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STEAM DISTRIBUTION SYSTEM
U OF I FACILITIES STANDARDS Page 1 of 4 STEAM DISTRIBUTIONLAST
UPDATED JUNE 15, 2013
Cogeneration:
Steam for distribution tocampus is generated at Abbott Power
Plant,the Universitys cogeneration power plant.
Campus Distr ibut ion System: Steam isdistributed to campus
buildings through twodistinct piping systems. These are referredto
as the medium pressure system (a.k.a.Campus Steam system) and the
highpressure system (a.k.a. Utility Steamsystem). Distributed steam
is available year-round through each system. These aregenerally
laid out in an interconnecting gridconfiguration encompassing the
majority ofcampus buildings. Pressure delivered topoints of use is
generally regulated withineach building.
Geography: Historically, steam from themedium pressure Campus
Steam system
served as the source of heating steam foressentially all campus
buildings. As thecampus expanded geographically it
becameincreasingly impractical to serve remotebuildings with steam
from this system.Thus, the majority of the buildings locatednorth
of Springfield Avenue are servedexclusively by the high pressure
UtilitySteamsystem. In this region of campus thebuildings west of
Mathews Avenue areserved with 50-60 PSIG steam deliveredthrough a
pressure regulating station locatedwithin the North Campus Chiller
Plant. The
buildings east of Mathews Avenue areserved with 150-165 PSIG
steam directlyfrom the Utility Steam System. TheVeterinary Medicine
Campus is also servedby the high pressure Utility Steamsystem viaa
southward extension of the system.Throughout campus, a limited
number ofbuildings are fed with steam from both theCampusand
Utility Steam systems. Theseare typically buildings with
laboratorysterilizing equipment, kitchen cookingequipment or
laundry facilities.
Medium Pressure System: Mediumpressure Campus Steam typically
exits thepower plant at pressures of 20-25 PSIG inthe heat of
summer and 30-40 PSIG in thecold of winter in order to maintain a
year-round set point of approximately 15 PSIG atthe opposite side
of campus (see SpecificDesign Information below). This system
isprotected by safety relief valves locatedwithin the plant. The
highest trip setting for
the medium pressure system is 129 PSIG.Per code, the piping
system must bedesigned for the highest trip setting plus
6%tolerance. Thus, the design pressure for themedium pressure
system with all itscomponents is 137 PSIG.
High Pressure System: High pressureUtility Steamtypically exits
the power plant atpressures up to 165 PSIG. Under normaloperating
conditions high pressure steam isavailable at campus buildings at
pressuresranging from 150 to 165 PSIG (see SpecificDesign
Information below). This system isalso protected by safety relief
valves locatedwithin the plant. The highest safety valve
tripsetting for the high pressure system is 175PSIG. Adding the 6%
tolerance yields adesign pressure for the high pressuresystem of
186 PSIG.
Steam Temperatures: Steam within bothsystems typically exits the
plant attemperatures of 350-400 degrees F(superheated).
Steam Puri ty : Distributed steam is of highpurity due to the
use of deionized water forsystem makeup. USDA/FDA approvedboiler
water and steam treatment chemicalsare used. The steam is treated
withMorpholine and DEAE to less than 25 PPMto control condensate
corrosion. The steam
meets standards for use in soil sterilization.No filming amines
are used. The use ofboiler additives results in negligible
carryoverinto the steam. Condensate pH isapproximately 7.5-8.5 and
conductivity isapproximately 3-20 micromhos (a.k.a.microsiemens).
The steam is currently notapproved for direct contact with
food.
Condens ate Return System: A dedicatedpumped condensate return
system alsoexists that parallels the steam distributionsystem. The
pressure in this systemfluctuates widely. However, for the sake
ofconsistency and interchangeability, a systempressure of 50 PSIG
shall be used for sizingpumping equipment that discharges into
thecentral condensate return system. Allsteam-utilizing
systems/equipment oncampus shall be designed and installed soas to
return 100% of the condensate back tothe power plant through the
centralcondensate return system. Steam
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STEAM DISTRIBUTION SYSTEM
U OF I FACILITIES STANDARDS Page 4 of 4 STEAM DISTRIBUTIONLAST
UPDATED JUNE 15, 2013
connected to condensate return units withinadjacent buildings or
to condensate pumpstations within the tunnel system as directedby
the Energy Service Division within F&S.
Pipe Stress Analys is: When modificationsor additions are made
to existing steamdistribution piping systems, pipe stressanalysis
per ASME B31.1 shall beperformed. At a minimum, stress
analysisshall be performed upon anchor adjacent tothe areas of
modification. Analysis resultsshall be presented to the Energy
ServiceDivision within F&S.
Specif ic Design Information: Thefollowing project-specific
information anddesign directives shall be obtained from theUtility
Program Statement:1. Distribution system to be used for a
specific project (medium pressure vs.high pressure)
2. Operating pressure and temperature tobe used for specific
project designpurposes
3. Type, placement and sizing of systemextensions
4. Available plant and distribution systemcapacities
Documentat ion and Subm i t tals : The AEshall review the
Project SubmittalRequirements.
