**November 21, 1997**

**Contract \# TW-0928**

**SPECIAL SPECIFICATION**

**SECTION 15495-S**

**[LIQUID NITROGEN SYSTEMS]{.underline}**

[Page]{.underline}

[PART 1 - GENERAL]{.underline}

1.01 Materials and Operations 2

1.02 Applicable Specifications and Standards 2

1.03 Design 3

1.04 Submittal Drawings 3

1.05 Shop Drawings Submittals 3

1.06 As-built Drawings 3

[PART 2 - PRODUCTS]{.underline}

2.01 Piping 4

2.02 V.I.P. Components 4

2.03 Pressure Gauges 4

2.04 Joints on Vacuum Insulated Pipe 4

2.05 Ball Valves 5

2.06 Vent Valve 5

[PART 3 - EXECUTION]{.underline}

3.01 General 6

3.02 Workmanship 6

3.03 Tests 8

**SPECIAL SPECIFICATION**

**SECTION 15495-S**

**[LIQUID NITROGEN SYSTEMS]{.underline}**

[PART 1 GENERAL]{.underline}

1.01 [MATERIALS AND OPERATIONS]{.underline}

A.  Material and operations required for the complete installation of
    piped cryogenic liquid nitrogen system using vacuum insulated pipe
    as shown on drawings, including design, shop drawings, equipment,
    piping, pipe fittings and components, operation instructions,
    identification, tests and sterilization.

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B.  Material required for a liquid nitrogen system using pre-insulated
    piping.

1.02 [APPLICABLE SPECIFICATIONS AND STANDARDS]{.underline}

A.  The following specifications and standards form a part of these
    Specifications.

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1.  Department of Transportation (DOT)

2.  Department of Labor, Occupational Safety and Health Act (OSHA)

3.  American Society for Testing Materials (ASTM)

4.  American National Standards Institute (ANSI, B49.1, B57.1, CSA-B96)

5.  Compressed Gas Association, Inc. (CGA)

6.  National Bureau of Standards (Handbook 44)

7.  National Association of Corrosion Engineers (NACE)

8.  American Standard Code for Pressure Piping (ASA-B31.1.)

9.  Ref. SNL Specification Section 01700 " Commissioning ".

1.03 [DESIGN]{.underline}

A.  The design and installation of the cryogenic liquid nitrogen piped
    system shall be complete with all necessary components and
    accessories for proper operation and delivery of product (LN~2~) and
    shall be accomplished according to the workmanship section of this
    Specification. The installation shall comply with all mandatory
    advisory and recommended applicable rules of the latest editions of
    the drawings or specified herein. The Contract drawings are
    schematic only, indicating the piping sizes, the extent and general
    routing arrangement of the cryogenic liquid nitrogen piping systems.

1.04 [SUBMITTAL DRAWINGS]{.underline}

A.  These drawings shall follow as closely as possible the suggested
    routing of the Contract Drawings. Any additional fittings or
    connections to facilitate easier installation shall be supplied by
    the Contractor at no additional cost. These drawings and any changes
    are subject to approval by the SDR. All submittals per 1300-S.

1.05 [SHOP DRAWINGS SUBMITTALS]{.underline}

A.  As soon as practical after award of Contract, and prior to
    fabrication, complete shop drawings of the LN piping system shall be
    submitted for approval. No installation will be permitted prior to
    approval of complete shop drawings. Submittal in sequence of
    complete shop drawings for individual or group installations may be
    permitted with proper programming and prior approval. All submittals
    per 1300-S.

1.06 [AS BUILT DRAWINGS]{.underline}

A.  Upon completion of the work, the Contractor shall revise all
    drawings to agree with the construction as actually accomplished and
    stamped "As-Built, No Change." The original "As-Built" drawings
    shall be delivered as directed.

[PART 2 PRODUCTS]{.underline}

2.01 [PIPING]{.underline}

A.  V.I.P.: Shall be a modular factory sealed high vacuum jacketed and
    all welded construction, schedule 5, type 304 stainless steel or
    invar-36% nickel alloy inner pipe and jacket pipe with multi-layer
    super insulation (alternating layers of glass fiber paper and
    aluminum foil). Vacuum insulated pipe shall be of design and
    manufactured in accordance with ANSI Code Section B31.3. V.I.P.
    shall have working pressure rating of 140 psig. All vacuum jackets
    shall have molecular sieve, hydrogen getters or activated charcoal
    getter to assure vacuum longevity. Evacuation pipe system shall be
    sealed at 10 microns or less in heated operating condition, without
    use of vacuum pump. Pipe lengths shall be as per manufacturer's
    standards. Each pipe section shall have a vacuum test port with
    isolation valve. The modular factory sealed high vacuum insulated
    pipe (V.I.P.) shall be as manufactured by the Cryogenic Energy
    Company of Minnesota Valley Engineering, Inc., Cryogen Services
    Inc., or CVI Inc. Substitutions: only under provisions of Section
    1600-S.

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B.  Pre-Insulated Piping: 3/4 inch, Type K copper tubing surrounded by 3
    inch polyurethane foam insulation (factory applied). "K" factory not
    to exceed 0.15 Btu-in/ft^2^ -hr-°F outer jacket to be PVC with a
    minimum of 110 mils thickness, all fittings to be pre-insulated.
    Joints to be 45% silver soldered. Southland cryogenics or approved
    substitute.

2.02 [V.I.P COMPONENTS]{.underline}

A.  Shall be of same manufacturer and specifications of V.I.P. used and
    ANSI Code, Section B31.3. V.I.P. components such as "Bayonet
    Couplings," "Flexible Sections, Etc., as determined by Contractor's
    final design and layout. Contract Drawings (being schematic only)
    show minimum components required.

2.03 [PRESSURE GAUGES]{.underline}

A. Shall be suitable for cryogenic service, with range of 0-200 psig.

2.04 [JOINTS ON VACUUM INSULATED PIPE]{.underline}

A. Shall be as per manufacturer of (V.I.P.) pipe and fittings, standard
band couplings and bayonet connectors, etc. Covering of joints, elbows,
tees, couplings, etc., shall be made in accordance with the manufacturer
standard installation instructions and as indicated on Drawings.

2.05 [BALL VALVES]{.underline}

A.  Ball valves to have stainless steel ball and stem, brass body,
    polyfill seats, 7 inch stem extension solder joint end, 1.4 turn
    throttling range, 1,500 psi working pressure. Worcester cryogenic
    ball valve, CVI, Inc., or approved substitute.

2.06 [VENT VALVES]{.underline}

> A. A liquid/gas differentiating cryogenic control valve designed to
> vent generated gas without discharging the liquid. The gas
> supply/pressure tap shall employ rocess stream pressure to operate a
> pneumatic diaphragm of the normally closed cryogenic valve.
>
> The liquid/gas differentiating cryogenic control valve shall be free
> from freeze-up. CVI, Inc. GN~2~ Vent valve or approved substitute.

[PART 3 - EXECUTION]{.underline}

3.01 [GENERAL]{.underline}

A.  The liquid nitrogen (LN~2~) modular factory seal high vacuum V.I.P.
    system installation shall be coordinated with respect to space
    available with all other work to be performed by other trades on
    this occupancy. In every instance where there is a conflict in the
    routing of V.I.P. and other work, the V.I.P. shall be coordinated
    with the other work. Installed V.I.P. shall not interfere with the
    operation or accessibility of doors or windows; shall not encroach
    on aisle, passageways, and equipment and shall not interfere with
    the servicing or maintenance of equipment.

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B.  It will be the V.I.P Contractor's responsibility to make accurate
    measurements established at the construction site prior to placing
    order of V.I.P from approved supplier. V.I.P. shall be factory
    fabricated and shall be worked into place without springing or
    forcing, properly clearing all openings and equipment. Cutting or
    weakening of structural members to facilitate piping installations
    is not permitted. Pipes shall be so installed as to permit free
    expansion and contraction without damage to joints or hangers.
    Piping shall be run parallel with the lines of the building unless
    otherwise noted on the Drawings. Unless otherwise shown on the
    Drawings, horizontal piping shall pitch down in the opposite
    direction of flow with grade of not less than 1/8" per foot.

3.02 [WORKMANSHIP]{.underline}

A.  General: The vacuum insulated pipe manufacturer is required to
    prepare a written installation guide for use by the Contractor.
    These written instructions shall be approved by the SDR prior to
    installation of any vacuum insulated pipe. The Contractor shall be
    entirely responsible for the quality of workmanship and for the
    satisfactory installation of the V.I.P. system.

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B.  The V.I.P. manufacturer shall assist the Contractor by training and
    instructing selected Contractor personnel in proper installation
    procedures and techniques. Acknowledgment will be required in
    writing from the manufacturer listing the names of those individuals
    so qualified. Personnel not qualified will not be permitted to work
    on V.I.P. systems. Qualification can be obtained with training by
    manufacturer's representative during installation of tracer line for
    V.I.P. system. The V.I.P. Contractor's project superintendent will
    assume the roll of coordinator between the manufacturer, his written
    instructions, and the project inspector. He shall also be authorized
    by the Contractor and manufacturer to prepare and sign daily written
    reports during installation. The reports shall cover unsatisfactory
    conditions, such as rejection of improperly factory sealed V.I.P.
    and improperly made up joints. The Contractor shall take prompt
    action to return to the factory all damaged and defective materials
    and shall order prompt replacement of such materials.

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C.  Responsibility for Materials: It shall be the Contractor's
    responsibility to have V.I.P. manufacturer's qualified
    representative at the construction site at the date of V.I.P.
    delivery to examine and inspect all vacuum insulated open products
    and materials delivered. The Contractor and manufacturer's
    representative shall read the vacuum on each section of pipe, using
    Hasting Vacuum Gauge Model TV-4A. any section of pipe reading higher
    than 35 microns shall be replaced or repaired. If field repaired, a
    written statement describing repair required will be submitted. In
    addition, any pipe re-evacuated in the field will be monitored and
    recorded every other day for five working days. If vacuum degrades
    to the disapproval of the SDR, the section will be replaced. Upon
    verification of acceptable vacuum for all sections of V.I.P. system,
    each section will be numbered and the vacuum level records. An
    additional vacuum check will be performed after installation, prior
    to filling with LN~2.~ This recording will be submitted, along with
    the received levels, for comparison and evaluation by the
    Contracting Officer. Any installed sections 35 microns or greater
    will be subject to rejection. A final vacuum reading will be taken
    when LN~2~ has activated the molecular sieve. This reading of 10
    microns or less shall be on the submittal report.

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D.  Handling of Pipe and Accessories: Handling shall be done in
    accordance with manufacturer's recommendation..

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E.  Pipe Size Reduction: Reduction in pipe size shall be made with
    V.I.P. reducing tees and/or V.I.P. reducing sections.

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F.  Installation of Valves: Valves shall be installed at location shown
    on the Contract Drawings of the type specified. All valves shall be
    installed with their stems vertical.

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G.  Pipe Hangers: Unless otherwise noted on the drawings, horizontal
    overhead runs of pipe shall be hung with adjustable wrought-iron,
    the malleable-iron hanger, spaced not over 8' apart. Use J-hangers,
    U-bolts, split clamps,. Or roller type support. Chain strap,
    perforated bar, or wire hangers will not be permitted. Trapeze
    hangers may be used in lieu of separate hangers on pipes running
    parallel to each other and close together. All hangers shall have
    short turnbuckles or other approved means of adjustment, and should
    be suspended form structural members. Hangers and collars shall be a
    size proportional to the weight of the pipe supported. Where the
    piping is attached to metal partitions, full-length through bolts
    should be used with large washers on both sides. Copper pipe hangers
    shall be copper or copper plated. Piping in tunnels or chases shall
    be supported on Unistrut using pipe clamps, or approved substitute.

> H. Joints: All V.I.P. shall be connected with couplings and bayonet
> connectors, as per V.I.P. manufacturer's type and specification.

3.03 [TESTS]{.underline}

> A. General: All vacuum insulated piping, components, equipment and
> accessories installed under this Contract shall be inspected and
> tested by other than the Contractor and the V.I.P. manufacturer's
> representative, through the entire duration of testing, in the
> presence of the SDR, and approved before acceptance. All labor,
> material, and equipment required for testing shall be furnished by the
> Contractor. The Contractor shall be responsible for all repairs and
> retesting as required. All instruments and other equipment whose safe
> pressure range is below that of the test pressure shall be removed
> from the line or blanked off before applying the tests. Prior to
> performing tests, all lines shall be "blown" free of all loose dirt
> and foreign particles. The Lines shall then be thoroughly blown with
> dry nitrogen at a sufficient flow rate and period of time to ensure
> complete cleaning on the line of all dirt, scale, and foreign matter.
> Cleaning of the lines shall be subject to approval.
>
> B. Testing: The entire LN~2~ pipe systems shall be pressurized with
> dry nitrogen gas (furnished by Contractor) to and not exceed 1.25
> times V.I.P. pressure rating. The test duration shall be maintained at
> 100 psig minimum over a four-hour period. If pressure drop occurs
> during the four-hour period, the entire system shall be leak-bubble
> tested with the Winston Products Co., Inc. "Sherlock 5 second leak
> detector" o.a.e., until leak is located and repaired. Repeat test
> procedures until pressure hold test successful. A cool down test
> follows with the introduction of (cryogenic) liquid nitrogen into the
> LN~2~ pipe system from the LN~2~ pressure vessel supply tank, allowing
> gaseous nitrogen to flow until liquid nitrogen begins to issue from
> the valve. Close valve and then repeat procedure at all use points
> unit entire system is cooled down to operating temperature. The next
> step is to carefully and thoroughly visually inspect the entire V.I.P.
> section and shall be corrected or replaced as determined necessary.
> All above testing procedures shall be accomplished to the satisfaction
> of the SDR. The Contractor shall be responsible for all costs of
> testing,
>
> correcting and/or replacing materials that may be defective. The
> Contractor shall also be responsible for system problems due to poor
> workmanship.

END OF SECTION