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Historic Preservation - Technical Procedures

Spectitle:

Supplemental Guidelines For Specifying Repairs To Ornamental Copper Metal Work

Procedure code:

0575001R

Source:

Us Ct Of Appeals/New Orleans, La - Fromherz Engineers, Inc.

Division:

Metals

Section:

Ornamental Copper

Last Modified:

02/24/2012

Details:

Supplemental Guidelines For Specifying Repairs To Ornamental Copper Metal Work



 SUPPLEMENTAL GUIDELINES FOR SP= ECIFYING REPAIRS TO ORNAMENTAL
COPPER METALWORK


PART 1---GENERAL

1.01 SUMMARY

    A.   This procedure provides supplemental guidelines to be
         used when specifying any type of repairs to copper metal
         work.  Guidelines for shop drawings, qualifications for
         subcontractors, materials and finishes, shop assembly,
         and general guidelines for installation are included.

    B.   These guidelines may be used in conjunction with the
         following procedures:

         1.   07602-01-R "Repairing Pinch Cracks in Long Copper
              Gutters".

         2.   07610-02-R "Installing a Transverse Expansion Joint
              in a Standing Seam Copper Sheetmetal Roof".

         3.   07610-03-R "Repairing a Bowing Sheetmetal Roof".

         4.   07610-04-R "Repairing a Wind-damaged Copper
              Sheetmetal Roof Ridge and Installing a New Ridge
              Cap".

         5.   07610-05-R "Repairing Holes in a Sheetmetal Roof".

         6.   07610-06-R "Repairing Corroded Copper Sheetmetal
              Roofing Materials".<= br>
         7.   07610-12-R "Repair of Star Cracks in Copper Roofs".

    C.   Procedures for the repair of copper metalwork shall
         include all work, materials and equipment required to:

         1.   Remove required ornamental metalwork and securely
              re-install ornamental metalwork to its original
              place and position.

         2.   Repair ornamental metalwork with RHPO approval.

         3.   Provide for historical photos of work done.

    D.   See 01100-07-S for general project guidelines to be
         reviewed along with this procedure.  These guidelines
         cover the following sections:

         1.   Safety Precautions

         2.   Historic Structures Precaution= s

         3.   Submittals

         4.   Quality Assurance

         5.   Delivery, Storage and Handling=

         6.   Project/Site Conditions

         7.   Sequencing and Scheduling

         8.   General Protection (Surface and Surrounding)

         These guidelines should be reviewed prior to performing
         this procedure and should be followed, when applicable,
         along with recommendations from the Regional Historic
         Preservation Officer (RHPO).

1.02 SUBMITTALS

    A.   Product Data:  Submit product data for each product used
         in ornamental metalwork, including finis= hing materials
         and methods to RHPO for prior approval.<= br>
    B.   Shop Drawings:  Submit to RHPO three copies of shop
         drawings showing fabrication and install= ation of
         ornamental metalwork including plans, elevations and
         details of components and attachments to other units of
         work. Indicate materials, profiles of each ornamental
         metalwork member and fitting, joinery, finishes,
         fasteners, anchorages and accessory items.

         1.   Include setting drawings, templates, and directions
              for installation of anchor bolts and other
              anchorages to be installed as unit of work of other
              sections.

         2.   Where installed products are indicated to comply
              with certain design loadi= ngs, include structural
              computations, material properties, and other
              information needed for structural analysis which
              has been prepared by, or under the supervision of,
              a qualified professional engineer.

    C.   Samples:  Submit to RHPO samples for initial selection
         purposes in form of conservator's color samples of patina
         consisting of actual units or sections of units showing
         full range of patina colors and other finish
         characteristics for each item indicated below.

    D.   Submit to RHPO samples for verification purposes of each
         type of metal finish required, prepared on metal of same
         thickness and alloy indicated for final unit of work.
         Where finishes involve normal color and texture
         variations, include sample sets composed of two or more
         units showing full range of variations expected.

    E.   Submit to RHPO conservator/installer certificates signed
         by Contractor certifying that conservato= r/installers
         comply with requirements specified under "Quality
         Assurance" article.

    F.   Submit to RHPO qualification data for firms and persons
         specified in "Quality Assurance&quo= t; article to demonstrate
         their capabilities and experience.  = ;Include list of
         completed projects with project name, addresses, names of
         architects and owners, plus other inform= ation specified.

    G.   Photography:

         1.   Contractor shall ensure that the conservator takes
              one 8" x 10" black and white photo "before" shot of
              each metalwork assembly as required.  "After"
              photos in the same format shall be taken from the
              same locations and of the same items after all
              items are re-installed and conservation is
              complete.  Submit two copies and the negatives of
              each shot.  All copies shall be archivally sound.

         2.   Submit one set of color slides showing de-
              installation, progress of repair and restoration,
              and re-installation, to RHPO at close of contract.
              Views shall be chosen by conservator.  The slides
              shall present a picture story of the entire
              conservation process.

         3.   Label all photos and slides in such a manner that
              photo location and process shown corresponds to
              label.

1.03 QUALITY ASSURANCE

    A.   Qualifications:

         1.   Conservator/Fabricator Qualifi= cations:  Firm
              experienced in successful= ly producing ornamental
              repousse metalwork similar to that indicated for
              this project, with suffic= ient production capacity
              to produce required units without causing delay in
              the work.

         2.   Conservator Qualifications:  Contractor shall
              provide a professional conservator who must be
              approved by RHPO and GSA Contracting Officer prior
              to award of contract.  The conservator shall have
              the following qualificati= ons:

              a.   Experience of at least five years in providing
                   servi= ces of the kind indicated which has
                   resul= ted in the successful installation of
                   assem= blies similar in material, design, and
                   extent to that indicated for this project.

              b.   Extensive repou= sse metalwork experience is an
                   absol= ute requirement for this project. Common
                   sheet metal work does not qualify as
                   exper= ience in this instance.

              c.   The same conser= vator used for the repair of
                   metal= work should be used to remove and re-install the metalwork.

              d.   For conservation referral services, write or
                   call the following:

                   Ameri= can Institute for Conservation of
                   Histo= ric and Artistic Works
                   1400 16th Street N.W., Ste. 340
                   Washi= ngton, DC  20036
                   202/4= 52-9545

                   This agency is listed for Contractor
                   conve= nience ONLY.  Any conservator chosen by
                   the contractor must submit their
                   quali= fications for government approval.

         3.   Use Only experienced riggers with at least three
              years successful experien= ce to move all pieces from
              their existing positions to the truck, to the
              studio, and back again.
    B.   Pre-Installation Conference:  Conduct confere= nce at
         project site to review scope of project and ensure the
         understanding of the Scope of Work by all parties.
         Attendees shall include the RHPO, GSA Contracting
         Officer, contractor and conservator.  The installer and
         fabricator may be in attendance as neces= sary.

1.04 DELIVERY, STORAGE, AND HANDLING

    A.   Packing and Shipping:  Perform conservation work in such
         a manner that the safety of all ornament= al metal
         components is assured during all loading and unloading
         operations, removal from existing locati= ons,
         transportation to place of repair, repair itself,
         transportation back to building, reinsta= llation, and
         patination.

    B.   Storage and Protection:

         1.   All conservation work on remov= ed ornamental metal
              shall be performed in the conservator's studio.
              The studio shall comply with OSHA regulations
              regarding environmental precautions for the work
              necessary to repair and refurbish required pieces.

         2.   Store all materials in clean, dry location, away
              from uncured concrete and masonry.  Cover with
              waterproof paper, tarpaul= in or polyethylene
              sheeting in a manner that permits air circulation
              within covering.

         3.   Handle ornamental metalwork on site to a minimum.
              Exercise care to avoid damaging metal finishes.

1.05 PROJECT/SITE CONDITIONS

    A.   Field Measurements: Take field measurements prior to
         preparation of shop drawings and fabrica= tion, where
         possible, to ensure proper fitting of ornamental
         metalwork.  Do not delay job progre= ss.  Allow for
         adjustments and fitting where taking of field
         measurements before fabrication might delay Work.


PART 2---PRODUCTS

2.01 MATERIALS

    A.   Metals:

         1.   General:  Provide ornamen= tal copper metalwork
              composed of the forms and types which comply with
              project requirements and match as closely as
              possible existing copper metalwork.

         2.   New and repaired work is to be free from surface
              blemishes where exposed to view in the finished
              unit.  Exposed-to-vi= ew surfaces exhibiting pitting,
              seam marks, roller marks, "oil canning," stains,
              discolorations or other imperfections on finished
              units are not acceptable.=

    B.   Miscellaneous Materials:

         1.   Welding Electrodes and Filler Metal:  Type and
              alloy of filler metal and electrodes as recommended
              by producer of metal to be welded, complying with
              applicable the American Welder's Society (AWS)
              specifications, and as required for color match,
              strength and compatibility in the fabricated items.
              Conservator shall supply the Government with
              manufacturer's certificat= ion that material
              recommended is compatible with metal on which use
              is recommended.

         2.   Fasteners:  Of same basic metal and alloy as
              fastened metal, unless otherwise indicated.  Do not
              use metals which are corrosive or incompatible with
              metals joined.

              a.   Provide conceal= ed fasteners similar to
                   exist= ing fasteners for interconnection of
                   ornam= ental metalwork components and for their
                   attac= hment to other work, except where
                   other= wise indicated.

              b.   Provide exposed fasteners for interconnection
                   of ornamental metalwork components and for
                   their attachment to other work only where
                   expos= ed fasteners are unavoidable.

         3.   Anchors and Inserts:  Pro= vide anchors of type, size
              and material required for type of loading and
              installation condition shown, as recommended by
              manufacturer, unless otherwise indicated.  Use
              nonferrous metal or hot-d= ipped galvanized anchors
              and inserts for exterior locations and elsewhere as
              required for corrosion resistance.  Use toothed
              steel or expansion bolt devices for
              drilled-in-place anchors.=

    C.   Finishes:

         1.   General:  Prepare, pretre= at, and apply patina and
              protective acrylic lacquer and/or wax coating to
              all raw copper that resul= ts from repair of
              metalwork copper.  T= he patination color shall match
              existing as closely as possible.  Patina color
              shall be as approved by RHPO.  Comply with patina
              and coating manufacturer's instructions.  

         2.   Copper:  Finishes shall conform with the system
              established by the Copper Development Association
              for designating copper alloy finish systems.
              Protective finishes shall be as directed by project
              conservator.

2.02 FABRICATION

    A.   Shop Assembly:

         1.   Form ornamental copper metalwo= rk to required shapes
              and sizes, with true curves, lines and angles using
              repousse technique similar to original repousse
              technique.  Provide components in sizes and
              profiles indicated, but not less than required to
              comply with requirements indicated by Secretary of
              the Interior's "Stan= dards for Rehabilitation and
              Guidelines for Rehabilita= ting Historic Buildings."

         2.   Allow for thermal movement resulting from the
              following maximum change (range) in ambient
              temperature, in the desig= n, fabrication, and
              installation of installed metal assemblies to
              prevent buckling, opening up of joints and
              overstressing of welds and fasteners.  Base design
              calculations on actual surface temperatures of
              metals due to both solar heat gain and night time
              sky heat loss.  Range of temperature change shall
              be from 10=F8 F to 180=F8 F.

         3.   Provide necessary lugs and brackets for assembly of
              units.  Use concealed fasteners wherever possible.

         4.   Comply with AWS for recommended practices in shop
              welding.  Provide welds, if needed, behind finished
              surfaces without distorti= on or discoloration of
              exposed side.  Clean exposed welded joints of all
              welding flux, and dress on all exposed and contact
              surfaces.

         5.   Mill joints to a tight, hairli= ne fit.  Cope or
              miter corner joints.  Form joints exposed to
              weather to exclude water penetration.

         6.   Provide bronze bracket castings that are sound and
              free of warp or defects which would impair strength
              and appearance.

         7.   Finish exposed surfaces to smooth, sharp,
              well-defined lines and arises.

         8.   Pre-assemble items in shop to greatest extent
              possible to minimize splicing and assembly.
              Disassemble units only as necessary for shipping
              and handling limitations.  Clearly mark units for
              re-assembly and coordinat= ed installation.

    B.   Performance Requirements:  Structural Perform= ance of
         Repaired Statuary Assemblies:  Desi= gn, engineer, remove,
         fabricate, repair and install ornamental metalwork to
         comply with requirements of this specifi= cation for
         structural performance.


PART 3---EXECUTION

3.01 PREPARATION

    A.   Surface Preparation:

         1.   Coordinate and furnish anchora= ges and setting
              drawings, diagrams, templ= ates, instructions and
              directions for installati= on of items having
              integral anchors which are to be embedded in
              concrete or masonry const= ruction.  Coordinate
              delivery of such items to the project site.

         2.   Preparation for Patina:  = Clean metal surfaces of
              dirt, grease, black atmos= pheric pollution, and
              corrosion products, inclu= ding any material that
              would prohibit adherence of patina.  

3.02 ERECTION, INSTALLATION, APPLICATION

    A.   De-Installation:  De-installation of all ornamental
         metalwork is the responsibility of the conservator and
         shall be performed according to the conservator's
         instructions and under the conservator's supervision.  

    B.   Repair and Restoration:

         1.   All repair and restoration work of this contract
              shall be performed in accordance with the Secretary
              of the Interior's "S= tandards for Rehabilitation and
              Guidelines for Rehabilita= ting Historic Buildings"
              (see 01091-04-S through 01091-19-S for guidance).

         2.   Repair to sound condition all ornamental metalwork
              and seams using RHPO approved fabrication and
              repair techniques.

    C.   Installation, General:

         1.   Provide anchorage devices and fasteners where
              necessary for securing ornamental metalwork and
              other items to in-place construction including,
              threaded fasteners for concrete and masonry
              inserts, toggle bolts, through-bolts, lag bolts,
              wood screws and other connectors as required.

         2.   Contractor shall provide for conservator to perform
              cutting, drilling and fitting required for
              installation of ornamental metalwork, and to
              reinstall items accurately in same location and
              position, alignment and elevation, from which
              removed.  These items shall be plumb, level and
              true, measured from estab= lished lines and levels.
              Provide temporary bracing or anchors for items
              which are to be built into concrete, masonry or
              similar construction.

         3.   Fit exposed connections accura= tely together to form
              tight, hairline joints or, where indicated, with
              uniform reveals and spaces for sealants and joint
              fillers.  Where cutting, welding and grinding are
              required for proper shop fitting and jointing of
              ornamental metal items, restore finishes to
              eliminate any evidence of such corrective work.

         4.   Do not cut or abrade finishes which cannot be
              completely restored in the field.  Return items
              with such finishes to the shop for required
              alterations, followed by complete refinishing or
              provide new units as required.

         5.   Install concealed gaskets, joint fillers, and
              flashings as the work progresses, so as to make
              work weathertight.

         6.   Restore protective coverings which have been
              damaged during shipment or installation of the
              work.  Remove protec= tive coverings only when there
              is no possibility of damage from other work yet to
              be performed at the same location.

         7.   Retain protective coverings intact and remove
              simultaneously from simil= arly finished items to
              preclude nonuniform oxida= tion and discoloration.

         8.   Field Welding:  Comply with applicable AWS
              specification for procedu= res of manual shielded
              metal-arc welding, for appearance and quality of
              welds made, and for metho= ds used in correcting
              welding work.

         9.   Perform all other functions required to effect
              complete conservation and repair of all ornamental
              metalwork.

3.03 ADJUSTING/CLEANING

    A.   Touch-Up Patination:  Conservator shall perfo= rm touch-up
         patination and coating with acrylic sealer and/or wax at
         all areas of ornamental metalwork that are not patinated
         to the satisfaction of the RHPO.

3.04 PROTECTION

    A.   Protect finishes of ornamental metalwork from damage
         during construction period by use of temporary protective
         coverings approved by ornamental metalwo= rk conservator.
         Remove protective covering at time of Substantial
         Completion.

    B.   Restore finishes damaged during installation and          construction period so that no evidence remains of
         correction work.  Return items which cannot be refinished
         in the field to the shop.  Make required alterations and
         refinish entire unit, or provide new units as required.

                         END OF SECTION