Liquid Nitrogen (LN2) Fire Extinction - Phase II Dennis Bernal, Paul Brownsey, John Falkowski, Chris Forrest, Josh Miranda Client: Professor Levendis Chris NEU Engineering Co. Inspired Innovation

Background Prof. Levendis has developed a fire extinction technique using the direct application of the cryogen Liquid Nitrogen (LN2) to fires This technique has been validated through testing on liquid pool fires about 1m2 in area; the results of which were recently published in the journal of the Fire Protection Association (FPA) Chris

LN2 Characteristics Nitrogen boils at 77K Displaces oxygen molecules Environmentally benign Atmosphere contains 78% nitrogen Cost efficient ($0.75/gallon) Josh

Video used with permission, © 2008 Y. Levendis Client’s Testing Tests conducted by our client at the Commonwealth Scientific and Industrial Research Organization (CSIRO) National Laboratories in Australia Josh Video used with permission, © 2008 Y. Levendis

Problem Statement Evolution Our client wishes to have a device for applying liquid nitrogen from a distance, to fires of 10 m² in area and eventually 100 m² A previous consulting firm determined that a feasible and effective concept of delivering liquid nitrogen to a small fire is by a hose and nozzle. This concept was validated through construction of a bench scale prototype and conduction of small laboratory tests Josh Previous Firm’s Prototype

Current Problem Statement Make the new system safe and easy to use Have “dead man” valve to prevent dropping accidents Pressure relief valve to guarantee safe use near fire as well as after shut-off Our task is to design a commercial hose and nozzle delivery system that is cost effective and proven to work This will take extensive field testing Use of as many commercially available parts as possible to reduce cost Careful material analysis and selection Josh Provide the client with a way to deliver liquid nitrogen to a fire from a safe distance.

Design Specifications Fire Area Application method Amount of LN2 1 sq meter Manual application (as demonstrated in video) ½ liter of LN2, Few seconds to extinguish 10 sq meters Hose application desired 13 m horizontal distance (10 m to edge of fire, plus 3 m across area of fire) 5 liters x FOS of 2 = 10 liters in 10 seconds Desired flow rate 1 liter/s 100 sq meters (future consideration) Bulk Delivery of LN2 50 liters x FOS of 2 = 100 liters in 100 seconds Josh

Design Considerations Weight Must be equal to or less than a standard water nozzle currently used by fire department Size Comfortable and similar in size to current water nozzle (46cm) Safety of User Insulated Housing “Dead Man” Release Mechanism Pressure Relief Valve Cool Down Period Minimize time for nozzle and hose assembly to cool before LN2 fires Dennis Traditional Water Nozzle 8.1 kg (17.9 lbs)

Overall Design Concept Custom Designed Nozzle Cryogenic Ball Valve Reducer Protective Housing Vacuum Jacketed Supply Hose Truck Storage Tank Cryogenic Pump Flow Control/Monitoring Dennis

(Dead-Man Mechanism)‏ Recommended Design Torsion Spring (Dead-Man Mechanism)‏ Linkage & Handle Cryogenic Hose Housing Ball Valve Extender Nozzle Dennis

Difference in Thermal Expansion between materials: 0.017 [mm] Red Brass (85% Cu – 15% Zn) Stainless Steel (Type 316) [1/K] [1/K] L = Wall thickness Tfinal – Tinitial = 77-293 K [meters] [meters] John [meters] [meters] Difference in Thermal Expansion between materials: 0.017 [mm]

John

COSMOS - Nozzle (Time = 300 sec.) 163 K 125 K John 90 K

John

COSMOS - Hose (Time = 300 sec.) 300 K 190 K 78 K John 125 K

Test Specifications and Setup Test Goals Prove that N2 can be shot and stay in liquid form through air Shoot LN2 10 meters Extinguish a fire from 10 meters Test Variables Supply pressure Orifice Size Nozzle Angle Tests were visually recorded with digital cameras and camcorders Measured Values Cool Down Time Size of gas plume Throw Distance Time to extinguish fire Cryogenic ball valve effectiveness Chris Supply pressure – Tested in a range of 62 kPa to 517 kPa Nozzle Size – Two different orifice sizes (3.3 mm and 4.2 mm), and no nozzle tip (just the reducer opening 13.9 mm) Nozzle Angle – 45 degrees from horizontal, and between 0 and 15 degrees

Test Photos Setup: 3m hose, brass ball valve, extender, 12.7mm nozzle opening Time – 0 sec Fire is lit at 4.88m Chris Time – 7 sec GN2 & LN2 reaches fire Time – 36 sec Liquid nitrogen boils in fire Time – 90 sec Fire is completely extinguished

Test Results and Conclusions Cool down time to steady state 120 seconds (3.3 m hose) 150 seconds (7 m hose) Plume Ball Valve Effectiveness Ability to shoot liquid nitrogen a distance Fire Extinction Chris Found to be narrow enough that cone is not needed On/Off control – instant liquid at nozzle tip Max distance achieved with prototype: 6.1 meters

Flow Optimization Unique considerations for cryogen flow Large pressure drops cause flash vaporization As fluid vaporizes pressure and velocity increase Test data was used to develop assumptions to calculate flow characteristics for larger systems Paul

Final Nozzle Design Recommended Specifications LN2:GN2 Distance Low Pressure High Short High Pressure Low Long Paul Recommended Specifications 1” Vacuum jacketed supply hose ~3/4” Nozzle orifice

Cost Analysis Prototype BOM Actual Design BOM Component Qty Price per Total Price Component Qty Price per Total Price 304 SS 1/2" ID NPT coupler 2 $4.81 $9.62 304 SS 1" ID NPT coupler 2 $11.18 $22.36 304 SS 1/2" ID NPT reducer 1 $6.31 $6.31 304 SS 1" ID NPT/welded to 3/4" reducer 1 $18.14 $18.14 304 SS 1/2" ID NPT 5"L extender 1 $16.86 $16.86 304 SS 1" ID NPT 4"L extender 1 $6.39 $6.39 Housing pipe and couplers 1 $99.78 $99.78 Housing pipe and couplers 1 $99.78 $99.78 32 in-lb torsion springs 2 $11.03 $22.06 1/2" ID bushings 2 $1.89 $3.78 32 in-lb torsion springs 2 $11.03 $22.06 Cryogenic brass ball valve 1/2" NPT 1 $260.41 $260.41 1/2" ID bushings 2 $1.89 $3.78 Paul 5/8" ID Semiflex hose - 10 ft 1 $0.00 $0.00 40' Semiflex 1" ID hose, safety relief valve, cryogenic ball valve 1 $4,446 $4,446 Safety relief valve - 1/2" NPT 1 $0.00 $0.00 Welding 2 $75.00 $150.00 Welding 0.5 $75.00 $37.50 Machining 1.5 $75.00 $112.50 Machining 1.5 $75.00 $112.50   Prototype Total Cost: $568.82   Design Total Cost: $4,881

Recommendations Nozzle Optimization Find relationship between supply pressure, hose size and orifice size – to maximize flow, for a decent distance. Re-design consideration for larger fires A system that dumps a large amount of LN2 at once Paul

Questions? Paul