a1-60 Stone Cladding

NPQS A1-60 Stone Cladding

National Productivity and Quality Specifications (NPQS)

A1-60 Stone Cladding

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NPQS A1-60 Stone Cladding

CONTENTS

Page

1. 1.1 1.2 1.3 1.4 1.5

GENERAL Scope Related Sections Standards Trade Preambles Abbreviations

3 3 3 3 5 7

2. 2.1

PERFORMANCE REQUIREMENTS Contractor’s Brief

8 8

3. 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12

MATERIALS AND COMPONENTS Types of Stone Cladding General Material Requirements Stone Aluminium Steel Fixings and Fasteners Brackets Cast-in Anchors Back up walls Joint Sealants Gaskets Joint Mortars

14 14 14 14 18 18 19 20 20 20 21 21 21

4. 4.1 4.2 4.3 4.4

WORKMANSHIP Stone Procurement Fabrication Installation Protection and Cleaning

22 22 23 25 27

5. 5.1 5.2 5.3 5.4 5.5

VERIFICATION AND SUBMISSION Submissions Warranty Quality Control Plan Submission Samples and Mock-ups Tests

29 29 31 31 31 32

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1.

GENERAL Read with the General Requirements section, and all other contract documents.

1.1

Scope This section covers the work requirements for mechanically fixed stone cladding onto both internal and external walls. The following types of stone are covered: a. Granite b. Limestone c. Sandstone d. Quartzite e. Marble

1.2

Related Sections Read this work section in conjunction with the relevant requirements of the other work sections as follows: A1-70

1.3

External Masonry

Standards Unless otherwise agreed by the SO, ensure all of the Works comply with the relevant requirements of the Standards and Codes listed below or referenced in the body of the Specification. Alternative Standards and Codes may be proposed for approval by the SO, provided it can be demonstrated that the alternative Standards and Codes comply with the requirements of the standards specified. All Standards and Codes quoted are the current version, unless specific year references are noted. Singapore Standards SS CP 33

Lightning protection

Other Standards BS 6496

Specification for powder organic coatings for application to aluminium

BS 4842

Specification for liquid organic coatings for application to aluminium alloy extrusions, sheet and preformed sections for external architectural purposes, and for the finish on aluminium alloy extrusions, sheet and preformed sections coated with liquid organic coatings.

BS 6497

Specification for powder organic coatings for application and stoving to hot-dip galvanised hot-rolled steel sections and preformed steel sheet for windows and associated external architectural purposes, and for the finish on galvanised steel sections and preformed sheet coated with powder organic coatings.

BS 5250

Condensation prediction

BS 8298

Code of practice for design and installation of natural stone

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cladding and lining BS1474,

Aluminium and aluminium alloys .Extruded rod/bar,tube and profilel

BS EN 573-3

Aluminium and aluminium alloysChemical composition and form of wrought products. Chemical composition

BS 1161

Aluminium and aluminium alloys for structural purposes.

BS EN 1925

Natural stone test methods – Determination of water absorption coefficient by capillary

BS EN 1926

Natural stone test methods – Determination of compressive strengths

BS EN 1936

Natural stone test methods – Determination of real density and apparent density and of total porosity and open porosity

BS EN 12372

Natural stone test methods – Determination of flexural strength under concentrated load

BS EN 12407

Natural stone test methods – Petrographic examination

BS EN 12440

Natural stone test methods – Denomination criteria

ASTM C97

Test method for absorption and bulk specific gravity of dimension stone

ASTM C99

Test method for modulus of rupture of dimension

ASTM C170

Test method for compressive strength of dimension stone

ASTM C503

Specification for marble dimension stone (exterior)

ASTM C568

Specification for limestone dimension stone

ASTM C615

Specification for granite dimension stone

ASTM C616

Specification for quartz based dimension stone

ASTM C1242

Guide to design, selection, and installation of exterior dimension stone anchors and anchoring

ASTM C1354

Test method for strength of individual anchorages in dimension stone

CP 3012

Code of practice for cleaning and preparation of metal surfaces

BS EN 12373

Aluminium and aluminium alloys -Anodizing. Method for specifying decorative and protective anodic oxidation coatings on aluminium

BS EN 14713

Protection against corrosion of iron and steel in structures-zinc and aluminium coatings-guidelines.

ASTM D1400

Standard test method for non-destructive measurement of dry film thickness of non-conductive coatings applied to a nonferrous metal base

ASTM D714

Test method for evaluating degree of blistering of paints

ASTM D2244

Method for instrumental evaluation of colour differences of opaque materials

ASTM D2247

Method for testing coated metal specimens at 100% relative

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humidity ASTM D3363

1.4

Test method for film hardness by pencil

Trade Preambles 1.4.1

Contractor’s Proposals and Submissions

The design intent including type and locations of stone claddings for the project are indicated in the drawings and schedules. Base on the information supplied, engage qualified and experienced personnel to carry out and submit the following items for the SO’s acceptance: a. Develop all necessary details for the fabrication and installation of the stone cladding system(s), and to meet with the performance requirements as set out in clause 2.1 below. Details to develop may include shape and sizing of components, structural support, accessories, joints, waterproofing and connections to the building etc. b. Propose quarry site/supplier c. Propose method of fabrication, erection/installation d. Propose details of weather/waterproofing.

1.4.2

Shop Drawings

Produce shop drawings to enable the fabrication and installation of the cladding system. 1.4.3

Co-ordination with Other Works

Co-ordinate the stone cladding works particularly with the following trades: a. Structural frame b. External windows

1.4.4

Provide Spare Materials

Deliver to site in strong protective packages marked for identification, and store where directed, components and materials for future replacement and repair. Refer to PSD for list. 1.4.5

Submission to Authorities

Engage a PE (Structural) to carry out the design of the structural supports for the cladding system and submit for BCA approval as a QP for this design. 1.4.6

Warranty

Provide a ten-year warranty in accordance with contract conditions for the entire cladding system including all components and accessories for the specified performance.

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1.4.7

Maintenance Manual

Refer to the PSD for any requirement to provide a maintenance manual. 1.4.8

Quality Control Plan

Refer to the PSD for any requirement to provide a quality control plan.

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1.5

Abbreviations a.

AS

Australian Standard

b.

ASHRAE

American Society of Heating, Refrigerating and Airconditioning Engineers

c.

ASTM

American Society for Testing and Materials

d.

B(C)R

e.

BMS

Building Management System

f.

BMU

Building Maintenance Unit (Also known as Gondola system, Façade Maintenance Unit)

g.

BRE

Building Research Establishment

h.

BS

British Standard

i.

CWCT

Centre for window and cladding technology

j.

EPDM

Ethylene propylene diene monomer.

k.

IGU

Insulating glazing unit (Also known as a double glazing unit)

l.

PVF2

Wet applied heat cured polyvinylidene fluoropolymer coating

m.

SAA

Standards Association of Australia

n.

SA

Standards Australia

o.

SHGC

Solar Heat Gain Coefficient

p.

SS

Singapore Standard

q.

STL

Sound Transmission Loss value.

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2.

PERFORMANCE REQUIREMENTS

2.1

Contractor’s Brief When carrying out the proposals as set out in clause 1.4.1, take account of the following requirements: The performance requirements apply to the complete wall assembly consisting of panels, support frames and backing walls. 2.1.1

Resistance to Loading

2.1.1.1

Loading General

Withstand loading from inside and outside the building determined in accordance with CP3 using a basic wind speed v = 35 m/s and terrain category suitable for the site. Transmit all the design loads to the building structure via the points of attachment as designed with an adequate margin of safety appropriate to each material and product. 2.1.1.2

Gravity Loading

Support the Work’s self weight and transmit this weight safely back to the supporting structure without overstressing or permanently deforming any components 2.1.1.3

Wind Loading

Support the design dynamic pressure and transmit these loads safely back to the supporting structure without overstressing or permanently deforming any of components. Account shall be taken of all applicable local pressure coefficients. Sustain no permanent damage to framing members when tested at both positive and negative applications of the design wind loads multiplied by a factor of 1.5. Framing members shall not be buckled. Stone panels, decorative capping pieces shall remain securely held and gaskets shall not be displaced. Permanent deformation to framing members shall not exceed 1/500 of the span measured between points of attachment to the structure after loading. 2.1.1.4

Impact Loading

Satisfy the requirements of Tables 3 and 4 of BS 8200 "Design of non-load bearing vertical enclosures" for category B in table 2 up to 1.5m above ground level where the cladding is exposed to impact and Category F elsewhere described in table 2 of BS 8200. 2.1.1.5

Maintenance Loading

Sustain and safely transmit a static load of 500 N applied horizontally through a square of 100 mm side on any stone or its framing in vertical or near vertical wall. 2.1.1.6

Barrier Loading

Sustain and safely transmit each of the following static horizontal loads acting separately: a. 0.75 kN/m for all occupied spaces acting in all directions at a height of 1.0 m above finished floor level b. A uniformly distributed load of 1.0 kN/m² and a point load of 0.5kN acting on any part, up to and including 1.0 m above finished floor level.

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Sustain and safely transmit crowd loading if requirement confirmed by the SO. 2.1.1.7

Loading from Temporary Conditions

Sustain and safely transmit any temporary loading that may arise from lifting, storing, transporting, hoisting and installing of stone cladding or other Works that may affect the stone cladding. 2.1.1.8

Combinations of Loading

Sustain and safely transmit combinations of loads determined in accordance with the procedures set out in BCR. 2.1.2

Structural Design

2.1.2.1

Design Codes

Design stone cladding and its fixings in accordance with the following codes and standards: a. BS 8298 Code of practice for design and installation of natural stone cladding and lining. b. BS 5950 Structural use of Steelwork in buildings Undertake the design to achieve the performance requirements with appropriate factors of safety as required in this specification for the materials and components used. Submit calculations to the SO for review. Submit calculations endorsed by a PE for onward statutory submission. 2.1.2.2

Fixing, Anchor and Bracket Design

Take account of any reduction in safe working loads in fixings due to their spacing, location in areas of tension, near edges or proximity to cast in inserts/existing fixings, or thickness of shims. Design anchors and their connection to the building structure in order to resist loading. Take account of structural and stone tolerances to determine loading and eccentricity 2.1.2.3

Cast-in Anchor Design

Design cast-in anchors and their connection to the building structure in order to resist loading. Take account of tolerances in structure, sub-frame and stone cladding to determine loading and eccentricity. Provide calculations verifying that cast in inserts will resist the loading as follows: a. No permanent deformation of the insert at 1.5 times design load. b. No failure of the insert at 2 times the designed load. c. No failure of structural concrete at 3 times the design working load. Identify locations of cast in anchors and pass this information to the concrete contractor for incorporation in structure. 2.1.2.4

Components Subject to the Full Wind Load

Design the air seal and all components external to this to resist the full cladding design pressure.

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2.1.2.5

Vibration and Repetitive Loading

Design the fixing systems so that the stone cladding does not work loose due to the effects of vibrations, or cyclic effects of load, deflections and thermal expansion on anchors and fixing systems. 2.1.2.6

Locked in Stresses

Avoid the introduction of locked-in stresses that may be detrimental to the performance of the stone cladding. Fixings must allow for thermal expansion of stone. 2.1.3

Resistance to Climatic and Environmental Conditions

2.1.3.1

Avoidance of Algae Growth

Where applicable, agree suitable measures with the SO for protecting against algae growth on the surface of the stone. Sealants must be tested on sample panels and approved by the SO. 2.1.3.2

Thermal Stress

Resist cracking to stone, glass, and ceramic materials caused by thermal stress. 2.1.3.3

Condensation Performance

Resist the formation of condensation on visible surfaces, interstices or locations where it is unable to drain. 2.1.3.4

Resistance to Acid Rain

Obtain local pollution data and rainfall data. Design stone cladding to maintain integrity and appearance for the design life of the building. Advise any coatings, maintenance and cleaning treatments necessary. 2.1.3.5

Design for Thermal and Condensation Performance

Use insulation of appropriate performance to provide adequate level of performance without localised cold bridging where insulation must be locally reduced in thickness such as anchor positions. Use vapour barriers as necessary to eliminate condensation around the cladding. Assess the heat transferred through stone cladding by 2-dimensional numerical analysis. Use software validated against benchmarks. Summarise the results of the assessment as thermal transmittance (U-values) for the central and perimeter zone of each relevant cladding type. Calculate overall U values for each relevant cladding type as a weighted average of constituent areas, with the weighting method defined. Take into account the internal and external surface heat transfer resistances. Quote these resistances and the parameters that affect them. Take into account the effects of any air spaces, porous materials, and the thermal interaction between elements of the facade.

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2.1.3.6

Climatic Data

Assume: Ambient temperature range

16°C to 40°C

Radiant temperature range

16°C to 80°C

Relative humidity range

90%±10%

Environment

Coastal

Gather any additional climatic data required from the Singapore Meteorological Observatory. Submit for review to the SO any additional assumptions concerning temperatures, humidity levels, etc. 2.1.4

Building Movements and Structural Tolerance

2.1.4.1

Structural Movement and Movement Between Works by Others

Accommodate the following movements in combination; without any reduction in the specified performance, refer to the SO for further guidance and data for calculation input: a. Deflections and movements of the structure and building wall under design loads. b. Changes in dimension and shape of building elements arising from building movements, including settlement, shrinkage, elastic shortening, floor beam deflections, creep, wind sway, twisting and racking and thermal and moisture movement. c. Changes due to movement of any joint in the supporting structure or building frame. d. Deflection of framing members under design dead loads and live loads. Incorporate these calculations in the design. e. Thermal and moisture induced movements of the stone cladding. Incorporate these in the design based on maximum range of temperature and humidity. Propose nominal, minimum and maximum joint widths accounting for tolerances and movements for the SO’s acceptance. Refer to PSD for design movements and deflections to account for. 2.1.4.2

Structural Tolerances

Accommodate construction tolerances on structure and back up walls as indicated in the PSD. 2.1.5

Fire and Smoke Performance

2.1.5.1

Non-combustible Materials

Do not include materials that readily support combustion or add significantly to the fire load or give off toxic fumes.

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2.1.5.2

Fire and Smoke Stopping

The complete perimeter wall construction shall prevent the passage of smoke from floor to floor in accordance with the requirements of Building Control Regulations and BS 476: Parts 20-24. 2.1.5.3

Smoke Vents

Refer to clause 3.1 for the need to include Smoke vents. 2.1.6

Acoustic Performance

Achieve the following STL values against noise break-in: Frequency (Hz) 125 250 500 1000 2000 4000 STL (dB) 25 27 32 33 30 26 Achieve resistance to flanking and floor to floor sound transmission of STC40 unless indicated otherwise in clause 3.1. 2.1.7

Functionality

2.1.7.1

Appearance

Agree Range Samples with the SO as described. Supply stone to meet the visual requirement identified in the Range Samples Achieve the mandatory geometry and presented in the Architect’s drawings. Achieve colours and appearances presented in the Architect’s drawings. Use “non-rusting” granites (i.e. granites that do not develop rust spots or patches). 2.1.7.2

Maintenance and Replacement

Design stone cladding and its fixings to permit removal and replacement of individual assemblies without affecting adjacent assemblies or supporting framework. The method of installing panels must make clear where fixing methods are revised for closing elements. 2.1.7.3

Drainage

Drain rain water predominantly at the outer surface. Provide passage for any rainwater entering the cavity to allow it to drain to the outside without being impeded by fixings, flashings etc. Design fixings and flashings to shed water outwards. Do not concentrate points of re-emergence that may cause localised staining or surcharging. Eliminate possible areas of prolonged wetting that may cause staining. 2.1.7.4

Infestation

Resist attack or infestation by micro organisms, fungi, insects, reptiles, birds or bats and rodents. Have no openings in the stone cladding that permit entry of insects, reptiles, birds or bats and rodents. 2.1.8

Lightning Protection

Design the cladding system as a whole to electrically continuous to earth. 12 Version 1.0

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Meet or exceed the requirements of CP SS 33. Where necessary, co-ordinate between the stone cladding and the main lightning protection systems for the building and shall propose appropriate connection points. No external tapes will be accepted. 2.1.9

Brackets and Fixings

Carry out the design of all fixings supporting and/or restraining to the stone cladding. Provide details with supporting calculations of the design for every type of fixing together with the loading on those fixings, proving compliance with the requirements. Take note that brackets and anchors may be required to penetrate waterproof membranes, renders etc. 2.1.10

Design for Durability

2.1.10.1

Do not use carbon steel in locations subject to wetting or condensation or where this will result in corrosion; shortening their design life or compromising safety, however long-term; or, causing rust staining; or, establishing a bimetallic cell with other metals or carbon.

2.1.10.2

Identify materials and components which under normal service conditions cannot meet the specified design life and design to allow their monitoring and replacement

2.1.10.3

Identify any recommendations for spare materials.

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3.

MATERIALS AND COMPONENTS

3.1

Types of Stone Cladding Refer to the PSD for the types of cladding and component requirement for this project.

3.2

General Material Requirements 3.2.1

Volatiles in Materials and Components

All materials and components shall be free from volatile components that may migrate with time, or evaporate and re-condense onto other components. 3.2.2

Compatibility

Materials shall be selected, designed and installed to prevent bimetallic corrosion. All materials shall be compatible with the other materials around it within its range of influence for the service life of the stone cladding. 3.3

Stone 3.3.1

General

Stone shall be: a. Natural stone that is compact and hard. b. Free of any inherent characteristic that was not brought to the attention of the SO at the time of agreeing the visual Range Samples. c. Not exhibit any textural variation or rift that will cause excessive differential weathering or cracks to develop. d. Of sound quality, free from defects (e.g. rusting, cracks, voids, fissures, inclusions of deleterious or foreign matter) liable to affect the physical properties, durability or appearance, other than those agreed as acceptable by the SO. Guideline requirements for different types of stone are given below. Take cognisance that the actual requirement is dependent on panel design and be satisfied that the stone cladding design (i.e. panel size, thickness, fixing arrangement) is appropriate given the anticipated wind loading and strength of the proposed stone. 3.3.2

Granite

Granite shall satisfy the technical requirements given below: (Min. Unless Stated) Density Absorption (max) Compressive Strength Flexural Strength

Requirement 2560 kg/m3 0.4 % 131 MPa

Test Method ASTM C97 ASTM C97 ASTM C170

Notes

*8.27

ASTM C880

* Dependent on panel design

MPa

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3.3.3

Limestone

Technical requirements for limestones to be used as external cladding shall satisfy the technical requirements set out below: 3.3.3.1

Low-Density Limestone

(Min. Unless Stated) Density Absorption (max) Porosity Saturation Coefficient (max) Microporosity

Compressive Strength Flexural Strength 3.3.3.2

Test Method

1760 12

kg/m3 %

ASTM C97 ASTM C97

N.A. 0.85

%

BRE 141 BRE 141

When combined with saturation coefficient as per BRE Report A112, produces value below 115 12 MPa

BRE Method

*

ASTM C880

MPa

Notes

Only for Portland Stone

ASTM C170

Medium-Density Limestone for External Cladding

(Min. Unless Stated) Density Absorption (max) Porosity Saturation Coefficient (max) Microporosity

Compressive Strength Flexural Strength 3.3.3.3

Requirement

Requirement

Test Method

2160 7.5

kg/m3 %

ASTM C97 ASTM C97

N.A. 0.85

%

BRE 141 BRE 141

When combined with saturation coefficient as per BRE Report A112, produces value below 115 28 MPa

ASTM C170

*

ASTM C880

MPa

BRE Method

Notes

Only for Portland Stone

High-Density Limestone for External Cladding

(Min. Unless Stated) Density Absorption (max) Porosity

Requirement

Test Method

2560 3

kg/m3 %

ASTM C97 ASTM C97

N.A.

%

BRE 141

Notes

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Saturation Coefficient (max) Microporosity

Compressive Strength Flexural Strength 3.3.4

0.85

BRE 141

When combined with saturation coefficient as per BRE Report A112, produces value below 115 55 MPa

BRE Method

*

ASTM C880

MPa

Only for Portland Stone

ASTM C170

Sandstone

Technical requirements for Sandstones to be used as external cladding shall satisfy the technical requirements set out below. 3.3.4.1

Sandstone (Contains a Minimum of 60% Free Silica)

(Min. Unless Stated) Density Absorption (max) Porosity Acid Resistance Compressive Strength Flexural Strength 3.3.4.2

Test Method

2003 8

kg/m3 %

ASTM C97 ASTM C97

N.A. pass

%

BRE 141 BRE 141

14

MPa

ASTM C170

*2.5

MPa

ASTM C880

Notes

No weight loss allowed

Quartzitic Sandstone (Contains a Minimum of 90% Free Silica)

(Min. Unless Stated) Density Absorption (max) Porosity Acid Resistance Compressive Strength Flexural Strength 3.3.4.3

Requirement

Requirement

Test Method

2400 3

kg/m3 %

ASTM C97 ASTM C97

N.A. pass

%

BRE 141 BRE 141

70

MPa

ASTM C170

*2.8

MPa

ASTM C880

Notes

No weight loss allowed

Quartzite (Contains a Minimum of 95% Free Silica)

(Min. Unless Stated) Density

Requirement 2560

Test Method kg/m3

Notes

ASTM C97

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Absorption (max) Porosity Acid Resistance Compressive Strength Flexural Strength

3.3.5

1

%

ASTM C97

N.A. pass

%

BRE 141 BRE 141

140

MPa

ASTM C170

*5.5

MPa

ASTM C880

No weight loss allowed

Marble

Technical requirements for Marble to be used as external cladding as follows: 3.3.5.1

Calcite Marble

(Min. Unless Stated) Density Absorption (max) Compressive Strength Flexural Strength 3.3.5.2

Requirement 2595 kg/m3 0.20 % 52 MPa *7 MPa

Notes

Dolomite Marble

(Min. Unless Stated) Density Absorption (max) Compressive Strength Flexural Strength 3.3.5.3

Test Method ASTM C97 ASTM C97 ASTM C170 ASTM C880

Requirement 2800 kg/m3 0.20 % 52 MPa *7 MPa

Test Method ASTM C97 ASTM C97 ASTM C170 ASTM C880

Notes

Serpentine Marble

(Min. Unless Stated) Density Absorption (max) Compressive Strength Flexural Strength

Requirement 2690 kg/m3 0.20 % 52 MPa

Test Method ASTM C97 ASTM C97 ASTM C170

*7

ASTM C880

MPa

Notes

Travertine (Min. Unless Stated) Density Absorption (max) Compressive Strength Flexural Strength

Requirement 2305 kg/m3 0.20 % 52 MPa

Test Method ASTM C97 ASTM C97 ASTM C170

*7

ASTM C880

MPa

Notes

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3.4

Aluminium 3.4.1

Extrusions

Designation 6063, temper T6 of BS 1474 unless otherwise agreed with the SO. Comply with BS EN 486, BS EN 573-3 and BS 1161. Minimum wall thickness in structural parts of 2.5mm. Platforms, webs, flanges, races and screw flutes of sufficient size to satisfy all structural requirements and eliminate distortion of elements in the works. 3.4.2

Sheet, Strip and Plate

Not less than 1.6mm thick for hidden flashings Not less than 3mm thick for components exposed to view or to impact Isolate all components in direct contact with, but not totally encased in, cementitious surfaces with thin dense PVC or EPDM isolation packs. The use of bituminous paint shall not be accepted. 3.4.3

Aluminium Finishes

Concealed aluminium in wetted areas to be anodised. Applicator is to be approved by the coating manufacturer. Apply PVF2 coating to exposed aluminium in accordance with the coating manufacturer’s instructions. Coating shall be supplied by a single applicator PVF2 coating shall (be / have) a. Dense and consistent b. Minimum cured coating thickness 25 microns. c. Fully cured d. No seeding e. Free from flow lines, streaks, pin holes, blisters, ‘orange peel’, tears, damage, contamination, inclusions and other defects and surface imperfections when viewed from a distance of 1meter under normal diffused daylight. f.

Neither be significantly thicker or thinner than adjacent areas nor be split at changes of angle.

g. No exposed areas of uncoated metal.

3.5

Steel 3.5.1

Stainless Steel Components

Stainless steel components shall be austenitic, complying with BS EN 10088 grades: a. X2CrNi18-10 (formerly 304 S11) for concealed locations only b. X8CrNi18-9 (formerly 304 S31) for concealed locations only c. X2CrNiMo17-12-2 (formerly 316 S11) for exposed locations only 18 Version 1.0

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d. X2CrNiMo17-12-2 (formerly 316 S13) for exposed locations only

3.5.2

Carbon Steel Components

Refer to structural steelwork specifications for requirements relating to secondary steel framing. The use of carbon steel shall only be permitted where the component is readily accessible for regular inspection and maintenance. Where used, it shall be one of the following: a. Hot rolled steel complying with the requirements of BS EN 10025. b. Hot rolled sections to BS 4: Part 1, BS EN 10210-2 and BS EN 10021-1, tubes to BS 6323: Parts 1, 2 & 3 and angles to BS 4848: Part 4. c. Cold formed pre-galvanised steel sections to BS EN 10142, BS EN 10143, BS EN 10147 d. Steel sheet to BS 1449: Part 1.

3.5.3

Steelwork Corrosion Protection

For general requirements refer to structural specifications. 3.5.3.1

Hot Dip Galvanising

Hot dip galvanise all carbon steel components after forming and drilling in accordance with BS EN 1461 for items less than 5mm thick and BS EN 14713 for items more than 5mm thick. Isolate all galvanised steel components in direct contact with, but not totally encased in, cementitious surfaces with thin dense PVC or EPDM isolation packs. The use of bituminous paint shall not be accepted. 3.5.3.2

Paint Finishes

Refer to structural specifications. Colours and gloss levels of any exposed items to the SO’s direction. Finished surfaces shall be: a. Dense and consistent b. Free from flow lines, streaks, pin holes, blisters, tears, lumps and other coating defects or surface imperfections when viewed from a distance of 1 metre under normal diffused daylight.

3.6

Fixings and Fasteners 3.6.1

Wet areas

Use stainless steel fixings and fasteners with stainless steel and aluminium, or with non-metallic components wherever wetting may occur. Stainless steel fasteners may have hardened tips of other composition for self-drill and self-tap screws only. a. grade A4 to BS 6105 where visible

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b. may be reduced to grade A2 to BS 6105 where not visible

3.6.2

Other areas

Use carbon steel bolts with carbon steel components a. Ordinary bolts and nuts to BS EN 24032, BS EN 24033, BS EN 24034. All plain and tapered washers to BS 4320, Form E. b. Nuts to BS 4190 for grade 8.8. c. The use of zinc plating to BS 1706 – Fe/Zn 8 is acceptable where serrated fixings are used.

3.7

Brackets Use stainless steel or aluminium brackets and stainless steel fixings wherever wetting may occur (including condensation) Brackets shall (have / be): a. Resist all loads, movements and dimensional changes that may occur in the building due to thermal changes, deflections, settlement and creep. b. Resist all loads, movements and dimensional changes that may occur to the stone cladding. c. Allow for construction tolerance in the all components and structure. d. Adjust by small increments in and out, up and down and side to side e. Use lock nuts to prevent loosening due to movements and/or vibrations. f.

State the torque values for tightening all bolts on the Contractor's drawings

g. State the maximum allowable shim dimension on the Contractor's drawings and verify the capacity of the bolt by calculation for this case. Shimming shall not be greater than 10mm. h. Shims shall be of the same metal as the bracket

3.8

Cast-in Anchors Use cast in anchors unless otherwise agreed with the SO. Post-fixed anchors will not normally be accepted.

3.9

Back up walls Back up walls may be in situ concrete blockwork, brickwork, steel stud and panelling. The backing wall shall withstand the full design wind pressure. Do not attach framing members, rails or fixings to non-structural back up walls unless the wall has been designed to carry these loads. Compartment the cavity between stone cladding and back up wall Design and install back up wall to achieve airflow not more than 1.5 cu m/hr/m² at 600 Pa. There shall be no region of concentrated airflow through the background wall or at any interfaces.

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Ensure that all flashings, fixings and other items within cavities shed water outwards. The wall shall incorporate appropriate water barrier appropriate to resist and control the expected water passing the cladding. Water barriers may include as a single layer or in combination render, membranes, water resistant coatings, etc. 3.10

Joint Sealants Use non-staining joint sealants Provide Trade literature on the proposed sealant and primer at Tender stage Use the proposed sealant in visual mock up Select and install sealants in accordance with BS 6213. Use in accordance with the manufacturer’s directions, particularly relating to the use of primers. Reject all sealant beyond its ‘best before’ date as identified by the manufacturer on the packaging Sealants shall (be / have): a. Non-gassing polyethylene closed cell foam backing rods b. Primers and joint preparation materials as recommended by the sealant manufacturer. c. Silicone sealants shall comply with BS 5889. Refer colour selection of any visibly exposed sealants to the SO.

3.11

Gaskets All gaskets shall (be / have): a. Extruded EPDM complying with the provisions of BS 4255. b. Cellular profiled gaskets shall comply with ASTM C509.

3.12

Joint Mortars Use mortar in accordance with section 2.4 of BS 8298.

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4.

WORKMANSHIP

4.1

Stone Procurement 4.1.1

Sourcing

Source each type of stone from a single quarry possessing sufficient reserves under development or available from stock to meet the project requirements. Before ordering the chosen stone secure an agreement in writing with the quarry owner which will commit to produce the chosen stone in the quantity and quality required by the contract documents at the times required by the programme of the cladding, and that this agreement can be continued in favour of the project client in the event of default by the contractor. 4.1.2

Range Samples and Quarry Visit

4.1.2.1

Range Samples

Unless otherwise agreed arrange for: a. 12 number slabs of each stone type at the thickness proposed for the cladding, to be cut from four randomly selected blocks taken from current workings at the quarry. That is, 1 number sample each to be taken from each of the 2 outermost usable slabs of the block, and 1 number sample to be taken from the centre of the block. b. The 12 number slabs to have the specified finish applied and shall be set up in the quarry with a neutral background and orientated facing east or west to enable viewing in shadow or sunlight. c. Each slab to be identifiable by a block number and slab number. d. Visit the quarry with the SO, to view the 12 finished slabs and agree an acceptable range of colour, veining, blemishes and other relevant visual criteria with the contractor. Features considered unacceptable shall be clearly marked on the slabs by the SO. At the same time all parties shall agree the steps that shall be taken to ensure the correct tonal distribution of stones in the cladding. e. Sign off, with the SO, at the rear surfaces of each accepted range sample. f.

Cut Range Samples 1000 mm x 450 mm from the accepted slabs. Six range samples shall be cut and shall be divided into two sets of three. Each set of three shall illustrate the agreed range. Set up one set of three in the fabrication yard and one set upon site to the SO’s acceptance. Set up the slabs marked with unacceptable features in the contractors' yard or as directed.

Use these range samples as the reference to control the visual quality of the stones processed during the fabrication and installation of the cladding. Stones outside the identified range will be deemed unacceptable unless authorised otherwise by the SO. 4.1.3

Quarrying

Immediately notify the SO of any variations outside the agreed range. a. Cut all stone from a designated part of the quarry that exhibits consistent mechanical properties.

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b. Undertake the extraction of the stone by experienced and competent quarrymen and using only those techniques and practices which will not impair the performance of the finished product. c. Cut blocks so that their orientation is in sympathy with any natural bedding plane or rift in the stone. Prepare slabs so that the natural bedding planes or rifts are arranged to provide the best possible weathering performance. d. Give individual blocks a unique reference number/block number at the quarry indicating the location from which they were removed from the quarry face. Keep a record of the date on which individual blocks were numbered. e. Should the character of the stone change during the progress of extraction from the quarry, immediately inform the SO, so that an alternative location of working can be agreed. Do not obtain stone from another quarry or another part of the quarry without the prior agreement of the SO. In the case of stone that requires "seasoning" ensure that sufficient time has been allowed under suitable storage conditions for the stone to achieve maximum strength and durability. 4.2

Fabrication 4.2.1

Submissions

4.2.1.1

Submit method statements describing how it is proposed to select, fabricate and install the Works to the SO for review.

4.2.1.2

Provide calculations to demonstrate that the dimensions of stone as specified and as shown on the Contract Documents will provide adequate strength to maintain the structural integrity of the individual elements and units at all stages during production, fabrication and erection.

4.2.1.3

Make known to the SO at the time of proposal if the prescribed size is not suitable.

4.2.1.4

Where a thickness is proposed less than that given in table 4 of BS 8298, prove that the proposed thickness is suitable by means of structural calculation in accordance with BRE IP 7/98.

4.2.1.5

Refer to clause 5.4.1 for prototypes and demonstrations of fabrication.

4.2.1.6

Following review of samples, prototypes and demonstrations all subsequent materials and workmanship are to be the same or better standard.

4.2.2

General Requirements

a. Use personnel skilled in the trade, with modern, well maintained equipment to carry out all cutting finishing and edge labours. Use the correct tools for each task and equipment that is well maintained. Do not use blunt and worn tools. b. Use experienced operatives skilled in using the techniques involved. c. Maintain all equipment, to be fit for its intended purpose and capable of achieving the tolerances prescribed. d. Carry out grinding, cutting, shaping and finishing materials using tools, techniques and ancillary materials that will not contaminate stone cladding or curtain wall components with particles or substances, which could disfigure, stain or corrode them. 23 Version 1.0

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e. Form stones to the required shapes without flaws and defects. f.

Ensure stone is not subjected to excessive heat generated by any grinding, shaping, drilling or polishing processes.

g. Use suitable lubricants where appropriate to dissipate or reduce the heat generated, and not cause staining. h. Do not use percussive tools to undertake drilling. i.

Use only diamond or tungsten tipped bits, together with appropriate cooling methods and drill speeds.

j.

Carry out all drilling in the factory using jigs.

k. Clean exposed surfaces and edges leaving them free of rust stains, iron particles and cutting fluids. l.

Select methods used for installation that will achieve the specified performance.

m. Use jigs laser lines, and computer controlled methods wherever appropriate to achieve accuracy.

4.2.3

Stone Tolerances

4.2.3.1

Manufacture individual stone elements to achieve the tolerances described below, not those given in Section 4 of BS8298.

a. Length

± 1.0mm

b. Width

± 1.0mm

c. Thickness

± 1.0mm

d. Bow or Twist Should not vary by more than ± 1.5mm in 1200mm e. Squareness The length of the diagonals should not vary by more than ± 2.0mm 4.2.3.2

In addition, holes for studs and fixings:

a. Position: ± 2.0 mm from specified position b. Depth: ± 2.0 mm c. Diameter: ± 2.0 mm d. Angle: ± 0.5 from designated angle

4.2.4

Cracks and Fissures

Inspect all stones, particularly at fixing positions. Notify the SO of all minute cracks or natural fissures at vulnerable places and seek his approval. 4.2.5

Repairs

Replace all damaged stonework with new stone. Do not carry out on-site or off-site repair of damaged stonework without the prior written agreement from the SO.

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4.3

Installation 4.3.1

Submissions

Submit method statements describing how it is proposed to install the Works to the SO for review. 4.3.2

Methods

a. Select methods used for fabrication that will achieve the specified performance. b. Use jigs and computer controlled tools wherever appropriate to achieve accuracy. c. Use the correct tools for each task and equipment that is well maintained. Do not use blunt and worn tools. d. Carry out grinding, cutting, shaping and finishing materials using tools, techniques and ancillary materials that will not contaminate windows components with particles or substances which could disfigure, stain or corrode them. e. Use experienced operatives skilled in using the techniques involved. f.

Undertake the assembly of components under factory controlled conditions

4.3.3

Marking

Mark components and materials clearly wherever this is required in order to: a. identify strong points for lifting, b. permit assembly or installation in a particular sequence; or where: a. interlocks occur; b. confusion could foreseeably arise between upper and lower faces, left and right handed pieces, top and bottom, c. lengths close but critically different from one another. Mark in such a way as not to affect the performance of the Works with removable or marks that will be concealed when installed. 4.3.4

Site survey

Before the installation of the Cladding: a. Undertake a survey of the preceding elements of work including the details of points of attachments for the primary brackets where appropriate. Carry this out as soon as possible. Submit the results to the SO without delay. b. Advise the SO of tolerances that exceed those allowed for at the time of Proposal. Inform the SO of any preceding elements of work including any prepared fixing points to be outside the stipulated tolerances, Agree the remedial action to be taken, allowing sufficient time for rectification, so as not to delay the construction programme.

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4.3.5

Brackets

Use stainless steel or aluminium brackets and stainless steel fixings wherever wetting may occur (including condensation) Brackets shall: a. Resist all loads, movements and dimensional changes that may occur in the building due to thermal changes, deflections, settlement and creep. b. Resist all loads, movements and dimensional changes that may occur to the stone cladding. c. Allow for construction tolerance in the all components and structure. d. Adjust by small increments in and out, up and down and side to side Use lock nuts to prevent loosening due to movements and/or vibrations. State the torque values for tightening all bolts on the submission drawings State the maximum allowable shim dimension on the submission drawings. This shall not be greater than 10mm. 4.3.6

Cast-in anchors

Use cast in anchors unless otherwise agreed with the SO. Postfixed anchors will not normally be accepted. Anchors to be hot dipped galvanised after fabrication to give coating of 50-70 microns or of stainless steel grade A4 to Bs 1449 Part 2. 4.3.7

Tolerances

4.3.7.1

Building Frame Tolerances

a. Review the available documents to establish the anticipated tolerances for the building frame. b. Allow for the anticipated tolerances in the design of fixings and components such that the completed Cladding are always within the tolerances specified. Advise the SO at the time of proposal. c. Obtain any further tolerance information required taking into account all criteria relevant to the design and construction of the stone cladding. 4.3.7.2

Accuracy of Erection for Stone Elements

Erect the Cladding to the more onerous of the following permitted deviations: a. Line:

± 2 mm in any one storey height, or structural bay width.

b. Level:

± 2 mm in any one structural bay.

c. Plumb: ± 2 mm in any one-storey height. d. Plane:

± 2 mm in any one storey height or structural bay width.

e. Intersection: ± 2 mm in alignment in any direction between any two adjoining panels, at a 4-way intersection of panels.

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4.3.7.3

Accuracy of Junctions Between Stone Components

Construct joints between components to the following permitted deviations: a. Within the length of any joint (including in line continuations across transverse joints) the greatest width shall not exceed the least width by more than 10%. Any variation shall be evenly distributed with no sudden changes. b. The offset end elevation between nominally in-line edges across a transverse joint shall be not more than 10% of the width of the transverse joint. c. The offset in plan or section between flat faces of adjacent panels across any joint shall not be more than 10% of the width of the joint or 1.5 mm whichever is lesser.

4.3.8

Working on Site

Store stone on wood A frames or pallets with nonstaining separators and nonstaining waterproof covers. Do not carry out cutting, drilling or surface finishing (grinding or ‘spinning’) of stone on site. 4.3.9

Visual Appearance of the Cladding

Monitor the stonework in the Cladding on a daily basis. Note the distribution of light, dark and intermediate tones/colours on elevation drawings and submit to the SO for review. Remove and refix any stonework that is outside the agreed tonal variation. 4.3.10

Site Sealant Work

Apply and cure sealants in accordance with their manufacturer’s directions on minimum and maximum temperature and RH conditions. Achieve the depth to width geometry. Prevent three-sided adhesion. Use appropriate backer rods, tapes, surface preparation and primers as manufacturer’s directions. Tool off sealants neatly. 4.3.11

Installation of Fire and Smoke Stopping

Install fire and smoke stopping at all voids and penetrations between compartments at designated locations to achieve the specified fire and smoke stopping performance. 4.4

Protection and Cleaning Protect vulnerable coated surfaces; glass, metal edges, corners and features. Apply temporary removable protection against damage from following trades or operations and the anticipated hazards. Materials used for temporary protection shall be compatible with and subsequently removed from the surface and finishes without detriment to the finish. The component suppliers and finishers shall approve the methods for removal.

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Unless agreed otherwise by the SO protection should remain in place until all work potentially damaging to the components or their finish has been undertaken. Replace any damaged components in the stone cladding. Carry out repair to damaged components only with the agreement of the SO and proper warranty to the works is arranged.

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5.

VERIFICATION AND SUBMISSION

5.1

Submissions 5.1.1

Tender Submissions

5.1.1.1

General

Submit the following information with the tender: a. All material descriptions and sources including stone, secondary support structure for stone, metal parts, gaskets, flashings, seals, linings, stops, vapour barriers, insulation, inter-layers, thermal breaks, fire stopping and barriers. b. Test certificate for the stone or for a proposed alternative. Include the following information: Requirement

Test and method

Unit

Density

ASTM C97

kg/m³

Water Absorption

ASTM C97

%

Flexural Strength

ASTM C880

MPa

Compressive Strength

ASTM C170

MPa

Petrographic Description

ISRM method

Obtain the data above from stone at or near the intended extraction zones in the selected quarries. The data shall reflect as closely as possible the quality and performance that will be expected of the stone. Ensure that none of the submitted data is more than 18 months old. f.

The suppliers and location of the stone within the quarry, including i. A recent history of the quarry. ii. An assessment of the viability of the quarry. iii. An estimate of the stone reserves immediately available. iv. An assessment of the quarry's current workload. v. A description of the work practices in the quarry.

g. The current rate of output of useable stone and any factors such as adverse weather access restrictions, block sizes, etc. that could cause an interruption in the supply of stone. h. The cost of the stone. i.

The location of prominent buildings clad with the stone.

j.

Samples

5.1.1.2

Alternative Stone Proposals

Provide details on alternative stones or thicknesses that may be considered appropriate as alternative to the specified stone and thickness. Identify where the

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stone occur in the quarry and relate all of the above information to these levels. Submit the necessary test certificates to demonstrate suitability. 5.1.1.3

Samples

a. Provide at least 3 nos. 600x 600mm samples of the proposed stone. The number of samples submitted should be sufficient to define the colour range, figuring and normal features (e.g. veining, textural changes, inclusions and spots) of each of the proposed stones for the project. The SO to retain samples and to use them to establish an initial range samples. b. Samples of stone fixings proposed together with relevant trade literature. Retain the samples and use as control samples. 5.1.2

Work Submissions

Upon commencement submit: a. Any outstanding submissions required at tender. b. The location and component referencing system for use throughout the stone cladding. c. Assembly and installation drawings: These are to show: i. Panelisation plans and elevations uniquely identifying and locating every stone cladding panel in the building ii. Horizontal and vertical sections identifying requirements for any cast in anchors, sub-framing, cavity trays and dpc’s and windows and meet the requirements of this specification. iii. Horizontal and vertical sectional details and elevations illustrating the stone cladding profiles, anchors, fixings and fasteners, glazing, gaskets, sub heads and sub sills, storm flashings, baffles and sealant work and interfaces to adjacent elements of cladding, masonry and finishes. iv. Drainage routes and weepholes clearly. v. Allowance for tolerance and movement and means of adjustment. d. Range Samples e. Results of the approval tests f.

Any design assumptions additional to given data.

g. Data and calculations to verify that structural, noise, thermal transmittance, weathering, risk of thermal breakage and solar control requirements can be met. h. Detailed testing proposals i.

PVF2 samples onto a typical extrusion 300mm length.

j.

Mock-up of panel showing joint. Refer to clause 5.4.2 for details

k. Results of the impact tests l.

Weathertightness specimen and test reports

m. Calculations supporting all design proposals. Clearly state basic data used and all assumptions

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Do not commence fabrication until assembly and installation drawings have been reviewed. 5.1.3

Certification of Materials

5.1.3.1

Submit to the SO certification from the manufacturers of finishes and sealants that the manufacturers have reviewed the contractors details and confirms the appropriateness of the materials for use in their application.

5.1.3.2

Submit to the SO certification from the applicator that finishes have been properly applied and meet the requirements of the applicators quality control system

5.1.4

Method Statements

Prepare and submit method statements to the SO for review. These are to describe: a. Method of fabrication of stone claddings including method of fixing b. Method of installation of stone claddings, in particular any sequencing issues requiring other elements to be completed before installation Do not commence fabrication or installation until method has been accepted. 5.2

Warranty Submit the warranty for the SO’s acceptance upon completion of the works.

5.3

Quality Control Plan Submission Prepare and submit the quality control plan for SO’s acceptance prior to starting work. 5.3.1

Maintenance Manual

Include the following information in the maintenance manual and logbook: a. Method and frequency for cleaning every type of stone used on the project.

5.4

Samples and Mock-ups 5.4.1

Samples

Refer to clause 5.1.1 above. Refer to the PSD for additional sample requirement if any. 5.4.2

Mock-ups

Subsequent to acceptance of the contractor’s detail design and prior to production, fabricate and build at locations as directed, a full size visual mock up for the SO to review. Undertake any modifications throughout the stone cladding identified from the mockup by the SO in order to meet the performance requirements and design intent. Refer to the PSD for additional mock-up requirement if any.

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5.5

Tests 5.5.1

Stone Testing

5.5.1.1

General

a. Submit method statements to the SO for review, describing how it is proposed to test the Works. b. Test the Works and achieve results that verify to the SO that the performance requirements have been met. 5.5.1.2

Mechanical and Physical Properties of Stone

Submit to the SO test data for the proposed stone demonstrating compliance with the mechanical and physical properties as set out in clause 3.1. The test data shall be no more than 18 months old and from a laboratory accredited to carry out these tests. 5.5.1.3

Sampling

When the quarry has been selected and before any stone is processed for the cladding: a. Take samples of each stone type from blocks representative of three widely spaced numbered locations in the intended extraction zone at the respective quarry (if all of the blocks for the project have already been delivered to the production facility then sampling may take place from these blocks rather than the quarry). b. Arrange for the samples to be tested by the Testing Authority accredited to carry out the required tests and previously agreed with the SO. Submit the results to the SO. c. If the results do not confirm the information previously submitted prior to procurement or any modifications agreed at the time of Contract award, identify other extraction zones and continue sampling and testing until stones are found which comply with the agreed properties. Retain all test specimens after testing to allow further inspection if required. 5.5.1.4

Acceptance

Reject all the stones represented by samples which fail to meet the requirements of mechanical and physical properties prior to procurement. Remove the rejected blocks and slabs from the factory and place them in a separate disposal area. 5.5.2

Stone Approval Testing of Granite

From each of three number blocks (selected as part of the Sampling stage above), perform the following tests. a. Density and Water Absorption. ASTM C97. From each block take three number specimens (nine in total). b. Flexural Strength. ASTM C880. From each block take twenty number specimens (sixty in total). Ten specimens shall cut perpendicular to the rift in the stone and ten parallel to the rift. These shall be designated sets A and B. Test five specimens from set A and five from B in the saturated condition and test the remaining ten specimens (again 5 from A and 5 from B) in the dry condition. 32 Version 1.0

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c. Compressive Strength ASTM C170. From each block take five number specimens (fifteen in total). 5.5.2.1

Acceptance

For each location calculate an average value for each group of tested samples. Use the result of all samples tested within each group in determining the average value, except if any specimen gives a value of 20% or more below/above the average. Report any results 20% or more below/above the average to the SO and obtain authorisation of acceptability. 5.5.3

Tests for Fixings in Stone Prior to Processing

5.5.3.1

Samples for Testing

Provide 20 samples for testing unless otherwise directed. The samples used to carry out the tests shall be taken from blocks taken from at least three separate parts of the quarry currently being worked. One or two samples shall be taken from an area as close as possible to that part of the quarry from which the stone for the project will be cut. The same blocks shall be used to provide specimens for the stone property tests described elsewhere in this Contract Document, so that a relationship between the stone properties and the fixing tests can be established. The bedding plane or rift shall be marked on the specimens by the quarry. The test specimens shall be not less than 300 mm x 300 mm by the minimum design thickness proposed by the Sub-contractor and shall be conditioned in accordance with the requirements of the most recent edition of ASTM C99. Larger specimens may be required if the failure cone in the stone is likely to be affected by the testing equipment. The Independent Testing Authority shall keep all test specimens after testing to allow further inspections if necessary. 5.5.3.2

Pull-out Tests for Stud Fixings

a. 20 nos. pull out tests to destruction with the proposed stud fixings inserted into the appropriate thickness of stone parallel to the bedding plane or rift and with the stone wet and 20 nos. with the stone dry. b. 20 nos. pull out tests to destruction with the proposed stud fixings inserted into the appropriate thickness of stone at right angles to the bedding plane or rift and with the stone wet and 20 nos. with the stone dry. Calculate the mean and standard deviation of the failure loads for each set of 20 results. Calculate the characteristic pull out value for each set as the mean pull out value of each set minus 1.83 times the standard deviation. The characteristic pull out value to be used for design shall be the lowest characteristic value calculated. Submit results to the SO. 5.5.3.3

Shear Tests on Wind Tie Pins in Stone Edges

a. 20 nos. load tests to destruction with the proposed pin fixing inserted into the edge of the appropriate thickness of stone, with the bedding plane or rift parallel to the pin and with the stone wet, and 20 nos. with the stone dry.

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b. 20 nos. load tests to destruction with the proposed pin fixing inserted into the edge of the appropriate thickness of stone, with the bedding plane or rift at right angles to the pin and with the stone wet, and 20 nos. with the stone dry. Calculate the mean and standard deviation of the failure loads for each set of 20 results. Calculate the characteristic breaking value for each set as the mean breaking value of each set minus 1.83 times the standard deviation. The characteristic breaking strength to be used for the pin fixing shall be the lowest characteristic value calculated. Submit results to the SO. 5.5.3.4

Shear Tests on Horizontal Bottom Bracket Slots

a. 20 nos. load tests to destruction with the proposed horizontal kerf bracket design in the bottom edge of the appropriate thickness of stone, with the bedding plane or rift parallel to the kerf slot cut in the stone, and with the stone wet, and 20 nos. with the stone dry. b. 20 nos. load tests to destruction with the proposed horizontal kerf bracket design in the bottom edge of the appropriate thickness of stone, with the bedding plane or rift at right angles to the kerf slot cut in the stone, and with the stone wet, and 20 nos. with the stone dry. Calculate the mean and standard deviation of the failure loads for each set of 20 results. Calculate the characteristic breaking strength of each set as the mean strength of each set minus 1.83 times its standard deviation. The characteristic value to be used for design shall be the lowest value calculated. Submit results to the SO. 5.5.4

Production Control Testing

5.5.4.1

General

Closely monitor the quality of the stone during production. Arrange for the Independent Testing Authority to carry out the following programme of physical testing. Carry out the following production control tests. Block Number Blocks 1 to 20

Flexural Strength Density and Water Absorption From every 5th Block. Six From every 5th block 3 specimens, 3 from each specimens shall be tested orientation shall be tested in the dry condition. Blocks 21 to As above but from every 10th As above but from every 10th 50 block. block. Blocks 50+ As above but from every 20th As above but from every 20th block. block. Should any significant variation occur in the results of the tests obtained during production then the testing regime shall revert back to that for blocks 1 to 20. 5.5.5

Visual Inspection

Carry out a visual inspection:

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a. After gang sawing and prior to further processing. b. After initial processing and cutting to size. c. After edge labours and surface finishing. Submit a record with substantiating photographs to the SO. 5.5.6

Dye Testing (Granites Only)

Dye test the two outermost usable slabs from the first five blocks to be produced using a fluorescent dye to determine the presence of potentially harmful cracks and micro cracks. The necessity for an additional dye testing shall be determined following the results of these tests. Any stone exhibiting cracks deemed to be potentially harmful by the SO shall be excluded from production. 5.5.7

Impact Testing

Carry out impact tests where required as indicated in the PSD. 5.5.8

Weathertightness and Load Testing of Stone Cladding Specimen

Provide stone for weathertightness and load testing where identified by the SO. 5.5.9

Site Load Testing of Fixings

5.5.9.1

General

Demonstrate by test that fixings are adequate Laboratory tests shall be carried out generally in accordance with BS 5080 Parts 1 and 2. Site testing shall be carried out in accordance with the methods described in Construction Fixing Association Guidance Note “Procedure for site testing construction fixings” Retain all test specimens. 5.5.9.2

Site Inspections of Fixings

As the Works proceed check that: a. The fixings as detailed on the installation drawings have been installed. b. Every cladding fixing to structure is the right size and is in the right place and has been correctly tightened using a calibrated torque wrench. c. Fixings do not restrain any intended movement and generate locked-up stresses. 5.5.9.3

Quality Control Testing of Bolts Embedded in Concrete

As the Works are installed, carry out 10 nos. tests at each floor level on any embedded bolts: Load to a minimum load of 1.1 times the design load acting on the bolt. Record and submit displacement measurements. Displacement shall not exceed 0.1 mm. 35 Version 1.0