exploration point. Soils of low permeability and high moisture content (lean
and fat clays (CL-CH)) shall not require under-drains when the shallow trench
system is designed to accommodate all anticipated inflow with systems or
equipment such as direct connections to storm sewers or the use of dual sump
pumps. Connect drainage system sump pump discharge pipes to storm sewer
system where feasible. If not feasible, provide discharge to splash blocks on
grade. When discharging to grade install the pump discharge line without a
check valve to allow complete drainage of the discharge pipe to prevent
freezing. Do not use under-trench drainage to alter ground water level to
meet requirements of Table 5.
Reinforced Thermosetting Resin Plastic (RTRP) Pipe. RTRP pipe is
normally supplied under Mil Spec. MIL-P-28584, when used for condensate
systems. This pipe is suitable for service pressures up to 150 psig (1034
kPa) and temperatures up to 200 degrees F (93 degrees C). Above 200 degrees F
(93 degrees C) the pressure rating drops off rapidly. At 250 degrees F (121
degrees C) the pressure rating is 125 psig (861.3 kPa) and drops to 45 psig
(310.1 kPa) at 270 degrees F (132 degrees C). These ratings are for hot
water. Live steam cannot be tolerated, although RTRP pipe may be used for
vented gravity condensate piping as well as for pumped condensate piping.
RTRP pipe is acceptable at Class B sites (refer to para. 3.2.3). It is
recommended for Class A sites, as permitted in para. 2.1.2, due to its low
cost and long service life. Procure and install RTRP condensate piping in
accordance with NFGS-02697. Take special care in the design of steam drip
connections to protect the RTRP piping from live steam from failed traps.
Insulate condensate piping only when a life-cycle cost analysis indicates a
payback in energy savings, or where needed for personnel protection (manholes,
Service and Loads. Determine from Section 2 the services, such as
steam, high temperature water, hot water, chilled water, compressed air, fuel
gas and others, required for each load center or building, the load demands
for each service, and the capacity of a source or central plant for each
service. (Refer to Section 2 for fluid conditions inside service lines, for
sizing pipes for these conditions, and for the required capacities.)
and size to accommodate future construction.
Pressure Drop. From the total allowable pressure drop and ultimate
length of a line, determine the pressure drop per 100 feet (30.5 m). Note the
maximum flow between each load center and size the different pipeline sections
From a field survey, note all obstacles for each route.
Future Loads. Refer to Master Plan and consider system routing to
accommodate future construction.