramic, before installation. A new plan is needed for renovations that affect barriers, increased use or adjacent occupancy, and upgrades from pan to pan/ceph, pan/tomography or pan/CT (NC DHHS).
• South Carolina: all dental cephalometric, TMJ and dental CT units, plus relocations. A Facility Registration Approval is needed before installing any x-ray machine (2.50 fee) (SC DES).
• Washington: the state lists "Dental shielding including CBCT" among installations it doesn't review (WA DOH).

"Not reviewed" doesn't mean "not needed." The barriers still have to protect people, and the post-install survey will show whether they do. Check your state program before the architect finalizes walls.

When can the contractor build and install?

In North Carolina, the facility must not install the x-ray unit until it receives the state's acknowledgement letter. Plans should be submitted at least one month but no earlier than six months before installation (NC DHHS). South Carolina says a facility shall not install an x-ray machine until the Department has issued the Facility Registration Approval (SC DES).

Put the approval in the schedule ahead of the equipment delivery date, and track it in the permit & inspection tracker (free tool, coming soon). The details in the plan that the contractor has to build:

• Barrier material and extent for each wall, floor and ceiling the expert specifies
• Doors where required
• The exposure switch location: NC requires the plan to show where the control will be fixed (NC DHHS)
• Administrative controls for open-bay operatories, documented in the radiation protection program (NC DHHS)

Photograph the barrier before drywall closes, and mark the walls on the shared plan in Studio.

Who coordinates between the expert, installer and GC?

Usually the owner, unless the contract says otherwise. NC says administrative controls for open-bay rooms should come out of discussions among the facility, the qualified expert and the unit installer (NC DHHS). That conversation also belongs on the GC's schedule. Name one person in the contract to send the expert the final room dimensions and equipment specs, and to send the approved plan back to the architect and framer.

Who inspects after installation?

Three paper trails close the loop:

1. FDA Form 2579. The assembler files a report of assembly certifying the components were assembled per the manufacturer's instructions. It goes to the purchaser and, where applicable, the state radiation agency within 15 days of completing assembly (FDA, 21 CFR 1020.30).
2. State registration. South Carolina requires registration within 30 calendar days of installation (SC DES).
3. Area survey. NC requires a post-installation survey by a registered service provider within 30 days of first operation (NC DHHS). SC requires a radiation area survey within 30 calendar days of installation (SC DES).

What about CBCT and buying a practice?

CBCT changes the plan. NC requires a new review when a pan is upgraded to a pan/CT (NC DHHS), and SC requires shielding plans for all dental CT units (SC DES). Before you order, run the unit past the compatibility checker (free tool, coming soon), and see CBCT compatibility.

For acquisitions, SC's Facility Registration Approval doesn't transfer to a new owner (SC DES).

How FloorStack helps

The free Studio plan puts the qualified expert's barrier walls, door and exposure switch on the same floor plan the framer and drywaller use. The permit & inspection tracker (free tool, coming soon) will hold the plan review, approval letter, FDA 2579 and survey dates. The compatibility checker (free tool, coming soon) will flag CBCT and pan requirements before you order. FloorStack is a vendor-neutral dental build-out platform. See the Dental Office Construction hub, dental office permits and the inspection checklist.

Free tools for this step

• Studio (live, free plan): mark barriers and exposure switch locations.
• Permit & inspection tracker (free tool, coming soon): track plan review, approval and surveys.
• Compatibility checker (free tool, coming soon): check imaging units before ordering.