Architectural & Engineering Design Standards
15700
LIQUID HEAT TRANSFER
SCOPE:
Buildings shall be connected to the University Steam Distribution System unless approved otherwise by the Project Manager. Space heating shall be accomplished with steam-to-water heat exchangers. The use of steam for space heating is limited to unit heaters or preheat coils. Hot water is prefered.
The transfer of heat from points of generation to coils or terminal units within the building require Water or Steam piping systems.
PRODUCTS:
Water Piping shall be black steel schedule 40 with screwed joints or type "L" copper with sweat connections for nominal pipe sizes 2-inch or less. Larger piping shall be steel of the same type and schedule but with welded fittings.
Steam Supply Piping shall be black steel schedule 40 with 150 PSIG screwed malleable iron fittings through 2-inch. Larger piping shall be of the same type and schedule but with welded 150 PSIG fittings. Steam Condensate Piping shall comply with the requirements for steam supply for the various sizes except that schedule 80 is to be used.
EXECUTION:
Water and steam piping shall be installed so that the systems can be drained. Manual Vents are to be located at all high points with Manual Drains at each low point. Provide Floor Drains near the piping drain points. Each valve, coil, or terminal shall have Isolation Valves with Unions or Flanged Connections for normal maintenance and repair.
Where main piping branches to two or more heat transfer terminals, Isolation Valves shall be installed in all heat transfer piping systems.
Each building connected to the University Steam Distribution System shall have Pressure Reduction Stations (PRS) installed to satisfy heat exchanger, chiller, water heater, or other terminal equipment design inlet pressures.
Pressure Reducing Stations shall have dual valves with a manual globe valve bypass. One sized for 1/3 of the total building steam load; the other for 2/3. Pressure gauges shall be installed upstream and downstream of each PRS. Design Loops for 125PSIG, Design PPV Valves to 30 - 50 PSIG.
ASME pressure relief valves shall be installed downstream of all PRS and on the leaving side of all water-to-air heat exchangers. The discharge of each relief valve shall terminate on the roof.
Steam piping systems shall
be designed and installed for condensate and steam flow in the same direction.
Steam Control Valves and steam pressure reducing valves and Condensate
Traps shall have a valved bypass and upstream strainer for maintenance
and removal without shutting down the system. The Contract drawings shall
indicate all trap locations and their capacity in LB/HR. Traps shall be
selected with a factor of safety of 2. Thermal expansion provisions must
be detailed on the drawings.
All heat transfer piping systems shall be identified whether exposed or
concealed; all valves are to be tagged and identified with by a Valve
Schedule appropriately inside mechanical rooms.
-END-
Date: December 2001
Revised
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