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Site Alpha Symbol Reference

Blueprint, P&ID, electrical, fire-protection and plumbing legend sheets for the Commissioning Agent line · Edition 1.0 · October 2026

G-002 GeneralM-001 / M-002 Mechanical and P&IDE-001 ElectricalF-001 FireP-001 Plumbing

These six sheets are the legend for every Site Alpha drawing used in Commissioning Agent modules and Virtual Bench exercises. On a real project the set's own legend sheets govern. Read them first, and never guess a symbol.

G-002 · GENERAL SYMBOLS AND ABBREVIATIONS

ENGINEER OF RECORDseal area — training drawingSITE ALPHA DATA CENTERHall 1 · Alpha 360 LLC training setREVISIONS003-02ISSUED FOR CONSTR.105-18ASI-07 / RFI-112DRAWN AB · CHECKED CDJOB 26-014 · SCALE: NTSSHEET TITLEGENERAL SYMBOLS ANDABBREVIATIONSG-0021 · GENERAL SYMBOLSLINES AND ANNOTATIONObject line (visible edge)Hidden line (behind / below)CenterlineSection cut line with viewarrowsBreak line12'-0"Dimension line3M-301Section / detail bubble (viewover sheet)BColumn grid bubble2Revision cloud and deltaNNorth arrow04'8'Graphic scale bar7Keynote tagCH-1Equipment tagABBREVIATIONSABBRMEANING(E)existing(N)new(R)remove(RL)relocateAFFabove finished floorABBRMEANINGBODbasis of designCLcenterlineELelevationEQequalNICnot in contractABBRMEANINGNTSnot to scaleSIMsimilarTYPtypicalUONunless otherwise notedVIFverify in fieldNOTES1. Each discipline's 0-series sheet governs its own symbols on its own sheets.2. Office conventions vary — read this sheet before any other sheet in the set.3. Training drawing — Site Alpha is fictional.

M-001 · MECHANICAL AND P&ID LEGEND

ENGINEER OF RECORDseal area — training drawingSITE ALPHA DATA CENTERHall 1 · Alpha 360 LLC training setREVISIONS003-02ISSUED FOR CONSTR.105-18ASI-07 / RFI-112DRAWN AB · CHECKED CDJOB 26-014 · SCALE: NTSSHEET TITLEMECHANICAL AND P&IDLEGENDM-0011 · MECHANICAL AND P&ID SYMBOLS (instrument symbols and tags per ANSI/ISA-5.1)VALVES AND ACTUATORSGate valve(generic two-way)Globe valveBall valveButterfly valveCheck valve (flowleft to right)Three-way valvePressure safety /relief valveBalancing /flow-measuringvalveFCControl valve,diaphragmactuator, failclosed (FC)MFOControl valve,electric motoractuator, failopen (FO)SFLSolenoid valve,fail last (FL)Manual handwheeloperatorEQUIPMENT AND FITTINGSCentrifugal pumpPlate / shellheat exchangerTank / vesselY-strainerFlexibleconnectorConcentricreducerCooling coilCooling towerINSTRUMENT BUBBLESTT101Instrument — field mountedTI101Instrument — primary location,operator accessible (controlroom / panel front)TY101Instrument — behind panel, notnormally accessibleTIC101Shared display / sharedcontrol (BAS / DCS function)TY101Computer functionXS11Programmable logic controllerfunctionSIGNAL LINESProcess line / instrumentconnection to processElectrical signalPneumatic signalSoftware / data link (network)Capillary tubeFail positions and pipe services: see M-002.

M-002 · INSTRUMENT TAG LETTERS AND EXAMPLES

ENGINEER OF RECORDseal area — training drawingSITE ALPHA DATA CENTERHall 1 · Alpha 360 LLC training setREVISIONS003-02ISSUED FOR CONSTR.105-18ASI-07 / RFI-112DRAWN AB · CHECKED CDJOB 26-014 · SCALE: NTSSHEET TITLEINSTRUMENT TAG LETTERS ANDEXAMPLESM-0021 · INSTRUMENT TAG LETTERS (ANSI/ISA-5.1) AND SITE ALPHA EXAMPLESTAG LETTERS1STMEASURED VARIABLENEXTFUNCTIONAanalysisAalarmEvoltageCcontrolFflowEprimary element (sensor)IcurrentIindicateJpowerRrecordLlevelSswitchPpressureTtransmitPDpressure differentialVvalve / final elementSspeed / frequencyYrelay / compute / convertTtemperatureH / Lhigh / low (modifiers)ZpositionZdriver / actuatorHOW A TAG READSTtemperatureIindicateCcontrol–101loop numberRead left to right: what is measured, then what the device does, then the loop it belongs to.SITE ALPHA TAGSTAGWHAT IT ISTT-101temp. transmitter, CHW supplyTT-102temp. transmitter, CHW returnFT-101flow transmitter, CHW supplyPDT-101diff. pressure across Hall 1FS-11…41flow switches, evaporator proofTV-101valve, loop 101 (storage)TIC-101temp. controller (BAS, shared)ZSO / ZSCvalve position switch open / closedXS-11PLC function, chiller startLOOP EXAMPLETT101TIC101MTV-101 · FOTransmitter → controller (shared display) → valve.Dashed = electrical signal.FAIL POSITIONSFO fail open · FC fail closed · FL fail last (stays put) · FL/DO fail last, drift open · FL/DC fail last, drift closedFail position is what the valve does on loss of air, power or signal — it decides ride-through behavior, so it is a commissioning criterion.PIPE SERVICESCHWS / CHWR chilled water supply / return · CWS / CWR condenser water · HWS / HWR heating water · D drain · V vent

E-001 · ELECTRICAL LEGEND AND DEVICE NUMBERS

ENGINEER OF RECORDseal area — training drawingSITE ALPHA DATA CENTERHall 1 · Alpha 360 LLC training setREVISIONS003-02ISSUED FOR CONSTR.105-18ASI-07 / RFI-112DRAWN AB · CHECKED CDJOB 26-014 · SCALE: NTSSHEET TITLEELECTRICAL LEGEND ANDDEVICE NUMBERSE-0011 · ELECTRICAL SYMBOLS (device numbers per IEEE C37.2)POWER — ONE-LINE AND BUILDING WIRINGCircuit breaker(one-line)Draw-out circuitbreakerFuseDisconnect switch(open)TransformerGGeneratorMMotor~=UPS (rectifier /inverter)ATSAutomatictransfer switchCTCurrenttransformerGroundBus (switchgear /switchboard)PMMeter (powermonitor)27Protective relay(device number inthe bubble)Duplex receptaclePanelboard(surface)JJunction boxLP-1·3Home run to panel(circuit numbers)CONTROL — LADDER AND WIRINGContact, normallyopenContact, normallyclosedTimed contact,on-delay (timedclosing)CRRelay / contactorcoilPushbutton,normally openPushbutton,normally closedEmergency stop(mushroom head,NC)Thermal overloadrelay contactFlow switchcontact (NO)GPilot light(letter = color)Selector switch,two-positionDEVICE NUMBERSNO.FUNCTION2time-delay starting relay25sync-check27undervoltage32directional power49thermal overloadNO.FUNCTION50instantaneous overcurrent51time overcurrent51Gground time overcurrent52AC circuit breaker59overvoltageNO.FUNCTION81frequency86lockout relay87differentialSuffixes: G ground or generator · N neutral · T transformer (e.g. 87T). Pilot light letters: R red · G green · A amber · W white.

F-001 · FIRE PROTECTION AND LIFE SAFETY LEGEND

ENGINEER OF RECORDseal area — training drawingSITE ALPHA DATA CENTERHall 1 · Alpha 360 LLC training setREVISIONS003-02ISSUED FOR CONSTR.DRAWN AB · CHECKED CDJOB 26-014 · SCALE: NTSSHEET TITLEFIRE PROTECTION AND LIFESAFETY LEGENDF-0011 · FIRE PROTECTION AND LIFE SAFETY SYMBOLSSPRINKLER, DETECTION, NOTIFICATIONSprinkler head, uprightSprinkler head, pendentPAVPreaction / deluge valveFSWaterflow switch (FS) onriserTSValve tamper switch (TS)SSmoke detectorHHeat detectorFManual pull stationHSHorn / strobeEPOEmergency power off (EPO)stationNOTES1. Fire alarm device symbols vary by office; this sheet governs this set.2. Integrated testing of fire and life-safety interfaces per NFPA 4; commissioning per NFPA 3.3. EPO and preaction release are proven in a controlled way per the IST plan — never by surprise on live load.

P-001 · PLUMBING AND FUEL LEGEND

ENGINEER OF RECORDseal area — training drawingSITE ALPHA DATA CENTERHall 1 · Alpha 360 LLC training setREVISIONS003-02ISSUED FOR CONSTR.DRAWN AB · CHECKED CDJOB 26-014 · SCALE: NTSSHEET TITLEPLUMBING AND FUEL LEGENDP-0011 · PLUMBING AND FUEL SYMBOLSDOMESTIC WATER, DRAINAGE, FUELRPZReduced-pressure backflowpreventerMWater meterFloor drainCOCleanoutHose bibbWHWater heaterEWEmergency eyewash / showerFOSFORFuel oil supply / return(generator)PIPE SERVICESCW domestic cold water · HW domestic hot water · HWR hot water return · SAN sanitary · V ventSD storm drain · IW industrial (CHW makeup) water · FOS / FOR fuel oil supply / return (generators)

Symbol index

Every symbol on the legend sheets, by group, at a readable size.

General — G-002

Object line (visible edge)
Hidden line (behind / below)
Centerline
Section cut line with view arrows
Break line
12'-0"Dimension line
3M-301Section / detail bubble (view over sheet)
BColumn grid bubble
2Revision cloud and delta
NNorth arrow
04'8'Graphic scale bar
7Keynote tag
CH-1Equipment tag

Valves — M-001

Gate valve (generic two-way)
Globe valve
Ball valve
Butterfly valve
Check valve (flow left to right)
Three-way valve
Pressure safety / relief valve
Balancing / flow-measuring valve

Actuators and fail positions — M-001

FCControl valve, diaphragm actuator, fail closed (FC)
MFOControl valve, electric motor actuator, fail open (FO)
SFLSolenoid valve, fail last (FL)
Manual handwheel operator

Mechanical equipment and fittings — M-001

Centrifugal pump
Plate / shell heat exchanger
Tank / vessel
Y-strainer
Flexible connector
Concentric reducer
Cooling coil
Cooling tower

Instrument bubbles — M-001

TT101Instrument — field mounted
TI101Instrument — primary location, operator accessible (control room / panel front)
TY101Instrument — behind panel, not normally accessible
TIC101Shared display / shared control (BAS / DCS function)
TY101Computer function
XS11Programmable logic controller function

Signal lines — M-001

Process line / instrument connection to process
Electrical signal
Pneumatic signal
Software / data link (network)
Capillary tube

Power — E-001

Circuit breaker (one-line)
Draw-out circuit breaker
Fuse
Disconnect switch (open)
Transformer
GGenerator
MMotor
~=UPS (rectifier / inverter)
ATSAutomatic transfer switch
CTCurrent transformer
Ground
Bus (switchgear / switchboard)
PMMeter (power monitor)

Relays — E-001

27Protective relay (device number in the bubble)

Control — E-001

Contact, normally open
Contact, normally closed
Timed contact, on-delay (timed closing)
CRRelay / contactor coil
Pushbutton, normally open
Pushbutton, normally closed
Emergency stop (mushroom head, NC)
Thermal overload relay contact
Flow switch contact (NO)
GPilot light (letter = color)
Selector switch, two-position

Building wiring — E-001

Duplex receptacle
Panelboard (surface)
JJunction box
LP-1·3Home run to panel (circuit numbers)

Fire protection and life safety — F-001

Sprinkler head, upright
Sprinkler head, pendent
PAVPreaction / deluge valve
SSmoke detector
HHeat detector
FManual pull station
FSWaterflow switch (FS) on riser
TSValve tamper switch (TS)
HSHorn / strobe
EPOEmergency power off (EPO) station

Plumbing and fuel — P-001

RPZReduced-pressure backflow preventer
Floor drain
COCleanout
Hose bibb
WHWater heater
EWEmergency eyewash / shower
MWater meter
FOSFORFuel oil supply / return (generator)

Sources

  1. ANSI/ISA-5.1-2024, Instrumentation and Control Symbols and Identification. International Society of Automation.
  2. IEEE C37.2, Electrical Power System Device Function Numbers, Acronyms and Contact Designations (current edition).
  3. IEEE 315, Graphic Symbols for Electrical and Electronics Diagrams, and common NEMA control-diagram practice.
  4. United States National CAD Standard — sheet identification and the general (0-series) legend sheets. National Institute of Building Sciences.
  5. NFPA 3 and NFPA 4 (2024 editions) — fire and life-safety commissioning and integrated testing (F-001 notes).