METAL SIDING, ROOF AND INTERIOR WALLS


SCOPE

This specification covers the requirements for metal siding, roofing and interior wall and shall include contractor's designing, detailing, fabricating, furnishing, installing, inspecting and testing of the work and shall conform to the requirements of this specification and as shown on the drawing.

WORK INCLUDED

Designing detailing, fabricating, furnishing and installing metal siding and roofing, with all penetration through the siding, walls and roofing.

Interior metal wall works.

Louvers, sunshades, and other appurtenances.


Detailing, fabricating, furnishing and installing all Rain Water Gutters, Flashing, fasteners and other material necessary to ensure a watertight construction.

Furnishing and insulation for siding and roofing and wall as required.

Surface protection and painting.

CODES AND STANDARDS

Comply with the requirements of the applicable codes and standards published by the following organisations:

AISI                              American Iron Metal Institute
ANSI                            American National Standards Institute
ASTM                           American Society for Testing and Materials
NBS                              National Bureau of Standards, USA
SAE                              Society of Automotive Engineers,
UL                                 Underwriters' Laboratories, Inc,

Conform especially to the applicable provisions of the following codes and standards

ASTM A525      Galvanized Metal
ASTM B 1 17     Salt Spray
ASTM C423      Noise Reduction Coef
ASTM D3363   Pencil Hardness
ASTM D2247   Humidity
ASTM 623         Wentherometer
ASTM D1737    Flexibility
ASTM D523      Gloss
ANSI A58.1       Design Load

QUALITY ASSURANCE/QUALITY CONTROL (QA/QC)

Contractor shall fully comply with the Project Quality Assurance/Quality Control Requirements. For submitting Quality Assurance/Quality Control Procedures and Documentation the provision of “Submittals” of this specification shall be applied.

SUBMITTALS

After the contract signed, the contractor shall furnish complete and comprehensive data on materials specification regarding a component and accessories of his propose system for the Owner's approval.

Test data and report and the quality control procedures and documentation shall be submitted to the Owner for review.

 Written Warranty on siding & roofing coating for a minimum period of 10 (ten) years shall be submitted to the Owner's after acceptance of works.

Engineering calculation shall support the design in conformance with this specification.


DEFINITIONS

Metal Siding: Exterior enclosure of one or more sides of a structure, insulated or uninsulated. If the siding is insulated, it shall consist of exterior metal sheets, insulation, subgirts and interior Metal sheets (which are the siding components). If the siding is uninsulated, it shall consist of the single exterior metal sheets only. Both types of the siding shall also include all related fasteners and other accessories.

Metal Roofing.  Exterior enclosure of the roof of a structure, insulated or uninsulated, constructed of the same components, fasteners and other accessories as for Metal siding (in contrast to metal decking covered with concrete and/or built-up roofing).

If the roofs are insulated, the components shall consist of exterior metal sheets with insulation underneath, and with interior Metal sheets. If roofs are uninsulated, components shall consist of the single exterior metal sheets only.

Metal Interior Wall: Enclosure of one or more sides of a space within a structure, insulated or uninsulated, constructed of the same components, fasteners and other accessories for metal siding (in contrast to prefabricated metal partitions or similar constructions).  If walls are insulated, components shall consist of two metal sheets enclosing an insulation core, and with or without subgirts depending on the method of construction. If walls are uninsulated, components shall consist of an assembly of single metal sheets.

Fire Rated Insulated Fluted metal Siding: To be used where indicated and approved by the Owner and shall have its exterior fire rated which shall consist of field assembled panels utilizing a liner panel insulation, subgirts, gypsum board and fluted extension metal sheet.


DESIGN REQUIREMENTS

STRUCTURAL REQUIREMENTS

The Contractor shall be fully responsible for the design of siding, roofs and interior walls to withstand the specified loads, without exceeding the maximum allowable unit stresses according to AISI, and without exceeding the allowable deflections as specified in paragraph below. Subgirts shall be used for all insulated siding.  Panels may be designed as continuous over two or more spans, according to the girt or purlin spacings covered.

The Contractor shall have qualified engineers to perform or supervise the design work.

Fasteners for attaching siding, roof and interior wall component to each other and to grits and other structural supports shall be designed to withstand the specified loads without exceeding maximum allowable unit stresses for such fasteners.

The Maximum allowable deflection for insulated or uninsulated siding, roofs or interior walls subjected to the design loads shall not exceed 1/180 of the clear span between grits or purlins, in the direction normal to the plane of the siding, roof or interior wall.

Design wind loads shall conform to all applicable requirement of ANSI A58.1, with wind loads based on a basic wind speed of 120 km/hr, and the minimum design live load for the roof deck shall be 100 kg/m2.
The maximum fibre stress shall not exceed for the foregoing specified deflection 14 kg/m² for steel panels.

THERMAL REQUIREMENTS

The overall coefficient of thermal transmission U for insulated siding, roofs and interior walls shall not exceed 0.75 watt/m2 °C in still air.

Test data shall be submitted to Owner if requested to substantiate Contractors claims as to the thermal properties of his materials used for construction.
                  
ACOUSTIC REQUIREMENTS

If acoustically treated areas are required, they shall have a Noise Reduction Coefficient (NRC), in conformance with ASTM C423, of not less than 0.85 and the Contractor shall submit a test report to the Owner if requested to support his claims for the NRC value of his materials used for construction.

WEATHERTIGHTNESS

All completed siding and roofs shall be weather watertight and dust tight.

Provision shall be made, in the design of insulated siding to drain to the exterior of siding of any condensation forming within the assemblies.

STORAGE
All siding materials, components, fasteners and other accessories shall be stored dry, off the ground and under protective cover, in a satisfactory manner.

The Contractor shall arrange with the Owner for temporary storage of materials not erected, and shall be responsible for storing these materials in such a manner as to preclude damage, deterioration, etc.  All costs for such protection shall be included in the Contract Price.

MATERIALS AND DETAILS

METAL SHEETS
Metal sheets shall be of steel and be compatible with the coat finish system. Cold rolled steel sheets of structural quality shall confirm to the requirement of ASTM A446, Grade B, G 90 “Zinc Coated Steel Sheets”. European Norm EN 10142 : 1990, EN. 10147: 1992 with galvanize Z 275 gr/m². Two side at three point test according to EN 10142: 1990.

The metal thickness shall comply with one of the following requirements.

a)                                                      Metal thickness shall be determined from the defined loading requirements, but shall be not less than that determined from the width-of-flat surface in accordance with the following table. Beads may be incorporated into flat surface to reduce the width-of-flat.

3-inch flat                  
4-inch flat                  
6-inch flat
US Std. 22 ga            
US Std. 20 ga            
US Std. 18 ga

b)                                                     The thickness shall be minimum 0.72 mm nominal thickness (TCT) up to maximum 0.85 mm TCT regardless of loading and span when sheets are fluted as required for loading and span.

METAL SHEET FINISHES

Finish of siding, roofing, trim, flashing and gutter shall be one of the following specified coatings, coil coated on the sheets metal prior to forming, and modified as necessary to comply with the requirements defined in section “Coating Test”.

Finish coating shall comprise of PVF2 Plus, a double-two layer polyvinylidene fluoride applied on primer for both exterior and interior surface on insulated or uninsulated roof and wall panels.

The “PVF2 Plus” acting as top coat, is a double coated “PVF2 Kynar 500”, a 80 % or 80/20 fluorocarbon (polyvinylidene fluoride) applied to the special steel substrate in accordance with the requirements of the metal siding and roofing fabricator but conform with the metal sheet requirement as stipulated on previous section.

Total dry film thikness of min. 46 microns composed of both an epoxy corrosion inhibitive premier and the top coat PVF2 plus Kynar 500.

The color of reverse side shall be light gray or standard manufacturer’s light gray. The final colour coat of steel cladding shall be submitted to the employer / owner for approval.

Acoustic Treatment
Where an acoustic treatment is required for insulated siding, or roofing, the interior sheet shall be fully perforated with 3.0 mm diameter holes and 5 mm triangle spacing that will provide NRC value of not less than 0.85 as specified in Clause mentioned before.

INSULATION

Where insulated siding & roof (external wall & electrical room) is indicated, the insulation shall conform to the following requirements:

Material: shall be fibrous glass, rock or slag with minimum density of 60 kg/m3.

The roof insulation shall be reinforced on down face with vinyl or aluminum foil. The thickness of vinyl shall not be less than 0. 0 1 mm and the thickness of aluminum shall not be less than 0.0025 mm.

The wall insulation shall be completely enclosed with 150-micron thick polyethylene protective cover.

Thickness of insulation: shall be a minimum of 3.75 cm if not otherwise stated.

FIRE HAZARD CLASSIFICATION RATING

The layer of insulation, including aluminum foil facing, shall meet the following Fire Hazard Classification Rating of Underwriter’s Laboratories, Inc:

Flame Spread            = 10- 15

Fuel Contributed                = 0 - 5

Smoke Developed               = 0

FIRE RATED EXTERIOR WALLS
The material shall be the same as insulated exterior metal siding with the addition of gypsum boards, the thickness and number of which shall be determined for a two-hour fire rating.

Panel thickness shall be 3.75 cm nominal overall.

Interior panel sheets shall be galvanized interior type sheets as refers to section ‘Metal Sheet Finishes’.

INSULATED INTERIOR WALLS

Panel thickness shall be 3.75 cm nominal overall.

Panel sheets shall be galvanized interior type sheets, prime coated similar the interior metal sheets in section ‘Metal Sheet Finishes’.

FLASHING

Exterior flashing: material, Pattern and finish shall be same as exterior sheet of siding and roofs with minimum thickness of 0.70 mm.
Interior flashing: material shall be galvanized Metal with thickness and finish same as interior sheet of insulated siding and roofs.

Flashing shall be provided wherever required but not limited to the following:

Corners, roofs, ridges, caps, etc.

Beam penetrations, wall or roof sleeves, duct openings and miscellaneous openings etc.

FASTENERS
Type of Fasteners
One of the following three types of screw Fasteners shall be used as indicated for the fastening of metal siding, roofs and interior walls:

Type A: Type A sheet metal screws are those having pointed ends and wide pitch threads. This type of screw is used for connecting gauge metal to gauge metal.
Type B: Type B self-tapping screws are those having flat ends and close pitch threads. This type of screw is used for connecting gauge metal to a structural member.
Type AB: Type AB self-tapping screws are those having pointed ends and close pitch threads.  This type of screw is used for connecting gauge metal to a structural member.

Material: Shall be type 305 or approved stainless steel with cadmium-plated finish and the heads painted to match colour of siding.

Size of Fasteners: No. 12 or larger.

Length of Fasteners

The length of type A screw shall be sufficient to engage gauge metal sheets together with a minimum projection of 1.0 cm beyond the sheet surface.

The length of the type B or type AB screws shall be such as to engage a sufficient thickness of supports to which they attached, to develop the full capacity of fasteners.

PARAPET CAP

Same as exterior flashing

CAULKING & SEALING TAPE

Manufacturer's standard
LAPS

Lap fines for siding shall line up all around the building.

End laps at walls and roofs shall be 15 cm minimum and 25 cm minimum respectively.

Side laps shall not be less than 1/2 rib.

Side and end raps in the exterior roof shall be sealed with mastic tape.
         
COATING FOR METAL SIDING AND ROOFS

Shall be organic coating and meet the detail requirement specified on Table in section ’Metal Sheets’.

RAINWATER GUTTERS AND ROOF SHEET METAL ITEMS

Rainwater Gutters and Supports shall comprised steel sheet plate and must be protected by beam hot dip galvanized with minimum weight of zinc coating of 0.250 kg/m².

The outlet surface shall complete with and applied protective colour finish same as exterior flashing to match the siding.

The lay out and sizing of gutters and roof drains shall be designed for the maximum anticipated rain fill intensity at the site, but not less than of 3 mm in 1 minute.

Each dewatering section shall be provided with at least 2 roof drains and 1 overflow pipe.

All sheet metal items shall be rigid, true to line and neat in appearance. They shall be designed and manufacture in such a way that both soldering work on site can be reduced to a minimum, and need and easy installation will be allowed.

Provision shall be need for separating sheet metal items from wood boards and / or concrete / plaster surface by mean of adequate roofing felt.

Longitudinal slope of gutter bottoms shall not be less than 0.5 %.

Box gutters shall be adequately supported and be designed to support rigidly the loads and below permanent flow of water.

Gutter outlets of diameter between 15cm to 20cm shall be provided for connection to rain water down pipes.

Basket strainers of non corrosive wire

Overflow pipes of 10 cm diameters and of lengths between 50cm and 80 cm shall be provided. The projecting part from the outer alignment of exterior walls and / or siding shall not be less than 25 cm. Overflow pipes to be routed through concrete and / or masonry parapet walls shall be wrapped by means of adequate roofing felt.

Provision shall be made for expansion joints in box gutters, wall flashings and cap strips etc. The expansion joints shall be adequate for the type of works specified. They shall not be spaced more than 10.00 m.

Flashings shall be provided where required to reach full water tightness. The thickness of steel shall not be less than 0.7 mm. Cap strips, if required shall have a girth comprised between 15 cm and 25 cm.

PENETRATIONS, WALL OR ROOF SLEEVES

Penetrations, sleeves, duct openings, etc, in siding, roofs, and interior walls shall be shown on Contractors drawings and shall be soundly designed for weather tightness.

LOUVERS

Louver shall comply with the requirement defined in the general technical specifications refers to sub section ‘Metal Sheets’ and ‘Metal Sheet Finishes’. The Material, fasteners and finishing shall be the same as the siding material defined in this general technical specification.

ERECTION

Erection shall be in strict accordance with manufacturers’ procedure for this type of work.  Care shall be taken to insure that Metal and aluminium are at all times separated such that a galvanic reaction cannot take place.


PROTECTION OF INSULATION DURING ERECTION

For all insulated constructions, satisfactorily protect all insulation from the weather during erection so as to eliminate soaking of insulation by water, or other moisture contaminants.

CLEANING OF SIDING, ROOFS AND INTERIOR WALLS

All exposed faces of siding, metal roofs and interior walls shall be cleaned of labels, dirt, streaks, caulking or sealing materials, undue discoloration etc. and as a minimum a dry wipe down shall be provided at the time of erection.

All exposed faces of siding, metal roofs and interior walls, prior to acceptance by Owner shall be completely satisfactory to the Owner in appearance.

REMEDY OF DEFECTS IN APPEARANCE

Defects in appearance shall include nicking, scratching, gouging, dimpling, denting, abrasions, and marring of any nature due to shipping, storing, handling, erection, weathering etc. and shall be remedied at Contractors expense as follows:

Touch up the baked enamel organic coating finish with one or more coats of the same coating material used for the original finish.  Thickness, appearance and colour of the touch-up shall match adjacent surfaces. If touch-up is not satisfactory to Owner, damaged sheets or accessories shall be replaced.

INSPECTION AND TESTING

The Contractor shall be responsible for all inspection and testing required by this specification unless otherwise specified. The Owner may during the course of the work, observe various phases of the work performed by Contractor, at the Contractors plant and at the site.

 

Coating Tests


General
The coating system of the external steel sheet for roof and wall has to meet the following performance criteria and test results and must be substantiated and certified by a recognized independent testing organization.

          Result of following tests shall be submitted to the Employer, proving the compliance with the following requirements.

Colour Change and Fade Resistance

A sample with a minimum of two raw-cut edges shall withstand a minimum of 60 days emmaqua weathering test exposure (exterior equatorial mount with mirrors and water spray) and/or 200.000 Langley’s of ultra violet radiation without cracking, peeling, blistering or loss of adhesion. Maximum colour change, including all exterior surface deposits such as dirt or chalk, shall not exceed 2 nbs units.

Abrasion – Resistance Test for Coating System

A flat specimen shall be subject to abrasion-resistance test. Test shall be conducted in accordance with ASTM D-968-51 (falling sand) which specifies that the end point shall be the first appearance of the base metal. Coating system shall resist abrasion to the extent indicated by the use of not less than 200 litters of sand to procedure a first appearance of base metal.

Coating System Integrity Test

A sample shall withstand a salt-fog test for a minimum of 1.000 hours in accordance with ASTM B – 117 – 64, including the scribe requirement in the test. Immediately upon removal of the specimen from the test, the coating system shall show no signs of cracking, peeling, blistering or loss of adhesion.

Pollution-Resistance Test

A flat specimen, with no protected edge, shall be subjected to the 30 cycles of Kesternich testing without blistering, peeling or any other of joss of adhesion. The Kesternich test consist of eight hours of exposures at 40 ºC.

With 100% relative humidity (condension) in a controlled sulphur dioxide (SO2), carbon dioxide (CO2) atmosphere. Atmospheric concentrations of pullutant gases shall be in accordance with Kesternich test standards DIN 50018. This is followed by 16 hours of dry time, which concludes one cycle of testing.

Humidity-Resistance Test

A sample shall be tested for 1000 hours at 100 deg F in accordance with ASTM D – 2247 – 68 with no blistering, peeling or loss adhesion.

Glare-Resistance Test

A flat sample shall be tested at 60 deg in accordance with ASTM D – 523 – 67. The rating shall fall in the 10 to 15 range.

Pencil Hardness (ASTM D3363) : Shall be F minimum

Weatherometer (ASTM G23) after 5000 hours exposure in sunshine Arc. Weatherometer or Atlas Twin Arc Weatherometer, no chalk in excess of No. 8 per ASTM D 659 and no colour fade more than 5 NBS units perSTM D2244, as operated under Dew Cycle conditions using 60/60 cycle.

Flexibility (ASTM D 1737) : Withstand 1T – 2T bends

Gloss (ASTM D 523) : 25-35 % reflectivity measured on 60 ºC gloss meter.

Impact : no removal of finish when tested as follows :

Using as sharp knife, make 6 or more parallel cuts at 1.5 mm intervals through finish to bare metal.

Cross hatch similarly.

Reserve impact to east 92 cm – kg or to point of metal rupture.

Apply Scotch cellophane tape firmly to scribe impacted are. Remove tape with sharp pull.

There shall be no loss of adhesion.

WATER TESTING

The completed roofing and siding installation shall be such that absolutely no water shall leak through. The Employer reserves the right to conduct water leakage tests on installed roofing and siding at any time during the installation.

Should any leakage be discovered during such leakage test. The roofing and/or siding shall disassemble to the extent directed by the Employer and joints shall be resealed with specified sealant or tape, and the roofing and/or siding reinstalled. Joints shall be sealed as directed by the Employer on all subsequent panels.

Warranty

The Contractor shall furnish the Owner, upon acceptance installation, a written warranty that fluorocarbon organic coating has been applied in accordance with licensee manufacturers process instructions and under normal conditions; and it shall meet the following standards for a minimum period of 10 years (the Contractor shall state the number of years warranty and also the number of times he will replace any defective panels without charges of any kind):

Will not chalk in excess of ASTM D659 No. 8 rating. Chalk rating shall be determined by the procedure outlined in ASTM D659.

Will not change colour more than 5 NBS units as determined in accordance with procedures set forth in ASTM D 2244, after removal of external deposits and chalk.

Will not crack, check or peel (lose adhesion).

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