PACKAGE : I Bid Document VOLUME : II - Public Health Engineering

The trench shall be so dug that the pipeline may be laid to the required gradient and
to the required depth, mentioned in the Table below. A minimum cover of 1.2m is
to be provided above the crown level of pipe upto the Ground level / Road level.
Table showing details of trench size.
Diameter (mm) Trench width (m)
100 0.70
150 0.75
200 0.80
250 0.85
300 0.90
350 0.95
400 1.00
450 1.05
500 1.10
600 1.20
700 1.30
750 1.35
800 1.40
900 1.50
1000 1.60
1100 1.70
1200 1.80
1300 1.90
1400 2.00
1500 2.10
1600 2.20
5.7 Maximum length of open trench.
Except by special permission of the Engineer, only that length of trench excavation
shall be permitted in advance of the pipe jointing, such that laying and jointing of
pipes can reasonably be expected to be completed and the trench refilled not later
than 3 days after excavation of the trench. The contractor will not be permitted to
keep trenches open for unduly long periods, creating public hazards. The Engineer's
decision in this respect shall be final.
5.8 Widening trench at joints etc..
Any widening or deepening of the trench, whether in ordinary soil or rock,
necessary to accommodate curves, joints or bends as shown on the drawings or
ordered by the Engineer shall be carried out by the Contractor, after taking all the
necessary safety measures.
GTS : General Technical Specification. Page 35