GE Power SystemsGas Turbine

June 2001GEK 110090

These instructions do not purport to cover all details or variations in equipment nor to provide for every possiblecontingency to be met in connection with installation, operation or maintenance. Should further information be desired orshould particular problems arise which are not covered sufficiently for the purchaser’s purposes the matter should bereferred to the GE Company. 2001 GENERAL ELECTRIC COMPANY

Fire Protection System

I. GENERAL INFORMATION

The carbon dioxide fire protection system used for the gas turbine unit extinguishes fires by reducing theoxygen content of the air in the compartment from an atmospheric normal of 21% to below the levelnecessary to support combustion (normally 15%). To reduce the oxygen content, a quantity of carbon dioxide(CO2) equal to or greater than 34% of the compartment volume is discharged into the compartment in oneminute and, recognizing the reflash potential of combustibles exposed to high temperature metal, anextended discharge is provided to maintain an extinguishing concentration for a prolonged period tominimize potential reflash conditions.

The fire protection system design conforms to the requirements specified in NFPA Pamphlet 12-Standardon Carbon Dioxide Extinguishing Systems.

II. FUNCTIONAL DESCRIPTION AND SYSTEM OPERATION

To gain a better understanding of the fire protection system, a brief description of its operation and distinctivefeatures is provided in the following paragraphs. Refer to the fire protection system schematic diagram (MLI0426) located in the Reference Drawings section of the Service Manuals.

The fire protection system is comprised of a distribution system of piping for the delivery of CO2 from a lowpressure storage tank to the required gas turbine compartments in the event of a fire. This low pressurestorage tank is usually located on an off-base skid and maintains saturated liquid carbon dioxide at a storagepressure of 300 psig (21.09kg/cm2 or 2069 kPa) at 0°F (-18°C) by means of a refrigeration compressor. Thefire protection system control panel is usually mounted on the off-base skid (or in the turbine control roomif customer requested). The interconnecting field piping, which is usually supplied by the installer, deliversthe CO2 from the off-base skid to the gas turbine compartments, where it connects to the on-base piping thatdistributes the CO2 into the compartments through nozzle orifices.

Two separate distribution systems are used: an initial discharge and an extended discharge. Within a fewseconds after actuation, sufficient CO2 flows from the initial discharge system into the gas turbinecompartments to rapidly build up an extinguishing concentration (normally 34%). A CO2 concentration(usually 30%) is then maintained by the gradual addition of more CO2 from the extended discharge systemcompensating for compartment leakage. Carbon dioxide flow rate is controlled by the size of the orifices inthe discharge nozzles in each compartment for both the initial and extended discharge systems. The orificesfor the initial discharge system are large, permitting the rapid discharge of CO2 to quickly obtain theextinguishing concentration mentioned above. Orifices for the extended discharge system are smaller and

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permit a relatively slow discharge rate to maintain the extinguishing concentration over a prolonged periodof time (based on the turbine frame size’s emergency roll down and cool down periods) to minimize thelikelihood of a fire reigniting.

Each standard gas turbine unit has three zones of fire protection, with each zone consisting of an initial andan extended discharge. This three-zone fire protection system allows each zone to act independently of theother; a fire in zone 1 will not initiate a discharge of CO2 in zones 2, or 3, a fire in zone 2 will not initiatea discharge of CO2 in zones 1, or 3, nor will a fire in zone 3 initiate a discharge of CO2 in zones 1, or 2. Thiszone protection/detection is achieved by using separate A and B loops of heat-sensitive fire detectors. Eachfire detector is wired into the fire protection control panel in such a way that both an A and B detector in thatparticular zone must be tripped in order for CO2 to be discharged. Strobes and horns, as well as CO2 warningsigns, are strategically positioned on the outside and/or inside of the appropriate compartments to warnpersonnel of CO2 discharge.

Should a fire occur in one of the protected gas turbine compartments, the contacts of the heat-sensitive firedetectors will close and complete an electrical circuit that energizes and opens solenoid valves 45CR-1A and-2A (zone 1 initial and extended discharge), solenoid valves 45CR-3A and -4A (zone 2 initial and extendeddischarge), solenoid valves 45CR-5A and -6A (zone 3 initial and extended discharge), which are all locatedin the Pilot Control Cabinet. Actuation of the solenoid valves allows CO2 from the storage tank to pressurizethe pistons of that particular zones’ initial and extended discharge pilot operated selector valves located onthe CO2 discharge manifold. Carbon dioxide then flows from the storage tank, through the initial andextended discharge selector valves into the piping distribution system and into the compartments of theparticular zone.

The system may also be manually actuated by means of the manual toggle switches (43CP-1A for zone 1,43CP-2A for zone 2, and 43CP-3A for zone 3) located on the outside of the Electrical Control Cabinet orby the manual pilot valves located in the Pilot Control Cabinet. If customer requested, there may also bemanual release switches mounted on the enclosure external walls of the protected zones. These devices,which will normally have 43MRT-1A, -1B, -1C, -1D, and 43MRLC-1A, 1B for zone 1, and 43MRA-3A,-3B, -3C for zone 3 nomenclature (refer to the system schematic), are equipped with a pin which must bepulled before the push button can be depressed to activate the system and discharge the CO2. Actuation ofthe system, either automatically or manually, will trip the turbine to shut off, shut down the ventilationsystem, and cause the discharge of CO2.

For the purposes of maintenance on the fire protection system or the gas turbine itself, the accidentaldischarge of CO2 can be prevented by either closing the main shut off valve located on top of the storagetank or by closing the ball valve/limit switch (33CL-1A) located in the Pilot Control Cabinet. If customerrequested, there may also be manual lockout switches mounted on the enclosure external walls of theprotected zones. These devices, which will normally have 86MLT-1A, -1B, -1C, -1D, 86MLLC-1A, 1B(zone 1), and 86MLA-3A, -3B (zone 3) (refer to the system schematic), are for remote lockout of CO2discharge.

Initial and extended discharge timers, 2CP-1A, -2A (zone 1), 2CP-3A, -4A (zone 2), and 2CP-5A, -6A (zone3) are located on the control panel in the Electrical Control Cabinet and control the length of time the solenoidvalves are energized and thus the CO2 discharge time (these times are factory set refer to MLI A068 forthe specific times). After CO2 discharge, these timers should be reset by depressing the timer reset buttons( 86FP-1A (zone 1), 86FP-2A (zone 2), and 86FP-3A (zone 3) located on the outside of the Electrical ControlCabinet (this will also serve to shut off the alarms). Predischarge timers (which are usually factory set fora suggested 30 seconds to allow personnel to evacuate the compartments, but can be changed in the field ifrequired) are also located on the control panel and control the time between the detection of the fire and theactivation of the solenoid valves.

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CAUTION

If the carbon dioxide system is to be effective, the compartment panels mustbe in place and the compartment doors closed. There is sufficient CO2 in thesystem to compensate for leakage through ventilation openings which areclosed by gravity dampers or CO2 pressure operated dampers (which must bemanually reset) and unavoidable cracks in the package lagging. There is notenough to allow for uncontrolled escape of CO2 through open panels or doors.

* * * WARNING * * *

Carbon dioxide, in a concentration sufficient to extinguish fire, creates anatmosphere that will not support life. It is extremely hazardous to enter thecompartments after the CO2 system has been discharged. Anyonerendered unconscious by CO2 must be rescued as quickly as possible andresuscitated immediately. It is essential that personnel be adequatelytrained as to the proper action to take in case of such an emergency.

III. INSTALLATION, MAINTENANCE, AND TESTING

For installation, inspection, and maintenance of the fire protection system, refer to the vendor instructionsfollowing this text. For fire protection/detection system testing instructions, refer to MLI 0113, and the CO2Concentration Test instructions following this text.

A. CO2 CONCENTRATION TEST INSTRUCTIONS

This test involves running a full CO2 concentration test consisting of both the initial and extendeddischarges for each zone of protection. The initial discharge runs for one minute following the releaseof the CO2; while the extended discharge runs simultaneously, but continues for at least 30 minutes ormore depending upon the discharge times required. Due to varying site conditions, differing locationsof the off-base supply of CO2 from the turbine, and potential leaks in the lagging and piping, a CO2concentration test, though not required, is highly recommended to ensure the integrity of the fireprotection system design and compliance with NFPA 12 (a simple Puff Test is not satisfactory to ensurethe system functions and is designed properly). In order to perform the concentration test, a qualifiedtechnician must be present to make sure the test is run properly. The vendor, whose instruction manualfollows this text, should be contacted in order to locate and schedule a technician to come to the particularsite and oversee the concentration test.

The CO2 concentration test should be conducted as follows:

1. Inspect the ventilation dampers in the accessory, turbine, load, and/or any additional compartmentsthat are being protected by CO2. They should all be attached in the OPEN position for the dampersthat have CO2 operated latches.

2. Check to make sure the predischarge timers that are located in the control panel are set for thesuggested 30 second time delay to allow personnel time to evacuate the compartment before CO2is released. The predischarge timers can be changed in the field if a different time delay is required.

3. Check to make sure all compartments protected by CO2 (except the #2 bearing area whereapplicable) have a minimum of two external CO2 warning signs applied, one on of each side of eachcompartment for personnel warning.

General Electric CompanyOne River Road, Schenectady, NY 12345518 • 385 •2211 TX: 145354

GE Power Systems

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4. Clear all personnel from the compartments and close all compartment doors. At this time, anyobvious cracks or leaks in the lagging should be sealed to ensure compartment integrity.

5. Initiate the release of the CO2 by electrical means within the fire protection control panel: for LPCO2 systems, toggle the control panel release switches (43CP devices where applicable) to beginrelease of the CO2; and for HP CO2 systems, pull the operating pin on the pressure switch (45CPdevices where applicable) to activate the pilot cylinder solenoids to release the CO2. Each zoneshould be tested separately for both the initial and extended discharge. Upon initiating release ofthe CO2, the fire alarm strobes and horns in the accessory compartment and in any othercompartments should be activated and be clearly heard. During the test, inspect the outside of eachcompartment to see if quantities of CO2 are leaking out of cracks in the lagging, meaningcompartment integrity has not yet been achieved.

6. After the CO2 discharge has stopped, the applicable switches should be reset. A compartmentinspection should be carried out to verify that all ventilation dampers have functioned properly.Once this operation has been performed, the dampers should be reset to the OPEN position.PERSONNEL SHOULD NOT ENTER COMPARTMENTS TESTED UNTIL CO2CONCENTRATIONS HAVE DISSIPATED.

7. For High Pressure CO2 systems, which are normally designed for one full discharge only, thedischarged cylinders should be removed and recharged to full capacity. These cylinders should bereturned to their respective rack locations and secured. For Low Pressure CO2 systems, which arenormally designed for two full discharges, the LP CO2 tank should be refilled to 90-95% capacityas soon as a CO2 refill is possible.

8. Upon successful completion of the CO2 concentration test, G.E. Design Engineering should beconsulted and the results of the concentration test should be sent to the appropriate design engineerfor design documentation purposes.