36C25622R0094 076000 Flashing and Sheet Metal .docx

REPLACE AHU #104 AND DUCTWORK BLDG. 7

DEPARTMENT OF VETERANS AFFAIRS HEALTH CARE SYSTEM-ALEXANDRIA, LA

PROJECT NO.: 502-19-107

SECTION 07 60 00

FLASHING AND SHEET METAL

GENERAL

DESCRIPTION

Formed sheet metal work for wall flashing, copings and caps, are specified in this section.

RELATED WORK

Section 07 92 00, JOINT SEALANTS: Joint Sealants.

Section 09 06 00, SCHEDULE FOR FINISHES: Color of factory coated exterior architectural metal and anodized aluminum items.

Section 09 91 00, PAINTING: Paint materials and application.

APPLICABLE PUBLICATIONS

Publications listed below form a part of this specification to the extent referenced. Publications are referenced in the text by the basic designation only. Editions of applicable publications current on date of issue of bidding documents apply unless otherwise indicated.

American National Standards Institute/Single-Ply Roofing Institute/Factory Mutual (ANSI/SPRI/FM):

4435/ES-1-11 Wind Design Standard for Edge Systems Used with Low Slope Roofing Systems ASTM International (ASTM):

A240/A240M-20 Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet and Strip for Pressure Vessels and for General Applications.

Sheet Metal and Air Conditioning Contractors National Association (SMACNA): Architectural Sheet Metal Manual.

National Association of Architectural Metal Manufacturers (NAAMM):

AMP 500-06 Metal Finishes Manual Federal Specification (Fed. Spec):

International Code Commission (ICC): International Building Code, Current Edition

PERFORMANCE REQUIREMENTS

Wind Uplift Forces: Resist the following forces per FM Approvals 1-49:

Wind Zone 3: 2.20 to 4.98 kPa (46-to-104-pound force/square foot): 9.96-kPa (208-pound force/square foot) perimeter uplift force, 14.94-kPa (312-pound force/square foot) corner uplift force, and 4.98-kPa (104-pound force/square foot) outward force.

Wind Design Standard: Fabricate and install cap/copings and flashings tested per ANSI/SPRI/FM ES-1 to resist design pressure.

SUBMITTALS

Submit in accordance with Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA, AND SAMPLES.

Shop Drawings: For all specified items, including:

Flashings Copings Fascia-cant Manufacturer's Literature and Data: For all specified items, including:

Two-piece counterflashing Certificates: Indicating compliance with specified finishing requirements, from applicator and contractor.

PRODUCTS

FLASHING AND SHEET METAL MATERIALS

Stainless Steel: ASTM A240, Type 302B, dead soft temper.

FLASHING ACCESSORIES

Solder: ASTM B32; flux type and alloy composition as required for use with metals to be soldered.

Rosin Paper: Fed-Spec. UU-B-790, Type I, Grade D, Style 1b, Rosin-sized sheathing paper, weighing approximately 3 Kg/10 m²(6 pounds/100 square feet).

Bituminous Paint: ASTM D1187, Type I.

Fasteners:

Use stainless steel for stainless steel and aluminum alloy.

Nails:

Minimum diameter for stainless steel nails: 2 mm (0.095 inch) and annular threaded.

Length to provide not less than 22 mm (7/8 inch) penetration into anchorage.

Rivets: Not less than 3 mm (1/8 inch) diameter.

Expansion Shields: Fed Spec A-A-1925A.

Sealant: As specified in Section 07 92 00, JOINT SEALANTS for exterior locations.

Roof Cement: ASTM D4586.

SHEET METAL THICKNESS

Except as otherwise shown or specified use thickness or weight of sheet metal as follows:

Concealed Locations (Built into Construction):

Stainless steel: 0.25 mm (0.010 inch) thick.

Exposed Locations:

Stainless steel: 0.4 mm (0.015 inch).

FABRICATION, GENERAL

Jointing:

In general, stainless-steel joints, except expansion and contraction joints, shall be locked and soldered.

Joints shall conform to following requirements:

Flat-lock joints shall finish not less than 19 mm (3/4 inch) wide.

Lap joints subject to stress shall finish not less than 25 mm (one inch) wide and shall be soldered and riveted.

Unsoldered lap joints shall finish not less than 100 mm (4 inches) wide.

Flat and lap joints shall be made in direction of flow.

Soldering:

Pre tin both mating surfaces with solder for a width not less than 38 mm (1 1/2 inches) of uncoated copper, stainless steel, and copper clad stainless steel.

Wire brush to produce a bright surface before soldering lead coated copper.

Treat in accordance with metal producers’ recommendations other sheet metal required to be soldered.

Completely remove acid and flux after soldering is completed.

Cleats:

Fabricate cleats to secure flashings and sheet metal work over 300 mm (12 inches) wide and where specified.

Provide cleats for maximum spacing of 300 mm (12 inch) centers unless specified otherwise.

Form cleats of same metal and weights or thickness as the sheet metal being installed unless specified otherwise.

Fabricate cleats from 50 mm (2 inch) wide strip. Form end with not less than 19 mm (3/4 inch) wide loose lock to item for anchorage. Form other end of length to receive nails free of item to be anchored and end edge to be folded over and cover nail heads.

Edge Strips or Continuous Cleats:

Fabricate continuous edge strips where shown and specified to secure loose edges of the sheet metal work.

Except as otherwise specified, fabricate edge strips or minimum 0.6 mm (0.024 inch) thick stainless steel.

Use material compatible with sheet metal to be secured by the edge strip.

Fabricate in 3000 mm (10 feet) maximum lengths with not less than 19 mm (3/4 inch) loose lock into metal secured by edge strip.

Fabricate Strips for fascia anchorage to extend below the supporting wood construction to form a drip and to allow the flashing to be hooked over the lower edge at least 19 mm (3/4-inch).

Fabricate anchor edge maximum width of 75 mm (3 inches) or of sufficient width to provide adequate bearing area to ensure a rigid installation using 0.8 mm (0.031 inch) thick stainless steel.

Drips:

Form drips at lower edge of sheet metal counter-flashings (cap flashings), and wall copings, by folding edge back 13 mm (1/2 inch) and bending out 45 degrees from vertical to carry water away from the wall.

Form drip to provide hook to engage cleat or edge strip for fastening for not less than 19 mm (3/4 inch) loose lock where shown.

Edges:

Finish exposed edges of flashing with a 6 mm (1/4 inch) hem formed by folding edge of flashing back on itself when not hooked to edge strip or cleat. Use 6 mm (1/4 inch) minimum penetration beyond wall face with drip for through-wall flashing exposed edge.

All metal roof edges shall meet requirements of IBC, current edition.

Metal Options:

Where options are permitted for different metals use only one metal throughout.

FINISHES

Use same finish on adjacent metal or components and exposed metal surfaces unless specified or shown otherwise.

In accordance with NAAMM Metal Finishes Manual AMP 500, unless otherwise specified.

Finish exposed metal surfaces as follows, unless specified otherwise:

Stainless Steel: Finish No. 2B or 2D.

BASE FLASHING

Use metal base flashing at vertical surfaces intersecting built-up roofing without cant strips or where shown.

Use stainless steel, thickness specified unless specified otherwise.

Use stainless steel at pipe flashings.

Fabricate metal base flashing up vertical surfaces not less than 200 mm (8 inch) nor more than 400 mm (16 inch).

Form base flashing bent from strip except pipe flashing. Fabricate ends for riveted soldered lap seam joints. Fabricate expansion joint ends as specified.

Pipe Flashing: (Other than engine exhaust or flue stack) Fabricate roof flange not less than 100 mm (4 inches) beyond sleeve on all sides.

Extend sleeve up and around pipe and flange out at bottom not less than 13 mm (1/2 inch) and solder to flange and sleeve seam to make watertight.

At low pipes 200 mm (8 inch) to 450 mm (18 inch) above roof:

Form top of sleeve to turn down into the pipe at least 25 mm (one inch).

Allow for loose fit around and into the pipe.

At high pipes and pipes with goosenecks or other obstructions which would prevent turning the flashing down into the pipe:

Extend sleeve up not less than 300 mm (12 inch) above roofing.

Allow for loose fit around pipe.

COUNTERFLASHING (CAP FLASHING OR HOODS)

Stainless steel, unless specified otherwise.

Fabricate to lap base flashing a minimum of 100 mm (4 inches) with drip:

Form lock seams for outside corners. Allow for lap joints at ends and inside corners.

In general, form flashing in lengths not less than 2400 mm (8 feet) and not more than 3000 mm (10 feet).

Two-piece, lock in type flashing may be used in-lieu-of one-piece counterflashing.

Manufactured assemblies may be used.

Where counterflashing is installed at new work use an integral flange at the top designed to be extended into the masonry joint or reglet in concrete.

Where counterflashing is installed at existing work use surface applied type, formed to provide a space for the application of sealant at the top edge.

One-piece Counterflashing:

Back edge turned up and fabricate to lock into reglet in concrete/stucco.

Two-Piece Counterflashing:

Receiver to extend into masonry wall depth of masonry unit with back edge turned up 6 mm (1/4 inch) and exposed edge designed to receive and lock counterflashing upper edge when inserted.

Counterflashing upper edge designed to snap lock into receiver.

Surface Mounted Counterflashing; one or two pieces:

Use at existing or new surfaces where flashing cannot be inserted in vertical surface.

One piece fabricate upper edge folded double for 65 mm (2 1/2 inches) with top 19 mm (3/4 inch) bent out to form "V" joint sealant pocket with vertical surface. Perforate flat double area against vertical surface with horizontally slotted fastener holes at 400 mm (16 inch) centers between end holes. Option: One piece surface mounted counterflashing (cap flashing) may be used. Fabricate as detailed on Plate 51 of SMACNA Architectural Sheet Metal Manual.

Two pieces: Fabricate upper edge to lock into surface mounted receiver. Fabricate receiver joint sealant pocket on upper edge and lower edge to receive counterflashing, with slotted fastener holes at 400 mm (16 inch) centers between upper and lower edge.

Pipe Counterflashing:

Form flashing for water-tight umbrella with upper portion against pipe to receive a draw band and upper edge to form a "V" joint sealant receiver approximately 19 mm (3/4 inch) deep.

Fabricate 100 mm (4 inch) overlap at end.

Fabricate draw band of same metal as counter flashing. Use 0.33 mm (0.013 inch) thick stainless steel.

Use stainless steel bolt on draw band tightening assembly.

REGLETS

Fabricate reglets of one of the following materials:

Stainless steel, not less than 0.3 mm (0.012 inch) thick.

Fill open-type reglets with fiberboard or other suitable separator, to prevent crushing of the slot during installation.

Bend edges of reglets for setting into concrete to an angle of not less than 45 degrees and make wide enough to provide firm anchorage in the concrete.

Fabricate reglets for building into horizontal masonry mortar joints not less than 19 mm (3/4 inch) deep, nor more than 25 mm (one inch) deep.

Fabricate mitered corners, fittings, and special shapes as may be required by details.

EXECUTION

INSTALLATION

General:

Install flashing and sheet metal items as shown in Sheet Metal and Air Conditioning Contractors National Association, Inc., publication, ARCHITECTURAL SHEET METAL MANUAL, except as otherwise shown or specified.

Apply Sealant as specified in Section 07 92 00, JOINT SEALANTS.

Apply sheet metal and other flashing material to surfaces which are smooth, sound, clean, dry and free from defects that might affect the application.

Remove projections which would puncture the materials and fill holes and depressions with material compatible with the substrate. Cover holes or cracks in wood wider than 6 mm (1/4 inch) with sheet metal compatible with the roofing and flashing material used.

Confine direct nailing of sheet metal to strips 300 mm (12 inch) or less wide. Nail flashing along one edge only. Space nail not over 100 mm (4 inches) on center unless specified otherwise.

Install bolts, rivets, and screws where indicated, specified, or required in accordance with the SMACNA Sheet Metal Manual. Space rivets at 75 mm (3 inch) on centers in two rows in a staggered position. Use neoprene washers under fastener heads when fastener head is exposed.

Nail continuous cleats on 75 mm (3 inch) on centers in two rows in a staggered position.

Nail individual cleats with two nails and bend end tab over nail heads. Lock other end of cleat into hemmed edge.

Install flashings in conjunction with other trades so that flashings are inserted in other materials and joined together to provide a watertight installation.

Where required to prevent galvanic action between dissimilar metal isolate the contact areas of dissimilar metal with sheet lead, waterproof building paper, or a coat of bituminous paint.

Isolate aluminum in contact with dissimilar metals others than stainless steel, white bronze, or other metal compatible with aluminum by:

Paint dissimilar metal with a prime coat of zinc-chromate or other suitable primer, followed by two coats of aluminum paint.

Paint dissimilar metal with a coat of bituminous paint.

Apply an approved caulking material between aluminum and dissimilar metal.

Paint aluminum in contact with or built into mortar, concrete, plaster, or other masonry materials with a coat of bituminous paint.

Paint aluminum in contact with absorptive materials that may become repeatedly wet with two coats of bituminous paint or two coats of aluminum paint.

Bitumen Stops:

Install bitumen stops for built-up roof opening penetrations through deck and at formed sheet metal gravel stops.

Nail leg of bitumen stop at 300 mm (12 inch) intervals to nailing strip at roof edge before roofing material is installed.

BASE FLASHING

Extend base flashing up under counter flashing of roof specialties and accessories or equipment not less than 75 mm (3 inch).

COUNTERFLASHING (CAP FLASHING OR HOODS)

General:

Install counterflashing over and in conjunction with installation of base flashings, except as otherwise specified or shown.

Install counterflashing to lap base flashings not less than 100 mm (4 inch).

Install upper edge or top of counterflashing not less than 225 mm (9 inch) above top of the roofing.

Lap joints not less than 100 mm (4 inch). Stagger joints with relation to metal base flashing joints.

Use surface applied counterflashing on existing surfaces and new work where not possible to integrate into item.

When fastening to concrete or masonry, use screws driven in expansion shields set in concrete or masonry. Use screws to wood and sheet metal. Set fasteners in mortar joints of masonry work.

One Piece Counterflashing:

Where flashing is installed at new masonry, coordinate to ensure proper height, embed in mortar, and end lap.

Where flashing is installed in reglet in concrete insert upper edge into reglet. Hold flashing in place with lead wedges spaced not more than 200 mm (8 inch) apart. Fill joint with sealant.

Where flashing is surface mounted on flat surfaces.

When top edge is double folded anchor flat portion below sealant "V" joint with fasteners spaced not over 400 mm (16 inch) on center:

Locate fasteners in masonry mortar joints.

Use screws to sheet metal or wood.

Fill joint at top with sealant.

Where flashing or hood is mounted on pipe.

Secure with draw band tight against pipe.

Set hood and secure to pipe with a one by 25 mm x 3 mm (1 x 1/8 inch) bolt on stainless steel draw band type clamp, or a stainless worm gear type clamp.

Completely fill joint at top with sealant.

Two-Piece Counterflashing:

Where receiver is installed at new masonry coordinate to ensure proper height, embed in mortar, and lap.

Surface applied type receiver:

Secure to face construction in accordance, with manufacturers’ instructions.

Completely fill space at the top edge of receiver with sealant.

Insert counter flashing in receiver in accordance with fabricator or manufacturer's instructions and to fit tight against base flashing.

Where vented edge occurs install so lower edge of counterflashing is against base flashing.

When counter flashing is a component of other flashing install as shown.

REGLETS

Install reglets in a manner to provide a watertight installation.

Locate reglets not less than 225 mm (9 inch) nor more than 400 mm (16 inch) above roofing, and not less than 125 mm (5 inch) nor more than 325 mm (13 inch) above cant strip.

Butt and align end joints or each section of reglet and securely hold in position until concrete or mortar are hardened:

Coordinate reglets for anchorage into concrete with formwork construction.

Coordinate reglets for masonry to locate horizontally into mortar joints.

COPINGS

General:

Install ends adjoining existing construction so as to form space for installation of sealants. Sealant is specified in Section 07 92 00, JOINT SEALANTS.

Aluminum Coping:

Install with 6 mm (1/4 inch) joint between ends of coping sections.

Install joint covers, centered at each joint, and securely lock in place.

Stainless steel Copings:

Join ends of sheets by a 19 mm (3/4 inch) locked and soldered seam, except at intervals of 9600 mm (32 feet), provide a 38 mm (1 1/2 inch) loose locked expansion joint filled with sealant or mastic.

At straight runs between 7200 mm (24 feet) and 19200 mm (64 feet) locate expansion joint at center.

At straight runs that exceed 9600 mm (32 feet) and form the leg of a corner locate the expansion joint not more than 4800 mm (16 feet) from the corner.

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