5-06M
expansion loops and bends being furnished as part of a direct buried system.
These are the responsibility of the manufacturer of the direct buried system
to design.
5.6.4 Design steam systems for boiler plant header pressure and temperature
(930 kPa, 181 C)(135 PSI, 358 F) minimum, and design condensate systems for
207 kPa, 135 C (30 PSI, 275 F). Pipe stresses must not exceed allowable
stresses calculated in accordance with ASME B31.1, ASME Code for Pressure
Piping, Power Piping.
5.7 Fiberglas Reinforced Plastic (FRP) Pipe for Condensate: This not
permitted.
5.8 Manholes:
5.8.1 In direct buried systems and in concrete trench systems all devices
requiring access for operation and maintenance shall be located in manholes.
These devices include valves, steam traps, expansion joints, flanged and
threaded joints, unions.
5.8.2 Manholes shall be reinforced concrete. Prefabricated manholes are not
permitted because of the difficulty of properly locating underground pipe
openings in the manhole walls. Concrete floor slabs shall be of sufficient
weight to prevent floatation in high water table areas.
5.8.3 Do not locate manholes in roads or parking areas because of access and
ventilation problems.
5.8.4 Manhole structure and mechanical layout shall be completely designed by
the A/E. Allow adequate working space and headroom.
5.8.5 Provide two separate entrances from grade with full-size manhole covers.
One shall be for access with grab-bars set in the manhole wall, the other
shall be for ventilation while working in the manhole. Locate the ventilation
access directly above the sump.
5.8.6 Provide 600 mm (24 inch) square by 600 mm (24 inch) deep sump in floor
and provide duplex submersible sump pumps. Where feasible, provide gravity
drainage to a storm sewer.
5.8.7 The engineer must review the "confined space" regulations of the
facility and design the manholes to allow maximum possible access convenience.
The designs must be reviewed by the appropriate facility officials regarding
these regulations. A possible design feature to ease the "confined space"
limitations could be the use of sidewalk-type access doors instead of manhole
covers.
Completely design all pipe anchors to withstand
the applied forces.
5.8.9 Place waterproof membranes in or below the concrete bottom slabs and
continue them up the outer sides to the top of the sidewalls.
5.8.10 Provide ventilation pipes through the top of the manhole.
5.9 Site Investigations:
5.9.1 The design engineer must determine the most economical and practical
locations for the system and accessories. In addition, the determination of
soil conditions is necessary when direct buried systems are selected.
5.9.2 It will be necessary to perform:
5.9.2.1 Land surveys to determine routing and grades and location of
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