PD08WRGBGBEA07.pdf

REVISION 1

10 JANUARY 2008

PD08WRGBGBEA07

Purchase Description

NEW GENERATION HEATER MODEL B

(NGH-B)

Paragraph 4.2: Edit last sentence to read: Pre-production inspections and testing which include all requirements of 4.8 and 4.9 shall be considered Full Pre-production Testing.

Insert the following paragraphs:

4.2.1 Pre-Production Testing Waivers. The available pre-production samples shall undergo Full Pre-Production Testing (see 4.2) unless a waiver is granted by the Government contracting officer. A waiver will be considered by the contracting officer if the contractor has previously furnished production quantities of the same or similar articles to the Air Force provided not more than 48 months have elapsed since completion of the contract. The articles provided must have exhibited satisfactory performance in the opinion of the Air Force. If a waiver is granted, the pre-production samples shall be subjected to Limited Pre-production Testing (see 4.2.2).

4.2.2 Limited Pre-Production Testing. Limited Pre-Production Testing shall consist of all testing outlined in section 4 except the following: 4.8.2, 4.8.3, 4.8.4, 4.8.5, 4.8.7.1, 4.8.7.2, 4.8.7.10, 4.8.8, 4.8.9, 4.8.10, 4.8.12, 4.8.13, 4.8.14, 4.8.15, 4.8.16, 4.8.17, and 4.8.18

WARNER ROBINS AIR LOGISTICS CENTER PURCHASE DESCRIPTION

642 COMBAT SUSTAINMENT GROUP PD08WRGBGBEA07

FLIGHTLINE EQUIPMENT ENGINEERING BRANCH 14 DECEMBER 2007

642 CBSG/GBEA CAGE 98752

DISTRIBUTION STATEMENT A; Approved for public release; distribution is unlimited. FSC 4520

PURCHASE DESCRIPTION

NEW GENERATION HEATER MODEL B

(NGH-B)

This specification is approved for use by the Department of the Air Force and is available for use by all Departments and Agencies of the Department of Defense.

1. SCOPE

1.1 Scope. This specification describes performance requirements for the New Generation Heater Model B (NGH-B). The NGH-B is a mobile, self-contained, ground support heater, with a diesel engine driven generator powering a motor driven blower and fuel burner. The NGH-B delivers 1600 ± 5% standard cubic feet per minute (SCFM) airflow at a selectable 160°F ± 15ºF or 280°F ± 15ºF output air temperature. The NGH-B is air transportable in C-130, C-17, and C-5 aircraft.

2. APPLICABLE DOCUMENTS

2.1 General. All documents listed in this section are referenced in sections 3 and 4. Contractors are cautioned that they must meet the requirements of all documents cited in sections 3 and 4 of this specification, whether or not the documents are listed in this section.

2.2 Government documents.

2.2.1 Specifications, standards, and handbooks. The following specifications, standards and handbooks (including supplements and notices) form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract.

FEDERAL SPECIFICATIONS

A-A-50271 Plate, Identification A-A-52464 Coupler, Drawbar, Ring, Light Duty A-A-52550 Pintle Assembly, Towing, Manual Release A-A-52557 Diesel Fuel Oil for Posts, Camps, and Stations A-A-59494 Wheels and Hubs for Industrial Pneumatic Tires

FOREIGN SPECIFICATIONS:

GOST 10227-86 Fuels for Jet Engines

FEDERAL STANDARDS

FED-STD-595 Colors

DEPARTMENT OF DEFENSE SPECIFICATIONS

MIL-DTL-83133 Turbine Fuels, Aviation, Kerosene Types, NATO F-34 (JP-8), NATO F-35, and JP-8+100

DEPARTMENT OF DEFENSE STANDARDS

MIL-STD-461 Requirements for the Control of Electromagnetic Interference Emissions and Susceptibility

MIL-STD-810 Environmental Test Methods and Engineering Guidelines MIL-STD-1366 Transportability Criteria MIL-STD-130 Identification Marking of US Military Property MIL-STD-882 System Safety Program Requirements MIL-STD-889 Dissimilar Metals MIL-STD-1472 Human Engineering MIL-STD-1474 Noise Limits

(Copies of these documents except GOST 10227-86 are available online at http://assist.daps.dla.mil/quicksearch/ or www.dodssp.daps.mil or from the Standardization Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094. A copy of GOST 10227-86 can be obtained from Interstandard, 117049 Moscow, B-49, Russia).

2.2.2 Other Government documents, drawings, and publications. The following documents, drawings, and publications form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract.

USAF DRAWINGS

8227040 Adapter, Assembly Duct (CAGE: 98752) 8227065 Adapter, 12” Diameter to 6” Diameter Conn. (CAGE: 98752)

(Copies of Government drawings required by the contractor in connection with this acquisition should be obtained from or as directed by the contracting activity.)

2.3 Non-Government publications. The following documents form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract.

AMERICAN WELDING SOCIETY (AWS)

B2.1:2005 Specification for Welding Procedure and Performance Qualification

(Copies are available from the American Welding Society, 2501 NW Seventh Street, Miami FL 33125.)

SOCIETY OF AUTOMOTIVE ENGINEERS (SAE)

J534 Lubrication Fittings

ARP1247 General Requirements for Aerospace Ground Support Equipment, Motorized and Non-motorized

ARP1801 Measurement of Exterior Sound Level of Specialized Aircraft Ground Support Equipment

AS8090 General Requirements For Mobility, Towed Aerospace Ground Equipment

AS7365 Duct Assembly, Ground, Conditioned Air, Metallic Reinforced, Low Pressure, 350ºF.

(Copies are available from the Society of Automotive Engineers, 400 Commonwealth Dr.

Warrendale PA 15096.)

ASTM International (ASTM)

D 975 Standard Specification for Diesel Fuel Oil

(Copies are available from ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959)

American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.

(ASHRAE)

52.2 Method of Testing General Ventilation Air-Cleaning Devices for Removal Efficiency by Particle Size

(Copies are available from the American Society of Heating, Refrigerating, and Air-Conditioning Engineers, 1791 Tullie Circle NE, Atlanta, GA 30329)

2.4 Order of precedence. In the event there is a conflict between the text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.

3. REQUIREMENTS

3.1 Pre-production Unit. When specified (see 6.3), samples shall be subject to pre-production testing in accordance with 4.2.

3.2 Materials. NGH-B components and all materials shall be selected based on the defined purpose and the design service life at the environmental extremes stated herein. Materials shall be certifiable for the application and survivable when exposed to high air discharge temperatures, fuels, lubricants and coolants that are a part of the heater. Proprietary materials or processes shall not be used. Components shall not be used outside of the ratings specified by the manufacturer of the component.

3.2.1 Prohibited materials. Magnesium alloys, wood products, or asbestos shall not be used in any component or assembly of the NGH-B. Ozone depleting substances/materials shall not be used in the construction of the heater.

3.2.2 Recycled, recovered, or environmentally preferable materials. Recycled, recovered, or environmentally preferable materials should be used to the maximum extent possible, provided that the material meets or exceeds the operational and maintenance requirements, and promotes economically advantageous life cycle costs. Used or rebuilt parts shall not be defined as recycled, recovered, or environmentally preferable materials, and shall not be used.

3.2.3 Fungus proof materials. Materials used in construction of the NGH-B shall not be nutrients for fungi.

3.2.4 Galvanic corrosion. Use of combinations of metals that are separated in the galvanic series to such an extent as to cause galvanic corrosion, as defined by MIL-STD-889, shall not be used.

3.2.5 Protective treatment. Coatings subject to failures such as fading, cracking, peeling, and chipping as a result of exposure to environmental and operational extremes specified herein shall not be used.

3.3 Design and construction. The NGH-B general arrangement shall be a tow-able, self-contained, enclosed cart design, including; a JP-8 fueled diesel engine driven generator and a JP-8 fuel burner with heat exchanger; a single pass forced air and duct delivery system, and all necessary controls. The design service life shall be not less than 20 years at an average annual usage of 1000 hours. Except for the engine driven generator, all major components of the heater shall not require periodic rebuilds to attain the service life. Rebuilding of the engine driven generator shall be no more frequent than 5000 hours of operation. Unless otherwise specified, the NGH-B shall be configured and tested in accordance with SAE AS8090, Requirements for Mobility, Towed Aerospace Ground Equipment, for classification Type II, Group A, and with SAE ARP1247, Requirements for Aerospace Ground Support Equipment. NGH-Bs shall be towable in two rows of four units from a single tow-tractor, with pintles at eight-foot centers, without interference during 90 degree turning maneuvers at a minimum 18.5-foot radius, without binding or interference. System safety features, as defined by MIL-STD-882, shall be used.

Except as otherwise required by changes to applicable laws during the contract period or as authorized by the Government, all heaters shall be identical in configuration.

3.3.1 Human engineering. All system operation, servicing, and maintenance clearances shall be in accordance with MIL-STD-1472, human engineering, for extreme low temperatures while wearing arctic clothing. A 5th percentile female, in accordance with MIL-STD-1472, shall be capable of accomplishing all mobility, operational, and maintenance functions.

3.3.2 Foolproof design. Components shall be designed by shape or by mounting pattern to prevent improper installation.

3.3.3 Foreign Object Damage (FOD). Any metal cap, plug, pin, or plate, requiring removal for inspection, service or operation, shall be retained by wire rope lanyard or chain, so it cannot become separated from the heater.

3.3.4 Fastening devices. Threaded fasteners shall include features to prevent the loss of torque, while allowing for disassembly. Assembly torques shall be specified for all threaded fasteners.

Internal threads in aluminum shall withstand not less than twenty fastener installation cycles to the specified torque. Adhesive supports for wiring or other components shall not be used.

3.3.4.1 Permanent fasteners. Permanently fastened overlapping surfaces shall be sealed. Rivet selection shall be for a minimum joint strength. Rivet heading shall be consistent with specifications of the rivet manufacturer.

3.3.5 Welding. Welding procedures and performance shall be in accordance with American Welding Society standard B2.1:2005.

3.3.6 Air transportability. The NGH-B shall be air transportable, without shoring, as specified in MIL-STD-1366 in Types C-130, C-17, and C-5 aircraft, or in pairs on a 463L pallet. Except for stowing the engine exhaust, the burner flue, air ducts, duct adapters, and folding the tow-bar, no component shall require removal or repositioning for air transport. The design shall not exceed any worst case constraint for dimensions, axle loading, ramp angle, g-loading, or rapid decompression. A transportation data plate (see 3.13.2) shall be provided, with the following minimum information:

a. Side and rear silhouettes, with the center-of-gravity locations identified.

b. Shipping weight.

c. Loading cubage.

d. Overall height, width, and length.

3.3.6.1 Tie downs. Air transport tie-down points shall restrain movement, with respect to either the aircraft or the 463L pallet. Tie-down points shall provide clearance for hooks and restraining chains/straps and shall coordinate with the defined aircraft or pallet attaching points.

3.3.7 Lifting provisions. The NGH-B shall be capable of being hoisted or forklifted.

3.3.7.1 Hoisting provisions. Hoisting provisions shall include attaching points for a four point lift using equal length cables to a single hook. The heater shall not tilt more than 15° from the horizontal while suspended. A fully fueled heater shall not leak when hoisted.

3.3.7.2 Forklifting provisions. The enclosure shall include two transverse mounted tubes, each capable of accommodating 8 inch wide by 2 3/4 inch thick forks. The tubes shall be placed 40 inches apart (inside dimension). The channels shall be designed to allow for safe lifting of the NGH-B and the center of gravity of the heater (with the tow bar in the folded and locked position) shall be no more than 12 inches from the midpoint between the two channels.

3.3.8 Workmanship. All NGH-B assemblies and subcomponents shall be constructed and finished consistent with the engineering drawings and manufacturing instructions.

3.4 Maintainability. The NGH-B shall be configured with maintainability as a consideration.

Design for maintainability shall include the following:

a. A 15 minute time limit for one person to perform all prior-to-use inspections, including, but not limited to; lubricant and coolant level checks and topping off, drive coupling checks, drive belts wear, engine and ambient air filters restrictions. Special tools shall not be required for any routine inspection.

b. Lubrication fittings shall conform to SAE J534.

c. Assuming a serviceable component is available, a one task time limit of four hours to restore operational readiness. Tasks may include, but are not limited to, removal and replacement of a motor, a pump, a heat exchanger, a blower, an engine, a clutch, a generator, or like item.

d. Selection of wear items for a minimum of 2,000 hours of operation.

e. During normal operating conditions, preventive maintenance tasks, except for engine oil changes, shall occur no more frequently than annually. Normal operating conditions are defined as between -40°F and +60°F, at any humidity, no blowing dust or sand, and no salt fog.

f. Not less than 200 operational hours between scheduled preventive maintenance intervals at any environmental extreme.

g. Government approval shall be required for any custom hand tool or any custom shop equipment, determined by the manufacturer to be necessary for repair. The Government will assess the need for the custom tool and determine if the proposed tool design is reasonable. If approved the tool shall be provided with every heater delivered.

3.5 Performance.

3.5.1 Environmental conditions. The NGH-B shall not be degraded by any of the following environmental conditions, as tested in accordance with MIL-STD-810:

a. Operation after storage at temperatures ranging from -65° F. to +165° F.

b. Operation in ambient temperatures from -65° F to +70° F.

c. Operation during rainfall at four inches per hour with a wind velocity of 40 miles per hour.

d. Full time exposure to a relative humidity of 100 percent.

e. Part-time (5%) exposure to a five percent salt solution, with fallout rate of 3 ml of per hour per each 80cm² of horizontal collecting area.

f. Operation during exposure to part-time (5%) exposure to blowing dust; less than 150 microns, 0.3 g/ft³ concentration, and 20 mph air velocity.

g. Operation during exposure to part-time (5%) exposure to blowing sand; 150 to 850 microns, 0.06 g/ft³ concentration, and 40 mph air velocity.

f. Full time exposure to the solar radiation of hot and dry desert conditions.

g. Exposure to fungus.

h. Operation at altitudes from sea level to 5000 feet.

3.5.2 Tilted operation. The NGH-B shall be capable of operating satisfactorily when its normal operation plane is at an angle of 8 ½ degrees in any direction from true horizontal.

3.6 Enclosed trailer design. The NGH-B shall consist of a weather resistant enclosure for the diesel engine generator, the heating and air delivery systems, system controls, and the fuel tank.

The enclosure shall be fully suspended over a single axle. The enclosure design shall incorporate a retractable wheeled jack in front of the heater to support the tongue weight and aid in connection to a tow vehicle.

3.6.1 Tow-bar and pintle. The heater shall be equipped with a hinged tow-bar with a lunette eye conforming to A-A-52464. The tow-bar shall store in a vertical position when not in use. An A- A-52550 pintle assembly shall be rear center mounted for towing in trains of four heaters.

3.6.2 Wheels. Wheels shall be split-rim type conforming to A-A-59494. Tires shall be industrial pneumatic, and approved for the application. Tire pressure shall be stenciled on the enclosure at each wheel location.

3.6.3 Parking brakes. Parking brakes shall hold the NGH-B on the worst case ramp angle of any air transport aircraft defined herein. The brakes shall be applied with a manual control located within reach of the tow bar connection

3.6.4 Enclosure. The enclosure shall contain all components necessary to power, heat, and distribute air. The enclosure shall form smooth surfaces (top and four sides) when in transport or mobility mode. The enclosure shall meet the stated mobility, tiedown and hoisting requirements, and shall store and function at the extreme environmental conditions stated herein. The enclosure shall prevent accumulation of water, sand, dust, or spilled fuel in quantities capable of affecting any function of the heater. Component service inspection access shall not require panel removal.

The enclosure shall provide the accessibility necessary to meet the maintainability requirement stated herein. Doors or panels shall be provided over the ambient air intake(s), the controls, and any other opening required for operation and shall hinge and latch back to the enclosure. A rigid mesh shall protect all openings uncovered for operation. Ambient air intake(s) shall not draw extreme condition rainfall into the air delivery system. The air discharge connection shall have a removable cap, secured to the enclosure by cable or chain.

3.6.4.1 Doors. Latches shall secure the doors in both closed and open positions, and shall not release due to vibration, g-loading, high wind, or jet aircraft exhaust encountered during mobility, transport or operation.

3.6.4.2 Duct storage compartment. The enclosure shall include a weather-resistant compartment for storage of one complete set of ducts and the duct adapter (see 3.6.6.3.4).

3.6.4.3 Engine exhaust pipe compartment. The enclosure shall include a weather resistant compartment for the engine exhaust pipe (see 3.6.5.1.3).

3.6.4.4 Heat exchanger flue compartment. The enclosure shall include a weather resistant compartment for the heat exchanger flue pipe (see 3.6.6.1).

3.6.4.5 Forms compartment. The enclosure shall incorporate an external access weather sealed compartment (not less than 10 inches by 14 inches by 3 inches) for storage of servicing forms.

3.6.5 Diesel generator. The heater shall include a diesel engine powered generator capable of providing the total power requirement for stand-alone operation. The generator power output shall be connected to a power distribution panel, which in-turn supplies the system controls and all motors within the system. The power distribution panel design shall not provide for the generator to be used as an independent power source.

3.6.5.1 Engine. The generator shall be powered by a commercial diesel engine with a total power output exceeding the gross total power requirement of all driven components. The engine shall be certified to meet all performance requirements specified herein, at 5,000 feet elevation, while operating on JP-8 fuel, in accordance with MIL-DTL-83133. The engine shall also run on any commercial diesel fuel.

3.6.5.1.1 Engine cooling system. The engine manufacturer shall approve the application and the cooling system design for either acceptable return to engine coolant temperatures or for adequate airflow, while operating under full design load at any worst case environmental extreme.

3.6.5.1.2 Engine air intake. A common commercial type serviceable air filter shall be provided.

3.6.5.1.3 Exhaust pipe and muffler. Engine exhaust shall discharge vertically, such that expelled gasses are not drawn into the engine air intake, the engine cooling system, or the ambient airflow intake to the heat exchanger. The exhaust outlet shall be protected from environmental extremes and water intrusion from cleaning equipment or pressure washing. Hot surfaces shall be guarded from hand contact (see 3.6.4.3).

3.6.5.1.4 Engine starting. The engine shall start without external assistance and shall produce design generator output within 5 minutes, following an eight-hour cold soak at -25°F.

3.6.5.1.5 Engine exhaust emissions. The engine shall be certified to comply with the Environmental Protection Agency (EPA) non-road diesel engine emission requirements at the time of manufacture.

3.6.5.2 Generator. The generator shall deliver the combined component continuous load power requirement at any defined environmental extreme, at a 0.8 power factor.

3.6.5.2.1 Controls Systems. Control and protection of voltage and frequency shall be consistent with industry standards, considering the service life and defined environmental extremes.

3.6.6 Heating system. The NGH-B shall include an electric motor driven blower fan and an electric powered burner/heat exchanger. The NGH-B shall deliver 1600 ± 5% SCFM (CFM corrected to 68ºF and sea level conditions) of air to the end of two 12-inch diameter air ducts (see 3.6.6.3.4), at a selectable low or high temperature discharge. The heating system low-temperature setting shall increase entering air conditions to +160°F ± 15ºF. The heating system high-temperature setting shall increase entering air conditions to +280°F ± 15ºF. Entering air conditions shall vary from -65 ºF to +70ºF. The heating system burner shall be sealed from the ambient airflow and shall meet all performance requirements while operating on JP-8 fuel in accordance with MIL-DTL-83133. The heating system burner shall operate, without an adjustment, from sea level to 5,000 feet elevation. The heating system shall ignite and deliver 280°F ± 15ºF air temperature within 5 minutes, following engine start (see 3.6.5.1.4) at -25°F.

3.6.6.1 Burner flue. The burner flue shall discharge vertically, such that stack gasses are not drawn into the engine air intake, the engine cooling system, or the conditioned air intake. The burner flue, in operating mode, and the burner flue opening, in storage mode, shall be protected from the environmental extremes and water intrusion from cleaning equipment or pressure washing. Hot surfaces shall be guarded from hand contact (see 3.6.4.4).

3.6.6.2 Carbon monoxide (CO). Carbon monoxide content of the delivered air shall not exceed 25 parts per million (PPM).

3.6.6.3 Air delivery system. The air delivery system shall include an intake air filter, an electric motor driven blower, a discharge outlet and a set of flexible discharge air ducts.

3.6.6.3.1 Air filters. The ambient air intake to the heat exchanger shall incorporate a serviceable filter media certified to meet ASHRAE Standard 52.2, with a Minimum Efficiency Reporting Value of 7 or a dust spot efficiency of 25 percent. The filter shall be serviceable through the intake air opening. A re-settable gauge on the control panel (see 3.7) shall show filter restriction and shall include a red line to identify the service requirement point.

3.6.6.3.2 Air blower. The air blower shall deliver the design flow rate at an air filter restriction, equivalent to 50% obstructed, between the clean and the indicated service point. Air volumes and restriction shall be taken from the blower manufacturer’s published fan curve and filter data.

3.6.6.3.3 Discharge air outlet. The discharge air outlet shall mate with Air Force drawing 8227040 for a 12 inch diameter female adapter to three pins located 120 degrees apart. The inside diameter of the ring (-10), the pin diameter and locations are provided for duct interchangeability.

3.6.6.3.4 Air duct set. The air duct set shall include two 12-inch diameter flexible ducts, each 15 feet long, and three 6-inch diameter flexible ducts, each 15 feet long, and a duct adapter (Air Force Drawing 8227065). Each flexible duct shall be fabricated in accordance with AS7365 except that the duct color shall be gray, FED-STD-595 color 26173, or as specified by ordering data (see 6.2). The ducts shall collapse to a length of no more than 18 inches and latch closed (see 3.6.4.2).

3.6.6.4 Fuel. The primary fuel for diesel generator and heater function shall be JP-8, in accordance with MIL-DTL-83133. If necessary, the diesel engine generator shall provide for supplemental fuel heating during operation below -40°F. Alternative fuels shall include:

a. DL2, DF-2, LS2, DS2 in accordance with A-A-52557 and ASTM D 975

b. DL1, DF-1 ,LS1, DS1 in accordance with A-A-52557 and ASTM D 975

c. Jet A, Jet A1 in accordance with ASTM D1655-05

d. TS-1 in accordance with GOST 10227-86

3.6.6.4.1 Fuel tank. The fuel tank minimum capacity shall provide for eight hours of operation at maximum heating output. The tank shall have a minimum three-inch diameter fill opening, accessible from outside of the enclosure, behind a filler door or in a recess. The tank fill rate shall be not less than 30 gallons per minute. A gravity drain port shall empty a full tank within 15 minutes. Spillage of fuel during filling shall not flow onto an engine or electrical component.

3.6.6.4.2 Fuel supply. Fuel supply line(s) shall include both a filter and a water separator or a combination capable of water removal to less than 5 ppm and particulate removal to 10 microns.

Fuel supply line valves shall allow for filter servicing and drainage of water without introducing air into the system or spilling of fuel. The control panel shall contain a water-in-fuel indicator.

3.6.6.4.3 Fuel gauge. A fuel gauge shall be located on the control panel (see 3.7). Fuel gauge graduations shall be a close representation of the amount of fuel in the tank. A blinking amber light near the fuel gauge shall indicate fuel levels below 25%.

3.6.6.5 Efficiency. With the heater operating at maximum, heater burner shall have a measured efficiency of at least 83% and an indicated efficiency of at least 70%. The measured efficiency shall be based on the fuel input to the heater (burner and generator) and its output capacity at the heater outlet. The indicated efficiency shall be based on flue gas analysis. Total unit fuel consumption shall not exceed 3.7 gallons per hour.

3.7 Controls. The NGH-B shall have a single panel with all controls and instruments required for operation of the diesel engine generator and the heater assembly, visible and accessible to an operator standing on the ground. The panel shall be equipped with a switched light for visibility at night. Controls shall be grouped on the panel by function. The panel shall be hinged for access to the back for service. 12-volt battery(s) of a sealed and maintenance free design shall provide power for engine starting and panel lighting. Battery inspection and service shall be accessible through an enclosure door or panel.

3.7.1 Diesel engine generator controls. The control panel shall include engine start and stop controls, an hour-meter, and a resetable emergency engine shut down. Emergency engine shut down shall be by either a switch or a button and shall not require the use of any other control.

The switch or button shall be labeled and encircled by a one inch wide red band.

3.7.2 Heating system airflow and temperature selection controls. Controls for activating the system in vent mode (fan only) or heat mode by selecting discharge air temperature (VENT-OFF- LOW-HIGH) shall be provided. Airflow and burner firing sequences shall be automatic once a heating mode is selected. Switching between heating modes shall not require a system shutdown.

Selecting OFF from a heating mode shall start an automatic shutdown sequence. A gauge shall indicate discharge air temperature.

3.7.3 Safety controls. Safety controls shall automatically shut down the diesel engine due to low oil pressure. Safety controls shall automatically shut down the heating system if the airflow, fuel flow, or burner flame is interrupted, or if discharge air temperature exceeds 350ºF. An identified manual reset shall be required for each individual safety shutdown.

3.7.4 Operating instructions. Instructions for operation of all controls shall be located on the lighted control panel or lighted on the inside of the control panel cover, if visible from the operator’s standing position.

3.8 Noise limits. Noise produced by the NGH-B at any condition shall not exceed 85 dB(A), when measured at a 7-meter radius from the heater at 1.2 meters above the ground, per MIL-STD- 1474.

3.9 Electromagnetic interference. Electromagnetic interference generation and susceptibility of the NGH-B shall comply with class C1, Group II requirements of MIL-STD-461.

3.10 Dimensions. Two complete NGH-B assemblies, with towbars folded, shall secure to and shall be air transportable on one 463L pallet without interference between or damage to the heaters.

3.11 Weight. The NGH-B weight shall be minimal, consistent with performance requirements and service life. Weight and design shall allow one (1) one-fifth percentile female, in accordance with MIL-STD-1472, to manually reposition the heater on a flat dry paved surface.

3.12 Cleaning, painting, plating, anodic films, and chemical treatments. Cleaning, chemical treatments, painting, plating, and films for the NGH-B shall be in accordance with best commercial practice.

3.12.1 Gray. All exterior surfaces and all interior surfaces exposed during normal operations shall be painted gray, color 26173 per FED-STD-595. The undercarriage and running gear may be gray or black. Markings shall be painted black, color 37038 per FED-STD-595. Commercial components may retain factory finishes, provided there is no evidence of surface deterioration from the extreme environmental conditions testing stated herein.

3.13 Markings, data plates and operating instructions.

3.13.1 Identification marking. The NGH-B, plus component parts and subassemblies shall be marked for identification in accordance with MIL-STD-130. The diesel engine, generator and burner shall have permanently attached manufacturer identification plates.

3.13.2 Data plates and operating instructions. All NGH-B data plates, placards, charts, diagrams, and instruction plates shall conform to Class 2, Composition C, of A-A-50271. All controls, valves, gauges, and operational indicators shall be identified with nameplates. Diagrams of the airflow, heating, and electrical systems, shall be mounted near the respective control locations.

Precautionary warnings shall be located near the affected system control and shall identify components by the nameplate reference on the diagrams. Tags or decals shall not be used.

Temporary nameplates may be used during testing.

3.13.3 Nameplate. A NGH-B identification nameplate shall contain the following information inscribed, except for the serial number and date of delivery, which must be stamped. Ten (10) additional blank spaces, 1/4 inch high by 4 inches long, shall be provided.

Serial Number Date of Delivery

Make and Model National Stock Number Contract Number Weight, Unloaded (Pounds) (Air Transport weight) Gross Weight (Pounds) Fuel Type Oil, Engine, SAE Grade

3.13.4 Warning and other marking. A warning plate, legible at fifteen feet, shall be affixed to all sides of the NGH-B indicating it is unsafe to use in a fuel vapor area.

4. VERIFICATION

4.1 Classification of inspections. Inspection requirements are classified as follows:

a. Pre-production tests (see 4.2)

b. Acceptance tests (see 4.3)

4.2 Pre-production testing. Pre-production (see 3.1) inspections and tests shall be performed on only complete NGH-B units. Unless otherwise stated, Pre-production tests shall be conducted at prevailing ambient temperatures. All Pre-production units shall pass “Acceptance tests” (see 4.3) prior to starting other testing. Pre-production tests may be divided between available samples.

Pre-production samples shall be identical throughout all testing. Pre-production inspections and testing shall include all requirements of 4.8 and 4.9.

4.3 Acceptance tests. Every NGH-B shall complete all acceptance tests prior to delivery.

Acceptance tests include 4.8.1 Examination of product, 4.8.12 Conformance test, and 4.8.19 Final inspection.

4.4 Contractor responsibility. The contractor shall be responsible for performing all pre-production and acceptance testing.

4.5 Preparation for testing. Each NGH-B pre-production unit shall be fully serviced and fueled, unless otherwise specified. Periodic servicing, at intervals defined by the contractor, shall be performed throughout testing. Repairs or reconditioning of a pre-production sample is not permitted without prior knowledge and concurrence of the Government.

4.5.1 Lubricants. Lubricants used during each test shall be as specified by the contractor.

4.5.2 Test fuel. Pre-production test fuel shall be Grade JP-8, in accordance with MIL-DTL- 83133.

4.5.3 Apparatus. Any apparatus or gauge used in conjunction with pre-production testing shall be laboratory precision type and shall be calibrated at intervals to ensure accuracy.

4.5.4 Data. The following data shall be recorded at 10-minute intervals during pre-production testing, except where testing does not involve system operation;

1. Engine start time.

2. Engine revolutions per minute.

3. Mode of operation.

4. Ambient air temperature entering heater intake opening.

5. Heated air temperature leaving air duct.

6. Carbon monoxide level entering heater intake opening.

7. Carbon monoxide level leaving air duct.

4.6 Test rejection criteria. The below listed criteria shall be cause for test rejection.

a. Instability or other than tire contact with the ground or an obstacle encountered during the applicable testing.

b. Overheating of a power generation, heating or ventilation system component.

c. Creation of a personnel safety hazard during operation, service, or maintenance.

d. Failure or impending failure, permanent deformation, or wear beyond limits.

e. Interference or changes of alignment between components during operations.

f. Failure to attain any performance requirements.

g. Spillage or leakage of liquids, lubricants or air, except where specifically allowed.

h. Carbon monoxide content exceeding 25 PPM.

i. loose parts, finish failures, or evidence of corrosion.

4.7 Rejection and retest. Should a failure occur during testing, the heater shall be considered rejected until the contractor discovers the cause of the failure and determines corrective action.

The contractor shall provide the Government an evaluation of the impact of the failure on previously completed testing. Government concurrence shall be required on not repeating previous testing. Testing shall not resume until corrections are completed and Government concurrence to resume has been obtained.

4.8 Testing methods.

4.8.1 Examination of product. The NGH-B shall be examined to determine compliance with all salient characteristics specified in Section 3 Requirements. Particular attention shall be given to service life, performance, controls, safety, materials, maintainability, welding, fasteners, and finish. The contractor shall develop a checklist for use in the examination of product. The checklist shall be submitted for Government review as a part of the pre-production test plan. The checklist shall be used to verify the requirements of this document which are not addressed in other tests.

4.8.2 Air transportability. An engineering analysis of the air transportability of the NGH-B shall be submitted with the pre-production test report. The analysis shall show compliance with MIL- STD-1366 requirements for loading and securing the NGH-B aboard the listed aircraft, considering the worst case constraints of; dimension, axle loading, ramp clearance, g-loading, rapid decompression, and tie downs. The engineering analysis shall also show compliance for loading and securing two NGH-Bs to a 463L pallet.

4.8.3 Parking brake test. The NGH-B shall be positioned on the worst case ramp angle in both upward and downward positions, as determined by the engineering analysis of 4.8.2. The parking brakes shall be set. The NGH-B shall not move.

4.8.4 Hoisting tests. The NGH-B shall be hoisted with four equal length cables to a single hook (see 3.3.7.1). Tilt angles shall be measured. A fully fueled NGH-B shall be raised by forklift to a height of five feet above the ground (see 3.3.7.2) from both sides.

4.8.5 Maintainability tests. The NGH-B maintainability design considerations (see 3.4) shall be demonstrated. Selections of wear items, in terms of operating hours and/or maintenance intervals during normal and extreme conditions shall be reported.

4.8.5.1 Prior-to-use inspection test. Performance of the prior-to-use inspections (see 3.4.a), within a 15-minute time limit, shall be demonstrated.

4.8.5.2 Corrective maintenance test. Compliance with corrective maintenance downtime (see 3.4.c) shall be demonstrated by task performance. All single item replacement maintenance tasks shall be listed. The Government will select any 10 tasks, which shall be demonstrated. Task times and personnel skill level shall be established at the demonstration. Fluid drainage times, if required, shall not be recorded.

4.8.6 Airflow capacity test. An airflow capacity test shall determine the output airflow of the heater. Two 12-inch diameter ducts (see 3.6.6.3.4) shall be connected to the air discharge connection and deployed on the ground in straight lines. The NGH-B shall be started and the airflow shall be activated. Airflow shall be maintained for one hour with 50% filter restriction (see 3.6.6.3.2) and one hour with an unrestricted filter. Total airflow shall be measured at 10-minute intervals at the end of two 12-inch diameter ducts. The pressure drop across the ducts shall also be measured for use in other tests.

4.8.7 Environmental tests. Tests shall be conducted in accordance with MIL-STD-810. Base-line performance of the NGH-B shall be established prior to environmental testing.

4.8.7.1 High temperature test. The NGH-B shall be subjected to high temperature testing in accordance with Method 501.4, Procedures I and II. The heater shall be subjected to three 24-hour high temperature cycles, climactic category, Hot, Induced Conditions. Following the third cycle, the test cell shall then be stabilized at +70±3° F. for 24 hours prior to operational testing and during the test period. An airflow resistance equivalent to two 12-inch diameter ducts (see 3.6.6.3.4) shall be fitted to the discharge connection. The diesel generator shall be started.

Engine start time and fully operational time shall be recorded. The heater shall be operated in high fire rate mode for 30 minutes. Total airflow shall be recorded. Discharge air temperatures shall hold steady at 280°F ± 15ºF at the heater outlet. The heater shall be reset to low fire rate mode and run for 30 minutes. Total airflow shall be recorded. Discharge air temperatures shall hold steady at 160°F ± 5% at the heater outlet. The heater shall operate in both fire rate modes without a system safety shutdown. During testing, lubricants and component temperatures shall remain within the respective manufacturer’s safe operating limits, as established prior to testing.

The generator load shall be recorded and shown to be within the power factor requirement.

4.8.7.2 Low temperature test. The NGH-B shall be filled with fuel and shall be subjected to low temperature testing in accordance with Method 502.4, Procedure II. The heater shall be cold soaked for 72 hours at -65°F. Following the cold soak, the test cell temperature shall be increased and stabilized at -25±3°F. for 24 hours. An airflow resistance equivalent to that of two 12-inch diameter ducts (see 3.6.6.3.4) shall be fitted to the discharge connection. The diesel generator shall be started. Engine start time shall be recorded. High temperature heating mode shall be selected. The time required to attain 280°F ± 15ºF at the heater outlet shall be recorded. Total airflow shall be recorded. Discharge air temperatures shall hold steady at 280°F ± 15ºF. While the heater continues to run, the test cell temperature shall be reduced to -65°F. The NGH-B shall continue to run until all fuel is consumed. The time required to consume all fuel shall be recorded. During testing, lubricants and component temperatures shall remain within the respective manufacturer’s safe operating limits, as established prior to testing. Generator load shall be recorded and shown to be within the power factor requirement.

4.8.7.3 Rain test. The NGH-B shall be subjected to a rain test in accordance with Method 506.4, Procedure I, a rainfall rate of 4 inches per hour with a concurrent 40 miles per hour wind. The heater enclosure shall be in a storage mode during the four-side rain test. The enclosure shall be inspected for accumulation of water. An airflow resistance equivalent to two 12-inch diameter ducts (see 3.6.6.3.4) shall be fitted to the discharge connection. The heater shall be started and operated in high fire rate mode. A repeat four-side rain test shall be conducted (15 minutes per surface). Open panels and doors shall not release or deform due to wind velocity from any quarter. No water shall collect at any point within the enclosure or in the air path and no water shall reach the heat exchanger.

4.8.7.4 Humidity test. The NGH-B shall be subjected to a humidity test in accordance with Method 507.4, Procedure III, 10 cycles. The enclosure shall be open, ready for service, during the humidity test.

4.8.7.5 Salt-fog-test. The NGH-B shall be subjected to a salt-fog test in accordance with Method 509.4, with four, 24-hour exposures, alternating wet and dry, periods. The heater enclosure shall be in a storage mode during the salt-fog test. Following the final exposure period, all accesses and system functional components shall be demonstrated to operate at original design levels.

4.8.7.6 Blowing dust test. The NGH-B shall be subjected to a blowing dust in accordance with method 510.4, Procedure I. Test duration shall be six hours. The heater enclosure shall be in a storage mode during the blowing dust test. At the conclusion of the test, the heater shall be prepared for operation, two 12-inch diameter ducts installed, started, and operated in high fire rate mode. All heater systems shall be demonstrated to operate at original design levels.

4.8.7.7 Blowing sand test. The NGH-B shall be subjected to a blowing sand test in accordance with method 510.4, Procedure II. Test duration shall include 90-minute exposures to each side.

At the conclusion of the test, the heater shall be prepared for operation and started. All heater systems shall be demonstrated to operate at original design levels.

4.8.7.8 Solar radiation test. The NGH-B shall be subjected to a solar radiation test in accordance with method 505.4, Procedure I, five hot dry cycles.

4.8.7.9 Exposure to fungus. The NGH-B shall be subjected to a fungus test in accordance with method 508.4, 28 days duration.

4.8.7.10 Altitude test. The NGH-B shall be demonstrated to start and operate at 5000 feet elevation.

4.8.8 Performance and endurance test. The NGH-B shall be performance and endurance tested for 1000 hours total duration. All pre-production samples may be used to accumulate total hours.

Ambient or test cell conditions shall be cold enough to maintain high-temperature mode burner firing for a minimum of 50% of the run time. An airflow resistance equivalent to two 12-inch diameter ducts (see 3.6.6.3.4) shall be fitted to the discharge connection. Individual test cycles shall be a minimum of eight hours duration, including; 15 minutes for a prior-to-use inspection, five minutes for generator start-up, three hours operation in high-temperature mode, switch for two hours in low-temperature mode, switch for 2 1/2 hours in high-temperature mode, and a shut-down sequence. Refueling shall not be part of a test cycle. Data shall be gathered to determine compliance with the measured and indicated burner efficiency and fuel consumption requirements of 3.6.6.5 while the heater is in high mode and the burner is operating.

4.8.9 Controls. Individual safety controls of the NGH-B shall be demonstrated to provide the system protections required. No system damage shall occur from activation of any system safety control. The emergency engine shutdown shall be demonstrated one time by activation of the control panel switch. The low oil pressure engine shutdown shall be demonstrated one time. A one time heating system shutdown shall be demonstrated for loss of airflow. A one time heating system shutdown shall be demonstrated for an interruption of fuel flow to the burner. A one time heating system shutdown shall be demonstrated for loss of ignition source to the burner. Heating system burner mode controls (High and Low) shall be over-ridden to increase discharge air temperature to 350 degrees. The high temperature safety control shall be demonstrated to shutdown the heating system five times for each mode setting. Carbon monoxide shall be introduced into the ambient air intake to demonstrate the CO sensor in the discharge air stream shuts down the burner and airflow system at a concentration of 25 PPM. The CO sensor system shutdown shall be repeated five times.

4.8.10 Tilted operation test. The NGH-B shall be demonstrated to operate at an angle of 8 ½ degrees in any direction from true horizontal.

4.8.11 Mobility tests. The NGH-B, including ducts, engine exhaust, and burner flue stowed in respective compartments, and a full fuel tank shall be subjected to mobility tests stated herein.

Following completion of each mobility test, a Conformance test (see 4.8.12) shall be conducted.

4.8.11.1 Highway. The NGH-B shall be towed for a distance of 200 miles over paved highways at speeds between 20 mph and 25 mph (average speed must exceed 20 mph). A 90-degree tight radius turn at 8 mph and a sudden stop shall occur every five miles.

4.8.11.2 Gravel road. The NGH-B shall be towed for a distance of 50 miles over graded gravel roads at speeds between 10 mph and 12.5 mph (average speed must exceed 10 mph). A 90-degree tight radius turn at 8 mph and a sudden stop shall occur every five miles.

4.8.11.3 Multiple tow. The contractor shall create an engineering analysis which confirms that eight NGH-Bs can be towed in two rows of four heaters in tandem by a tow vehicle with two pintle hooks on eight-foot centers. The analysis shall show that the tow vehicle is able to make 90-degree turns to the right and left at radius of 18.5 feet and a speed of 5 mph with no binding or interference between the NGH-Bs in the tow. The analysis shall be submitted as a part of the pre-production test report.

4.8.12 Conformance tests.

4.8.12.1 Leakage test. The heat exchanger shall be pressurized to 5 psig. With the air supply disconnected, air pressure shall not fall below 4 psig after five minutes duration.

4.8.12.2 Run-in test. The NGH-B shall be tested for one hour. An airflow resistance equivalent to two 12-inch diameter ducts (see 3.6.6.3.4) shall be fitted to the discharge connection. The diesel generator shall be started and the system heating control placed in low-firing rate for 30 minutes, followed by the system heating control placed in high-fire rate for 30 minutes.

Discharge airflow and heating performance shall be measured at 10-minute intervals and shall maintain design performance tolerances for the duration of the test. The contractor shall include the recorded data from the pre-production units as part of the test report for Government review and acceptance.

4.8.13 Operational sound level test. The sound levels produced by the NGH-B (see 3.8), with two 12-inch diameter ducts (see 3.6.6.3.4) installed, shall be measured in accordance with the testing procedures of SAE ARP1801 for trailer-mounted equipment. The discharge airflow (sound producing) shall be directed away from any microphone during sound measurement recordings.

The sound level of airflow shall be recorded for data only.

4.8.14 Fastener tests. If the NGH-B includes any threaded fasteners into aluminum, the Government may select any five fasteners for a torque test. Prior to all other testing, the selected fasteners shall be removed and re-installed twenty times each to the torque specified by the contractor for the application. These fasteners shall be identified and observed throughout all testing for loss of torque.

4.8.15 Electromagnetic interference test. The NGH-B shall be tested as specified in the requirements of MIL-STD-461, class C1, Group II for electromagnetic interference and susceptibility.

4.8.16 Dimensional check. The length, width, and height of the NGH-B in operational, storage, and mobility configurations shall be recorded.

4.8.17 Weight check. Individual wheel loads for the heater shall be taken. Wheel loading for the curb weight (air transportable) and for operational (fully fueled) configurations shall be recorded.

The center of gravity shall be established and shown to be no more than 12 inches from the mid-point between forklift tube locations. One 5th percentile female shall reposition the heater a total distance of 25 feet on a dry, flat, smooth, concrete surface. The test shall include; releasing the parking brake, initiation of motion, a 90-degree left and a 90-degree right turn, and resetting the parking brake.

4.8.18 Operational testing. Immediately upon conclusion of the contractor’s preproduction testing and approval by the Government to proceed, the contractor shall be responsible for sending two preproduction units to Eielson AFB, AK and two preproduction units to Peterson…