PurchaseDescription.pdf

PD13WRGRVEA05

Comments, suggestions, or questions on this document should be addressed to:

AFLCMC/WMZEA, Robins AFB GA 31098-1813.

AMSC N/A FSC 3655

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

INCH-POUND

CAGE 98752

13 December 2012

Rev A

PURCHASE DESCRIPTION

TANK, STORAGE, LIQUID OXYGEN/LIQUID NITROGEN

1. SCOPE

1.1 Scope. This Purchase Description (PD) covers the requirements for trailer-mounted, 500-gallon tank assemblies (hereafter called the tank assembly or tank assemblies). The tank assemblies will be used for air transport and storage of liquid oxygen and liquid nitrogen product.

1.2 Classification. The tank assemblies shall be of the following types as specified (see section

6.2).

1.2.1 Types.

Type I Liquid Oxygen 500 Gallon

Type II Liquid Nitrogen 500 Gallon

2. APPLICABLE DOCUMENTS

2.1 General. The documents listed in this section are specified in sections 3, 4, or 5 of this specification. This section does not include documents cited in other sections of this specification 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, 4, or 5 of this specification, 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.

FEDERAL STANDARDS

FED-STD-595C/24052 Green Semigloss

FED-STD-595C/36118 Gray, Flat or Lusterless

COMMERCIAL ITEM DESCRIPTION

A-A-50271 Plate, Identification

A-A-58092 Tape, Antiseize, Polytetrafluorethylene

A-A-52464B Coupler, Drawbar, Ring: Light Duty, 60,000 lb

GVW; Offset (Taper Shank), 60,000 lb GVW; and

Heavy-Duty 120,000 LB GVW

A-A-52550 Pintle Assembly, Towing, Manual Release, 18000, 40000 and 100000 lbs Capacity

A-A-59494 Wheels and Hubs for Industrial Pneumatic Tires

DEPARTMENT OF DEFENSE STANDARDS

AN929 Rev 12 Cap Insert, Assembly, Pressure Seal, Flared Tube Fitting w/ AMENDMENT 2

MIL-C-83413B Connectors and Assemblies, Electrical, Aircraft

Grounding, General Specification for

MIL-H-27301D Hose Assembly, Metal, Cryogenic Liquid Transfer

MIL-STD-130N Identification Marking of U.S. Military Property

MIL-STD-810G Environmental Engineering Considerations and

Laboratory Tests

MIL-STD-882D

MIL-STD-889

MIL-STD-1474

MIL-STD-461

MIL-STD-1472

MIL-STD-209

MIL-DTL-81706

MIL-DTL-5541

MIL-DTL-53030

MIL-PRF-26915

MIL-PRF-23377

MIL-PRF-85285

MIL-PRF-83772

MIL-PRF-38201

Standard Practice for System Safety

Dissimilar Metals

Noise Limits

Requirements for the Control of Electromagnetic

Interference Characteristics of Subsystems and Equipment

Human Engineering

Interface Standard for Lifting and Tiedown Provisions

Chemical Conversion Materials for Coating Aluminum and Aluminum Alloys

Primer Coating, Epoxy, Water Based, Lead And Chromate

Free

Primer Coating, Epoxy, Water Based, Lead and Chromate

Free

Primer Coating, for Steel Surfaces

Primer Coatings: Epoxy, High-Solids

Coating: Polyurethane, Aircraft and Support Equipment

Hose Assembly, Cryogenic Liquid, Aircraft Servicing

Valve, Filler, Liquid Oxygen, Female, CRU-59/E

DEPARTMENT OF DEFENSE HANDBOOKS

MIL-HDBK-838 Lubrication of Military Equipment

MIL-HDBK-1791(2) Designing for Internal Aerial Delivery in Fixed

Wing Aircraft

MIL-HDBK-1791C-17 Designing for Internal Aerial Delivery in Fixed

Appendix Wing Aircraft C-17 Appendix

MIL-HDBK-808 Finish, Protective, and Codes for Finishing Schemes for

Ground and Ground Support Equipment

(Copies of these documents, except for MIL-HDBK-1791 C-17 Appendix, are available online at http://assist.daps.dla.mil/quicksearch/ or from the Standardization Document Order Desk, 700

Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094. A copy of MIL-HDBK-1791 C-17

Appendix can be requested by contacting Air Transportability Test Loading Agency (ATTLA) at

937-255-6296.)

2.2.2 Other Government documents, drawings, and publications. The following other

Government documents, drawings, and publications of the exact revision level shown form a part of this document to the extent specified herein.

USAF DRAWINGS

48B7796 Ring Assembly-Tiedown, 10,000 Pounds

68A39469 Plug

68A39470 Body

68A39471 Vacuum Pump Out and Relief Assembly

68A39472 Cap

68A39473 Vacuum Pump Out Assembly Filter Assembly

7545352 Requirements for Finishes SA-ALC Ground Support

Equipment

68B39474 Filter Assembly, LOX

ORDNANCE CORPS

C8987830 Assembly, LOX Coupling, Male Half, All Sizes

C8987831 Assembly, LOX Coupling, Female

B8987832 Gasket, LOX and LN2, All Sizes

B8987833 Gasket, LOX or LN2-Dummy Drawing

B8987839 Ring, Retaining

A8987840 Ring, Retaining-Dummy Drawing

C8987855 Seat, LOX Coupling, 1 inch

C8987856 Cone, LOX Coupling

C8987857 Nut, LOX Coupling

C8987869 Cap, LOX, 1 inch

C8987870 Plug, LOX

C8987876 Seat, LN2 Coupling

C8987877 Cone, LN2 Coupling

C8987878 Nut, LN2 Coupling

C8987888 Assembly, Liquid Nitrogen (LN2) Coupling, Male

C8987889 Assembly, Liquid Nitrogen (LN2) Coupling, Female

C8987890 Cap, LN2

C8987891 Plug, LN2

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 NATIONAL STANDARDS INSTITUTE/AMERICAN SOCIETY FOR

QUALITY (ANSI/ASQ)

ANSI/ASQC Z1.4 Sampling Procedures and Tables for Inspection by

Attributes (DoD-adopted)

(ASNI documents may be obtained at www.ansi.org or from American National Standards

Institute 25 West 43nd Street, New York, NY 10036.)

AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME)

ASME Boiler and Pressure Vessel Code

Section VIII Unfired Pressure Vessels

(ASME documents may be obtained at www.amse.org or from American Society of Mechanical

Engineers, PO Box 2900, Fairfield, NJ 07007.)

AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM)

ASTM E 1417 Liquid Penetrant Examination, Standard Practice For

(DoD adopted)

ASTM E1444 Particle Examination, Magnetic (DoD adopted)

(ASTM documents may be obtained at www.astm.org or from American Society for Testing and

Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.)

SOCIETY OF AUTOMOTIVE ENGINEERS (SAE)

SAE ARP901 Bubble-Point Test Method

SAE ARP1176 Oxygen System and Component Cleaning and Packaging

SAE AS4395 Tube Connection, Fitting End - Flared, Design Standard

(DoD-adopted)

SAE AS8090 Equipment, Towed Aerospace Ground, Mobility

(DoD adopted)

(SAE documents may be obtained at www.sae.org or from Society of Automotive Engineers, 400 http://www.ansi.org/ http://www.amse.org/ http://www.astm.org/ http://www.sae.org/

Commonwealth Drive, Warrendale, PA 15096.)

AMERICAN WELDING SOCIETY

D1.1/D1.1M:2006 Structural Welding Code–Steel–20th Edition

D1.2/D1.2M:2003 Structural Welding Code–Aluminum–Fourth Edition

(Application for copies should be addressed to American Welding Society, 550 N.W. LeJeune

Road, Miami FL 33126.)

2.4 Order of precedence. Unless otherwise noted herein or in the contract, in the event of a conflict between the text of this document and the references cited herein (except for related specification sheets), 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), two samples (one of each type) shall be subjected to first article inspection in accordance with 4.2.

3.2 Tank assembly description. The tank assembly shall be trailer mounted with a 500 gallon capacity. The tank assembly shall be towable and air transportable. The tank design shall allow for the storage of liquid oxygen or liquid nitrogen.

3.3 Design and construction. The tank assembly shall be designed and constructed so that no parts will work loose in service. They shall be built to withstand the strains, jars, vibrations, and other conditions incident to shipping, storage, installation, and service. They shall be weatherproof and designed to prevent the intrusion of water and sand into critical operating components.

3.3.1 Materials, protective coatings, and finish.

3.3.1.1 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 cost. However, used, rebuilt, or refurbished items shall not be provided.

3.3.1.2 Protective coatings. Materials that deteriorate when exposed to sunlight, weather, or operational conditions normally encountered during the service life of the item shall not be used or shall have means of protection against such deterioration that does not prevent compliance with the performance requirements specified herein. Protective coatings that chip, crack, or scale with age or extremes of climatic conditions or when exposed to heat shall not be used. Fasteners, handles, and fittings used in the assembly of the item shall also be primed and painted.

3.3.1.2.1 Surface preparation and pretreatment. Surface preparation and pretreatment shall be in accordance with the respective primer and topcoat specifications. Structures shall be cleaned, degreased, and scuffed or blasted prior to priming; primer shall be applied before any oxidation or rusting occurs. Aluminum surfaces shall have MIL-DTL-81706, Type II, Class 1A, and MIL-

DTL-5541, Type II, Class 1A, chemical conversion coating applied in accordance with the manufacturer’s directions prior to priming.

3.3.1.2.2 Primer. Raw metal edges, to include fastener and drain holes, shall be coated with primer before applying topcoat.

3.3.1.2.2.1 Ferrous surfaces. Ferrous structures and surfaces shall be primed with a water reducible zinc rich primer in accordance with MIL-PRF-26915, Type II, Class B; this shall be followed, within four hours, by a coat of MIL-DTL-53030 intermediate primer in a wet-to-wet primer application. This two part primer system shall yield a dry-film thickness of 2.0-2.5 mils for the zinc primer and 0.9 to 1.1 mils for the intermediate primer. The two-primer system shall be allowed to dry and fully cure in accordance with the primer manufacturer’s directions prior to top coating.

3.3.1.2.2.2 Aluminum and mixed aluminum and ferrous surfaces. Aluminum, mixed aluminum, ferrous structures, and surfaces shall be primed with an epoxy primer, Type II, Class N of MIL-

PRF-23377. This single part primer system shall yield a dry-film thickness of 0.6 to 0.8 mils.

3.3.1.2.3 Topcoat. Topcoat shall be polyurethane in accordance with Type II, Class H of MIL-

PRF-85285. Neither Chemical Agent Resistant Coating (CARC) nor powder coating shall be used. Topcoat shall be applied to a dry film thickness of 1.6 to 2.4 mils in all instances, regardless of the primer system utilized. The coating shall be free from runs, sags, orange peel, or other defects.

3.3.1.3 Dissimilar metals. Dissimilar metals (see 6.3.2), 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 electromotive compatible abutting surfaces is acceptable. The use of dissimilar metals only 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 flaying surfaces and butt joints.

3.3.1.4 Finish.

3.3.1.4.1 Finish and color. All exposed metal parts and surfaces, except parts and surfaces that contact high purity oxygen/nitrogen, shall be cleaned, treated, and finished per USAF 7545352

(see 6.4) (see 4.6.1). The final finish paint coating shall be colored as follows:

a. For the Type I, liquid oxygen tank assembly, the control housing, frame, and tank shall be painted dark green, FED-STD-595, number 24052.

b. For the Type II, liquid nitrogen tank assembly, the control housing, frame, and tank shall be painted gray, FED-STD-595, number 36118.

3.3.1.5 Fluid traps and flaying surfaces. There shall be no fluid traps on the tank. Flaying surfaces of all structural joints, except welded joints, shall be sealed to preclude fluid intrusion.

3.3.1.5.1 Ventilation. Ventilation shall be sufficient to prevent moisture retention and buildup.

3.3.1.5.2 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 effect maximum drainage of accumulated fluids. The number and location of drain holes shall be sufficient to permit drainage of all fluids when the unit is in a 5 degree incline in any plane. The minimum size of the drain holes shall be 0.25 inch.

3.3.2 Markings. All external devices which require an operational or maintenance interface 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 FED-STD-595, and Markings, Warning / Danger shall be Lusterless Red, Color Number 31136 of FED-STD-595. The center of gravity of the tank shall be stenciled on the unit within 1.0 inch of the calculated center of gravity.

3.3.2.1 Tank marking. Tank assembly marking shall be in the form of decals, which shall be

Government furnished property. Each tank shall require 3 each of the decals, one centered on each side of the tank and one on the tank end opposite the control cabinet. For the two types of tank assemblies, the decals shall be as follows:

a. For Type I, liquid oxygen tank, tank description and warning markings shall be decals described by Warner Robins Air Logistics Center/SFRM Part Number 8221044.

b. For Type II, liquid nitrogen tank, tank description and warning markings shall be decals described by Warner Robins Air Logistics Center/SFRM Part Number 221045-

1.

3.3.2.2 Control marking. All valves, gages, controls, and indicators used during operation shall be identified by securely attached nameplates. The nameplates shall be in accordance with CID

A-A-50271. Tags shall not be used. The indicating scale of each instrument, such as pressure gages, temperature indicators, and liquid level indicators, used for normal operation and control of the tank, shall be permanently and clearly marked with green and red to show the proper operating and the improper or danger zones respectively.

3.3.3 Identification and information plates.

3.3.3.1 Identification plate. An identification plate (see 6.2) in accordance with MIL-STD-130 securely attached to the outside of the control housing assembly in a readily visible location. The tank 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. The identification plate shall contain the following information:

a. Tank, Storage, (Type I, Liquid Oxygen or Type II, Liquid Nitrogen)

b. Specification PD13WRGRVEA05

c. Stock Number

d. Manufacturer’s Part Number (or identification)

e. Contract or Order Number

f. Manufacturer’s Name or Trade-Mark and CAGE code

g. U.S. Property

3.3.3.2 Transportation data plate. A data plate containing transportation data shall be provided as specified in SAE AS8090. The plate shall contain at least the following information:

a. Side and rear silhouette views of the tank.

b. Horizontal and vertical location of the center of gravity of the tank in air transportable configuration, marked on the silhouette views.

c. Shipping weight.

d. Loading cubage.

e. Overall height, width, and length.

f. Front and rear axle loads.

g. Tie down information.

3.3.3.3 Warning plates.

3.3.3.3.1 Servicing line warning plate. A weatherproofed red warning plate containing the following information shall be provided adjacent to the liquid servicing line:

WARNING

DO NOT FILL THROUGH

ISSUE LINE – FOR SERVICING ONLY.

3.3.3.3.2 Air transport warning plate. A weatherproofed red warning plate containing the following information shall be provided adjacent to the vent line disconnect fitting:

WARNING

ENSURE OVERBOARD VENT LINE IS ATTACHED TO THE VENT LINE FITTING

DURING AIR TRANSPORT.

3.3.3.4 Operating and precautionary instructions. An information panel containing precautionary and operating instructions to preclude injury or damage shall be permanently affixed on or near the tank control panel.

3.3.3.5 Lifting instruction data plate. A data plate containing instructions necessary for lifting or moving the tank (empty or filled to any level up to design capacity) safely with a forklift truck shall be securely attached to the outside of the control housing assembly near the transportation data plate. Instructions shall include information on rigging a safe lifting sling from common cable and spreader bar components and safely lifting the full tank with a 3g acceleration.

3.3.3.6 Insulation identification plate. If insulation is installed in the tank annular space, an identification plate completely identifying the insulation shall be permanently affixed in an accessible location within the control housing assembly. If a powder-type insulation is used, the plate shall indicate the insulation weight in pounds.

3.3.4 Safety.

3.3.4.1 System safety. The design of the tank assemblies shall not contain any system safety mishap risk categories greater than medium as defined in Table A-IV of MIL-STD-882.

3.3.4.2 Component protection. 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 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.

3.3.4.3 Foreign object damage (FOD). All loose metal parts, such as pins or connector covers, shall be securely attached to the tank assembly with wire ropes or chains. “Dog tag” style beaded chains shall not be provided. Removable panels, if provided, shall be attached with captive fasteners. Tire valve stem caps shall be made of plastic.

3.3.4.4 Sound levels. The noise level generated by the tank assembly shall not exceed the values specified in MIL-STD-1474, Table II (Steady-state noise limits (dBA) for personnel-occupied areas), category D.

3.3.4.5 Electrostatic discharge (ESD). The design of the tank assembly shall preclude equipment damage due to ESD, protect personnel from electrical shock due to static charging, and prevent ignition of explosive atmospheres due to sparking.

3.3.5 Electromagnetic interference (EMI). The tank assembly shall be in accordance with the following radiated emission and susceptibility requirements of MIL-STD-461: RE102 and

RS103.

3.3.6 Human engineering. The tank assembly shall be designed in accordance with MIL-STD-

1472 for ease of operation, inspection, and maintenance, including the use of arctic mittens and

Mission-Oriented Protective Posture (MOPP) Level 4 Chemical Warfare Gear.

3.3.7 Fastening devices. 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 components. Tapped threads shall have a minimum thread engagement in accordance with Table I.

TABLE I. 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

3.3.8 Welders and welding. All welders shall be certified to weld in accordance with AWS D1.1 and AWS D1.2, as applicable. The contractor shall make available to the Government certifications for all welders being utilized on the tank assemblies. Welding procedures and all welding on the tank assemblies shall be in accordance with AWS D1.1 and AWS D1.2, as applicable. 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.

3.3.9 Service life. The tank assembly shall be designed for a minimum service life of 25 years.

3.4 Environmental conditions. The tank assembly shall operate and withstand the following environmental conditions without damage, including damage which could contaminate the tank’s contents:

3.4.1 Operating temperatures. The tank assembly shall perform all functions required herein in any ambient temperature between –65° and +130 °F, including exposure to solar, or equivalent heat radiation of 100 to 120 watts per square foot at the higher temperature, without shelter or external winterization provisions.

3.4.2 Storage temperature. The tank assembly shall not be damaged by storage in any ambient temperature from –80° to +160 °F for at least 72 hours.

3.4.3 Purge temperature conditions. To satisfy purging requirements, the tank assembly and all related components shall be capable of withstanding a purge air inlet temperature of up to 350 °F for minimum duration time of 4 hours (while the fill line outlet air temperature is maintained at

220°F) without any damage.

3.4.4 Vibration forces. The tank assembly, when empty or filled to any level up to design capacity with cryogenic liquid, shall not be damaged by vibration forces that will typically be encountered during its transportation in aircraft, railroad car, ship, or truck.

3.4.5 Precipitation.

3.4.5.1 Rain. The tank assembly shall be capable of storage and operation during rainfall of 5-inches per hour for three consecutive hours and 10-inches per hour for 10 consecutive minutes, with winds of up to 35 knots; and with 6-inches of rain per hour impinging on the tank at angles from vertical to 45°.

3.4.5.2 Wind. The tank assembly shall not be damaged by storage or operation in wind velocities of up to and including 70 miles per hour (mph).

3.4.5.3 Snow. The tank assembly shall be capable of storage and operation during accretion of wet snow up to 2-inches per hour for at least 12 hours on exposed horizontal surfaces.

3.4.5.4 Ice. The tank assembly shall be capable of storage and operation with ice accretion up to

1.5-inches on exposed horizontal surfaces. An operator may use an ice scraper for five minutes during the start-up process.

3.4.6 Solar radiation. The tank assembly shall not be adversely affected by full time exposure to solar radiation, such as those conditions encountered in desert environments.

3.4.7 Fungus. All materials used in the tank assembly 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 tank shall be suitable for operation and storage in conditions encountered in a tropical environment.

3.4.8 Salt fog. The tank assembly shall be capable of storage and operation in high temperature, high humidity, salt laden, sea coast environments without damage or deterioration of performance.

3.4.9 Sand and dust. The tank assembly shall be capable of storage and operation during exposure to wind-blown sand or dust without damage or deterioration of performance.

3.4.10 Humidity. The tank assembly shall not be damaged by operation or storage in any relative humidity up to and including 100%.

3.5 Weight and dimensions. Overall weight and dimensions in air transport configuration shall not exceed:

Weight 10,000 pounds.

Length 104 inches.

Width 84 inches.

Height 96 inches.

3.6 Transportability.

3.6.1 Ground mobility. The tank assembly shall be designed as a full trailer, with wheels and supported by its own suspension system. The tank assembly shall meet the ground mobility requirements of SAE AS 8090, Type II, Group C. The trailer chassis design shall be such that the Tank Assembly shall not be damaged when the tow bar is raised high enough for the back of the unit to touch the ground. The safe turning radius shall not exceed 20 feet wall to wall. The tank assembly when filled to design capacity shall be capable of being towed at 35 mph over paved highways, 10 mph over sand and gravel roads, and 5 to 6 mph (not to exceed 8 mph) over rough terrain.

3.6.1.1 Towing. The tank assembly shall be equipped with a pintle hook conforming to A-A-

52550 Type I, Class 2 mounted on the center of the rear frame.

3.6.1.2 Tandem towing. The tank assembly shall be equipped with a towbar and pintle hook to allow for tandem towing of two carts simultaneously.

3.6.1.3 Towbar. The tank assembly shall be equipped with a towbar that has a lunette eye in accordance with paragraph A-A-52464 Type II. While in operation or storage (i.e., not being towed), the towbar shall be stowed upright, secured, and shall not hinder visibility, operation, maintenance, or servicing.

3.6.1.4 Steering system. The tank assembly steering system shall be in accordance with 3.5.1.1 of SAE AS8090.

3.6.2 Air transportability. The tank assembly shall be air transportable when filled to design capacity without the need for adapters or spreaders by fixed wing aircraft such as the C-130, KC-

135, KC-10, C-17, and C-5 aircraft. Design criteria can be found in MIL-HDBK-1791 and MIL-

HDBK-1791, C-17 Appendix. In all air transport configurations, the tank 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 3 G lateral accelerations. The tank assembly shall be equipped with pressure relief devices or configured for air transport to prevent any part from becoming a projectile in the event of catastrophic loss of aircraft cabin pressure. The tank assembly shall roll on and off the aircraft, negotiating the required maximum ramp angles (20 degrees) without shoring. These same forces shall also apply while the unit is being transported on a railroad car, ship, or truck.

3.6.2.1 Emergency landing acceleration forces. The tank assembly shall withstand the emergency landing load shock force described in MIL-HDBK-1791, except the shock pulse shall be an approximate one-half sine wave of not less than 30 milliseconds (ms) or more than 40 ms duration. The peak acceleration of the shock pulse shall be not less than 18g for all three directions of shock input.

3.6.2.2 Shoring. The tank assembly shall be air transportable without shoring.

3.6.2.3 Tire pressure. Tire pressure shall not exceed 100 pounds per square inch (psi) and shall not be reduced for air transport.

3.6.2.4 Winch points. Winch points shall be provided at the front and rear of the tank assembly for aircraft loading using the aircraft’s winch.

3.6.2.5 Equipment removal and reconfiguration. Preparation for air transport and restoration to operating configuration shall take no more than 8 man-hours for 2 persons using common hand tools (see 6.3.5). All equipment removed shall be stored on the tank assembly; caps and plugs shall permit moving and storage in transport configuration.

3.6.3 Hoisting and tiedown attachments. Tiedown devices that shall serve for both tiedown and hoisting purposes shall be provided (see MIL-HDBK-1791 for guidance). These tiedown devices shall include four or more tiedown ring assemblies conforming to USAF 48B7796. The tiedown devices shall permit hoisting, with a 3g acceleration force, of the complete tank assembly filled to design capacity with liquid oxygen. The rings shall be located on the tank assembly so that transportation personnel can easily rig safe slings from common cable and spreader bar components for hoisting by a single-hook overhead crane. Each end of each tie down device shall terminate at a tie down point and not pass through any other tie down point. There shall be no interference between tie down devices and the tank assembly. The tie down provisions shall be in accordance with 4.1 through 4.12 of MIL-STD-209.

3.6.4 Forklift entries. The tank shall have two lateral forklift entries, each 3.25 ± 0.13 inches high by 10 ± 0.13 inches wide, spaced 40 ± 0.5 inches centerline distance. The forklift entries shall be placed approximately equal distance from the vertical center-of-gravity (CG) of the full tank. The entries shall extend the entire width of the trailer, and shall not contain any obstructions that could impede movement of the forklift tines through the length of the entries.

The entries shall restrain the forklift tines as necessary to prevent damage during lifting or movement of the tank assembly.

3.7 Maintainability. Parts and assemblies shall be located and mounted to provide adequate clearance for repair and other maintenance and, where practicable, to permit removal and replacement of any part or assembly by removing or disconnecting only mounting bolts or fasteners, panel doors, tubing, or control cables to the part or assembly being removed. All removable lines shall include special means for gripping the lines for attachment and detachment.

The tank assembly, where practicable, shall include readily detachable and attachable type fittings in the liquid and vapor lines to permit rapid component removal and replacement.

Disconnect points shall be clearly indicated and identified. The design shall ensure clearance for operation, servicing and maintenance at low ambient temperatures by personnel wearing heavy gloves or mittens, bulky clothing and footgear. The design shall ensure maintenance and servicing can be performed using only common hand tools. Intricate locking devices, controls, or fasteners that can be easily overtorque by personnel lacking feel through thick gloves or numbness shall be avoided. Component installation design shall be such that the items can only be installed in their proper operating position to avoid reverse installation.

3.7.1 Preventive maintenance. The recommended routine preventive maintenance interval (PMI) shall be at least 250 operating hours. Preventive maintenance tasks, other than tasks required daily or before operation, shall not require more than 8.0 man-hours.

3.7.2 Inspection and servicing provisions.

a. Routine servicing tasks and pre-use inspections shall require no tools.

b. Drain plugs and filters shall be directly accessible from the ground and oriented to have unimpeded drainage to a catch pan.

c. The tank assembly shall be designed with maximum usage of sealed lifetime lubrication bearings.

3.7.3 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.

3.7.4 Error-proof design. The design of the tank assembly 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 mismatching 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.

3.7.5 Special tools. The design of the tank assembly shall minimize the requirement for special tools (see 6.3.6). All special tools shall be provided with, and stored on, the tank assembly.

3.8 Performance.

3.8.1 Storage capacity. The tank shall store or transport, under the conditions specified herein, not less than 500 U.S. gallons of 99.5% pure liquid oxygen or liquid nitrogen at its atmospheric pressure boiling temperature. The tank assembly shall have an internal volume of not less than

550 U.S. gallons in order to provide an expansion (vapor) space of not less than 10% of the total design capacity.

3.8.2 Heat leak evaporation rate. The tank heat leak evaporation loss shall not exceed the equivalent of 19 pounds of oxygen per 24-hour period when the tank is filled to not less than

50% of capacity with liquid oxygen or nitrogen and subjected to the tests specified.

3.8.3 Pressure buildup system. The tank assembly pressure buildup system shall pressurize the inner shell vapor space to 50 psig within 10 minutes after closure of the vapor vent line shutoff valve and initiating buildup when the tank is filled to between 15 and 20 percent of rated capacity and has been vented to atmospheric pressure for not less than 4 hours.

3.8.4 Liquid fill line flow rate. The fill line shall be capable of filling the tank with liquid oxygen or liquid nitrogen through the liquid line at a rate of 50 gpm minimum with a maximum pressure drop through the fill line, filter, and the liquid line of 16 psig. With a flow rate of 25 gpm minimum, the pressure drop shall not exceed 6 psig.

3.8.5 Liquid servicing line flow rate. The liquid servicing line shall be capable of transferring liquid oxygen or liquid nitrogen from the inner shell through the liquid line, servicing line, and filter at a rate of 25 gpm minimum with a maximum pressure of 6 psig.

3.8.6 Vapor vent line. The vapor vent line shall permit the tank assembly to cool down within 15 minutes and allow filling flow rates up to and including 50 gpm without the inner shell vapor pressure exceeding 15 psig, when the tank assembly is subjected to the conditions and tests specified. The vent line shall allow venting of liquid when the inner shell is being filled and the tank contains between 500 and 510 gallons of liquid.

3.8.7 Vacuum retention. The tank assembly, after evacuation of the annular space, shall not show any increase in absolute pressure attributable to leakage or outgassing within 7 days (168 hours) when subjected to the tests specified.

3.8.8 Dissimilar metal vacuum joints. Any dissimilar metal vacuum joints used in the tank shall withstand thermal shocks, and axial and lateral vibration as specified.

3.8.9 Shutoff and control valve cycling and leakage. The valves shall withstand a closing torque of at least 300 in.-lb per inch of nominal size, with the valve bodies at either ambient temperature or the atmospheric pressure boiling temperature of liquid oxygen or nitrogen. When subsequently closed with a torque of 60 ± 5 in.-lb per inch of nominal size and a pressure of 50 psig applied to the inlet, the valves shall not leak more than 2 cubic inches of free air, oxygen, or nitrogen gas per hour per inch of nominal size. The valves shall be capable of not less than 2000 cycles of operation (see 6.3.3) when subjected to a differential pressure of 50 psig while closed, including at least 1,000 cycles at ambient temperature and 1,000 cycles with the valve body at the atmospheric pressure boiling temperature of liquid oxygen or nitrogen for Type I or Type II tank valves, respectively.

3.8.10 Line filters. The liquid fill line and the liquid servicing line shall each have a filter for the filtering of all liquid flowing into and out of the inner shell. Filters shall be of the in-line configuration conforming to USAF 68B39474. Each filter shall be installed such that it is readily accessible for inspection, cleaning, or removal. Sintered or powdered material shall not be used unless provisions are made to prevent media migration. The proper direction of flow shall be plainly marked on each side of the filter. The filters shall be a non-bypass type and shall withstand a pressure drop of 50 psi across their elements. Each filter shall remove 98% by weight of all particles whose smallest dimension is 10 microns or greater (10-micron nominal rating). The filter shall further remove all particles whose smallest dimension is 40 microns or greater (40-micron absolute rating). In addition, the filter shall be capable of a cryogenic liquid flow rate of 50-gpm at a maximum pressure drop of 3 psig, having previously ingested a minimum of 5 grams of particles of the sizes shown in Table II.

TABLE II. Particle size distribution.

Size of Particle (microns)

Percentage by weight (± 3%)

10 to 20 36

20 to 40 24

40 to 60 16

Over 60 24

3.8.10.1 Vacuum line filter. A vacuum line filter shall be provided if a powder or similar type insulation, which can be drawn into the vacuum pump, is used. The filter shall be a removable unit extending into the tank annular space, and shall have an effective filtering area of not less than 250 square inches.

3.9 Design requirements.

3.9.1 Tank assembly. The tank assembly, including all its accessories, shall be mounted on a structurally rigid trailer with Pintle hook connection. This trailer shall serve as a towing mechanism allowing movement. The trailer shall also serve as a platform to allow lifting, handling, and transporting of the complete unit. The overall size of the trailer shall be not less than the dimensions of the vertical projection of the tank assembly including the control housing.

Drain openings shall be provided at the bottom. The max weight of the tank assembly when full of product shall not exceed 10,000 lbs. Maximum dimensions of the tank assembly are a height of 96”, length of 104”, and width of 84”. Equipment will not to exceed the size limits of a single pallet position. The PSI limitation on a pallet is 250 pounds per square inch.

3.9.2 Trailer. The tank assembly shall be mounted on a trailer. This trailer shall comply with

SAE AS8090, Type II, Group C; have a suspension of torsion bar, leaf, or coil spring design;

have a Type II drawbar lunette coupler conforming to A-A-52464 and include safety chains. The trailer shall have a minimum capacity of the weight of all installed components and tank filled to design capacity plus a factor of safety 2 to 1 and shall be mounted on four wheels with pneumatic tires. The trailer shall be able to be towed by flight line towing vehicles with the tank assembly full of product and a pintle hook shall be installed on the rear frame to allow additional units to be towed in tandem. Provisions shall be included to allow the unit to be moved by forklift.

Forklift tine openings shall be in accordance with section 3.6.4. Parking brakes shall be furnished, shall apply to at least two wheels, and be capable of holding the tank assembly on a

20° slope. The tank assembly shall be mounted to the trailer as to minimize overhanging of parts.

3.9.3 Brakes, wheels, and tires.

3.9.3.1 Parking brakes. The tank assembly shall have parking brakes in accordance with 3.6.1 of

SAE AS8090. The tank assembly shall be provided with a rear wheel, two-wheel parking brake system. Brakes for both wheels shall be interconnected and shall operate from one handle. The control lever shall be located at the front of the unit near the lunette eye. The parking brake control device shall be appropriately marked with operating instructions for release and application of the brakes.

3.9.3.2 Wheels and tires. The tank assembly shall use split rim wheels in accordance with 3.5.1 of A-A-59494. The tires shall be rated-capacity at least equal to the maximum load experienced by each tire for a speed ranging from 0 to 10 mph, measured to each wheel at the ground with the trailer loaded to rated gross vehicle weight. Tires shall not drag on fenders when making a turn.

3.9.4 Liquid servicing hose. One 10-foot length of cryogenic liquid hose, conforming to MIL-H-

27301, shall be provided with the tank assembly. The tank assembly shall provide protection and storage for the hose while connected to the servicing line. The storage provisions shall securely retain and protect the hose when the tank is subjected to the accelerations specified herein. One end of the hose shall be connected to the 1-inch external pipe thread of the servicing line disconnect fitting. The other end of the hose shall be as follows:

a. For the Type I liquid oxygen tank, the other end of the hose shall be provided with a

1-inch close nipple and a 1-inch female liquid oxygen coupling half assembly consisting of a coupling plug, nut, cone, and retaining ring conforming to Ordnance

Corps drawings C8987870, C8987857, C8987856, and A8987840, respectively, assembled as shown on drawing C8987831.

b. For the Type II liquid nitrogen tank, the other end of the hose shall be provided with a

1-inch close nipple and a 1-inch female liquid nitrogen coupling half assembly consisting of a coupling plug, nut, cone, and retaining ring conforming to Ordnance

Corps drawings C8987891, C8987878, C8987877, and A8987840, respectively, assembled as shown on drawing C8987889.

c. An additional 10-foot hose conforming to MILPRF-83772 shall be provided with the tank. One end of the hose shall be able to connect to the hose specified in the previous paragraphs. The other end of the hose shall be provided with a female liquid oxygen filler valve conforming to MIL-PRF-38201. Provisions shall be made in the tank assembly for storing the hose in a coil and protecting it from damage during tank acceleration and other use conditions specified herein.

3.9.5 Tank assembly. The tank assembly shall be a self-contained liquid oxygen or nitrogen transport and storage unit, consisting of a storage tank with inner and outer shells, a control housing assembly, necessary controls and accessories, and trailer mounted. The tank assembly shall be capable of:

a. Being filled with liquid oxygen or nitrogen at a supply location.

b. Being air transported (see MIL-HDBK-1791(2) for guidance) while filled to design capacity with liquid oxygen or nitrogen and pressurized to 50 pounds per square inch gage (psig).

c. Storing the liquid with low evaporation loss rates during transport and at destination until needed, and at that time transferring the liquid into smaller servicing containers.

3.9.6 Pressure vessels. The liquid storage tank assembly, piping, and connections thereto shall meet the requirements of section VIII of the ASME Boiler and Pressure Vessel Code. Also, the inner shell shall be certified under the code for the specified working pressure (see 6.2).

3.9.7 Inner shell.

3.9.7.1 Design pressure. The inner shell shall have a maximum working pressure the same as the inner shell pressure relief device (see 3.9.7.2). The normal working pressure shall be not less than 50 psig for transferring liquid oxygen or nitrogen. The inner shell shall withstand an absolute pressure of 100 microns of mercury (Hg) or less with the annular space at atmospheric pressure. The shell shall not sustain damage when the annular space is evacuated to a high vacuum or is pressurized to the outer shell pressure relief device maximum opening pressure.

3.9.7.2 Inner shell safety head. A bursting-disc type safety head using a readily replaceable disc in a union-type fixture shall be provided to relieve the inner shell vapor phase pressure to atmosphere should this pressure become excessive and the pressure relief valve fail to open. The safety head relief pressure shall be not greater than 1-1/2 times the inner shell maximum working pressure.

3.9.7.3 Inner shell vapor space pressure relief device. An automatic pressure relief device shall be connected into the vapor vent line between the outer shell and the vent line shutoff valve to relieve excess pressure. The relief device shall open at a pressure sufficiently below the inner shell bursting-disc type safety head breaking pressure to ensure against rupture of the safety head unless the relief device fails, but not less than 50 psig, and shall be sized to insure against the inner shell vapor space pressure exceeding 65 psig under the conditions specified.

3.9.7.4 Sump and drain provisions. The inner shell shall have a sump with a drain line, and a smooth inside bottom surface throughout an arc of not less than 3 inches length on each side of the vertical centerline for the entire length of the shell for proper drainage under gravity, without inner shell pressurization. The drain line shall include an accessible, manual valve for draining the sump and obtaining liquid samples for analysis. The sump shall be not less than 3.0 inches in diameter and the drain line shall have an inside diameter of not less than 0.5 inch.

3.9.7.5 Baffles. The inner shell shall include lateral and longitudinal baffles to prevent liquid sloshing and surging during tank transportation. The baffles shall not restrict flow during liquid transfer operations or drainage, and shall permit pressure equalization between compartments.

3.9.8 Outer shell.

3.9.8.1 Design pressure. The outer shell shall be designed for a working pressure that will ensure sufficient strength and rigidity to prevent distortion or damage when the annular space is evacuated to a high vacuum or pressurized to the outer shell pressure relief device maximum opening pressure.

3.9.8.2 Vacuum seal-off valve. The outer shell shall have a vacuum seal-off valve that will serve as the vacuum pump-out for evacuation of the annular space, an isolation valve, and the outer shell safety relief device. The seal-off valve components and assembly shall conform to USAF

Drawings 68A39469, 68A39470, 68A39471, 68A39472, and 68A39473.

3.9.9 Annular space insulation. The annular insulation space shall contain an insulation that will, together with evacuation of the annular space, ensure compliance with the tank evaporation rate requirement (see 3.8.2). The insulating material shall be of a composition that will not ignite or burn when heated to 400 °F in 99.5% pure oxygen gas at a pressure of not less than 10 psig. The insulation shall not settle or be displaced in service. If a getter (impurity absorbing) material is used in the annular space, it shall be secured in direct thermal contact with the inner shell.

3.9.10 Liquid line. A single liquid line shall be provided between the inner and outer shells for filling and emptying the tank. The line shall be not less than 1 inch in diameter. The line shall permit liquid withdrawal at a height not less than 1.0 inch or more than 1.25 inches above the bottom of the inner shell to preclude withdrawing sediment with the liquid. The installation shall ensure against liquid entering the line from the inner shell when all liquid line valves are closed and the tank is tilted 20 degrees along either the longitudinal or lateral axis. The installation shall also ensure that the inner shell can be gravity drained to the level of the standpipe through the liquid fill line or liquid servicing line without pressurization.

3.9.10.1 Liquid fill line. The tank assembly shall have a liquid fill line for filling the tank with liquid oxygen or nitrogen. The fill line shall have a manual shutoff valve as near as possible to its connection to the liquid line (see 3.9.10). The line shall have a diameter of not less than 1 inch and shall terminate outside the control housing in a 1-inch external pipe thread for installation of the disconnect coupling. The fitting mounting shall withstand a torque of 300 ft-lb per inch of nominal line size applied to the fitting in either direction. The mounting shall have clearance to allow use of a 24-inch wrench. The disconnect coupling shall be as follows:

a. For the Type I oxygen tank, the disconnect coupling shall consist of a coupling cap, seat, and gasket, conforming to Ordnance Corps drawings C8987869, C8987855, and

B8987833, respectively, assembled as shown on drawing C8987830. The horizontal centerline distance between the fill line termination and the servicing line termination shall be a minimum of 9.0 inches.

b. For the Type II nitrogen tank, the disconnect coupling shall consist of a coupling cap, seat, and gasket, conforming to Ordnance Corps drawings C8987890, C8987876, and

B8987833, respectively, assembled as shown on drawing C8987888. The horizontal centerline distance between the fill line termination and the servicing line termination shall be a minimum of 9.0 inches.

3.9.10.2 Liquid servicing line. The tank assembly shall have a liquid servicing line for transferring liquid oxygen or nitrogen from the inner shell. The servicing line shall have a manual shutoff valve as near as possible to its connection to the liquid line (see 3.9.10). The line shall have a diameter of not less than 1 inch and shall terminate outside the control housing in a

1-inch external pipe thread disconnect fitting, oriented to discharge vertically upward, for attachment of the liquid servicing hose (see 3.9.4.