ZANZIBAR WATER
AUTHORITY, ZANZIBAR,
TANZANIA.
CRUX CONSULTANT
PVT LTD, DELHI, INDIA.
LARSEN & TOUBRO LIMITED
Project: Rehabilitation and Improvement of Water Supply System in Zanzibar - Lot - III
HDPE Pipe Laying – Consideration
Pipeline Type
HDPE
DI Pipe Dia
Quantity (Mtr)
Excavation (Cu. M)
75mm
49,446 Mtr
18,542
110mm
28,302 Mtr
12,764
160mm & 200mm
22,959 Mtr
14,943
250mm & 315mm
13,641 Mtr
9412
400mm & 450mm
10,565 Mtr
9957
124913 Mtr
65618
Total Length
One Unit: One Excavator Operator + Two Fitter + One Butt Fusion Operator (4
Personnel)
Standard Bucket capacity (Cu.M) for Excavator : 0.6 Cu. M (Considering the 80% of soil
retained)
No. of Strokes including swing : 75 strokes / min, Per Hour : 0.6 x 75 = 45 cu.meter
Average Excavation / day ( 10 Hrs = 8 Active working hrs & 2 hrs Cushion ) : 360 Cu.M
i.e. For 110 mm Pipe – 0.8 Kms stretch can be excavated & Laid in a Working day (10
hours) deploying one unit
Inference: More productivity can be achieved by deploying excavator with 1Cu. M capacity
bucket and maintaining pile of excavated soil next to trench which reduces the swing and
increases the number of stroke. Reducing the idle hours (Cushion Hours). Adjacent activities
of lowering HDPE pipes and butt fusion can be coupled with the Working hours in line with
the excavation
Points to be Considered:
 HDPE Butt fusion machine to be deployed suiting the various dia’s used at Project
 i.e. Commonly used Butt Fusion Machines such as Ritmo / Georg Fischer or others
confirming to ASTM F2620
 Butt fusion machine operator with skills to operate the machine
 Pipe handling shall be taken care using trolley and shouldn’t be dragged on ground
 Hydro test as per approved drawings & Method statement
 Anchor blocks to be constructed wherever necessary as per approved drawings
 Other Procedures as : LTCD/WET/ZANZIBAR/PQP/MECH/MS02 REV 0 ( HDPE Pipe
laying Works ) shall be followed