METHOD OF STATEMENT FOR
WATER SUPPLY PIPE INSTALLATION
- Open an approved toilet detail shop drawing. This drawing should be accompanied with the approved location of mechanical pipe sleeves for both A/C indoor unit refrigeration tubes/pipes and sanitary fixtures ventilation.
- Installation of pipes should be done after the block work inside the toilet.
- Locate the pipe locations in the wall and mark with the line corresponds to the total area to bury the pipe in the wall.
- Use block cutter or simply portable grinder to cut a side of block continuously along the line that had been marked. Absolute care should be done not to cut or damaged the pre-installed pipe sleeves of fixture vents and A/C refrigeration pipes/tubes.
- By using sharp- pointed steel rod and other proper chipping tools, chip the block side to the thickness required to fix the water pipes.
- Use approved pipes, pipe fittings, and joining compound.
- For solvent cement joints:
A-1. Select and follow manufacturers recommendations for types of solvent cement for such conditions as temperature over 100ºF (38ºC), humidity over 60% or use of schedule 80 fittings.
A-2. Proper handling of solvent cement should be strictly done to maintain effectiveness.
A-3. Keep solvent cement closed and in shade when not in used. When solvent cement becomes thicker, THROW IT AWAY. Solvent cement shall not be thinned.
- For pipe joining:
B-1. Cut pipe square with hand saw used for plastic.
B-2. Ream and chamfer the pipe (to eliminate sharp edges, and beads and all burrs).
B-3. Clean all dirt, moisture and grease from pipe and fitting socket. Use a clean and dry rag.
B-4. Check dry fit of pipe in fitting. Pipe should enter the fitting socket from 1/3 to 3/4 depth of socket.
B-5. Soften inside socket surface by applying an aggressive primer.
B-6. Soften mating surface of pipe to depth of socket by applying liberal coat of the (aggressive primer). Be sure entire surface is softened.
B-7. Again coat inside the socket surface with the (aggressive) primer. Then without delay, apply solvent cement liberally to outside the pipe. Use more than enough to fill any gaps.
B-8. Apply a light coat of PVC cement to inside the socket using inside straight outward strokes (to keep excess solvent of socket). This is also to prevent solvent cement damage to pipe. For loose fits, apply a second coat to solvent cement.
B-9. While both the inside socket surface and the outside surface of the pipe are soft and wet with solvent cement, forcefully bottom the pipe in the socket, giving the pipe a one-quarter turn, if possible. The pipe must go to the bottom of the socket.
B-10. Hold the joint together until tight.
B-11. Wipe excess cement from the pipe. A proper made joint will normally show a bead around its entire perimeter. Any gaps may indicate insufficient cement or the used of light bodied cement on larger diameters where heavy bodied cement should have been used.
B-12. Do not disturbed joint for the following periods:
B-12-1. 30mins minimum @ 60°F to 100°F (16°C to 38°C).
B-12-2. 1 hour minimum @ 40°F to 60°F (4°C to16°C).
B-12-3. 2 hours minimum @ 20°F to 40°F (-7°C to 4°C).
B-12-4. 4 hours minimum @ 0°F to 20°F (-18°C to -7°C).
Handle the newly assembled joints carefully during these
Periods. If gaps (step 11) or loose fits are encountered in the system, double these periods.
B-13. The system shall not be pressurized until the joints have cured at
Least as long as recommended by the manufacturer.
- For connection with threads (i.e. valve to pipes or fittings and vice-versa)
C-1. Secure the threaded valves or fittings to joint are good that the threads are not worn-out and the rotation to fix is reverse with the other.
C-2. Use approved fittings to join valves to metal threaded valves.
C-2. Wrap the threaded portion with the approved tape (Teflon tape) in reverse direction of the tightening. Align threads at point of assembly.
C-3. Tighten joints with wrench. Apply wrench to valve end and strap wrench to PVC pipes or fittings. Do not over tight the joints.
- For pipes passing the vertical columns, allowable chipping is up to two (2) centimeter on the sides of the column. Chipping more than 2cm is not allowed.
- For pipes passing through the wall, install sleeves of size larger than the pipes serving it. Seal annular space between sleeve and pipe using silicon sealant.
- Install the pipes at designated height and location on the wall and on the floor.
- Align the pipes horizontally and vertically without strain. Avoid pipe bending or sagging.
- Check the pipes securely and firmly fix on its location before leak testing.
- Leak test the pipes and proved tight under a water pressure not less than 1½ its working pressure under which it is to be used. Leak test the pipes for four (4) hours. Do not test the pipes without the presence of inspection Engineer.
After the approval of inspection Engineer, cover the pipes with cement plaster.
