Lead-Lined Drywall

(Also referred to as Lead Lined Sheetrock, Gyproc, Wallboard or Lead Lined Gypsum Board)

Purpose: MarShield’s drywall is laminated with sheet lead that is designed to cover necessary surfaces or walls in a room requiring radiation shielding. It is affixed to surfaces or walls ensuring a continuous layer of sheet lead under the drywall to a specified height. It is used in new construction or shielding upgrades/renovations for P.E.T and other types of diagnostic imaging rooms.

Product Details: MarShield starts with a piece of sheet lead meeting or exceeding Federal Specifications QQ-L-201F, Grade C, ASTM B-749-03 Standard Specification for lead and lead alloy strip, sheet, and plate products. The lead sheet is 99.9% Pure or better of un-pierced virgin lead, free of dross, oxide inclusions, scale, laminations, blisters and cracks and is factory laminated to drywall. The drywall is furnished as type “X” fire code or non fire-coded and is available in 1/2” to 5/8” thickness with a lead thickness of 1/32” to 1/8" maximum thickness. The drywall conforms to ASTM C36 and Federal Specifications QQ-L-201 F, GRADE C, ASTM B-29. Leaded drywall panels will be greater than, or equal to, the attenuation level specified by a health physicist. FOR LEAD THICKNESSES THAT EXCEED 1/8” PLEASE REFER TO OUR LEAD LINED PLYWOOD.

Lead is factory pressure-laminated and adhered to the drywall with permanent adhesive in 48” widths, equal to the width of the drywall, or in 49” widths giving the lead a 1” overlap at the vertical drywall joints. Due to the excessive weight, our drywall panels can be customized to smaller widths and lengths to suit most applications. 2” wide batten strips can be supplied to cover all vertical joints where applicable. Smaller panels will require more batten strips but the ease of handling these lighter panels will be offset in the extra cost and labor during the installation process. Standard drywall panels are available in 48” widths with 96” or 120” lengths.

The installer will need to take into account the loss of shielding in all penetrations, seams and cut outs in the leaded drywall. Shielding will need to be added to all receptacle switches, fastener penetrations and seams created when applying the leaded drywall. In the majority of installation jobs the leaded drywall panels can be mounted directly to the metal or wood studs with standard drywall screws. These screws are then covered with a small diameter lead tab. These tabs are available in various thicknesses up to 1/8” thick. Each fastener will be covered with a lead disc, equal in thickness to the lead that is laminated to the drywall to eliminate the possibility of radiation leakage at the point of fastening. Ensure the heads of the drywall screws are dimpled into drywall deep enough to allow the installer sufficient depth to glue the lead tabs over all screw heads with a quick-drying-time construction adhesive.

After gluing all screw heads with lead tabs, the installer can apply drywall compound and feather out all lead tabs with compound for a smooth drywall finish. Drywall can be taped, floated and finished as required. Leaded drywall panels may be used in the ceiling but may require additional support or fasteners to hold the panels to the ceiling.

Leaded Drywall can have lead laminated to the full drywall length or partial length – please specify.

Installation: It is important to ensure the installation is done in accordance to local state or provincial standards and code regulations as outlined for each municipality. All panels will be affixed to studs sufficient to support the leaded drywall. Install the leaded side of the sheetrock against wooden or metal studs ensuring that you match the joints of the lead lining. Drill pilot holes for screws to prevent deformation of lead. A minimum lead overlap of one inch is required at all drywall joints and corners. Extend the lead overhang at least one inch into all frames or openings. Sheet lead over 1/16" thick should have a minimum 2" overhang. MarShield™ recommends the use of drywall screws wherever possible. If using lead-headed nails (on wood studs only), then ensure that you drive them to the proper depth and cover them with drywall compound. Screw or fasten lead-lined drywall panels in a vertical orientation where possible or horizontally where required by local codes, ensuring that leaded drywall is inserted into window and door frames to maintain continuity of lead integrity. The lead laminated wallboard should be fastened at a minimum of 8" on center at the edges of each sheet, and at a minimum of 12" on centers at the intermediate stud framing members. Due to the extreme weight of lead lined drywall, extra care must be taken during handling, storage and installation. Have shielding tested by approved personnel.

Lead Lining in Floors and Ceilings.
In certain situations, the floor and/or ceiling of an x-ray room may require lead shielding. We recommend laying the lead in the floor before the final floor is poured. All joints should have a minimum of one-inch overlap. The lead should extend up each wall a minimum of two inches. Additional concrete can be applied over the lead finishing. If lead is required in the floor of an existing facility, we recommend installing the lead in the ceiling of the room below. Securing lead to existing concrete presents problems with attaching, protecting, and covering the lead. Ceiling lead is installed by laying 16 inch by 49 inch sheets of rolled lead on top of lead filled channels suspended from the structure above. Once again, one-inch overlap is required at each joint. A standard acoustical ceiling can be installed under the lead lined ceiling.

Available in 48 Inch and 49 inch Widths

Sample Leaded Drywall Weights
Drywall 1/2” thick with 1/32” thick lead = 3.575 pounds per square foot
Drywall 5/8” thick with 1/32” thick lead = 4.75 pounds per square foot
Drywall 5/8” thick with 1/16” thick lead = 6.05 pounds per square foot
Drywall 5/8” thick with 3/32” thick lead = 8.65 pounds per square foot
Drywall 5/8” thick with 1/8” thick lead = 9.8 pounds per square foot

DIAGNOSTIC RADIATION SHIELDING CONSIDERATIONS

All Lead Radiation Shielding requirements should be calculated and determined by a certified professional radiation health physicist based on the following information.

ENERGY: The end user must determine the output of the X-Ray machine. (KvP). Usually, the higher the output of the machine, the higher the lead shielding requirement.

EXPOSURE: The end-user must determine the exposure per hour, day, week and year and the maximum patient exposure accumulated and projected from radiation exposure, as radiation is cumulative and unnecessary extra exposure can cause biological damage on the cellular level. Each state or province has its own maximum permissible exposure level in addition to natural radiation exposure an average person is exposed to through environmental factors like ultra violet solar, radon gas and atmospheric radiation. Ensure you check with local governing health and safety laws and codes for current compliance requirements.

ORIENTATION/DIRECTION: All wall sections shall be calculated by your physicists in relation to the direction of the primary beam target. (Direction where it is aimed) and scatter or secondary radiation of the x-ray machine, as well as the floor or wall.

DISTANCE: Radiation dissipates as the distance increases; usually the closer a partition is to the radiation / x-ray source, the higher the lead shielding needed.

OCCUPANCY OR ROOM USEAGE: A critical and very important factor in your calculations is the amount of time, per day, a surrounding or adjoining room common to the x-ray room will be occupied and used by your personnel or public. An example would be a simple storage room, which would have a lower use or occupancy factor, compared to a waiting room or office that would have higher use. Therefore, it is calculated room by room for all rooms connected or that are common to the x-ray room. If there is no occupancy potential, then typically no shielding will be specified or required. (I.E. Floor or roof of a single story building with no basement).

CONSTRUCTION MATERIAL: Often a physicist will take into account the existing or the proposed construction materials used or to be used of the wall/partition or flooring material, as heavy density materials can attenuate (shield) radiation to a certain degree, such as concrete, steel, plaster, block or multiple layers of drywall. This may reduce, or in some instances, eliminate your lead shielding requirements, depending on the values of the previous factors to be considered.

URL: http://www.marshield.com/page/6/64