CONSTRUCTION STANDARD SPECIFICATION

SECTION 15215

[COMPRESSED GAS PIPING - INTERIOR]{.underline}

Page

PART 1 - GENERAL

1.01 Summary [2](#summary)

1.02 References [2](#references)

1.03 Submittals [4](#submittals)

1.04 Quality Assurance [4](#quality-assurance)

1.05 Delivery, Storage, and Handling [5](#delivery-storage-and-handling)

PART 2 - PRODUCTS

2.01 Materials [5](#materials)

2.02 Equipment [7](#equipment)

PART 3 - EXECUTION

3.01 Preparation [7](#preparation)

3.02 Installation -- General [8](#installation-general)

3.03 Hangers and Anchors [9](#hangers-and-anchors)

3.04 Joints [10](#joints)

3.05 Field Quality Control [12](#field-quality-control)

CONSTRUCTION STANDARD SPECIFICATION

SECTION 15215

[COMPRESSED GAS PIPING - INTERIOR]{.underline}

# [GENERAL]{.underline} {#general .SECTION-1}

## Summary {#summary .SECTION1.01}

A.  Section Includes: Materials and installation required for the
    installation of interior, low-pressure (below 150-psig) compressed
    gas piping systems, including argon, helium, nitrogen, oxygen,
    hydrogen, chlorine, acetylene, and methane piping, fittings, valves,
    equipment, joints, and tests.

B.  Related Sections: Refer to the following sections for related work:

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1.  Section 01330, \"Submittal Procedures" for administrative
    requirements for preparing and submitting information on material
    equipment and methods.

2.  Section 07270, "Firestop and Smoke Stop Systems" for sealing of
    mechanical penetrations through rated walls.

3.  Section 09900, "Painting" for painting of mechanical equipment and
    systems.

4.  Section 15050, "Basic Mechanical Materials and Methods."

## References {#references .SECTION1.01}

A.  American National Standards Institute (ANSI)

B31.1 Power Piping

B2.1 Standard Welding Procedure Specification (WPS) Gas Metal Arc
Welding of Austenitic Stainless Steel (M-8 or P-8), 10 through 18 Gage,
in the As-Welded Condition, With or Without Backing

B1.2 Hose Coupling Screw Threads

B16.11 Forged Fittings, Socket-Welding and Threaded

B16.22 Wrought Copper and Copper Alloy Solder Joint Pressure Fittings

B31.3 Code for Pressure Piping, Chemical Plant and Petroleum

B1.1 Unified Inch Screw Threads

A.  American Society of Mechanical Engineers (ASME)

Section IX Boiler and Pressure Vessel Code; Welding and Brazing
Qualifications

B.  American Society of Testing and Materials (ASTM)

> A53 Standard Specification for Pipe Steel, Black and Hot-Dipped, Zinc
> Coated, Welded and Seamless
>
> A269 Standard Specification for Seamless and Welded Austenitic
> Stainless Steel Tubing for General Service
>
> A334M Standard Specification for Seamless and Welded Carbon and
> Alloy-Steel Tubes for Low-Temperature Service
>
> A420M Standard Specification for Piping Fittings of Wrought Carbon
> Steel and Alloy Steel for Low-Temperature Service
>
> A632 Seamless and Welded Austenitic Stainless Steel Tubing (Small
> Diameter) for General Service
>
> B88 Standard Specification for Seamless Copper Water Tube for Air
> Conditioning
>
> A307 Standard Specification for Carbon Steel Bolts and Studs, 60,000
> psi Tensile Strength
>
> B16.18 Cast Copper Alloy Solder Joint Pressure Fittings
>
> B819 Standard Specification for Seamless Copper Tube for Medical Gas
> Systems

C.  American Welding Society (AWS)

A5.8 Specification for Filler Metals for Brazing

> Brazing Manual, 3rd Edition, 1976

B2.2 Standard for Brazing Procedure and Performance Qualifications

D.  Compressed Gas Association

> G-4.1 Pamphlet - Cleaning Equipment For Oxygen Service

E.  National Fire Protection Association (NFPA)

> 50 Standard for Bulk Oxygen Systems
>
> 50A Gaseous Hydrogen Systems
>
> 50B Liquefied Hydrogen Systems
>
> 99 Health Care Facilities

## Submittals {#submittals .SECTION1.01}

F.  General: Submit the following in accordance with Conditions of
    Contract documents and Section 01330, \"Submittal Procedures."

G.  Product Data: Submit product data for products used in Interior
    Compressed Gas Piping. Product data shall indicate the maximum
    allowable operating pressure and temperature of each component and
    any related manufacturing standard.

H.  As-Built Drawings

    1.  Upon completion of the work, the Contractor shall revise all
        drawings to agree with the construction materials, capacities,
        locations, and routing as actually accomplished. The notation
        "As-Built" shall be entered in the revision block, dated and
        initialed.

## Quality Assurance {#quality-assurance .SECTION1.01}

I.  Qualify welding/brazing processes and welder/brazer performance in
    accordance with AWS B2.2 or ASME Boiler and Pressure Vessel Code,
    Section IX. Certify that each welder/brazer has satisfactorily
    passed AWS or ASME qualification tests for welding/brazing processes
    involved and, if pertinent, has undergone re-certification.

J.  Welding and brazing procedures shall address cleaning, joint
    clearance, overlaps, internal purge gas, purge gas flow rate, and
    filler metal.

K.  Certification of procedures and operators applies for both shop and
    job site welding and brazing of pipe work.

L.  Soldering is to conform to ANSI/ASME B31.1, Power Piping.

M.  Operators shall have completed the Sandia National Laboratories
    Welding Safety Class.

N.  Performance qualification of welders/brazers shall remain in effect
    indefinitely unless the welder/brazer does not weld or braze with
    the qualified procedure for a period exceeding 12 months, or there
    is a specific reason to question the ability of the welder/brazer.

## Delivery, Storage, and Handling {#delivery-storage-and-handling .SECTION1.01}

O.  Deliver materials to the job site in good condition and properly
    protected against damage to finished surfaces.

P.  Storage on Site: Store materials in a location and in a manner to
    avoid damage. Stacking shall be done in a way that will prevent
    bending.

    1.  Store metal components and materials in a clean, dry location.
        Cover with waterproof paper, tarpaulin, or polyethylene sheeting
        in a manner that will permit circulation of air inside the
        cover.

Q.  Keep handling on-site to a minimum. Exercise care to avoid damage to
    finishes of material.

# [PRODUCTS]{.underline} {#products .SECTION-1}

## Materials {#materials .SECTION1.01}

A.  General: Materials shall be as follows unless otherwise indicated on
    the applicable Contract drawings. Valves of equal quality and
    characteristics may be substituted for those listed in this
    specification.

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R.  Piping, fittings, valves, and other components that are required to
    be "Cleaned and Capped/Packaged for Oxygen Service" shall be per CGA
    Pamphlet G-4.1.

S.  Pipe and fittings to be used for modifications or additions shall be
    the same material (steel or copper) as the existing systems being
    modified but shall conform to the following unless otherwise
    indicated on the applicable Contract drawings.

    1.  Argon, Helium, and Nitrogen Systems (150-psig and under):

        ½-inch Diameter and Larger:

        a.  Piping: Cleaned for oxygen service, Type L, hard drawn
            copper tubing, ASTM B88 or ASTM B819, and conforming to
            ANSI/ASME B31.3. Steel piping for modifications to existing
            systems, schedule 40 black steel, seamless or welded, ASTM
            A53.

        b.  Fittings: Wrought copper brazed-joint, ANSI/ASME B16.22.
            Cast copper fittings in sizes over 3-inch diameter (where
            wrought copper is not available), ASTM B16.18. All fittings
            shall be cleaned and packaged for oxygen service. Steel
            fittings for modifications to existing systems, 2000‑pound
            forged steel socket weld, ANSI B16.11.

        c.  Ball Valves: Worcester No. 416T, brass body, stainless steel
            ball and stem, Teflon seat, cleaned and packaged for oxygen
            service, 250-psig maximum working pressure.

            Less than ½-inch Diameter:

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        a.  Piping: Seamless, Type 304 stainless steel, ASTM A269, fully
            annealed with a hardness of Rb 80 or less, cleaned and
            capped. Minimum tube wall thickness shall be 1/8-inch O.D.
            -- 0.028-inch w.t., ¼-inch O.D. -- 0.028‑inch w.t., 3/8-inch
            O.D. -- 0.035-inch w.t.

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        d.  Fittings: Stainless steel compression-type tube fittings,
            Swagelok. Compression tube fittings from different
            manufactures shall not be used.

        e.  Ball Valves: Whitey 40 Series, 316 stainless steel.

    2.  Oxygen Systems (50-psig and under): NOTE: Oil and oxygen may
        combine with explosive violence.

        a.  Piping: Type L hard drawn copper tubing, ASTM B88; or for
            existing steel systems only, Schedule 40 black steel,
            seamless, ASTM A53, and conforming to ASME B31.3. Comply
            with NFPA 50.

        b.  Fittings: Wrought copper and bronze brazed-joint, ANSI/ASME
            B16.22; or for existing systems only, 2000-pound forged
            steel socket weld, ANSI/ASME B16.11 (cast iron not
            permitted).

        c.  Ball Valves: Worcester No. X416T, brass body, stainless
            steel ball and stem, Teflon seat, cleaned and packaged for
            oxygen service, 250-psig maximum working pressure.

    3.  Hydrogen Systems (50-psig and under):

        a.  Piping: Schedule 40 seamless pipe, 316L stainless steel per
            ASTM A312. Comply with NFPA 50A and 50B.

        b.  Fittings: 3,000-pound forged 316L stainless steel, socket
            welded per ANSI B16.11.

        c.  Ball Valves: Worcester No. 466TM 316L stainless steel body,
            stainless steel ball and stem, socket weld ends, Teflon
            seat, forged schedule 80 carbon steel socket weld ends,
            250-psig maximum working pressure.

        d.  Globe Valves: Crane No. 222 H, bar stock, steel, 3000 psig.

    4.  Chlorine Systems (50-psig and under):

        a.  Piping: Schedule 80 black steel, seamless Grades A or B,
            ASTM A53.

        b.  Fittings: 2000-pound forged steel socket weld, ANSI/ASME
            B16.11.

        c.  Needle Valves: Matheson No. 104, screwed, monel
            construction, 3000 psig.

    5.  Acetylene Systems (15-psig and under): NOTE: Contact between
        acetylene and unalloyed copper should be avoided, since the
        explosive compound, copper acetylide, might be formed.

        a.  Piping: Schedule 40 black steel, seamless Grades A or B,
            ASTM A53.

        b.  Fittings: 2000-pound forged steel socket weld, ANSI/ASME
            B16.11 (cast iron not permitted).

        c.  Valves: Crane No. 1652 (Underwriters' Approved) 15-psig
            rating, 180 degrees F maximum.

    6.  Methane Systems (50-psig and under):

        a.  Piping: Schedule 40 black steel, seamless Grades A or B,
            ASTM A53.

        b.  Fittings: 2000-pound forged steel socket weld, ANSI/ASME
            B16.11.

        c.  Ball Valves: Worcester No. 446T, carbon steel body,
            stainless steel ball and stem, Teflon seat, forged schedule
            80 carbon steel socket weld ends, 250 psig, maximum working
            pressure.

## Equipment {#equipment .SECTION1.01}

A.  All major items of equipment required for installation on this
    Contract shall be as specified on the applicable Contract drawings
    and shall be furnished complete with all accessories normally
    supplied with the catalog item listed and all other accessories
    necessary for a complete and satisfactory operating system.

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T.  Relief Valves: Shall be ASME constructed and stamped. Size,
    capacity, and setting shall be as indicated on the drawings.
    Discharge from relief valves shall be piped full size and extended
    to the outside where required by code, standard, or drawings.

U.  Identification and Labels: All piping systems shall be labeled and
    identified in accordance with Section 15050, "Basic Mechanical
    Materials and Methods."

V.  Gages: Gages shall be safety-type with rear blowout plug or panel,
    clear plastic cover, and sides and front consisting of one integral
    part. Range shall be at least 1.2 times the system relief pressure.
    Gages shall be installed with snubbers and ¼‑inch bronze needle
    valves. All gages shall be rated for the specific gas, pressure
    rating, and ambient conditions.

# [EXECUTION]{.underline} {#execution .SECTION-1}

## Preparation {#preparation .SECTION1.01}

A.  Materials for copper and stainless steel piping systems that are
    required to be "cleaned for oxygen service", including pipe, valves,
    fittings, and components, shall be cleaned and prepared in a
    facility equipped to clean, rinse, and purge the material in
    accordance with CGA Pamphlet G-4.1, "Cleaning Equipment for Oxygen
    Service," and shall be delivered to the job site capped, bagged, or
    plugged as necessary to protect materials from contamination.

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W.  On-site cleaning of the interior surfaces of materials in copper and
    stainless piping systems shall be limited to recleaning surfaces in
    the immediate vicinity of the joints that have become contaminated
    prior to brazing or welding.

    1.  Surfaces shall be cleaned by washing in a clean, hot
        water/alkaline solution of 1 lb. tri-sodium phosphate to 3
        gallons of water (protective gloves required). Scrubbing shall
        be employed as required to assure removal of dirt, metal
        filings, oil, and grease. After washing, materials shall be
        rinsed in clear, hot water. Dry using Argon purge to \<10 ppb
        moisture level. After drying, materials shall be plugged or
        capped until assembly.

X.  Black steel lines, before assembly, shall be hammered to loosen
    scale and wire brushed inside as required. Following scale removal
    pipe shall be cleaned and stored as described for copper until
    assembly.

## Installation -- General  {#installation-general .SECTION1.01}

A.  General: Piping installation shall be coordinated with all trades
    with respect to space available with heating, ventilating, and
    electrical installation. In every instance where there is a conflict
    in the routing of the piping and the ducting, the routing of the
    ducting shall govern. Installed piping shall not interfere with the
    operation or accessibility of doors or windows; shall not encroach
    on aisles, passageways, or equipment; and shall not interfere with
    the servicing or maintenance of equipment.

    1.  Pipe shall be cut accurately to measurements established at the
        construction site and shall be worked into place without
        springing or forcing, properly clearing all openings and
        equipment.

    2.  Cutting or weakening of structural members to facilitate piping
        installation is not permitted.

    3.  Pipes shall have burrs removed by reaming and shall be so
        installed as to permit free expansion and contraction without
        damage to joints or hangers.

    4.  Piping above ground shall be run parallel with the lines of the
        building unless otherwise noted on the drawings. Piping
        connections to equipment shall be in accordance with details
        shown on the drawings. Service pipe, valves, and fittings shall
        be kept a sufficient distance from other work to permit finished
        covering not less than ½ inch from such other work, and not less
        than ½ inch between finished covering on the different services.

    5.  Any penetrations through fire walls should be firestopped in
        accordance with Section 07270, "Fire Stop and Smoke Stop
        Systems."

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Y.  Reducers: Reduction in pipe sizes shall be made with one-piece
    reducing fittings. Bushings reducing at least two pipe sizes will be
    acceptable only when there is no room for reducing couplings or
    swaged nipples.

Z.  Unions: All piping unions shall be of the ground joint type
    constructed from materials equivalent in alloy composition and
    strength to other fittings specified with which they are used. Union
    pressure classes and end connections shall be the same as the
    fitting used in the lines with the unions. Steel unions shall have
    hardened stainless steel seating surfaces on both faces.

A.  Valves: Valves shall be installed at the locations shown on the
    drawings and where specified. All valves shall be installed with
    their stems horizontal or above.

## Hangers and Anchors {#hangers-and-anchors .SECTION1.01}

A.  All piping shall be rigidly supported from the building structure by
    means of adjustable ring-type hangers. (WELDING TO BUILDING
    STRUCTURE WILL NOT BE PERMITTED.) Where pipes run side by side,
    support on rod and angle iron or Unistrut trapeze hangers. Hanger
    spacing shall be as follows:

    1.  Horizontal:

> [Steel Piping]{.underline} [Maximum Spacing]{.underline}
>
> ½ inch and smaller 6 feet
>
> ¾ inch through 1 inch 8 feet
>
> 1¼ inch and larger 10 feet
>
> [Copper Piping]{.underline} [Maximum Spacing]{.underline}
>
> ½ inch 4 feet
>
> ¾ inch through 1 inch 6 feet
>
> 1¼ inch and larger 8 feet

2.  Vertical: Steel and copper shall be supported at 10-foot intervals,
    maximum, or at every floor level, whichever is less.

3.  Round rods supporting the pipe hangers shall be of the following
    dimensions:

  ---------------------------------- ---------- --------------------------
  3/8-inch to 2-inch pipe                       3/8-inch rod

  2½-inch to 3-inch pipe                        ½-inch rod

  4-inch to 5-inch pipe                         5/8-inch rod
  ---------------------------------- ---------- --------------------------

4.  Rods for trapeze hangers shall be a minimum of 3/8 inch and shall
    have the equivalent cross section, listed in 3.03 A.3, per pipe
    supported. The use of pipe hooks, perforated iron strapping or wire
    for pipe supports will not be permitted.

5.  Hanger rods shall be galvanized carbon steel per ASTM A307, Grade B,
    threaded per ANSI B1.1 coarse thread series, Class 2A fit:

a\. Hanger rods shall have minimum 6-inch threaded ends.

b\. All hanger rod connections shall use double nut fastening.

6.  Hanger rods shall be installed vertically. No offset in hanger rod
    will be permitted.

7.  Place a hanger within 1 foot of each horizontal elbow.

8.  Use hangers that are vertically adjustable 1½-inch minimum after
    piping is erected.

9.  Use copper straps on copper pipe and ferrous hangers on ferrous
    pipe. Steel to copper contact is not allowed.

10. Soft copper tubing, where permitted, shall be fastened to the
    building structure with Unistrut type clamps with cushion, spaced
    not more than 4 feet apart.

11. On 4-inch and larger piping, install hangers adjacent (within 1 foot
    on each side) to all horizontal elbows, strainers, check valves,
    valves, and all flanged items.

## Joints {#joints .SECTION1.01}

A.  Screwed Joints: Screwed pipe joints shall have American Standard
    Taper Pipe Threads ANSI/ASME B1.2. Burrs formed when cutting pipe
    shall be removed by reaming. Care shall be taken that the inside of
    the pipe is thoroughly clean and free of cutting oil and foreign
    matter before installation. Joints shall be made perfectly tight by
    the use of Teflon tape or approved Teflon thread sealing and
    lubricating compound.

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B.  Solder-Joints: (Soldered joints may only be used in existing systems
    where soldered joints were used originally.) Tubing shall be cut
    square and burrs removed. Both inside of fittings and outside of
    tubing shall be well cleaned with sand cloth or wire brush before
    sweating. Care shall be taken to prevent annealing of fittings and
    hard drawn tubing when making connections. Joints for sweated
    fittings on low-pressure piping (150-psig and below) shall be made
    with a noncorrosive paste flux and solid wire solder composed of 95
    percent tin and 5 percent antimony or similar solder of equal
    characteristics. Cored solder will not be permitted. Conform to AWS
    A5.8. Joints shall comply with ANSI/ASME B31.1 Power Piping.

    1.  Solder containing antimony SHALL NOT be used to join metals
        containing zinc (e.g., galvanized iron, galvanized steel, and
        brass).

    2.  Solder end valve: Use two-piece gate or globe valve or
        three-piece ball valve for solder end valves. When joining a
        gate or glove solder end valve, ensure valve is fully open.
        Apply heat to tube first. Transfer as much heat as possible
        through the tube to the valve. Avoid prolonged heating of valve.
        Use a non-corrosive paste flux and solid wire solder suitable
        for the service temperatures and pressures expected.

    3.  Use sand cloth or a stainless steel wire brush to clean surfaces
        to be joined. Steel wool IS NOT permitted.

C.  Brazed Joints: New copper systems shall be installed per CGA
    Pamphlet G-4.1, "Cleaning Equipment For Oxygen Service," with brazed
    socket type fittings and with an argon or nitrogen purge applied.
    Flux shall not be used except where joining specialty items and
    fittings that are not available in copper. Brazing filler metals
    shall comply with ANSI/AWA A5.8, "Specification for Filler Metals
    for Brazing." Copper-to-copper joints shall be brazed using a
    copper-phosphorus or copper-phosphorous-silver brazing filler metal
    (BCuP) without flux. Dissimilar metals, such as copper and bronze or
    brass, shall be brazed using an appropriate flux with a silver (BAg
    series) brazing filer metal.

    1.  Tube ends shall be cut square using a sharp tubing cutter. The
        wheel shall be free from grease, oil, or other lubricant not
        suitable for oxygen service. The cut end of the tubing shall be
        deburred with a sharp, clean deburring tool, taking care to
        prevent chips from entering the tube or pipe.

    2.  The surfaces to be brazed shall be mechanically cleaned with a
        stainless steel wire brush. The use of steal wool is prohibited
        due to the possible presence of oil. After mechanical cleaning
        the surfaces shall be wiped using a clean, lint-free white
        cloth. Joints shall be recleaned if contaminated prior to
        brazing. Joints shall be brazed within 1 hour of being cleaned.

    3.  Where dissimilar metals, such as copper and bronze or brass, are
        being brazed, flux shall be applied sparingly to minimize
        contamination of the inside of the tube with flux. Where
        possible, short sections of copper tube shall be brazed to the
        noncopper components and the interior of the subassembly shall
        be cleaned of the flux prior to installation in the piping
        system. Flux-coated brazing rods may be used in lieu of the
        application of flux to the surfaces to be joined for tubes
        ¾-inch size and smaller.

    4.  While being brazed, joints shall be continuously purged with
        oil-free dry nitrogen or argon to prevent the formation of
        copper oxide on the inside surface of the joint. The flow of the
        purge gas shall be maintained until the joint is cool to the
        touch.

> *Exception: A final connection to an existing system shall be
> permitted to be made without the use of a purge gas.*

5.  During and after installation, openings in the piping system shall
    be kept capped or plugged to avoid unnecessary loss of purge gas and
    to prevent contamination. While brazing, a discharge opening shall
    be provided on the opposite side of the joint from where the purge
    gas is introduced. During brazing, the purge gas flow rate shall be
    maintained at a level that will not produce a positive pressure in
    the piping system. While welding, the minimum purge rate shall be 15
    scfh for ¼-inch tubing, and 25 scfh for all tubing 3/8 inch and
    larger.

6.  After brazing, the outside of all joints shall be cleaned by washing
    with water and a stainless steel brush to remove any residue and
    permit clear visual inspection of the joint. Where flux has been
    permitted, hot water shall be used.

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D.  Swagelok Compression Fittings: Follow the manufacturer's
    installation instructions for assembly tubing and tube fittings. Use
    a sharp clean tube cutter wheel to cut tubing. Remove burrs, chips,
    and scratches from the end of the tubing. **Ensure that the tubing
    is fully bottomed in the fitting before final tightening.** After
    assembly, check that the fitting is properly tightened by using a
    Gap Inspection Gage.

E.  Welded Joints: Joints between sections of pipe and between pipe and
    fittings may be welded using either gas or electric welding
    equipment. Stainless steel welding shall conform to ANSI/AWS
    B2.1.005. All pipe surfaces shall be thoroughly cleaned before
    welding. Each joint, except socket-weld joints, shall be beveled
    before being welded. The Contractor shall provide a non-flammable
    mat or blanket to protect the structure and adequate fire protection
    equipment at all locations where welding is done. All elbows shall
    be long radius where space conditions allow. Wherever tee
    connections are made to piping systems on the main run, welding
    sockets or weld-o-lets may be used in lieu of reducing outlet tees
    for branch connections up to one-half the size of the main run. On
    connections larger than one-half the size of the main run, welding
    tees shall be used. The use of fittings formed from welded pipe
    sections will not be permitted. All welding shall conform to the
    requirements of Section 15050, "Basic Mechanical Materials and
    Methods."

Any welding work being done requires:

a.  A hot works permit from Firemark, Inc., located in MO119.

b.  A dedicated fire watch during work through thirty (30) minutes after
    operation.

c.  A minimum 2-A rated fire extinguisher located near the welding site.

d.  Any other requirements listed on the permit.

## Field Quality Control {#field-quality-control .SECTION1.01}

A.  General: All piping, equipment, and accessories installed under this
    Contract shall be inspected and tested by the Contractor in the
    presence of the Inspector, and approved before acceptance. The
    Contractor shall furnish all labor, material, and equipment required
    for testing. 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.

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F.  Brazed Joints: Each brazed joint shall be visually examined after
    cleaning of the outside of the joint. The following conditions shall
    be considered unacceptable:

    1.  Flux or flux residue

    2.  Excessive oxidation of the joint

    3.  Presence of un-melted filler metal

    4.  Failure of the filler metal to be clearly visible all the way
        around the joint at the interface between the socket and the
        tube

    5.  Cracks in the tube or component

    6.  Cracks in the braze filler metal

    7.  Failure of the joint to hold test pressure

        Brazed joints that are found to be defective under conditions 1,
        3, 4, 6, and 7 shall be permitted to be repaired except that no
        joint shall be repaired more that once. Brazed joints that are
        defective under 2 and 5 shall be replaced.

G.  Blow Down and Purge Test: In order to remove particulate matter in
    the pipelines, a heavy, intermittent purging of each outlet shall be
    performed with oil-free nitrogen. The outlet shall be allowed to
    flow until the purge produces no discoloration in a white cloth.

H.  Pressure Tests: Compressed gas piping shall be tested at the test
    pressures specified and shall not exceed the following drop in
    pressure (temperature compensated) in a 24-hour period. All system
    leaks shall be located by soap testing.

  -------------------- ------------------------ ------------------ -------------------
  [Compressed          [Test                    [Test              [Max. Pressure
  Gas]{.underline}     Pressures]{.underline}   Gas]{.underline}   Drop]{.underline}

                                                                   (24 hrs)

  Nitrogen Systems     225 psig                 Nitrogen           5 psi

  Argon Systems        225 psig                 Nitrogen           5 psi

  Helium Systems       225 psig                 Nitrogen           5 psi

  Oxygen Systems       150 psig                 Nitrogen           5 psi

  Hydrogen Systems     200 psig                 Nitrogen           P.D. = Zero

  Chlorine Systems     200 psig                 Nitrogen           P.D. = Zero

  Acetylene Systems    200 psig                 Nitrogen           P.D. = Zero

  Methane Systems      150 psig                 Nitrogen           P.D. = Zero
  -------------------- ------------------------ ------------------ -------------------

1.  The pressure test shall be conducted as follows:

    a.  Equipment that is not to be tested such as relief valves and
        gauges shall be removed and the openings plugged or capped.

    b.  The system shall be filled with the test gas to 25 psig and held
        while all joints are visually inspected for leaks.

    c.  The pressure shall be slowly increased to 150 psig and held
        while all joints are soap tested.

    d.  The system shall be increased to the test pressure and held for
        24 hours and the pressure drop recorded for acceptance.

    e.  Pressure shall be relieved from the system and equipment that
        was removed shall be reinstalled. The system shall be
        pressurized to the operating pressure and joints at previously
        removed equipment shall be soap tested.

    f.  Leaks, if any, shall be located, repaired, and retested.

    g.  For the test the contractor shall provide a calibrated 4-inch
        diameter pressure gauge of maximum 1% full scale accuracy,
        maximum 300 psig range and maximum 2 psig graduations. If the
        system is in an area where the temperature will fluctuate more
        than 10 degrees F over the test period, then the contractor
        shall also furnish an 8-inch temperature chart recorder or a
        combination temperature/pressure chart recorder.

END OF SECTION