Method Statement
This method statement shall apply for all plastering on brick internal wall in the X-Ray Room for clinics or hospital buildings.
Preparetory Work.
- Brickwork shall be ensured to be properly laid on the straight & level ground and void/ gap on the surface are properly filled up in advance.
- The installation of the window & door frame and M & E concealed paip shall be completed.
- All plug point boxes in the x-ray room will be fixed with a 2mm thk lead sheet (150mm x 150mm) thk at the back side.
- In oder to obtain a true surface and maintaining uniform thickness and level , a vertical strip shall be formed on the wall surface to serve as a gauges by fixing dots (about 25mm x 15mm patches of plaster) which are applied at a distance of 2m covering the entire wall surface.
- Floor area in the x-ray room must be thoroughly clean.
Work Methodology
- Plastering of the barium plaster is 25mm thk equivalent to 2.0 pb the requirement by Ministry of Health (MOH) as specification.
- The barium plaster ratio of
- (1) One part barium sulphate,
- (1) One part cement and (3) Three parts fine sand. Concrete mixer should be used to make sure the barium sulphate mixture of sand and cement to be mixed.
Measurement to obtain the ratio of 1 : 1 : 3, where the box size 300mm x 300mm must be provided.
For plastering 25mm thk layer of barium plaster the wall while making a plaster needed 3 methods:
i- The first layer 11mm thickness (barium sulphate, sand & cement).
ii- The second layer 11mm thickness (barium sulphate, sand & cement).
iii- The third layer 3mm thickness (barium sulphate, cement & skim coat).
Any mixture of barium plaster is not in accordance with the actual measurement the wall can be leak while making Testing & Commissioning (T & C).
None of the works (M & E) or the work of breaking the wall in the room x-ray ofter barium plasterwork completed since the occurrence of leakage radiation. Make sure the x-ray room must be closed with a temporary door after barium plaster works completed to prevent the occurrence of any wall that has been made of
initial Works
- This is the foundation of the whole work. It is more preparing the frameworks and lead sheet (plumbum) to be glue together before it is install to the location so as to safeguard the radiation from go out.
- All plug point boxes in the X – Ray room will be fixed with a 2mm lead sheet at the backside. The size of the lead sheet must be larger than the plug box. Once it is fixed, the boxes can put at it location.
- A timber frame for a Lead Glass should be done before barium plastering. But for this timber frame the lead sheet will be install after barium plastering done.
- Location for the X – Ray table must be confirmed since piece of the lead sheet need to fix on the floor under the X – Ray table. The lead sheet is put exactly under the X – Ray table before lifting of the table. The size of the lead sheet is (1200mm x 2500mm x 2mm).
- Installation of the timber frame for door must also be done before plastering works
Barium Plaster
A normal solid timber door from the manufacturer is used to create a lead door. A lead sheet with a thickness of 2mm will be cut exactly to the size of the timber door. The surface of the door, which the lead sheet is going to be applied on, is coated with adhesive compound (Dunlop A). It is then smoothen out using a piece of wood. After gluing the lead sheet to the base door, it is then installed with a piece of plywood, exactly the same size the the door.
The metal door frame mus be installed first at site before any barium plaster works are to be done. For installation of the lead door, 4 pieces of hinges (5’) heavy -duty stainless steel are required due to the weight of the lead door.
Lead Curtain Wall
The installation of rail is the most critical for the whole installation. The rails of the lead curtain mus be properly secured onto the slab. It must be leveled for smooth operation. The lab where the rail is to be installed must be well prepared and without obstacles. Installation of wall achors are done after its predetermined positions are marked on the slab. The false coiling level must be predetermined before furher installation.
Lead Glass
The installation of rail is the most critical for the whole installation. The rails of the lead curtain mus be properly secured onto the slab. It must be leveled for smooth operation. The lab where the rail is to be installed must be well prepared and without obstacles. Installation of wall achors are done after its predetermined positions are marked on the slab. The false coiling level must be predetermined before furher installation.
LEAD SHEET BEHIND THE SWITCH SOCKET OUTLET
Cut to size 125mm X 125mm lead sheets 2mm thk and used concrete nail to behind the switch box at the brick becouse no barium cement behind the switch box . None of the works (M&E) must be carried out by hacking the existing barium plaster wall to prevent radiation leakage. Abusive of the wall as mentioned above, the warranty (1 year) will be avoided.
LEAD SHEET METAL DOOR FRAME
Metal frame to be used for door frame with minimum thickness of 1.2mm thick.
Before install the metal door frame make sure lintol on top of the door frame to be install first by the main contractor.
2mm lead thickness will be installed inside of the metal frame to ensure non radiation slip through the frame.
barium cement will be infill inside the frame and bricks wall during installation the metal door frame and bricks wall to give the door frame strength and to ensure radiation energy will be absorb.
Finishing
After all barium plaster done properly and neatly applied, finishing works will initiate in the X-Ray room. Finishing works includes:
1) Lead sheet will be filled around the timber frame for the lead glass so radiation cannot penetrate the shielding.
2) The timber frames for the will also get the same finishing as in 1)
Testing
Testing will be conducted as per Class A and H license by the Atomic Energy License Board of Malaysia (AELB) to provide consultancy services in radiation protection and safety for industrial sector and Ministry of Health (MOH) for medical sector.