Measi Institute - Structral Glazing

7/25/2019 Measi Institute - Structral Glazing

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Use of Glass for Structural

Glazing

To Measi College Students7th May, 2103

SriRam N

IGBC - AP

Saint-Gobain Glass India


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Introduction to Facades

Facade is the exterior part of the buildingmeaning face in French

Made up of components or elements


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Facade - Requirements

The facade of a building should

Be safe during construction & use

Retain its appearance throughout its life

Keep out weather & provide comfortable environment

Be correctly designed, planned & installed


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Structural Design/Facade Systems

Types

Material used

Selection of Glass

Safety & Security

Energy performance


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STRUCTURAL DESIGN/FACADE SYSTEM

FRAMED

WINDOWSSTRUCTURAL

GLAZING

FRAMELESS

STRIP

PUNCHED

OPENABLE

UNITIZEDSYSTEM

SEMI UNITIZEDSYSTEM

GAS FIN SYSTEM

CABLE NET SYSTEM

SHELL FRAMEDSYSTEM

SPIDER BOLTEDSYSTEM

TENSION TRUSSSYSTEM



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Frameless Systems

Bolted systems without any frames

Contemporary designs; Provide unrestricted vision

An image showing the louvre pyramid during day and night


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Types of Frameless Systems

Wide range of visionGlass FinSystem

Cables - Modern

appearance

Cable Net

System

Articulated point fixingSpider Bolted

System

Small mechanicalfixtures

LightweightTension Truss

System


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Continuous Strip of window withsolid wall above & below

Framed glazing with opaque wallson both sides

Windows

TYPES OFWINDOWS

PUNCH STRIP

Glazed openings on solid walls of a building


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Structural Glazing

Bonding facade panels to curtain wall frame

Structural grade silicone adhesive / sealant

STRUCTURAL

GLAZING

TWO- SIDEDGLAZING

FOUR- SIDEDGLAZING


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Semi-unitized System

Mullion & transom - fixed at site

Glass - structurally glazed to sub-frame

Sub-frame - bolted to main frame


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Unitized System

Complete framework with

glass is factory fabricated

Prefabricated unit is

assembled at the site

Brackets secure unitized

units with structure


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Comparison


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Aluminium frames

Curtain wall sections

Gaskets

Sealants

Glass

Brackets & fixings

Vent panels

Pressure equalisation cavity

Setting block

Adaptors

Pressure plates

Cover caps

Thermal break

Elements of Facade System


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Elements of Facade System


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Aluminium Frames

Made from coated aluminium alloys

(aluminium alloy 6061, 6063-T5/T6)

Hollow sections

Corrosion resistant

Easy to design, form & finish

Types of aluminium frame coatings

Anodized aluminium

Electrophoresis painted

Fluorocarbon sprayed

Powder-coated aluminium


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Aluminium Properties

Properties of aluminium

Density: 2.70 g/cm3

Melting point: 660C

Thermal conductivity: 0.5

Thermal emissivity: 3.0 (at 100C)

U Value4-7 W/SqmK


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Thermal Break

Made from fibre glass reinforced polyamide

NeopreneCommonly used material for themal reak

THERMAL

BREAK


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Thermal Break - Benefits

Benefits of thermal breakProvides insulation

Improves energy efficiency

Structurally strong & durable

Watertight & chemically resistant

Same rate of expansion &contraction as aluminium

THERMAL BREAK


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Curtain Wall Sections

Mullion

Vertical section of the frame

Spans from floor to floor

Transfers glazing load to building

Has splice plates to fix transom

MULLIONS


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Curtain Wall Sections

Transom

Horizontal section of the frame

Spans from mullion to mullion

Transfers dead weight of glass to mullion

TRANSOMS


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SpandrelArea between false ceiling & below next floor level

Insulated non-vision area; blocks light

Fixed area; not Openable

Insulated for high thermal insulation

Vision

Area between floor level & false ceiling

Allows Daylight

Can be Ventilated or fixed

Spandrel and Vision Units


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Preformed components made of Ethylene Propylene Diene

Monomer (EPDM) or Neoprene

Provide a seal when compressed within a joint

Limit air leakage and water penetration

Allow relative movement

Accommodate tolerances

Gaskets


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Gaskets


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To prevent glass metal contact

To prevent water & air leakage through joints

To provide sufficient system space for expansion or

contraction as well as thermal breaks

Gasket - Uses

GASKET


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Used to resist wind, thermal & other stresses

Classified into structural & weather sealants

Staining or non-staining types

One-part or two-part

Sealants

SEALANT

SEALANT

APPLICATION


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A good sealant must have the following properties

Adhesion to substrate material

Ability to deform under stress

Weather resistance

Durability

Sealant - Properties

Cured sealant


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Prevent glass to metal contact in a facade

system

Setting Blocks

SETTING BLOCK


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Setting blocks are used to

Support the dead weight of glass

Prevent glass breakage

Support the entire glazing unit

Setting Blocks - Uses

SETTING

BLOCK

SETTING

BLOCK


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Used in deep joints along with wet sealant

Limit sealant wastage

Controls joint shape

Backer Rod

BACKER

ROD


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Extruded aluminium profile with mechanical screws

Fix glass to main mullion

Alternative to sealant in some cases

Cover Caps

Coated aluminium cap

Used to cover the visible screws

Neat finishing

Pressure Plates


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Made of mild steel or aluminium

Customizable based on the site requirements

Either welded or bolted

Support brackets

Restraint connections

Brackets


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Brackets have many functions

To transfer live/ dead loads to the structure

To connect curtain wall to the structure

To transfer frame load to slabs

Bracket - Functions

Face-mounted bracketSlab-mounted bracket


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Attach curtain wall brackets & windows to structure

Required to connect to steel, concrete or masonry

Selection of fixing depends on load & safety

Fixings

ANCHOR BOLT


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Selection of Glass

GLASS

Strength

and Safety

Energy

Performance


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Selection of Glass

GLASS

Strength

and Safety


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Glass For Exterior Faade

Glass For SafetyAgainst injury &people fallingthrough glass

Against glassfalling

Glass For SecurityOverhead Glazing

Vandalism andburglary

Fire-arm /Explosion & bullet


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Glass types

Types of Glass

Annealed Glass

Heat Strengthened glass

Tempered glass

Laminated glass

Insulation thermal unit (IGU)


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Annealed glass

Annealing is a heat treatment that alters the

microstructure of a material causing changes inproperties such as strength and hardness

Process : Very slow cooling

Reason: Ease & precise cutting of glass

Sketch: Glass manufacturing line

Annealing Lehr

typically 800m -1000m long for

slow cooling

Furnace

Float

Cutting & packing section


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Annealed glass

Benefits

Ease in cutting ofglass

Lower opticaldistortion

Lower waviness

Concern

Not a safety Glass;Breaks as largeSharpe pieces

Least structuralstrength

Tensile Strength40N/Sqmm


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Tempered Glass

Tempering Furnace

loading heating quenching

&

cooling


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Thermally Toughened glass

Heat to 600 - 700C

Quenching fast

cooling through Air

Fast cooling of thesurface

thermally"prestressed" glass

THERMAL TEMPERING

0 compressiontension

t

0.21 tsurface compressioncenter tension

(defines break pattern) (defines strength)

parabolic internal stress profile

T d / h d Gl


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Tempered / toughened Glass

Benefits

Safety Glass; breaksas small , non-sharpedged pieces

High Tensile

strengthTensile Strength

120N/Sqmm

Concern

Cannot be cut posttempering

Increased wavinessand optical distortion

compared to annealedglass

H t St th d l


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Heat Strengthened glass

Heat strengthening process is very similar toToughening, Except that the cooling is done isFaster than annealed glass & slower than temperedglass

Benefits

Better optical distortion & compared

to tempered glass

Concern

Not a safety Glass; Breaks as large Sharpe

pieces

Least structural strength

Tensile Strength 75N/Sqmm

Ch t i ti f P d l


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Characteristics of Processed glass

Characteristics Annealed Glass

Heat Strengthened

glass Tempered Glass

Tensile Strength 40N/Sqm 75N/Sqmm 120N/Sqm

Thermal Stress50C

130C

200C

Safety Glass No No Yes

Breakage Pattern Sharp large pieces Sharp large pieces Small Pieces

L i t d Gl


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Laminated Glass

A composite material consisting oftwo or more sheets of glasspermanently bonded togethergenerally by PVB

Vandalism, explosive & bullet

resistant is formulated by multifoldlaminated combination

Glass Glass

PVB

I l t d Gl P


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Unit is assembled

Insulated Glass - Process

Glass sheets separated by

Spacer bar

Primary/Secondary Sealant

used

Air space provides insulation

Benefits

Energy efficiency


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Use of Glass based on Application

A li ti


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Application

Hs > 0.75m - Any GlassHs


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Application

Laminated Safety Glass - Mandatory

Source : Guidelines on use of Glass in Buildings - Human Safety

Hs 1.5m

Safety Glass - Tempered Glass

Preferred laminated

S l ti f Gl


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Selection of Glass

GLASS

Energy

Performance

Electromagnetic Spectrum


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Electromagnetic Spectrum

Radiation emitted by the sun is called electromagnetic radiation

Solar radiation is the sum of

3% ultraviolet (UV) light

42% visible light

55% infrared (IR) light


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1# 2#

reflected

energyre-emitted

energy

re-emitted

energy

directly transmittedenergy

Heat gain

due to Direct

solar radiation

Directly +

Re-emitted energy

= S F / SHGC / g

Visual Light Transmission (VLT)


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Percentage of incident light transmitted

Percentage transmission depends Tint & Coating

Light Transmitted

out

Factors affecting SOLAR FACTOR (SF) or Solar Heat Gain Coefficient (SHGC)


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g ( ) ( )


Clear

SHGC = 0.84

VLT = 89%

Green

SHGC = 0.56

VLT = 73%

Blue

SHGC = 0.56

VLT = 56%

Clearsolar control

SHGC = 0.150.68

VLT = 10% - 75%

Greensolar control

SHGC = 0.160.47

VLT = 8% - 54%

Bluesolar control

SHGC = 0.160.47

VLT = 8% - 54%


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Area = 1 m2

T1= 1oC T2= 0

oC

U = 5.7 W/sqm K

Amount of heat

Transferred due to

temperature differenceU Value

U Value


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U Value

Single Glazed Unit

U value 3.8 to 5.7 W/Sqmk

Double Glazed Unit

U value 2.8 W/Sqmk

Double Glazed Unit

U value 1.8 W/Sqmk

Double Glazed Unit

U value 1.5 W/Sqmk

Total Heat Gain


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Solar Incidence Radiation X Solar Factor / SHGC of glass

Temperature Differential across Envelope X U Valueof Glass

+

Total Heat Gain

Total Heat Gain in Watts / square meter

=

HEAT GAIN DUE TO

SOLAR FACTOR

HEAT GAIN DUE TO

U value

SOLAR FACTOR + U Value


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Performance

COATING TECHNOLOGY

- Online Coating Technology

- Offline Coating Technology

Online Coating Facility


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Online Coating Facility

Coating during the manufacturing of glass at 650-700

C

Coating is done at the End of float bath area before annealinglehr

Solar Control PropertiesMaximum 2 Coating LayersPoor Spectral selectivity (Light transmission & SHGC ratio)

Online

Coating

Manufactured during manufacturing of glass it self.

Process of manufacturing known as pyrolysis

CVD Coating

Offline Coating Facility


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Offline Coating Facility

Spectrally Selective coatings (X10-9)mm(Nano- metric thickness)

Post temperable CoatingCan betempered, Heat strengthened & laminated

Solar + Thermal Insulation Coating

Single Silvered Low-e

Double Silvered Low-e

Offline

Coating

Manufactured in a separate process (offline) by

Magnetron sputtering on to raw glass

Nano-Multi layered coating

Electron Microscope

Energy Performance Comparison


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gy p

Solar

incident

energy =

415 W/sqm

Temperature

differential

= 8 C

Clear GlassIn SGU

SF / SHGC /g: 0.85

U Value: 5.7 W/sqm K

400 W/sqm

354

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Solar Control

SF / SHGC /g:0.40


212 W/sqm

166

46

Solar control+

Low-e

SF / SHGC /g:0.25


117 W/sqm104

13

Solar Factor contributes to over 80% of Heat Gain

Energy Performance Comparison


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gy p

Glass area

1000m2

Electricity

onsumption

For cooling0.6 kWHr / TR

Operation

Hours

8 Hrs for

240 days

Base

61,056

92,160

114 TR

61 TR

34 TR

131,328

70,272

39,168

Savings Annual

Electricity

Consumption

kWHrAC tonnagefor Cooling

Annual

ElectricityConsumption

kWHr

Clear Glass

In SGU

Solar control

Solar control+

Low-e

Reduced Capital investment on Cooling design

Reduces operation cost


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To Summarize

We have seen


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We have seen


Framed System

Frameless System

Windows

Structural GlazingFabrication types (unitized / Semi unitized)

Fabrication materials

Selection of Glass

Safety & Security

Application

Energy


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Thank You..!!

Documents

Measi Institute - Structral Glazing