Site Preparation

Newly poured concrete floors or foundations must be cured and capable of supporting formlift and palletized block - combined load total. Reasonable access to the site must be provided. Reasonable access assumes palletized Ledite block material weighing approximately 4,000 lbs. each, with skid dimensions of 48" x 48" x 30"-H, may be transported through corridors, doorways, elevators, etc. using conventional material handling (carts, electric pallet lift, forklift, etc.) equipment as necessary.

Access routing may require pallets be transported through hospital corridors utilizing propane or electric powered handling equipment. All existing pipes, ductwork, electrical conduits, clips and other items above or around the Ledite vault area must be removed. Where existing beams or columns fall within the shielding ceiling or walls, all fireproofing materials must be removed to allow proper grouting around beams to maintain shielding integrity.

Customer is responsible for pre-delivery inspection of construction zone and for providing:

• lay out isocenter of each room and other agreed upon boundaries or layout lines
• column locations
• clear path
• properly sized and fully cured footings
• floor slab - poured and cured
• no open trenches (need covering) that would prevent the movement of forklifts/pallet jacks to the jobsite
• no steps (can use elevators if properly coordinated and sized)
• ability to use a forklift on site
• temporary heat, power and water

Ledite Delivery Onsite

Reasonable access to the site must be provided. Materials needed for the first two weeks of installation must be located on site in close proximity to the vault construction area. Pallets will be shuttled from the storage area to the respective room footprints as needed. Single pallets of block may be set at ground level, or at each staged scaffolded area as needed. A 10' area (minimum) around the accelerator room footprint must be maintained throughout the course of installation. This area is used for pallet storage, scaffold setup, etc.

There are five methods of handling Ledite block:

1. Atomic Automated Robot
2. Mechanically (ARM)
3. Hand lifting half sized block
4. Two man lifting
5. Single man lifting w/proper safety protection

Wall Installation

Walls are constructed of multiple layers of Ledite block, a lift of blocks approximately 1200 mm high will be laid to a bunker, then appropriately designed scaffold will be erected within the footprint of the bunker. Once the scaffold is handed over, the next 1200 mm high lift of blocks will be installed. This sequence will continue until the bearing plate level for the roof steelwork has been reached. Bearing plates will be grouted in with high density grout and left to cure for 24 hours.

Block will be laid in a running bond pattern with staggered seams between each respective wythe of block. At the first course, a center bond beam must also be poured in place. This high-density grouted bond beam shall consist of steel reinforcing bar laid in accordance with installation drawings with grout materials placed and properly compacted. Bond beam sections shall require a minimum 24-hour curing period before erecting additional block above.

Once the bearing plate level has been reached, additional bond beams with steel embedded bearing plates shall be constructed.

Upon attaining the block elevation at which the bearing plates are to be installed, the second wythe of block from the inside of the room shall be left devoid of all block. That area forms the upper horizontal bond beam. Within this upper horizontal bond beam, #6 rebar is to be installed in the same manner and to the same requirement as in the lower bond beam. All bearing plates are to be installed solidly in Ledite grout bond beams. Bearing plates are to be installed level on both axes and perpendicular to the beams. All bearing plate elevations are to be within 1/16" of the elevation specified on Atomic's installation drawings. All bearing plate elevations are to be verified with a laser level.

The shielding of the mechanical penetrations opening is critical to the total overall shielding of the project. It is important that the shielding material be installed so that no gaps exist between the shielding materials. At the top of the mechanical penetrations opening (also termed the duct opening), a steel header lintel is installed. Usually, this header lintel is a steel channel that is installed with the flat side of the channel downward. The upper section of the channel then becomes the form into which Ledite grout and Ledite block is installed.

Ceiling Installation

Structural steelwork will then be installed spanning between bearing plates on opposites of bunker walls. One to three steel beams will be placed at correct positions starting from sidewall. Beam(s) will then be loaded with appropriate block thickness as called for on drawings. This process of setting beams and loading with block will then be repeated until the entire ceiling has been properly constructed and shielding installed. Once steel beams have been installed per drawings, they will be tack welded to bearing plates to hold them in position.

Door Installation

After walls and ceiling have been erected, the radiation shield door, motor drive and associated components shall be installed. The door finish frame is welded to the sub-frame after all Ledite block work is complete. The door is raised by first setting it on a door dolly and then hoisting it into place using a beam clamp in conjunction with a chain hoist.

After the door has been installed, the motor drive and associated components as specified (i.e. pushbuttons, safety edges, etc. ) for the project are to be installed.