Cogeneration/trigeneration plants run natural-gas turbines (GE Frame 5, Siemens SGT, Solar Taurus). On 50-100 MW class units lube oil, fuel gas and high temperatures drive fire risk. NFPA 37 (Stationary Combustion Engines and Gas Turbines) defines enclosure ventilation, CO2 protection and gas-detection rules.
Enclosure Ventilation
- Normal: 30-50 ACH for cooling
- Maximum: >55 C internal - increase fan
- Emergency: close dampers before CO2
- Purge: 30 ACH mandatory after CO2
CO2 Total Flooding
- Concentration: 50 percent (gas turbine)
- Hold time: 20 min
- Discharge: 1 min (surface fire)
- Reserve: 100 percent reserve bank (NFPA 37 option)
- Alarm: 20 sec pre-discharge warning
Lube Oil System
- Tank: 1,500-3,000 L, bearing cooling
- Pump: AC + DC emergency pump
- Level alarm: low-level shutdown
- Fire detection: linear heat (Listec), IR3 flame detector
- Water spray: lube oil tank and cooler (NFPA 15 alt)
Natural Gas Regulator
- Pressure reduction: 70 bar -> 30 bar -> 5 bar (turbine inlet)
- ESDV: dual Emergency Shut-Down Valves
- Gas detector: 20 percent LEL alarm, 40 percent ESD
- PSV: over-pressure vent to safe location
- Filter separator: removes liquid/solid particulates
Detection and Interlock
- UV/IR3 flame: detects within 3 sec
- Vibration: bearing/compressor fault
- Exhaust temp: >650 C alarm
- Hot gas path inspection: every 8,000 hours
- Trip logic: CO2 activation -> turbine shutdown
Gas turbine with MEP Calc
MEP Calc sizes gas turbine enclosure ventilation, CO2 total flooding and gas regulator per NFPA 37.
Download MEP Calc on the App Store
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Download SprinkCalc on the App StoreNFPA 37, NFPA 12, NFPA 54 Fuel Gas Code, ASME B31.3, API RP 556. NFPA 37 Combustion Engines standard.