METHOD OF STATEMENT FOR MECHANICAL WORKS FOR SANITARY DRAINAGE
Scope: This method of statement applies to mechanical works for sanitary drainage of buildings.
Purpose: The basis of construction /installation for effective and qualified results
Significant materials needed:
- Approved shop drawing (At site)
- PVC schedule 40 pipes and fittings (Trans.# )
- PVC Joining Compounds and cleaner
- Plumbing tools
- Level equipment
Abbreviations:
ASTM American Society for Testing Materials
UPC Uniform Plumbing Code
IAPINO International Association of Plumbing and Mechanical Officials
PVC Poly Vinyl Chloride
Execution:
- Open the approved shop drawing and know the location of pipes/ fittings.
- After determination of location based on measured distances, make markings/indications for excavations using pointed metal bars and paint spray or white sand, use straight Edge Wood, or Cloth Thread nylon rope or simply 2mm plastic rope to make line to be sure to excavate in straight run.
- Deep of execution should be enough to lay the pipe base on 1% slope invert level. The 10cm thick of fine sand around the pipe plus 5 cm clearance. Excavation should start from main sewer line and then inside the villa just to be sure that the drainage waste shall go directly to main sewer line.
- Install / layout the popes and fittings.
d1. Start pipe layout from deepest invert level that is located outside villa fence and below the grade beam by using level equipment it locates the right laid position and height of pipe.
d2. After getting the level, fixed the pipe not to move up and down on both sides.
D3 Finished fixing all horizontal pipes/fittings w/ mixing application of D2.
D4 Install vertical pipes (i.e. soil stack, fixtures and cleanouts). Cover the vertical pipes with end cap cover.
D5 Recheck the pipe installed before putting fine sand
D5.1 Check for straight look.
D5.2 Check presence of solvent cement in each joint
D5.3 Check for pipe support.
D5.4 Check for pipe invert level based on shop drawing.
D5.5 Check for unnecessary materials w/in the layout portion, remove and bring to safe location.
D6 Carefully put fine sand side by side up ¾ the diameter of the pipe. Compact the sand slowly as possible so as to project pipe from movement and hitting from solid material while compaction is on going.
D7 Make final check before leak testing.
D7.1 Check pipes for any cracks.
D7.2 Check pipes from undesired materials and should be removed at once.
D7.3 Check the appearance of pipes / fittings that means not fully covered by fine sand
D7.4 checks all end pipes are capped and the inside of pipe should be free from unnecessary materials. Remove if it has.
e. Leak testing of sanitary drain pipes
e1. Check all openings if tightly closed except the highest point.
e2. Fill the pipes with water up to the point of overflow.