CO 2 Suppression Systems

Transcription

1 گاز كربنيك اطفاء حريق سيستم و تنظيم : تهيه زهركش مجيد

2 CO 2 Suppression Systems

3 خصوصيات گاز اطفاء CO 2 What is CO 2? A colourless, dry, odourless, non-corrosive gas Density 1.5 times that of air Occurs naturally in atmosphere (0.03%) A by-product of combustion process eg. fossil fuels Produced as a by-product of industry

4 خصوصيات گاز اطفاء CO 2 How does it work? Reduces oxygen to less than 15% Discharges as liquid, expands at nozzle into dense cloud of vapour/ dry ice Expansion creates cooling effect, expansion ratio 1kg= 0.56m3 Effective on fire classes: A - Ordinary combustible material B - Liquid fuel fires C - Electrical fires Heat

5 Concentration - Vol. % Oxygen Depletion Curve Impaired Performance Zone Unimpaired Performance Zone 40 Inert Agents Pass Out 12.3% NASA Minimum FM-200 FE 13 TM Oxygen Conc %

6 خصوصيات گاز اطفاء CO 2 Inexpensive Readily available Effective on wide range of fires Versatile: high pressure/low pressure Total flood/local application Non corrosive: will not contaminate liquids or food Clean - no mess, CO2 dissipates to atmosphere

7 CO 2 & The Environment Normally present at 0.03% (increasing due to pollution/combustion) We breathe in CO 2 at 0.03% & breathe it out at 3-4% Harmless at low concentration Zero ODP

8 CO 2 & The Environment Significant GWP but non-emissive No environmental restrictions on CO 2 No restriction on testing (eg FMRC procedures) CO 2 is environmentally friendly

9 CO 2 Safety Clear exit routes Emergency lighting Alarms to operate on detection of fire - discharge delay to allow egress - delay on door closer to allow egress Exit doors to open outwards - panic bolts Continuous alarm until atmosphere safe again

10 CO 2 Safety Odoriser - adds distinctive smell to CO2 discharge Adequate warning signs and instruction inside and at entrance to risk Search & rescue drill by trained personnel (Fire Brigade) with BA sets. A person rendered unconscious by CO2 protected area can be revived with prompt first aid Safe ventilation of CO2 flooded areas

11 CO 2 Safety Cylinder safety: - Stored as a liquid at 58bar - Burst disc - Transport cover Container Storage Temperature range: - Local application: 0 º C to + 46 º C - Total Flood: -18 º C to + 54 º C

12 Hazards to Personnel Suffocation Drifting of gas to other areas which may be occupiedwarning signs Noise from discharge - quite loud Pre-discharge alarm & time delay: Sufficient to allow evacuation Visual alarms where ambient noise level is high

13 Hazards to Personnel Direct discharge of CO2 onto person - skin burns - eye injury - ear damage Precautions to prevent accidental discharge - isolation valve (BS requirement) - control head - lockout at control panel (NFPA/FM requirement) - lock off/door interlock (BS requirement) Clearance from live electrical apparatus - guidance provided in standards

14 Design Standards & Approvals Design Standards NFPA 12 BS 5306 Pt 4 Approvals FMRC ABS LRS MSA DNV CCS (China) NKK (Japan) BASEEFA

15 System Hardware Review Direct-acting solenoid assembly Metron actuator Weight-monitoring device

16 Direct-Acting Solenoid

17 Direct-Acting Solenoid Designed for use with standard 45 kg CO2 cylinders Modified version of existing cylinder valve Control head and nitrogen pilot cylinder replaced by solenoid assembly coupled to cylinder valve

18 Direct-Acting Solenoid Mode of Operation Inactivated State - pneumatic actuator subject to atmospheric pressure only Receipt of electrical signal from control panel - Solenoid coil activated - CO2 passes from cylinder to pneumatic actuator - Movement of actuator piston opens klem valve Agent exits via discharge port

19 Direct-Acting Solenoid Schematic

20 Direct-Acting Solenoid Specification Voltage range 18V DC to 28V DC Current at 18V DC 338mA Current at 28V DC 526mA Nominal coil resistance 53.2ohm Minimum firing pulse 60mS Maximum firing pulse Unlimited Electrical connection Din plug type Operating temperature -20º C DIN range to +55º C Maximum working bar (g) Environmental BS EN pressure protection IP65

21 Direct-Acting Solenoid Benefits Less hardware associated with system Compact actuation assembly Greater ease of installation More cost-effective Simple in-situ testing procedure

22 Metron Actuator D at net Direct fitting onto Klem Valve Manual Override Single or Multi Cylinder systems Four-year installed life

23 Weight Monitoring Device Development Rationale: Enables penetration of European specs Improved system reliability

24 Weight Monitoring Device Features: Robust construction - all metal One man installation Reliable - components selected for long life Low maintenance - 6 monthly visual inspection Simple test procedure Remote monitoring via optional switch

25 Weight Monitoring Device Assembly Diagram Downward force of cylinder exceeds leverage on weight rod Loss of mass 10% Reduces downward force and weight rod falls operating switch

26 Weight Monitoring Device Microswitch Details

27 Weight Monitoring device System Arrangement Installation Requires supporting frame Frame supports manifold No racking required

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29 Weight Monitoring Device System Actuation Options: Standard Solenoid Control Head & Pilot Nitrogen Cylinder Direct-Acting Solenoid Assembly Metron Operated Actuator Assembly

30 Weight Monitoring Device Benefits: Increased market acceptance Capital cost offset by reduced servicing and installation time More accurate determination of CO2 mass Increased system reliability Gas loss detected automatically Greater safety in cylinder storage area - detection of leaking CO2 Lower cost of ownership - reduced maintenance

31 Typical Applications Total Flood Switch Gear Rooms Cable Basements Fuel Stores Generators Gas Turbines Archive/Stores High Tech Filters Local Application Aluminium/ Steel Rolling Mills Flow Coating Machines Paint Booths Spark Erosion Machines Kitchen Range Hood, Ducts Quench Tanks High Value Machine Tools

32 Unsuitable Applications Reactive metals, e.g. Magnesium Chemicals which generate their own oxygen e.g. Cellulose Nitrate Metal hydrides Inerting - static discharge creates a hazard and a potential explosion Note: Where product is stored under another medium, e.g. Sodium under Kerosene (Paraffin), Magnesium chips under oil; CO2 will prevent spread of fire to these materials.

33 System Choices Total Flooding: - enclosed space - surface fires (limited leakage) - deep seated (no leakage) Local Application: - flat coated or liquid surface - 3 dimensional irregular shaped risks with or without partial enclosure.

34 System Choices Hose Reel: - Manual system - Uses high pressure hose & applicator - Useful for rapid knock down of spill fire in production areas.

35 System Design Surface Fire - discharge time 60 seconds Deep Seated Fire - discharge time up to 7 minutes Other Variables - Material Conversion Factor (MCF) - temperature compensation - leakage compensation - forced ventilation

36 System Design Use the design tools Preliminary Design Schedule Equipment Matrix CO 2 Flow Calculation Program The Manual

37 START YES Is the risk enclosed by a 1/2 hour fire rated construction? NO NO Are there any openings which cannot be closed at discharge? A: Calculate in M2 the area of uncloseable openings NO YES Will the fire be deep seated? Install dampers etc as required B: Calculate 10% of the total area in m2 of all sides top and bottom of the enclosure C: Calculate 10% of the volume in m3 YES NO Is A greater than B or C? YES Add extra CO2 at the rate of 5kg/m2 opening (multiply as necessary by material conversion NO Total Flooding System Calculation Local application system calculation

38 Surface Fire: Basic Quantity 9m 6m 3m V = 9 x 6 x 3 = 162m 3 Volume factor: 0.8kg/m 3..(from manual 2.1) Basic quantity of CO 2 = 162 x 0.8 = 129.6kg Total gas supplied: 45 X 3 = 135kg

39 Material Conversion Factor Check Fuel Hazard Against Table 2 Multiply the Basic Quantity by MCF, e.g. Vol 162m3 Basic Quantity = 129.6kg Butadine: MCF = 1.3 CO2 Quantity =129.6 x 1.3 = 168kg = 4x45Kg CO2 Cylinders If possible check competitors calculation.

40 Uncloseable Openings Vol = 162m 3 Surface Area = 198m 2 9m 6m 3m Method A Permissible Max Leakage Area = 10% of vol 162m 3 = 16.2m 2 Method B Permissible Max Leakage Area = 10% of SA 198m 2 = 19.8m 2 Always use the lowest figure compensate at 5Kgm 2

41 Total Flood Temperature Correction Usable range: -20 º C to +100 º C Above 100 º C add 2% CO2 every 5 º C Below -20 º C add 2% CO2 every 1 º C

42 Deep Seated Fire Refer to table 3 for hazard selection 20 minutes minimum hold time Leakage is not desirable (except high level venting) Extended discharge where leakage unavoidable Refer to KFP for guidance

43 Deep Seated Fires 10m 5m 3m Switch Room 3 Vol= 150 m Flooding Factor 1.35 kg/m 3 Basic quantity is found from Table 3. Do not use Table 1. Therefore basic quantity is: 150 x 1.35 = 202.5kg i.e. 5 Kidde 45kg Cylinders

44 Extended Discharge Typical Applications - rotating electrical machinery Extinguishing concentration - achieve in 1 min - maintain 30% for run-down-time Initial/extended discharge Refer to Table 4 for additional gas quantity

45 CO 2 Design - Local Application - 1 Protection against surface fires in: - Flammable liquids, vapours, shallow solids - Open areas CO2 discharged directly at the fire: nozzle position critical Hazards Dip Tank Quench Tank Printing Press Textile Machines Coating Machines Kitchen Range Risk Solvent Hot Oil Solvent Dust/ Fluff Solvent Grease, Hot Oil

46 CO 2 Design - Local Application - 2 In all the above cases protection should include extract ducts, fume hood filters. Services must be shut down e.g: - Ventilation fans - Solvent pumps - Heaters etc.

47 CO 2 Quantity Two methods of calculation depending on the hazard: Rate by Area- Using known nozzle characteristics the discharge rate can be calculated from the number of nozzles required to protect a given surface area. (See table 5) Rate by volume- Use to protect irregular 3D objects where it cannot be reduced to equivalent surface area or if an enclosure exists it does not meet the requirement for total flood Discharge duration: 30 seconds For high pressure systems increase gas quantity by 40% as only 70% of cylinder is effective

48 Local Application Rate by Area Method Used for flat surfaces Flammable liquid fires - 150mm freeboard is required 150mm freeboard Area of protection and rate of discharge varies with distance between nozzle and hazard surface. Within limitations in Manual

49 Local Application Rate by Area Method The area of hazard surface protected by each nozzle is determined by its side of square Select nozzle carefully to minimise quantity of CO 2 required See KFP CO2 design manual Table 5 Position nozzle centred over and at 90º to hazard. (May also be installed at between 45º - 90º) - Refer to 7.2 Fig 1 & Table 6

50 Rate by Area Method Surface Area: 0.92 x 1.07m = 0.99m 2 (Side of square = 1.08m) 2 Nozzles at height 1.14m Side of Square = 1.08m Flow Rate = 25.2 kg/m, Total flow = 2 x 25.2 = 50.4kg CO2 required = 50.4 x 1.4 x 0.5 = 35.3kg

51 Local Application Rate by Volume Method Also known as Assumed Volume method - 3 dimensional irregular objects which cannot be reduced to equivalent surface areas. - where the degree of enclosure does not conform to total flooding requirements. Total discharge rate based on volume of an imaginary enclosure. This hypothetical volume must have a floor. Assumed walls & ceiling to be 0.6m from hazard (except actual walls) and must enclose all areas of leakage, splashing or spillage.

52 Local Application Rate by Volume Method A minimum dimension of 1.2m shall be used. No allowance to be made for solid objects within the assumed volume. Discharge rate for basic system: 16kg min m 3 A reduction in the rate may be made when: - There are permanent fixed walls 0.6m above the risk - The rate must not be less than 4kg min m 3 - See KFP CO2 design manual Fig. 2

53 Rate by Volume Method Vol A= 1x2x3=6m Assumed Vol 0.6 Vol B = 1.6 x 3.2 x 4.2=21.5m 3 16kg min m 3 = 344kg CO2 quantity actual = 344 x 1.4 x 0.5 = 240kg 0.6

54 Nozzle Location Rate by Volume Method Use enough to cover the entire hazard volume. Position of nozzle & objects must be considered so as to retain CO2 within the hazard volume. Use table 5 as a guide for distance and area covered. Note: This method of system design always uses more gas than the rate by area method.

55 Sales Features of CO 2 CO 2 is cost-effective KFP is internationally competitive Convenient to engineer systems Robust, reliable product Widespread refilling facilities

56 A Comparison of CO 2 and Inert Blend Gases Composition A single gas (100% CO2 ) Blend of gases (52% N2, 40 % Air, 8% CO2) Storage 850psi (58 bar) 2175psi (150 bar) Pressure Application Three application methods; Only one application Flexibility total flooding, local application, method; total flooding hand hose lines

57 A Comparison of CO 2 and Inert Blend Gases Agent Just one cylinder provides 200 Takes three cylinders to provide Efficiency cubic feet (56 cubic metres) of 200 cubic feet (56 cubic metres) protection of protection-three times the floor space required Recharge Simple operation- worldwide Complicated blending operation availability limited availability Extinguishing Oxygen reduction- oxygen Oxygen reduction-oxygen Method content drops from 21% to 15% unsuitable for 12%- potential asphixiant with occupied spaces strict EPA SNAP design requirement when used in occupied spaces