Fire & Gas Detection and ProtectionPurpose:Required for protection of Personnel and assets.

Keys:Hazardous AreaGas DetectionFire DetectionFire Protection

Hazardous AreaIn Oil & Gas industry Combustible Materials such as Hydrocarbons and Hydrogen gas and Toxic gases such as H2S are handled.Combustible materials become Flammable in the presence of atmospheric Oxygen.If Flammable material comes into contact with an arc or spark or a hot surface, an Explosion may occur.

Hazardous AreaExposure to Toxic Gas above certain levels may be dangerous to human life.Therefore improperly handled combustible or toxic material may cause a loss of life and materials, which has to be prevented by suitable design practices..To prevent electrical devices from causing an explosion due to generatoin of an arc/ spark or hot surface, various protection techniques are employed viz. IS, Ex proof, Purging, Non incendive, Increased Safety, Oil Immersion, Encapsulation etc.

Gas DetectionGas leak may occur due to:Operational Requirements (Blowdown, Vents etc)Failure of Equipment and fittings

Type of Gas:HydrocarbonHydrogenHydrogen Sulphide (Toxic)

Types of Gas Detectors:Catalytic Bead Infra Red (Point or Line of Sight)Electrochemical, Semiconductor

Fire DetectionFusible Plugs(Non Electrical)Flame Detector (UV, UV/IR)Heat/ Thermal Detectors (Fixed, Rate of Rise)Smoke detectors

Fire ProtectionActive ProtectionPassive Protection

Active-Sprinkler/ Deluge-FM200/CO2/ Halon-Foam

Passive-Firewall-Protective Coatings

Sprinkler/ DelugeFire Water System:Two or three independently operated fire water pumps are located separately so that single fire incident does not put all these pumps out of action.Sprinkler (Wet System)-Pipework of Fire Water under pressure with Quartzoid Bulbs suitably placed along its length.Deluge (Dry System)-One Pipework of Pneumatic supply with Quartzoid Bulbs suitably placed along its length and Pressure Switch sensor. Second Pipework of Fire Water with a Deluge Valve that opens upon sensing of Low pressure in first network due to a broken bulb.- Deluge Valve for each system is located outside of but adlacent to the protected area (e.g DV for Main Deck is located on Cellar Deck and vice versa.)

Clean AgentUsed to protect the areas where primary risk is of Electrical fires. E.g Control Room, Switchgear, battery room, turbine enclosure etcDischarge of Clean Agent is generally activated by coincident Smoke detection.Control Box containing the following is placed at the entrance of the protected enclosure:-Audible Alarm to indicate that CA will be discharged after time delay of 20 seconds.Key Operated Switch to Inhibit the discharge.Pushbutton for Local Manual Activation.Indicating Lamp for Inhibit conditionIndicating Lamp for About to Discharge.Indicating Lamp for System Discharged.

FirewallsFirewall is used to limit the spread of fire from one area to another. These prevent the passage of smoke and flame as well as prevent temperature rise on the unexposed surface.Designed as per SOLAS (Safety of Life at Sea) regulations.

Alarms AnnunciationsGeneral Alarm:- It is activated upon detection of fire, gas, MAC or any ESD.-Audio Visual alarm (Red flashing, 2 secs on/ 2 secs off).

Toxic Gas Alarm:It is activated upon detection of toxic gas.It is a 1.4 sec ramp, sawtooth wave (slow increasing, fast reducing).

Abandon Platform:-It is manually activated by a rotary switch located in control room, near survival craft, helideck.-Audio Visual Alarm (Blue lamp, Siren tone)

Mimic Display:It provides the operator with information on type and location of a hazard. The system gives a geographical layout of installations including the following items:Fire, Smoke, Flammable Gas, Toxic Gas, Fire Extinguishing apparatus status, ESDs, MAC