Buderus Manual on Trenchless Installation of Ductile Cast ... - Duktus

8.3 Outside protection
Outside protection, joints, other points
With this technique, the outside protection of the ductile cast iron pipes consists of
plastic-modified cement mortar (ZMU) to DIN EN 1 2. The joint area has to be
protected with a shrink-on sleeve. Shrink-on sleeves of tape material should not be used
in this case.
8.4 Joints
Because the pipe for medium is pulled in by steered pilot boring, BLS ® joint also has to
be used in this case. The permitted tractive forces and operating pressures for the BLS ®
joint are shown in Table 2.1 in section 2. However, due to the oversize, the tractive
forces which can be expected will not be excessively high.
8.5 Other points
The individual sections of the pipeline can
be connected together in the conventional
way in the assembly pits (which were
previously the arrival and pull-in pits) using
standard fittings. For pipelines connected
entirely by longitudinal force-fit
joints, BLS ® collars conforming to a factory
standard are available (Fig. 8.7). For
pressure tests, the sections are sealed
off with thrust-locked fittings from the
BLS ® range (Fig. 8.8, 8.9 and 8.10). There
is thus no need for the end pieces to be
supported on the pit lining. At 20 millimetres,
the outside diameter of the casing
pipe is so adjusted that there is a small
oversize for the 20 millimetre sockets of
the cast iron pipes. The outside diameter
of the main body of the cast iron pipes,
including the cement mortar coating, is
approx. 33 millimetres.
Fig. 8.7 BLS ® collar
Fig. 8.8 BLS ® flanged socket
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