Section 13.12.220 Excavations -- Bedding -- Backfill.
A. All excavations required for the installation of a building sewer shall be
open trench work,
unless otherwise approved by the director of public works.
B. Pipe laying and backfill shall be performed in the following manner except
that no backfill
shall be placed until the work has been inspected.
1. Excavation. The pipe shall be laid in a ditch no less than ten inches wide
with smooth,
uniform, sloped bottom graded to meet the slope requirements.
2. Installation. The pipe shall be laid in a straight alignment and grade, with approved fittings
for
changes in direction.
3. Pipe Bedding. The bottom quadrant of sewer service pipe shall be continuously and uniformly
in contact with and supported by the trench bottom.
a. Fine uniform material free from lumps shall be used to afford full support to the pipe.
b. Hub and coupling projections shall be excavated so that no part of the pipe load is supported
by the hub or coupling.
c. Pipe laid in rock trenches, shall be provided with a supplementary foundation of fine
materials, such as sand, to provide continuous and uniform support.
C. Backfill and Cover. Backfill for sewer service pipe shall be firmly compacted with fine,
selected material, which will pass through a one-half inch screen, from the trench bottom to a
point six inches over the top of the pipe. The minimum cover over a sewer service pipe shall be
twelve (12) inches below grade. (Ord. 111 (part), 1996: prior code § 4.05.220)
D. All excavations, pipe laying, bedding and backfill shall conform to Montana
Public Works
Standards, most current edition.
E. Installation of sewer mains and/or sewer service lines up and to within three
(3) feet of the
building shall only be installed by a qualified master plumber and/or a qualified utility
contractor. (Ord. 215 (part), 2003)
