(Also referred to as Lead Lined Sheetrock, Gyproc, Wallboard or Lead Lined Gypsum Board)
Mars Metal'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.
Mars Metal 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.
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. Mars Metal 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.
Typical Details for Lead Lined Drywall:
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
Mars Metal is happy to supply and sell leaded drywall; however there are a few considerations before purchasing this material that may influence your purchasing decision: Mars Metal purchases standard drywall from the same suppliers as consumers, then laminates the sheet lead to the drywall and marks up the price accordingly. It is not necessary to purchase leaded drywall when specified for a job. An installer can purchase just the sheet lead from MarShield and buy drywall directly from local suppliers. You will be adding a step into the installation but potentially saving future problems and costs as listed below:
- Leaded drywall takes up more room on a truck therefore freight costs will be more costly compared to one small pallet containing all the sheet lead.
- When shipping leaded drywall Mars Metal takes all precautions in ensuring drywall is protected from damage and is well marked not to stack on the material and that shipper/receivers must handle with care. Unfortunately no matter how much we affix warning labels there is a very strong likelihood that some of the material will arrive cracked or broken while in transit. Mars Metal will not warrant any drywall freight claims.
- The handling of leaded drywall from the off-loading of the delivery truck to thefinal destination x-ray room the material is to be installed in can be tricky handling and very heavy with greater opportunity of more material being damaged during the transport of this material.
- The installation of the leaded drywall is much harder due to the heavy weights of the material while supporting and fastening it to the walls.
- Purchasing your own non-leaded drywall saves an extra mark up on costs from Mars Metal to the purchaser.
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.
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.
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.
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.
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).
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.