BEAR ECU Purchase Description.pdf

INCH-POUND

PD25WRROZ001

CAGE 98752

JULY 22 July 2025

PURCHASE DESCRIPTION

Expeditionary Environmental Control Unit, 5 Ton

1. SCOPE

1.1 Scope. This purchase description (PD) covers a 60,000 British Thermal Units/hour (Btu/hr) Environmental Control Unit (ECU), which will be a heat pump configuration to provide cooling and heating to enclosed living areas. The package unit is intended to be used outside a tent, on the ground or on a trailer, with flexible ducts attached to both inlet and outlet utility ports. It consists of an electric-motor-driven heat pump compressor with integral supplemental resistance heat.

2. APPLICABLE DOCUMENTS

2.1. General. The documents listed in this section are needed to meet the requirements specified in sections 3 and 4 of this document. This section does not include documents cited in other sections of this document or recommended for additional information or as examples. While every effort has been made to ensure the completeness of this list, document users are cautioned that they must meet all specified requirements documents cited in sections 3 and 4 of this document, whether or not they are listed.

2.2. Government documents.

2.2.1 Specifications, standards, and handbooks. The following specifications, standards, and handbooks of the exact revision listed below form a part of this specification to the extent specified herein.

SPECIFICATIONS

FEDERAL SPECIFICATION

TT-C-490 Chemical Conversion Coatings and Pretreatments

FED-STD-313 Material Safety Data, Transportation Data, Disposal Data for Hazardous Materials Furnished to Government Activities

DEPARTMENT OF DEFENSE

MIL-DTL-22992 Connectors, Plugs and Receptacles, Electrical, Waterproof, Quick Disconnect, Heavy Duty Type, General Specification

MIL-DTL-81706 Chemical Conversion Materials for Coating Aluminum and Aluminum Alloys

MIL-STD-130 Identification Marking of U.S. Military Property MIL-STD-1366 Interface Standard for Transportability Criteria MIL-STD-1791 Designing for Internal Aerial Delivery in Fixed Wing

Aircraft

MIL-STD-810 Test Method Standard for Environmental Test and

Engineering Guidelines MIL-STD-889 Dissimilar Metals MIL-STD-1472 Human Factors Engineering

MIL-PRF-32402 Container, Cargo Triple Container (Tricon 5) MIL-PRF-5541 Chemical Conversion Coatings on Aluminum and

Aluminum Alloys

(Unless otherwise indicated, copies of federal and military specifications, standards, and handbooks are available from the Standardization Documents Order Desk, Building 4D, 700 Robbins Ave., Philadelphia, PA 19111-5094.)

2.2.2. Other Government documents. The following other Government documents form a part of this document to the extent specified herein. Unless otherwise specified, the issues are those in effect on the date of the solicitation.

DRAWING

AF Drawing Number 72289 (60-amp cable)

DEPARTMENT OF THE AIR FORCE

DAFMAN 24-210 Packaging of Hazardous Material DAFMAN 24-604 Preparing Hazardous Material for Military Air Shipments

Publications and forms are available on the e-Publishing website at www.e-Publishing.af.mil for downloading or ordering.

2.3. Non-Government publications. The following documents form a part of this PD to the extent specified herein.

AIR-CONDITIONING AND REFRIGERATION INSTITUTE (ARI)

700 Specification for Fluorocarbon Refrigerants 720-97 Refrigerant Access Valves and Hose Connectors

(Applications for copies should be addressed to the Air-Conditioning and Refrigeration Institute, 4301 North Fairfax Drive, Arlington, VA 22203.)

AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI)

C101.1 Leakage Current for Appliances

(Application for copies should be addressed to the American National Standards Institute, 1430 Broadway, New York, NY 10018.)

NATIONAL FIRE PROTECTION ASSOCIATION (NFPA)

70 National Electrical Code

(Application for copies should be addressed to National Fire Protection Association, Battery March Park, Quincy, MA 02269.)

SOCIETY OF AUTOMOTIVE ENGINEERS (SAE)

AMS-STD-595 Colors Used in Government Procurement AS 33611 Tube Bend Radii AS 38386 Duct Assembly, Ground, Conditioned Air, Insulated Flexible J429 Mechanical and Material Requirements for Externally

Threaded Fasteners

J533 Flares for Tubing

(Application for copies should be addressed to SAE International Customer Service, 400 Commonwealth Drive, Warrendale PA 15096, http://www.sae.org/.)

2.4. Order of precedence. In the event of 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 First article. When specified (see 6.2), a quantity of 12 samples specified shall be subjected to first article inspection in accordance with 4.2.

3.2 Description and general layout. The ECU described herein is intended primarily for cooling and heating military shelters. The ECU:

http://www.sae.org/

a. Shall be provided with two 16-inch diameter flexible ducts attachable to inlet and outlet of inside coil compartment. These ducts shall be no less than 10-feet long and constructed according to SAE AS 38386 to provide a minimum “R” value of 3. The ducts shall be attachable cam over clamp, part no. 57-HT370-415SS, Protex Fastners or equivalent. The return-air duct shall have a detachable screen on the shelter end (away from ECU) to block any items from being sucked into the ECU return.

b. Shall be provided with 25-feet of detachable power, compatible to Table II interface specifications allowing cable to be connected directly to the power source.

c. Shall be provided with a 10-foot condensate hose.

d. Shall be provided with a washable and re-useable filter for the inside return air.

e. Shall be able to support the weight of three of the same ECUs on top (i.e., be able to stack four units high). The ECUs shall include captive stacking retainers to ensure that the ECUs can be securely fastened together for transportation and storage. No parts of the system shall extend beyond the exterior profile for transportation and storage.

f. Shall withstand a storage temperature of -65°F to +160°F for a life expectancy of 25 years minimum.

g. Shall be provided with 2 “Y” sections to allow splitting/joining the supply and the return ducts to allow connections to 2 separate shelters, “Y” s shall be designed to direct airflow evenly between the 2 shelters without dampers. The ducts shall be resistant to crushing and collapsing due to negative pressure.

h. Shall include retractable legs that allow the ECU to operate above the surface a minimum of 4 inches.

i. Shall have provisions to accommodate an additional wheel kit to move the ECU without the use of material handling equipment.

3.3 Performance.

3.3.1 Cooling capacity. At the conditions specified in Table II, the minimum sensible cooling capacity and the minimum total cooling capacity shall be as stated in Table I. Cooling capacities shall be determined for both 60- and 50-Hz input powers.

TABLE I. Cooling Capacity Conditions.

Ambient temperature

Evaporator Inlet temperature (dry bulb)

Evaporator Inlet temperature (wet bulb)

Static Pressure (inch) water column gauge (wg)

Minimum Cooling Capacity (Btu/hr)

125°F 90°F 75°F 1.0 60,000

3.3.2 Airflow. The minimum evaporator airflow shall be as specified in Table II.

3.3.3 Cooling.

3.3.3.1 High temperature operation. After exposure to 125°F for a 4-hour soak, the ECU shall be able to start and operate in the COOL mode.

3.3.3.2 Low temperature operation. The ECU shall be able to operate for 1 hour in COOL mode (heat pump only) after being subjected to 70°F on the evaporator side, and the temperature no greater than as specified Table II on the condenser side for 10 hours.

3.3.3.3 Coil frost. The ECU shall be able to operate in COOL mode (heat pump only) at 50°F ambient outdoor temperature, without significantly forming frost or ice on the evaporator (20% or greater of the coil face area), with air at 70°F dry bulb and 60°F wet bulb entering the evaporator.

3.3.4 Heating.

3.3.4.1 Low temperature operation. After being subjected to –25°F for not less than 12 hours, the ECU shall be able to start, operate and restart in the HEAT mode with air at –25°F into the condenser inlet.

3.3.4.2 Electrical resistance heating. Maximum additional resistive heating without exceeding the maximum power consumption. Minimum total heat output 40,000 BTU/hr.

3.3.5 Electrical performance. The ECU shall be able to operate when supplied with rated voltage up to +10% or down to –5%, and with input frequencies of either 50 or 60 Hz.

3.3.5.1 Power and steady-state current. The maximum power and maximum current consumption of the ECU operating in HEAT or COOL mode shall be as specified in Table II.

3.3.5.2 In-rush current. The in-rush current for the ECU, including startup and thermostatic cycle, shall not exceed the maximum operating amperage by 20%, with 10% being desirable.

3.3.5.3 Total Harmonic Distortion. The Total Harmonic Distortion (THD) of the current waveform imposed on the input power line by the ECU shall not exceed 25%.

3.3.6 Inclined operation. The ECU shall be capable of operating in COOL mode without malfunction when any of the four-side bases of the ECU is positioned 10 degrees from the horizontal plane. During inclined operation, all condensation shall be disposed of through the condensate drain line. There shall be no evidence of moisture “carryover” in the airflow leaving the evaporator outlet. The exterior opening of the condensate drain shall be sealable with a threaded plug.

3.3.7 Operating pressures. The suction and discharge pressures of the refrigerants shall be within the limits depicted in the compressor manufacturer’s specification.

3.3.8 Run-in. All units produced shall be required to pass an initial Run-in test in which each system will operate in every mode while maintaining safe and efficient performance parameters.

Run-in tests apply to all production units, as a Quality Conformance Test.

3.4 Controls. Controls shall be designed and located so that they are not susceptible to being moved accidentally, particularly critical controls whose inadvertent operation might cause damage to equipment, injury to personnel or degradation of system functions as stated in MIL-STD-1472.

The system shall be controllable either by the ECU control panel and/or by a tethered remote-control box. An indication of control activation shall be provided (e.g., snap feel, audible click, or indicator light illumination) along with displays of desired temperature setting.

3.4.1 Mode selector control. Operation of the ECU shall be controlled by a single mode selector switch. The mode selector switch shall have four modes of operation: OFF, VENT, COOL, and HEAT. The mode selector switch shall control operation of the ECU as follows (in a general sense without regarding actions due to the thermostat, safety cutouts, or other control actions).

a. When the control is in the OFF position, the electrical heaters, the fan motors and the compressor shall be de-energized regardless of the position of the thermostat.

b. When the control is in the COOL position, the evaporator fan motor, the condenser fan motor and the compressor shall be energized. The electric heater shall be de-energized.

c. When the control is in the HEAT position, the evaporator fan motor, the condenser fan motor and the compressor shall be energized. The electric supplemental heater shall be energized as necessary to provide/maintain desired temperature setting.

d. When the control is in the VENT position, the inside fan motor shall be energized. The compressor, outside fan motor, and the electric heaters shall be de-energized regardless of the position of the thermostat.

3.4.2 Conditioned air-thermostat. The thermostat shall allow operators to regulate the conditioned space temperature between 65 to 80°F via a selector and a digital display from the ECU control panel as well as the tethered remote-control box when used.

3.4.3 High pressure cutout. A switch shall de-energize the compressor when the discharge pressure exceeds the compressor manufacturer’s specified maximum operating pressure. When switch reset is activated and the pressure has returned to a manufacturer’s recommended range, the switch shall re-energize the compressor.

3.4.4 Low pressure cutout. A switch shall de-energize the compressor when the suction pressure reduces below the compressor manufacturer’s specified minimum operating pressure. When switch reset is activated and the pressure has returned to a manufacturer’s recommended range, the switch shall re-energize the compressor.

3.4.5 Heater high limit cutout. When in HEAT mode, a switch shall de-energize the heater when the interior of the evaporator compartment reaches 180°F. All materials used in the evaporator compartment shall be able to withstand this temperature without charring, becoming brittle, or otherwise becoming damaged during the period of time typical of a loss of airflow/over-temperature shutdown scenario. The switch shall automatically reset when the temperature declines to 120°F.

3.4.6 Remote Control Box. The ECU’s remote-control box shall have a mode selector switch, adjustable temp control and a thermostat. The remote-control box shall be able to be removed from the ECU cabinet allowing remote control capability via a tethered cable. No conductor connected into the box shall exceed 30 volts. The control box shall be assembled with a 25 ft cable and an environmentally resistant connector compatible with a mating recessed receptacle on the ECU.

The entire ECU remote-control box shall be considered ancillary equipment to be stowed with other components in additional support containers.

3.4.7 Pressure relief. The ECU shall have a mechanism to relieve pressure in a safe location and manner. This mechanism shall be resettable and shall be set above the High-Pressure Cutout set-point (see 3.4.3).

3.4.8 Fresh-air inlet. A fresh-air inlet, with a damper, shall allow outdoor air (or makeup air) to enter the indoor. With the damper opened, the VENT mode of the ECU shall allow the fresh-air airflow rate as specified in Table II. The damper shall be as close as is feasible to the exterior opening of the inlet. The damper shall be designed so the normal operation position is closed, but have the capability of being locked open at any incremental percentage of total air flow. The damper shall be labeled to indicate position.

3.5 Refrigeration system.

3.5.1 Refrigeration system type. The refrigerant system shall be of the vapor cycle type. The refrigerant shall have an ozone depletion potential (ODP) of zero. The refrigerant shall be from the EPA’s Significant New Alternatives Program (SNAP) list. The purity of the refrigerant shall be in accordance with ARI 700. The contractor shall select components suitable for use with the selected refrigerant and lubricant. The refrigerant shall have Global Warming Potential (GWP) ≤ 750.

3.5.2 Refrigeration functionality. The system shall use a thermal expansion valve to control the refrigerant flow to the evaporator as well as reversing valves and check valves to control the direction of refrigerant in the heat pump cycle. The system shall contain a filter-drier compatible with the refrigerant and lubricant used. The unit must be capable of being shut down and restarted within 10 seconds at any operating condition.

3.5.3 Refrigerant system leakage. The entire refrigerant system shall withstand up to the “pressure relief” setting determined in 3.4.3 without deformation of any component or any detectable leakage.

3.5.4 Refrigerant Tubing. Tubing shall be installed so that no contact is made between it and any adjacent component or structure except for brackets that restrain tubing. All tubing bends shall have a minimum centerline bend radius of twice the tube diameter in accordance with SAE AS 33611. Tube ends shall be flared at all flare nut joints in accordance with SAE J533, single 45° Flare.

3.5.5 Service connections. Two service connections designed to ARI Standard 720-97, shall be provided, one for high side (discharge) and one for low side (suction). The lines shall be mounted such that they can be accessed readily for maintenance/inspection. The charging valves shall have captive protective caps. The lines shall be permanently labeled “H” (discharge/high side) and “L” (suction/low side) with 0.5-inch letters in accordance with the marking criteria specified herein (see 3.14.2).

3.5.6 Refrigerant charge indicator. Visual indicators must be used in the design to provide valuable information on the condition of the refrigerant to maintainers.

3.6 Item specific equipment. The ECU shall have the physical and functional characteristics shown in Table II.

Table II: ECU, 60,000 Btu/hr

Ambient Operating Temp.

Range

Cooling: +50o to +125oF Heating: –25o to +75oF (Resistive Heat only below 38 oF)

Control Control panel and remote thermostat

Refrigerant EPA-approved, have an ozone depletion potential (ODP) of zero, a GWP <= 750. The refrigerant shall be listed on EPA SNAP approved list.

Minimum Cooling Capacity @ +125oF Ambient

60,000 Btu/hr, @ +90 oF dry bulb, +75°F wet bulb evaporator inlet and 60 Hz frequency input, 1.0-inch wg interior pressure

Minimum additional Heating Capacity

Minimum additional supplemental resistive heat equivalent to not exceed total allowable power consumption

Volts, AC 208VAC

Phase 3

Frequency, Hz 50/60

Wires 5

Maximum Power Consumption

13.0 kW (10.5 kW is desired)

Maximum In-rush Current Not to exceed 20% of maximum operating current (Not to exceed 10% of maximum operating current is desired)

Minimum Supply airflow, Standard Cubic Feet per Minute (SCFM)

2,000 SCFM @ 1.0-inch external wg (2,200 SCFM @ 1.0-inch external wg is desired)

Maximum Gross Weight 650 pounds (600 pounds is desired.)

Maximum Overall Packaged Dimension

Optimize dimension to allow a minimum of:

1. 4 ECUs and all support components within a standard

Tricon ISO container with door opening of 78¼ inches X 81½ inches

2. 12 ECUs per standard 463L pallet, usable cube 104 inches X 84 inches X 96 inches

Adjustable Fresh-Air Airflow

Min. 500 SCFM @ max setting

Power Connector Interface MS90558C32412P

3.7 Enclosure. The enclosure shall have the strength and rigidity to withstand the mobility, lifting, and environmental conditions stated herein. The enclosure shall be designed to minimize the entrance and retention of foreign material (rain, snow, sand, dust, etc.) while still providing maximum accessibility from all sides for service and maintenance. Any external intake and exhaust openings shall be provided with louvers, grilles, grates, or similar devices to aid in weather-proofing the ECU.

3.8 Environmental conditions.

3.8.1 Storage temperature range. The ECU shall be capable of being stored in ambient temperatures ranging from -65° F to +160° F.

3.8.2 Precipitation.

3.8.2.1 Rain. When subjected to MIL-STD-810, Rain, Procedure I, the ECU shall show no evidence of malfunction nor water accumulation which may pose safety hazard.

3.8.3 Solar radiation. The ECU shall not be adversely affected by full time exposure to solar radiation, such as those conditions encountered in desert environments and high altitudes.

3.8.4 Fungus. All materials used in the ECU shall be fungus resistant or shall be suitably treated to resist fungus. Materials treated for fungus resistance shall retain their original electronic and physical properties, shall not present toxic hazards, and treatment shall last for the entire service life of the part. The ECU shall be suitable for operation and storage in conditions encountered in a tropical environment.

3.8.5 Salt fog. The ECU shall be capable of sustained use and storage in high temperature, high humidity, salt laden, seacoast environments without damage or deterioration of performance. The ECU shall also be capable of storage and operation in part-time (5%) exposure to a five percent salt solution, with fallout rate of 0.10 oz (3 ml) per hour per each 12.40 sq. inch (80 sq. cm) of horizontal collecting area without damage or deterioration of performance.

3.8.6 Sand and dust. The ECU shall be capable of sustained use and storage with exposure to 0.062 grams/cubic foot wind-blown sand (particle size 150-1000 microns) or dust (particle size less than 150 microns) at wind speeds up to 35 knots without damage or deterioration of performance.

3.8.7 Noise. The noise levels produced by the ECUs shall not be greater than 80 dB(A) two meters away, one meter from the ground, on each side of the unit. (75 dB(A) or less is desired.)

3.8.8 Vibration. The ECU shall be designed to perform within the environment created by using MIL-STD 810G, Test Method 514.8C, Secured Cargo, representing transportation modes for a typical field/mission support scenario.

3.8.9 Altitude. The ECU shall be designed to operate at altitudes up to 10,000 feet.

3.9 Weight and dimensions. The size and weight of the ECU shall be as small and light as practicable, consistent with the requirements specified in Table II. The weight shall be measured with a full charge of refrigerant in operational configuration.

3.10 Transportability. The ECU shall be transportable as restrained cargo (to include roll on and roll off) by certain military cargo aircraft, truck or trailer, railcar, and ship.

3.10.1 Surface transportability. The ECU shall be transportable as restrained cargo via all modes of surface shipment (highway, rail, and water) in accordance with MIL-STD-1366, and shall be capable of withstanding the mechanical shock and vibration characteristics of highway, rail, and water transport, except that design for rail impact testing (see 5.2.5 of MIL-STD-1366) is not required.

3.10.2 Air transportability. The ECU shall be transportable on C-130H and J aircraft in accordance with MIL-STD-1791. In all air transport configurations, the ECU shall be capable of being restrained and withstanding, without loss of serviceability, 2.0 G up and 4.5 G down accelerations, and shall be capable of being restrained and withstanding, without loss of structural integrity, 3.0 G forward, 1.5 G aft, and 1.5 G lateral accelerations. The ECU shall be equipped with pressure relief devices and configured for air transport up to 40,000 feet to prevent any part from becoming a projectile in the event of catastrophic loss of aircraft cabin pressure.

3.11 Lift Provision. The unit shall be capable of being lifted with a forklift. The forklift openings shall be enclosed and each pocket shall not be smaller than 3.75 inches high and 14.5 inches wide.

The pockets shall be located on all four sides. The distance between pockets shall be maximum allowable per side.

3.12 Maintainability. The ECU shall be designed for maintainability in accordance with 5.9 through 5.9.22.9 of MIL-STD-1472; forces shall not exceed those specified for both males and females. No computers or other type external media interface shall be required for operations, maintenance, troubleshooting, and repairs.

3.12.1 Inspection and servicing provisions. The ECU shall be designed for serviceability in accordance with 5.9 through 5.9.22.9 of MIL-STD-1472; forces shall not exceed those specified for both males and females. All prior-to-use service and inspection shall be accomplishable by one person in a time period not to exceed 30 minutes, while wearing arctic clothing. The ECUs shall not require scheduled operational maintenance more often than once every 250 hours of operation.

The ECU shall be designed with a minimum periodic inspection interval of 24 months while in storage. All required maintenance and timed requirements shall be identified in the technical manual.

3.12.2 Relative accessibility. Critical items that require rapid maintenance shall be most accessible. When relative criticality is not a factor, items that require the most frequent access shall be most accessible. High failure rate items shall be accessible for replacement without moving non-failed items.

3.12.3 Special tools. The ECU shall be maintainable using only the tools specified in the Civil Engineering HVAC technician tool kit. (Appendix A)

3.12.4 Repair. The ECU shall be designed for ease of maintenance. Mean Time To Repair (MTTR), to include fault isolation and operational check, shall not exceed two hours. Standard parts shall be used whenever practicable. As many components as possible shall be derived from commercial parts without the risk of decreasing reliability.

3.13 Service life/shelf life. The ECU shall be designed for a minimum service life of 20 years. The ECU shall be suitable for extended storage in an outside environment for a minimum of 25 years.

3.14 Design and construction. The design shall promote cost effective, life-cycle sustainability by addressing considerations such as incorporating open standards, reducing pollutant emissions and waste, while satisfying system performance requirements. It shall be designed and constructed so that no parts will work loose in service, and to withstand the strains, jars, vibrations, and other conditions incident to shipping, storage, installation, and service. It shall be weatherproof and designed to prevent the intrusion of water, sand, and dust into critical operating components.

3.14.1 Materials, protective coatings, finish, and corrosion control.

3.14.1.1 Recycled, recovered, environmentally preferable, or biobased materials. Recycled, recovered, environmentally preferable, or biobased materials shall 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.

3.14.1.2 Protective coatings and corrosion control.

3.14.1.2.1 Protective coatings. Materials that deteriorate when exposed to sunlight, weather, or operational conditions normally encountered during the service life of the ECU shall not be used or shall have means of protection against such deterioration that does not prevent compliance with the performance requirements specified herein. The ECU shall be constructed of corrosion resistant materials to the maximum extent possible. Surface treatments, pre-treatments and coatings shall be applied to all components that are not corrosion resistant. Surface treatments include electroplated coatings, thermal sprayed coatings, and hard anodize coatings. Surface pre-treatments include thin film anodize, conversion coatings, zinc phosphate, and other coatings used to enhance subsequent corrosion protective coating adhesion and performance. Corrosion protective coatings include corrosion inhibited epoxy primers and polyurethane topcoats.

Corrosion protective coatings that chip, crack, or scale with age or extremes of climatic conditions or when exposed to heat shall not be used. Exposed surfaces of fasteners, handles, and fittings shall also be primed and painted. When in contact with ferrous materials, steel fasteners shall be plated with zinc/nickel in accordance with MIL-PRF-32647. When in contact with aluminum materials, steel fasteners shall be coated with a Zinc/Aluminum Corrosion Protective Coating in accordance with ASTM F1136 Grade 3.

3.14.1.2.2 Surface preparation. Components shall be cleaned, degreased, and prepared prior to any scuffing, sanding, blasting, or application of any pretreatment. Surface preparation and pretreatment shall be in accordance with the respective primer and topcoat specifications. All corrosion protection steps, regardless of material, shall be applied before any new oxidation or rusting occurs post-treatment and shall be completed prior to application of any coating used as either primer or topcoat. Surfaces shall be scuffed, sanded, and/or blasted, depending upon material type and thickness, to remove any existing surface impurities such as primer/paint/topcoat, corrosion, welding/grinding/cutting slag, etc. that may prevent adhesion and protection of further corrosion control measure. Any surface undergoing a media blasting process shall have the blasting pressure, blasting material type, and blasting material grit suitably chosen to prevent warpage or other structural damage. Coatings requiring a 'near-white' ferrous metal finish shall have the surface(s) prepared in accordance with SSPC-SP 10/NACE No. 2. General surface finish and cleanliness shall be in accordance with SSPC-Vis 1.

3.14.1.2.2.1 Aluminum pretreatment. Aluminum surfaces used in construction of the ECU shall be treated with a suitable conversion coating prior to application of any other corrosion prevention coating. Anodizing or a MIL-DTL-81706 conversion coating process may be utilized, at the discretion of the ECU manufacturer. Any anodizing shall be applied in accordance with MIL-A- 8625, Type II, Class 1; no further conversion coating is required on anodized aluminum surfaces.

Alternatively, aluminum surfaces shall have MIL-DTL-81706, Type II, Class 1A, Form I, Method C chemical conversion coating applied in accordance with MIL-DTL-5541, Type II, Class 1A.

3.14.1.2.2.2 Ferrous pretreatment. Ferrous surfaces used in construction of the ECU shall be treated with a metal etching compound prior to application of any further pretreatment process(es).

Ferrous surfaces with iron or zinc phosphate coatings/etches do not require further pretreatment.

Ferrous surfaces without iron or zinc phosphate coatings/etches shall be treated with a wash primer in accordance with TT-C-490 to seal out flash rust.

3.14.1.2.3 Primer. Raw metal edges, to include fastener and drain holes, shall be coated with primer prior to applying the topcoat. Any surfaces where primer and/or topcoat is not required, or intended to be applied, shall be masked off using materials and processes suitable for use with applied primer and/or topcoat system. A primer color shall be chosen that is compatible with the color of the topcoat used such that scratches in the topcoat do not yield an obtrusive contrast with any exposed primer (tone-down primer in a similar shade/color family as the topcoat).

3.14.1.2.3.1 Ferrous surfaces. Ferrous structures and surfaces shall be primed with a non-water reducible zinc rich primer in accordance with MIL-DTL-53022, Type IV, Class L. The primer system shall be allowed to dry and fully cure in accordance with the primer manufacturer's directions prior to applying the topcoat.

3.14.1.2.3.2 Aluminum and mixed aluminum and ferrous surfaces. Aluminum and mixed aluminum and ferrous structures and surfaces shall be primed with an epoxy primer in accordance with MIL-DTL-53022, Type IV, Class L.

3.14.1.2.4 Topcoat. All ECU components shall be top coated with polyurethane in accordance with

MIL-PRF-85285, Type IV, Class H. Neither Chemical Agent Resistant Coating (CARC) nor powder coating shall be used. The coating shall be free from runs, sags, orange peel, or other defects. The contractor shall utilize the topcoat material manufacturer's specifications to accomplish application of the coating system in accordance with the manufacturer's directions to the minimum dft required herein.

3.14.1.2.5 Finish color. The exterior finish color of the ECU and the inner surfaces of compartments, but not components installed in the compartments, shall be Camo (tan) Color Number 686A of SAE AMS-STD-595 or Camo (green) Color 483 of SAE AMS-STD-595.

3.14.1.2.6 Exclusion of water. The design of the ECU and its doors, panels, covers, etc., shall minimize or eliminate the entry of water when these items are correctly installed and closed. Sharp corners and recesses shall be avoided so that moisture and solid matter cannot accumulate to initiate localized attack. Sealed floors with suitable drainage shall be provided for compartments and other areas in the ECU that could collect and retain water.

3.14.1.2.7 Fluid traps and faying surfaces. There shall be no fluid traps on the ECU. Faying surfaces of all structural joints, except welded joints, shall be sealed to preclude fluid intrusion.

3.14.1.2.8 Drainage. Drain holes shall be provided to prevent collection or entrapment of water or other unwanted fluid in areas where exclusion is impractical. All designs shall include considerations for the prevention of water or fluid entrapment and ensure that drain holes are located to affect maximum drainage of accumulated fluids. The number and location of drain holes shall be sufficient to permit drainage of all fluids when the ECU is on a 10° longitudinal slope facing both up and down and on a 10° side slope in each direction (right and left side facing up the slope).

3.14.1.2.9 Dissimilar metals. Dissimilar metals, as defined in MIL-STD-889, shall not be in contact with each other. Metal plating or metal spraying of dissimilar base metals to provide electromotively compatible abutting surfaces is acceptable. The use of dissimilar metals when separated by suitable insulating material is permitted, except in systems where bridging of insulation materials by an electrically conductive fluid can occur. Sealants or gel type gasket materials shall be used between faying surfaces and butt joints.

3.14.2 Markings. All external devices which require an operational or maintenance interface (that is, cautions, warning, lifting, tie down, center of gravity, fuel type, emergency stop, tow speed, etc.) shall be marked in accordance with MIL-STD-130. Markings shall be applied with decals and shall be 1-inch-high block letters unless prohibited by the available space. In such cases, the markings shall be the largest size possible but shall not be less than ½-inch high. Markings, Information/Caution shall be Lusterless Black, Color Number 37038 of SAE AMS-STD-595, and Markings, Warning/Danger shall be Lusterless Red, Color Number 31136 of SAE AMS-STD-595.

3.14.3 Identification and information plates.

3.14.3.1 Identification plate. The ECU shall be provided with a permanently-marked identification data plate constructed of a non-corroding metal permanently affixed to the exterior of the ECU in a readily accessible location in accordance with MIL-STD-130. The identification plate shall contain the following information:

a. Item nomenclature (e.g., ENVIRONMENTAL CONTROL UNIT, 60,000 BTUH, 208 V, 3 PH, 50/60 HZ)

b. Manufacturer’s name

c. Model number

d. Serial number

e. Date of Manufacture (e.g., JUL 2004)

f. Contract number

g. National Stock Number

h. Type of refrigerant

i. The refrigerant charge amount in pounds and ounces (e.g., 12 LB 6 OZ)

j. Weight (e.g., 420 LB)

k. Technical Manual Number

In addition, the identification plate shall include six (6) blank lines across the bottom for future etching by the USAF. The identification plate shall be mounted at a conspicuous place on the exterior of the ECU.

3.14.3.2 Unique Identification (UID). Unique Identification (UID) The ECU and any of its components for which the Government's unit cost is more than $5,000, is serially managed, or the procuring agency determines is mission essential, shall have Unique Identification (UID) (also known as Item Unique Identification (IUID)) information permanently affixed on or near the respective identification plate(s), marked in accordance with MIL-STD-130. UID information shall be included as both a bar code and human readable markings and contain the following information.

a. National Stock Number (NSN)

b. Manufacturer's Part Number

c. Serial Number

d. Manufacturer's CAGE

3.14.3.3 Operating instructions. The ECU shall be provided with a permanently-marked operating instruction data plate constructed of a non-corroding metal containing step by step start up, operating, and shut down instructions that is permanently affixed to the exterior of the ECU and visible to the operator while operating the controls on the control panel.

3.14.3.4 Wiring schematic. The ECU shall be provided with a permanently-marked basic wiring schematic constructed of a non-corroding metal that is permanently affixed to the interior of the ECU for use as a quick reference by maintenance personnel during maintenance tasks.

3.14.4 Environment, Safety, and Occupational Health (ESOH).

3.14.4.1 System safety. The design of the ECU shall not contain any system safety mishap risk categories greater than medium as defined in MIL-STD-882.

3.14.4.2 Hazardous materials. The design shall minimize and control hazards associated with the inclusion or use of hazardous or toxic materials and the generation of toxic or noxious gases. The ECU shall not generate or use Class I or Class II Ozone Depleting Substances (ODS) during operation, maintenance, or disposal. Class I ODS and hazardous materials shall not be used in any system, component, or process. The ECU shall not contain or use either hexavalent chromium or cadmium without written approval by the procuring activity. The Environmental Protection Agency maintains an online list of toxic chemicals and hazardous substances at http://www.epa.gov/emergencies/tools.htm. Class I and Class II ODS are defined in 40 CFR 82.

The refrigerants used in the ECU shall comply with 49 CFR, AFMAN 24-604 and DAFMAN 24- 10.

3.14.4.3 Component protection. The ECU shall be designed so that all electrical/mechanical output components are enclosed and access is not required during normal operation. Further, the ECU shall be designed to safely permit access to internal components that may be required during troubleshooting for failures or other special needs. All space in which work is performed during operation, service, and maintenance shall be free of hazardous protrusions, sharp edges, or other features which may cause injury to personnel. All rotating and reciprocating parts and all parts subject to high operational temperatures or subject to being electrically energized, that are of such nature or so located as to be hazardous to personnel, shall be guarded or insulated to eliminate the hazard without impairing the function of the parts. All wires, cables, tubes, and hoses shall be supported and protected to minimize chafing and abrasion and shall be located to provide adequate clearance from moving parts and high operational temperatures. Grommets shall be provided wherever wires, cables, tubes, or hoses pass through bulkheads, partitions, or structural members.

3.14.4.4 FOD. Metal, rubber, and plastic tags, covers, or plugs commonly affixed to commercial items (see 6.3.2) during the manufacturing process shall be removed from the ECU to prevent FOD hazards. All loose metal parts, such as pins, connector covers, caps, etc. shall be securely attached to the ECU with wire ropes or chains. "Dog tag" style beaded chains shall not be provided.

Removable panels, if provided, shall be attached with captive fasteners.

3.14.5 Human systems integration (HSI). The ECU shall be designed in accordance with MIL- STD-1472 for ease of operation, inspection, and maintenance, including the use of arctic mittens.

3.14.6 Mechanical design. The mechanical design shall be as specified herein.

3.14.6.1 Fasteners. All screws, bolts, nuts, pins, and other fastening devices shall be properly designed, manufactured, and installed with adequate means of preventing loss of torque or adjustment. Cotter pins, lock washers, or nylon patches shall not be used for this purpose, except for the attachment of trim items or as provided in commercial (see 6.3.2) components. When applicable, fasteners shall be installed with the application of a design fastening torque such that an adequate preload is introduced in the fastener to prevent losing or fatiguing the fasteners.

Externally threaded fasteners for use with internally threaded nuts or holes shall be in accordance with SAE J429. Internally threaded nuts shall be in accordance with SAE J995. Tapped threads shall have a minimum thread engagement in accordance with Table III. To the maximum extent possible, fastening designs that utilize bolted connections shall be accomplished using a through-bolt method, and secured with locking nuts or weld-nuts. The use of riv-nuts and tapped threads is discouraged. The use of socket-head, flat, countersunk fasteners shall be minimized. When used, socket-head, flat, countersunk fasteners shall be in accordance with NASM 24667 and shall be used with a corresponding nut in lieu of a threaded hole to alleviate potential fastener/hole misalignment and bending stress on the head.

TABLE III. Minimum thread engagement.

Material Minimum Thread Engagement Steel 1.0 times the nominal fastener diameter Cast iron, brass, or bronze 1.5 times the nominal fastener diameter Aluminum, zinc, or plastic 2.0 times the nominal fastener diameter

3.14.6.2 Welders and welding. Welding procedures shall be in accordance with a nationally recognized welding code. The surface parts to be welded shall be free from rust, scale, paint, grease, and other foreign matter. Welds shall be of sufficient size and shape to develop the full strength of the welded parts. Welds shall transmit stress without cracking or permanent distortion when the parts connected by the welds are subjected to test, proof, and service loadings. Cast components, structural steel components with an ultimate tensile strength greater than 100,000 psi, and threaded fasteners (except for weld studs and weld nuts) shall not be welded. Heat treated components shall be in the annealed, normalized condition when welded.

3.14.7 Electrical system.

3.14.7.1 Wiring. All wires used in the ECU shall be multi-stranded copper conductor, flame retardant, moisture, heat, and oil resistant in accordance with NFPA 70. Cables and wiring shall provide fluid/contaminate resistance in accordance with 3.14.9. Cables and wiring shall be protected from breakage by providing strain relief so that the weight of a connector, or a cable assembly and connector, does not damage the boresight system or the aircraft. Wires, wire runs, and wiring harnesses shall be placed, bundled, and positioned so that access to other components is not inhibited or impeded. Any tying or lacing used to bundle individual wires into harnesses shall be of sufficient strength to hold the wires in position without crimping, slicing, or otherwise damaging wire insulation or strands. Wires, wire runs, and wiring harnesses shall be supported to retain position and provide support from stretching or sagging. Cables and wires shall not be spliced at any point throughout their cable/harness runs. Electrical isolators shall be used between all wiring and metal components to prevent abrasive action to wire insulation. The detachable primary input power cable shall be a minimum of 25 feet length and constructed of Type SOOW 6AWG /5 conductor cable (i.e. AF drawing number 72289, CAGE 07878).

3.14.7.1.1 Wire marking. All wires shall be numbered for easy identification. The marking shall be permanently applied to the wire to withstand all specified operating conditions herein throughout the life expectancy of the end item. Marking shall be applied within 3 inches of each end and at intervals not to exceed 12 inches throughout the wire length. Wires having a total length of less than 18 inches shall be marked within 3 inches of both ends and once in the (approximate) middle of the wire. The wire-numbering scheme shall be consistent with that currently being employed by industry standards. Wires energized from the battery (except the battery cables) shall be marked using red characters. All other wires shall be marked using black characters. The use of colored wire coating as a marking scheme is prohibited.

3.14.7.2 Plugs and connectors. All power connectors must comply with MIL-DTL-22992, Class L connectors. The connectors for input power to the ECU shall be as stated in Table II. A receptacle connector shall be mounted to the ECU allowing the power cable to be installed without internal electrical connections. The connector and protective cover must not extend beyond the ECU surfaces in transportation/storage.

3.14.7.3. Power conductor color-coding. The units shall use the following colors: black, red, and blue for A, B, and C hot legs, respectively, gray or white for neutral, and green for grounds.

3.14.7.4 Electrical Grounding. Hinges and slides shall not be relied upon as the sole means of grounding. Equipment leakage current to ground shall not exceed 3.5 mA, when tested in accordance with ANSI C101.1. Redundant equipment grounding conductors may be used to reduce the leakage current. An external grounding lug shall be wired for potential ground rod installation.

3.14.8 Error-proof design. The design of the ECU shall incorporate error-proofing in equipment mounting, installing, interchanging, connecting, and operating.

a. Equipment shall include physical features (for example, supports, guides, size, or shape differences, fastener locations, and alignment pins) that prevent improper mounting. In the absence of physical features, equipment shall be labeled or coded to identify proper mounting and alignment.

b. Equipment that has the same form and function shall be interchangeable throughout a system and related systems. If equipment is not interchangeable functionally, it shall not be interchangeable physically.

c. Connectors serving the same or similar functions shall be designed to preclude mismating or misalignment.

d. Design, location, procedural guidance, and suitable warning labels shall be provided to prevent damage to equipment while it is being handled, installed, operated, or maintained.

3.14.9 Fluid/contaminate resistance. The ECU, including all parts and accessories, shall provide protection against water and synthetic lubricating oils, as well as foreign objects, that is, dirt, dust, and sand found in deployed environments.

3.15 Workmanship. The ECU, including all parts and accessories, shall be constructed and finished in a thoroughly workmanlike manner. Workmanship objectives shall include freedom from blemishes, defects, burrs and sharp corners and edges; accuracy of dimensions, surface finish, and radii of fillets; thoroughness of welding, painting, and riveting; marking of parts and assemblies;

and proper alignment of parts and tightness of assembly fasteners.

3.15.1 Bolted connections. Bolt holes shall be accurately punched or drilled and shall be deburred.

Threaded fasteners shall be tight and shall not work loose during testing or service usage.

3.15.2 Riveted connections. Rivet holes shall be accurately punched or drilled and shall be deburred. Rivets shall be driven with pressure tools and shall completely fill the holes. Rivet heads shall be full, neatly made, concentric with the rivet holes, and in full contact with the surface of the component.

3.15.3 Cleaning. The ECU shall be thoroughly cleaned. Loose, spattered, or excess solder; welding slag; stray bolts, nuts, and washers; rust; metal particles; pipe compound; and other foreign matter shall be removed during and after final assembly.

3.15.4 Touch-up. Any minor dings, scuffs, or scratches that may occur during the assembly process shall be cleaned, scuffed (as required), primed (thin tie coat), and painted in accordance with the corrosion prevention requirements stated herein, using the same products as applied to the surface(s) prior to assembly.

4. VERIFICATION

4.1 Classification of inspections. The inspection requirements specified herein are classified as follows.

a. First article inspection (see 4.2).

b. Operational inspection (see 4.3).

c. Conformance inspection (see 4.4).

Requirements shall be verified in accordance with Table IV.

Table IV. Requirement verification matrix.

Test Unit # Section 3 Requirement Section 4 Verification 1 2 3 4 5 6

3.1 First article. 4.5.1 Examination of product.

7 8 9 10 11 12 1 3.2 Description and general layout. 4.5.1 Examination of product.

3.3 Performance. 4.5.2 Performance tests.

3.3.1 Cooling capacity. 4.5.2.1 Cooling capacity test.

3.3.2 Airflow. 4.5.2.2 Airflow tests.

4.5.2.2.1 Cooling airflow test.

3.3.3 Cooling. 4.5.2.3 Cooling tests.

1 3.3.3.1 High temperature operation.

4.5.2.3.1 High temperature operation

test.

1 3.3.3.2 Low temperature operation.

4.5.2.3.2 Low temperature operation

test.

3.3.3.3 Coil frost. 4.5.2.3.3 Coil frost test.

3.3.4 Heating. 4.5.2.4 Heating tests.

1 3.3.4.1 Low temperature operation.

4.5.2.4.1 Low temperature operation

test.

1 3.3.4.2 Electrical resistance heating. 4.5.2.4.2 Resistive Heating capacity test.

3.3.5 Electrical performance. 4.5.2.3.1 High temperature operation test.

1 3.3.5.1 Power and steady-state current.

4.5.2.3.1 High temperature operation

test.

3.3.5.2 In-rush current. 4.5.2.5 In-rush current test.

1 3.3.5.3 Total harmonic distortion.

4.5.2.3.1 High temperature operation

test.

3.3.6 Inclined operation. 4.5.2.6 Inclined operation test.

3.3.7 Operating pressures. 4.5.2.7 Operating pressures test.

1 2 3 4 5 6

3.3.8 Run-in. 4.5.3 Run-in test.

7 8 9 10 11 12

3.4 Controls. 4.5.4 Controls tests.

3.4.1 Mode selector control. 4.5.4.1 Operating modes test.

1 3.4.2 Conditioned air-thermostat. 4.5.4.2 Cooling process stoppage test.

3.4.3 High pressure cutout. 4.5.4.3 High pressure cutout test.

3.4.4 Low pressure cutout. 4.5.4.4 Low pressure cutout test.

3.4.5 Heater high limit cutout. 4.5.4.5 Heater high limit cutout test.

3.4.6 Remote Control Box. 4.5.4.6 Remote operation test.

3.4.7 Pressure relief. 4.5.4.7 Pressure relief test.

3.4.8 Fresh-air inlet. 4.5.2.2.2 Fresh-air inlet test.

3.5 Refrigeration system.

1 3.5.1 Refrigeration system type. 4.5.1 Examination of product.

1 3.5.2 Refrigeration functionality. 4.5.1 Examination of product.

1 2 3 4 5 6 3.5.3 Refrigerant system leakage.

4.5.1 Examination of product.

4.5.6 Refrigerant system leakage test. 7 8 9 10 11 12

3.5.4 Refrigerant Tubing. 4.5.1 Examination of product.

3.5.5 Service connections. 4.5.1 Examination of product.

1 3.5.6 Refrigerant charge indicator. 4.5.1 Examination of product.

1 3.6 Item specific equipment. 4.5.1 Examination of product.

3.7 Enclosure. 4.5.1 Examination of product.

3.8 Environmental conditions. 4.5.7 Environmental tests.

1 2 3 4

3.8.1 Storage temperature

range.

4.5.7.1 Extreme temperature storage

tests.

4.5.7.1.1 Low temperature storage test.

4.5.7.1.2 High temperature storage test.

3.8.2 Precipitation.

3.8.2.1 Rain. 4.5.7.2 Rain test.

3.8.3…