ANSUL Aircraft Hangars

7/24/2019 ANSUL Aircraft Hangars

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DESCRIPTION

Considering the value of commercial and militaryaircraft, it has become extremely important tohave a reliable fixed fire protection system inaircraft storage, servicing, maintenance and paintfacilities. This fire protection system is designedto give reasonable control and extinguishment ofany Class A or B type fire in the facility.

Most fire protection systems for aircraft handling

facilities are designed in accordance with NFPA409 Aircraft Hangars, Military Handbook 1008-FireProtection for Facilities Engineering Design andConstruction or the Airforce ETL (EngineeringTechnical Letter) Fire Protection EngineeringCriteria for Aircraft Maintenance, Servicing andStorage Facilities. Per NFPA 409 there are threebasic aircraft hangar designs that have beenclassified:

GROUP I AIRCRAFT HANGAR A hangar having

at least one of the following features and

operating conditions:

• An aircraft access door height over 28 ft. (8.5m).

• A single fire area in excess of 40,000 sq. ft.(3,716 sq. m).

• Provision for housing an aircraft with a tailheight over 28 ft. ( 8.5 m ).

• Provision for housing strategically importantmilitary aircraft as determined by the Depart-ment of Defense.

GROUP II AIRCRAFT HANGAR A hangar hav-

ing both of the following features:

• An aircraft access door height of 28 ft. (8.5 m)or less.

• A single fire area not larger than 40,000 sq. ft.( 3,716 sq. m ) per hangar construction type asdefined by NFPA 409.

AIRCRAFT HANGARS

Single Fire Area

Type of Equal or Greater Than But Not Larger Than

Construction Sq. Ft. (M2) Sq. Ft. (M

2)

_________________________________________________________

Type I (443)

and (332) 30001 (2787) 40000 (3716)

Type II (222) 20001 (1858) 40000 (3716)

Type II (111),

Type III (211), and

Type IV (2HH) 15001 (1394) 40000 (3716)

Type II (000) 12001 (1115) 40000 (3716)

Type III (200) 12001 (1115) 40000 (3716)

Type V (111) 8001 (743) 40000 (3716)

Type V (000) 5001 (465) 40000 (3716)

_________________________________________________________

Group III Aircraft Hangar A Group III hangar

may be a freestanding unit for single aircraft, arow hangar housing multiple aircraft that has acommon structural wall, roof system and openingsfor each aircraft or an open bay hangar capable ofhousing multiple aircraft with the followingfeatures:

• An aircraft access door height of 28 ft. (8.5 m)or less.

• A single fire area that measures up to themaximum square footage permitted for specifictypes of construction per NFPA 409.

MaximumType of Single Fire Area

Construction Sq. Ft. (M2)

Type I (443) and (332) 30000 (2787)Type II (222) 20000 (1858)Type II (111), Type III

(211) and Type IV (2HH) 15000 (1394)Type II (000) 12000 (1115)Type III (200) 12000 (1115)Type V (111) 8000 (743)Type V (000) 5000 (465) _______________________________________

Building construction types are defined in NFPA220, Standard on Types of Building Construction.



FIRE PROTECTION OPTIONS

Once the aircraft hangar classification has beendetermined, a suitable fire protection system/ requirement can be established. There are fourtypes of foam fire protection systems suitable for

the protection of an aircraft hangar. Thesesystems may be used separately or they may becombined.

• Overhead foam water sprinkler system.

• Foam monitor system.

• Foam hand hose line system.

• High Expansion system.

The overhead foam water sprinkler system canbe:

• Closed head pre-action.

• Standard wet pipe.

• Deluge system.

If used with either Protein or Fluoroprotein typefoam concentrate, the foam water sprinkler headsmust be air-aspirating. When used with AFFF,the sprinkler heads can be standard non air-aspirating.

Monitor Systems may be of the oscillating or fixednozzle type.

Oscillating Monitor Systems consist of moni-tors that automatically oscillate from side toside when discharging foam onto the hangarfloor. They are normally preset to oscillateover a given arc to provide the correct flowrate over a specific area.

Fixed Monitor Systems have nozzles that aretypically mounted on a manifold or as singleunits approximately 3 feet above the hangarfloor. They are preset for angle of elevationand discharge pattern to achieve the bestpossible stream pattern and range whilekeeping the stream low enough to flow underthe wing of any aircraft. This type of monitor

system is often used where aircraft ormaintenance equipment in the hangar couldinterfere in the normal operation of theoscillating type monitor.

Foam Hand Lines: These systems are required

as supplementary protection in Group I and IIaircraft hangars.

High Expansion Systems: These systems aredesigned to discharge an expanded mass of foambubbles over the protected area to a depth of atleast 3 ft. within 1 minute and flow for a minimumof 12 minutes.

GROUP I HANGAR FIRE PROTECTION DE-SIGN REQUIREMENTS

A Group I aircraft hangar is to have an approvedfoam-water deluge system covering the aircraftservice and storage areas. It is to be installed inaccordance with NFPA 16, Standard on DelugeFoam-Water Sprinkler and Foam-Water SpraySystems with an application rate of .16 gpm persq. ft. when standard sprinkler heads are used. Ifair-aspirating type heads are used, the applicationrate is to be .20 gpm per sq. ft. Sprinkler spacingshall be in accordance with NFPA 13, Standardfor the Installation of Sprinkler Systems, extra

hazard occupancy, normally 100 sq. ft. per head.The maximum protected area for each individualdeluge system is to be 15,000 sq. ft.

The quantity of foam concentrate required is to besufficient to operate the system for 10 minutes.

If the foam-water sprinkler system is also used forcolumn fire protection within the hangar in lieu ofthe column having a fire resistive rating of not lessthan 2 hours, allowances must be made for therequired additional foam concentrate.

A reserve supply of foam concentrate must bedirectly connected into the system and be readilyavailable if required.

If the foam concentrate is injected into the watersupply by foam pumps, two pumps are to beinstalled. Either pump should be capable ofsupplying the foam concentrate at the maximum



system demand flow rate. A jockey pump shouldbe installed where the foam concentrate pipingfrom the foam pump(s) to the injection point isbelow ground or if above ground 50 feet in lengthor greater. The jockey pump is to keep the foamconcentrate line pressurized at all times to ensure

prompt injection of concentrate into the systemwhen activated.

Where there is an aircraft with a wing area inexcess of 3,000 sq. ft., that DOES NOT have

drained and purged fuel tanks or where severalaircraft with wing areas less than 3,000 sq. ft. arestored or serviced, an approved supplementaryfoam-water fire protection monitor system is to beinstalled.

Foam-water hand hose systems shall be installedif the aircraft DO NOT have drained and purged

fuel tanks. If the aircraft HAS drained and purgedfuel tanks, water only hand hose lines may beinstalled.

RADIUS RULES

Where the ceiling height within the hangar is 25feet or less, for overhead system designpurposes, it is to be assumed that a fire at anypoint will operate all overhead systems that arepartially or wholly within 50 feet horizontally from

any potential fire.

If the hangar ceiling height is in excess of 25 feetbut less than 75 feet, the foam/water suppliesmust be sufficient to operate all systems that areeither partially or wholly within 75 feet horizontallyof any potential fire.

When the ceiling height is in excess of 75 feetabove the hangar floor, it is to be assumed that allsystems, either wholly or partially, within 100 feethorizontally of any potential fire within the hangarwill operate.

For design purposes, the water supply shouldoperate for a minimum of 60 minutes when allsystems designed to operate simultaneously flowat their designed pressure and rate. If the hangarhas a supplementary foam protection system, thewater supply shall be sufficient to flow for aminimum duration of 45 minutes.

High Expansion Foam System

A high expansion foam system installed in anaircraft hangar is to be designed to cover theprotected area to a depth of 3 feet with a mass of

foam bubbles within 1 minute. When a high ex-pansion system is installed inside a hangar, allow-ances must be made for the possibility that thefoam could be affected by any discharging sprink-ler system. Please refer to the section of HighExpansion Foam Systems for further information.

High expansion systems must have sufficientfoam concentrate and water to operate at thedesign application rate for a minimum of 12minutes.

The generators should only be mounted at theceiling or on exterior walls of the hangar whereoutside air only is used to generate the foam.

It is recommended that the high expansion gene-rators be installed so that the flow of foam on thefloor is directed to areas beneath aircraft wingsand center sections.

GROUP II HANGAR FIRE PROTECTION RE-QUIREMENTS

The fire protection requirements of a Group IIhangar may be one of the following.

• In accordance with the requirements for aGroup I hangar.

• A combination of either an overhead wet pipeor a pre-action water only sprinkler systemwith a low level foam-water monitor system.

• A combination of either an overhead wet pipeor a pre-action water only sprinkler systemwith an automatic high expansion foamsystem. The high expansion system is to beof a local application type system anddesigned per NFPA 11A Standard for Mediumand High Expansion Foam Systems.



GROUP III HANGAR FIRE PROTECTION RE-QUIREMENTS

• Fixed fire protection systems are not normallyrequired.

• If any hazardous operations such as fueltransfer, welding, painting, torch cutting, etc. isperformed in a Type III hangar, the hangarshould be protected as per a Type II aircrafthangar.

Additional Requirement for all Type aircraft han-

gars.

Fire extinguishers must be distributed throughoutthe aircraft hangar per NFPA 10 Standard forPortable Fire Extinguishers.

Foam System Application Information

Overhead primary protection systems.

• Discharge duration - 10 min.

• Application rate - .16 gpm per sq. ft. / AFFFthrough standard sprinkler heads.

- .20 gpm per sq. ft. / Protein,Fluoro Protein or AFFF through air aspiratingsprinkler heads.

• A reserve supply of foam concentrate shouldbe directly connected to the system and bereadily available.

• If the foam concentrate is injected into thewater supply by a foam pump, there is to betwo pumps ( one main, one reserve ), either ofwhich can supply the necessary supply offoam concentrate at the design rate.

• When using a 1% type of foam concentrate,multiply the total foam solution required by .01to obtain the quantity of foam concentraterequired. Multiply by .03 when using a 3%type concentrate and by .06 when using 6%.

SUPPLEMENTARY PROTECTION SYSTEMS

Monitors

Each supplementary fixed foam fire protectionsystem is to be designed to achieve control of the

protected specified floor area within 30 sec. ofactivation and to extinguish any fire within 60 sec.The specified floor area is the area under the wingand the wing center section of the aircraft. Thedifferent configurations of aircraft and theirpositioning within the hangar must be considered

for effective fire protection when positioning themonitors. If more than one aircraft is locatedwithin any drainage system, it is recommendedthat the supplementary foam monitor system becapable of effectively covering the complete floorbeneath all aircraft.

Minimum flow rates through supplementarymonitor systems for the area of coverage is to be0.10 gpm per sq. ft. when using AFFF and 0.16gpm per sq. ft. when using Protein orFluoroprotein foam concentrates.

It is recommended that a control valve be installedat the base of each oscillating monitor or fixednozzle system.

Foam Hand Line Protection System

Provisions are to be made in water flowcalculations for operating a minimum of two foamhand line systems. Each system must flow aminimum of 60 gpm at sufficient nozzle pressurewith a discharge duration of foam solution for 20minutes.

AHrv995



Tank ShellVentValve

Foam Concentrate

Foam Concentrate

Foam Concentrate

ProportioningController

Deluge Valve

OS & Y Valve

Water Supply

Water intoBladder Tank

BladderDrain/Fill Valve

BladderDrain/Fill Valve

Manual 1/4 Turn Ball ValveNormally Open

Manual 1/4 Turn Ball ValveNormally Closed

Hydraulic Actuated Ball ValveNormally Closed

Swing Check Valve

Typical of Three

Bladder VentValve

Bladder VentValve

D084rv1296

MainBladder Tank

ReserveBladder Tank

Tank ShellDrain/Fill Valve

Tank ShellDrain/Fill Valve

To Monitors To Overhead

Systems To Hose Reel

Stations

AIRCRAFT HANGAR

MAIN AND RESERVE BLADDER TANK SYSTEM

WITH THREE PROPORTIONING CONTROLLERS

DD D



WaterSupply

WaterSupply

WaterSupply

OS &YValve

OS &YValve

OS &YValve Alarm

Valve

Closed HeadFoamSprinkler

System

Hose ReelStation

Monitor

FlushValve

Flex Line

Back-up Pumpand Motor

J ockey PumpFlushValveFoamLiquid

Tank

Manway/Tank Pressure/VacuumVent

Ball ValveNormally Open

PressureControlValve

Ball ValveNormally Closed

In-Line BalancedPressure Unit

Swing CheckValve

Positive DisplacementConcentrate Pump

Hydraulic ActuatedBall Valve


AIRCRAFTHANGARIN-LINE BALANCEDPRESSURE SYSTEMWITH

JOCKEY,MAINANDRESERVE FOAMPUMPS

Main Pump

Pressure BalancingValve

TankFill/Drain

D-ILB3rv895

D

D

DelugeValve

DelugeValve

A



Back-up Pumpand Motor

Pressure BalancingValve

IN-LINE BALANCED PRESSURE SYSTEM WITH

MAIN AND RESERVE FOAM PUMPS AND TANKS

Main Pump

MainReserve

FIG. 8

D074rv895

D

A

WaterSupply

WaterSupply

OS &YValve

OS & YValve

AlarmValve

Deluge

Valve

Flush

Valve

Flush

Valve

Flex Line

FoamLiquid Tank

Foam Liquid Tank

Manway/TankPressure/VacuumVent

To DischargeDevices

To DischargeDevices

Ball ValveNormally Open

Pressure ControlValve

Ball ValveNormally Closed

In-Line BalancedPressure Unit

Swing CheckValve

Positive DisplacementConcentrate Pump

HydraulicActuated

Ball Valve




AIRCRAFT HANGER WITH POSSIBLE LOCATIONSFOR AUTOMATIC OSCILLATING MONITORS

Oscillating

Monitor

Office

Area

FloorDrains

D083rv195

Documents

ANSUL Aircraft Hangars