cladding report-version 3 (print out)

The Hong Kong Polytechnic UniversityDepartment of Building & Real Estate BRE391Construction Technology II

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Introduction

Cladding defined as a facing or architectural decoration additional to the external walls of building:

e.g. aluminium or metal cladding, polished slabs, limestone cladding, marble facing and the like,

(Follow PNAP 59). The classification of cladding system is the non-load-bearing exterior walls,

their primary functions are to: (a) protect the interior of the building from the elements and (b)

enhance its appearance.

Basically, a high-rise building is defined as a building 35 meters or greater in height, which is

divided at regular intervals into occipitals levels. To be considered a high-rise building an edifice

must be based on solid ground, and fabricated along its full height through deliberate processes.

In this report, we will mainly focus on five types of material claddings. There are the precast

concrete claddings, glass reinforced polyester (GRP), glass fibre reinforced cement (GRC), sheet

metal cladding panels and glazing curtain wall. Moreover, we also analysis of three cases of Hong

Kong high-rise buildings which are used the different kinds of cladding system.

BSc. (Hon) Building Engineering and Management BRE 32102P. 1/30


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Classification

Different kinds of cladding are connected to use different kinds of cladding system

A. Infill System This system is most representative of cast-in-place concrete structural frames. The cladding

materials are installed between the exterior floor slab edges, and sometimes the exterior columns of

the structural frame are also exposed. The cladding material may be precast concrete, masonry,

glass, or a combination of glass and another material at the windowsill or jambs. The identifying

feature of this system is that the structural frame is exposed.

Fig. 1: Infill systems

B . Unitized or Panel System This type of system has the exterior cladding attached directly to the structural frame in large panels

which span one or more stories and one or more bays, or it is constructed on the frame with the

back-up materials usually resting on the slab and the exterior finish covering the structural frame.

Fig. 2: Panel systems


Working Sequence:1. Installation of anchors2. Installation of framed

units.


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The example of the attached unitized or panel system is:

1. Precast concrete or steel-stud frames with frames with an exterior finish, which is lifted into

places by cranes and then welded or bolted to attachment, built into the structural frame.

2. Brick veneer wall in which is masonry or steel-stud back-up system is constructed on the slabs

with exterior brick veneer supported by shelf angles attached to the slab edges.

C. Curtain Wall SystemThis type of system is similar to the unitized system except that it is attached to the structural frame

with clip angles or sub-framing. The most prevalent types of curtain-wall systems are the metal and

metal and glass wall which enclose many high-rise building today.

Fig. 3: Curtain Wall System

Photo captured from - http://www.building.com.hk/feature/06_00kadoorie.htm

The characteristic of this kind of cladding system is while affording the worker the ability to handle

and erect smaller lightweight pieces. These often are of standard design and manufacture, requiring

less time in the preconstruction shop drawing and manufacturing phases of the project.


http://www.building.com.hk/feature/06_00kadoorie.htm


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Design Constraints

A. Weather resistance

Cladding system is an outer shelter of building; it is providing a shelter against typhoon and rain. In

Hong Kong, typhoon and rain is always occurs in summer, so the design on pressures and loads in

Hong Kong’s wind effects must minimum outward (negative) shall be 3.1 KPa. The minimum

inward (positive) wind pressure shall be 2.2 KPa. On the other hand, the weather seals shall not

experience adhesive or cohesive failure and the withstand movements up to the limits prescribed by

the manufacturer. Also the water leakage control is most important in cladding, so must be provided

the internal gutter and weep system to collect and drain water leakage and condensation to extenior.

B. Thermal insulation and condensation

Thermal insulation in cladding system, is always use the thermal fibre for the curtain wall spandrels

to achieve specified thermal requirement, this material can be cut into required size and lay inside

the panels. But this material can’t get wet, if not it will lose its function and disintegrate. In large

cladding glass, it create a huge energy loss especially in air conditioning is provided. In order to

reduce the loss, double-glazing or other material and design are being used. According to the

Building Regulation (Energy Efficiency) of Hong Kong, it requires to maintain the overall thermal

transfer value (OTTV) in a maximum of 30W/m2 in the design.

C. Sound insulation

The cladding systems are used on building which at a high noise level location. The special sound

barrier must be included. First, the sound-transmission must be calculated and determining the type

of sound by acoustic consultant, than select a type of material (e.g. using double glazed) to filter the

sound for reduce or less the sound to be standard.

D. Fire Resistance

Cladding system also has a function to protection of inhabitants. It needs to be stop or slow down

the spread of fire whether from external or internal. Therefore, cladding materials need to do testing

for fire resistance.



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Form of CladdingAs mentioned before, there are many different forms of cladding system. The most common forms

of cladding are: (a) Curtain wall, (b) Precast concrete cladding, (c) Glass-reinforced Polyester -

GRP, (d) Glass-fibre-reinforced Cement – GRC, (e) Metal cladding

A. Curtain wall

“Curtain walling” may be defined as being non-load bearing walls, usually suspended in front of a

structural frame; their own deadweight and wind loadings being transferred to the structural frame

through anchorage points. Usually they consist of a rectangular grid of vertical or horizontal

framing with infill panels of glass or some other lightweight materials panel; but that is not always

so for the term ‘curtain wall’ encompasses a wide variety of systems. In Hong Kong, the curtain

walls are very commonly used in high-rise building.

Classification of curtain wall system1. Sticks System

This system is similar to the attached system except that it is attached to the structural frame with

clip angles or sub-framing. The most prevalent types of curtain wall systems are the metal or metal

and glass walls, which enclosed many of today’s modern skyscrapers. Other materials, such as

natural stones and lightweight precast panels, are also commonly used as cladding material for

curtain wall system.

The advantages of this system are similar to those of the attached system while affording the

contractor or erector the ability to handle and erect smaller, lightweight pieces.

2. Unit ized or Panel System

This type of system has the exterior cladding attached directly to the structural frame in large panels

which span one or more stories and one or more bays, or it is constructed on the frame with the

back-up materials usually resting on the slab and the exterior finish covering the structural frame.



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3. Semi-unitized System

Semi-unitized system is a compromise between the stick and unit system. First, the mullion

members are installed separately, and then pre-assembled framed units are placed between them.

The cladding material may be glass, natural stones and lightweight precast panels, or a combination

of glass and another material at the windowsill or jambs.

Fig. 4: Semi-unitized System

4. Column cover and spandrel system

In column cover and spandrel system, the column cover is installed first which may be one or two

stories in height, then the long spandrel panels which span between the column cover are placed

between them. Finally, the glazing infill is fixed with the frame.

Fig. 5: Spandrel System


Working Sequence:1. Installation of anchors2. Installation of mullions3. Installation precast windows unit.4. Installation of interior mullion

trim.

Working Sequence:1. Installation of column covers

section.2. Installation of spandrel panel.3. Installation of glazing unit.


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B. Precast Concrete Claddin g

Precast concrete cladding is a new construction method for tiling works. The cladding panels are

manufactured in the precast factory. The panels are fixed by holding brackets and the backing is use

lightweight concrete. The main benefits of precast concrete over other cladding materials are its

good strength-to-weight ratio, so it’s a high mobility and, it is a non-combustible material, so it’s a

high fire performance. Precast concrete has been used for both non-loadbearing and loadbearing

cladding units. A concrete unit, structure or member is cast and cured at a factory and then

transported to a work site for erection. Precast concrete cladding use in a wide range of buildings,

from healthcare facilities to shopping malls, commercial office buildings to sports stadiums.

JointingA joint is a gap between adjoining cladding or between a cladding and some other portion of the

structure. Joints may be horizontal, vertical or inclined. The function of a joint between precast

concrete cladding elements is to provide physical separation between the units and, in conjunction

with joint sealants, prevent the ingress of water and air into the building; and also provided a fire

resistance.

The most common types of joint between precast concrete cladding are:

1. Open-drained

2. Face-sealed

1. Open-drainedIt is recommended for high-rise construction. It

consists of a rain barrier in the form of an

expansion chamber with a loose-fitting baffle and

an air-seal at the interior face of the panel. It can

tolerate relatively large movements. The rear

sealant is protected from UV light and weather. It

can be installed from inside the building so no

need to provided scaffolding. It must required

careful supervision is required during installation

as it is difficult to remedy defects due to poor

workmanship, design and construction of Open-

Drained Joints Fig. 6 Open-drained

(Picture captured from http://www.npcaa.com.au)

3.

Co



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mpression-seal

2. Face-sealedThese joints are simple, economical and are most

suited to low-rise construction. They are sealed by a

single run of gun-applied sealant close to the exterior

surface of the joint. A backing-rod forms the rear of

the sealant. It can be readily inspected, repaired or

replaced. And it must be applied from external

scaffolding or other form of access. Sealant is

exposed to UV light and weather must needs more

maintenance.

Fig. 7 Face-Sealed Joints


3. Compression-sealThis type of joint utilizes a compressible

polyethylene or polyurethane foam strip. The strip is

pre-compressed and inserted into the joint after the

panels are erected or it is fixed in position before

placement of the second panel. Then it expands to fill

the joint. It is simple and quick to install. And also it

is difficult to maintain and replace. The time-

consuming is more during erecting.

Fig. 8 Compression-Seal Joints


Panel fixingThere are two types of fixing are in common use. These are:

1. Dowel bar ,

It is fixings are a common and simple method of locating and holding the panel at its bottom

support nibs.

2. Angle cleats.

It can be used at the top-hung and base support position. There should be at least two cleats per

panel. Vertical adjustment is provided by the use of a slotted hole and low friction washer, and

horizontal adjustment is provided by 150mm length of channel cast into the floor slab.



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C. Glass-reinforced polyester (GRP)

The formal name for fiberglass is called Glassfibre Reinforced Polyester (GRP). It is a strong and

durable material can be applied in a wide range of building and construction applications which is

suitable for long-term use in external conditions including walkway covers, footbridge covers,

cladding panels, roof sheetings, water tanks, decorative planters, etc.

GRP is a composite material consisting of a resin reinforced with glass fibre, sometimes with fillers

and pigments of various kinds. Although the resin is brittle, the inclusion of a glass fibre can

produces a tough, high tensile strength material of low weight. You can see that the traditional

building materials like plywood aluminum panel and concrete are rapidly replaced by GRP due to

its unique properties. Generally, it can be formed into a wide variety of sizes, shapes and surface

finishes.

As you may know, GRP is the ideal material for infrastructure uses and all types of specialist

construction (Fig. 9 & 10).

Fig.9 & 10 GRP claddings in HK



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Weathering and fire resistance

GRP cladding would not be permitted on the side walls of buildings which are close to a boundary

and which may represent a risk of fire spread to and from adjacent buildings. The addition of fillers

and pigments to reach some sort of fire resistance acceptability through tests laid down in the

Building Regulations tends to weaken the material’s capacity to resist weathering, and a darkening

of the surface pigments may take place.

Standardization

It is more expensive on a volume basis than most other building materials. Therefore, essential to

use it in thin sections can achieve the cost comparability. However, economy of production can only

be really achieved with standardized identical units.

Thermal, noise and sound insulation

Basically, GRP cladding needs adequate back-up walling that protected against rain penetration and

providing thermal, noise and sound insulation.

Maintenance

Painting the surface of GRP is common, though great care is needed over specification. Joints

should be checked on a regular basis, and displaced gaskets renewed.

Stiffening

Four basic ways of stiffening GRP panels

commonly used in HK are as follows

(Fig. 3):

a) Shaped profiles

b) Ribbed construction

c) Sandwich construction using GRP

connector and foamed insulation core

d) Sandwich construction – stiff insulation

sheet laid into lamination

Fig. 11 Methods of stiffening GRP panels



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Jointing

Most problems of jointing GRP cladding panels occur at the external panel-to-panel joint,

particularly at the crossover situation. These external joints and their jointing materials must be able

to accommodate the thermal movements and deflection movements of the mouldings under

maximum dead and live load conditions, as well as allowing for manufacturing tolerances and

errors in erection.

Three types of joints including mastic sealant joints, gasket joints and open-drained joints are

commonly used in GRP cladding. (Fig. 12 & 13)

Fig. 12 Joints between panels Fig. 13 Neoprene jointing gaskets

(Ref: Cladding of Buildings) (Ref: The Building Envelope)

Fixings

GRP panels should be fixed rigidly at one point, with all other fixings being designed to

accommodate the movement likely to occur. The rigid fixing must in itself be able to be adjusted to

accommodate the manufacturing and building tolerances.

The mild steel stiffeners are allowed within the flanges of GRP. If these are subsequently site drilled

for bolt fixings and not treated or sealed, moisture penetration will lead to rusting and delamination

of the flanges.

The fixings of a large GRP panels for handling shall be considered as they are often difficult to

handle on site because of high wind speeds coupled with their own light weight, and the size and

number of fixings require a careful consideration. Although GRP as a material is relatively tough, it

is recommended that surface protection during transport and erection on site to avoid surface

scratching for GRP panels.



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D. Glass-fibre-reinforced Cement

Glass-fibre-reinforced cement is a composite of ordinary Portland cement, silica sand and water

mixing with alkali-resistant glass fibres. It is a polymer modified high strength fibre reinforced

cement product. The compositions of the GRC are as follow:

Portland cement (40% - 60%)

Water (20%)

Sand (up to 25%)

Glass Fibre (3.5% - 5%)

The GRC panels are ideal for re-habitation and renovation works. It is suitable for the architectural

works, because it has design flexibility in colour, texture pattern and surface finish. Moreover, it

should apply for the building façade, because it is the light weight structure In addition, it is good in

thermal insulation, because it is panels of polystyrene and add the Suitable foam between the GRC

panels is very common.

Typical Detail

There are four types of jointing methods of GRC cladding:

1. Gasket joint

2. Open-drained joint

3. Sealant-filled joint

4. Cover strip

It is very similar when comparing the jointing method of GRC to

GRP which mentioned above. However, there are four main types of

joins for GRC. Besides the gaskets joints, the open-drained joints

and the mastic sealants, the cover strips are adopted too.

Fig. 14 Jointing method of GRC



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The GRC are fixed by using angle cleats and dowel, the panel are restrained at the top and

supported at the base. There are two types of fixing:

1. The cast-in fixing

2. The single-skin fixing

In single-skin fixing, GRC can be mounted onto a metal stud faming, this framing provides support

and stiffness against out-of-plane forces, and permits expansion and contraction of the GRC skin.

Fig.15: Fixing method for a stud frame system.

Example

The Hong Kong Central Library is using GRC as the building façade.

Fig. 16: Photo of the Hong Kong Central Library

E. Metal Cladding BSc. (Hon) Building Engineering and Management BRE 32102

P. 13/30


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This type of cladding can be made by single metallic or combination material. In order to give a

better performance, the metal sheets are bonded to standard profile metal and different kinds of

insulation in order to achieve different requirements, there are mainly four types of exterior metal

cladding panel system:

1.Rain Screen panels 2.Sheet metal panels

3.Box-type panels 4.Laminated panels

Material of Sheet Metal / metal skin

Aluminum Bronze Copper Carbon Steel

Stainless Steel Low-Alloy Steel High-Strength

Finishes:

The commonly finishes are:

1.Anodized finishes 2. Painted finishes 3.Opaque Finishes

4.Mica Finishes 5.Metallic Finishes

Shapes:

Brake or roll (roller die) forming can produce an infinite variety of shapes.

Why does metal panels not commonly use in HK high-rise building?

1. Difficult to transportation of metal since metal industry are far away from HK

2. The developer / owner would like to have the great degree of view within building

3. Energy saving due to maximum use of sun light in glass curtain wall

4. Local contractor & installer are not experienced in construct the metal panel for high-rise

building, oversea contractor may required.

5. High humidity weather in HK, more maintenance problem compare with glass curtain wall

6. Thickness of metal wall (including supporting frame work) are thicker, the maximum use of

maximum plot ratio

7. Metal are not good in self-clean compare with the glass, also colored metal may appear the

watermark.



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Rain Screen Panels

DESCRIPTION

This panel type combine both rolled sheet and laminated panel technique. 4-6mm thick flat metal

sheet is mounted in front of a laminated panel.

Rainscreen Cladding is an exterior “dry joint” cladding system which is designed as part of a rain

penetration control assembly commonly referred to as a “rainscreen” wall. The cladding acts as the

first line of defense in controlling the impact of wind driven rain on exterior walls. The second line

of defense consists of a cavity space and the air barrier system behind the cladding.

With the cladding system, the air pressure load is not resisted by the cladding. Instead the air

induced pressure is transmitted through the cladding by way of vented openings in the metal panels.

The panel design allows rapid equalization of the cavity pressure with the local external pressure so

that the entire wind load is transferred to the insulated air/vapor barrier while preventing wind

driven rain from entering the cavity space.

The important in the rainscreen approach, the integrity of the structural elements of the exterior wall

are generally not affected by accidental rainwater penetration through the exterior face of the

cladding. This is assuming the second line of defense (cavity space and air barrier) are properly

designed and implemented. The result is a more durable and long lasting building requiring less

maintenance.

Fig. 17: Rain screen panel

Laminated panels

Panels standard thickness ranges from 6 mm to 100 mm. The metal sheet used in this type of panels

can be thin as about 1.2mm-2.0mm. The panel consists of two metal skins and layers of insulation

core. They are glued together under pressure to form a composed laminated panel

Fig. 18: Photo of the laminated panels



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The sheet metal

The sheet metal in rang 3- 6 mm are Rolled into required panels shape. By cutting and welding

angles surround the panels in order to forming the edging. Stiffness angle fixed on the back of the

panels, so as to increase overall stiffness of panel.

The sheet panels custom fabricated profile brake shapes for a wide variety of architectural

applications, and pre-finished in a variety of popular anodized and painted finishes.

Exacting manufacturing standards, architectural flatness and forming versatility lend themselves to

a host of specialty shapes. Metal profiles are an ideal medium for imaginative and discriminating

architects, builders, designers, engineers and owners.

Fig. 19: Photo of box-type panel

Box-Type panel consists of a

thermoplastic compound core

laminated between two approx

0.50 mm sheets of metal. The

finished panel provides the rigidity and strength of composite construction with excellent

architectural flatness for creating smooth, monolithic surfaces, exceptional load-bearing capacity

and flexural strength - all with the virtual elimination of dimpling, buckling and oil canning.

Panel thickness ranges from 3 mm to 6 mm and is also available with a proprietary fire resistant

(FR) core material.

Fig. 20 Photo of sheet panel



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Case Study 1

Fig. 21: The photo of L’ Hotel Causeway Bay Harbour View

The building is “L’ Hotel Causeway Bay Harbour View” is located at the 18 King's Road, North

Point, Hong Kong. It is the newest hotel in Causeway Bay and complete in June 2005. The site area

is about 11,000 sq. fit. The “L’ Hotel Causeway Bay Harbour View” is a 4-Star hotel, including a

40-storey complex comprises of 298 well appointed harbour view guest rooms

From the drawing, we find that there are two cladding system, which is curtain wall cladding and

aluminum cladding.



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Selection materials of curtain wall cladding

It is used the 6mm thick clear glass and spandrel glass.

Spandrel Glass is a heat-processed glass with

ceramic frit permanently fused to the surface of the

glass. Since it is tempered or heat-strengthened

glass, the spandrel glass is five or two times

stronger than annealed glass and more resistant to

uniform loading pressures and thermal stresses.

Spandrel glass is widely used in curtain wall

projects, which is non-transparence with high safety

and resistance to corrosion.

Fig. 22: Photo of curtain wall cladding

Aluminum Cladding Panel finish, it is 3mm thick formed aluminum panels in pain. It mainly used

in the corner transition panel. The following is the advantages and disadvantages of using

Aluminum Cladding Wall:

Advantages of aluminum cladding wall Disadvantages of aluminum cladding wall

1. Easy to fix

2. Design flexibility

3. Mould and lichen resistant

4. Easy to maintenance

5. Durable

6. Lightweight

7. Well-insulated and sealed to precent moisture

8. Keep a good quality by prefabrication

9. Good appearance

1. Easy for corrosion and oxidation of metal

2. Cost of manufacture and transportation

3. Large number of joints form

4. Problems of sound insulation

5. Non-combustible and not support the

spread of fire

Fire InsulationIt is used the “CSR” fire-seal with 2 hours fire resistance.

SealantsIt is using the “EMFI” Polyuethane expansion joint

sealant, which is excellent resistance to water, ultra

violet and high movement joints resistant to ageing

and damaged by acids and alkalis.



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Stick system in “ L ’ Hotel Causeway Bay Harbour View ” Installation Procedure1. Placement of precast halfen according to

approved embed drawing in a position within

the design tolerance.

2. Install the aluminum muillions on the Cast-in

halfen channels with T-bolts and proper

shimming where required.

3. Install aluminum transoms to the mullions with

two side brackets.

4. Both the thermal insulation and fire safing

insulation will be fixed on brackets and

mounted to the system.

5. Glass and aluminum cladding are than installed

with the waterproof sealant applied afterward.

6. At the same time opening windows will be mounted to the installed frame while the structural

sealant for these glazing is pre-applied in shop before delivery.

Fixing system of Aluminum CladdingAll curtain wall to be supported in aluminum angle formed angle anchor brackets. These anchor

brackets ate anchored to the structure using bolts fastened.

DrawingsDrawing is attached at the appendix for reference.


Fig. 24: Angle Cleats


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Case Study 2

Fig. 25 The photo of Langham Place Hotel

The site of “Langham Place Hotel” is located at the center of the Mongkok, and surrounded by four

busy streets, there are Argyle Street, Reclamation Street, Shan Tung Street and Shanghai Street. The

site is of “Langham Place Hotel” about 6000m2. The “Langham Place Hotel” is a 5-Star hotel,

including about 720 rooms and 40,000m2 areas.

Moreover, in the plan of drawings, we find that the curtain walls are constructed surrounding of the

“Langham Place Hotel”. In the elevation of drawings, we can divide into three parts of the external

finish. The lower part (from Level 1 to Lobby Level) is finish by stone cladding, the secondary

(from Lobby Level to Level 11) and upper part (from Level 12 to Roof Floor) are finish by curtain

wall cladding which are used the materials of aluminum panel and glass panel.

Total contract sum about $3.5 billion.

Contractor: Sun Fook Kong Holdings Limited.

Main Contracts commenced in December 2001, for completion in July 2004.



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Selection materials of curtain wall cladding

There are using two materials, the aluminum panel and glass panel. Some of glass panels can open

as windows, which are in order to provide good ventilation for the room. Aluminum cladding is not

transparent; it’s not allowing light to pass through so that objects behind cannot be seen. Therefore,

the room layout or partition between rooms can be more flexible and the area for good storage is

much easier to be selected. Glass curtain allow the natural sunlight directly pass into the building.

It can save energy on light energy consumption during the daytime. It can provide a better

environment for people who live in the hotel.

Fig. 26: The pictures are shown side elevation and the plan of construction site of “Langham Place Hotel”.

Maintenance of curtain wallFor maintenance consideration, both aluminum and glass curtain wall system have their advantages,

pollution may be in form of dust, which causes staining and disturbs the esthetic appearance of the

building, or it may be in form of airborne contaminants, such as acid rain or chemical discharge

from transportation. The aluminum cladding is easy to clean and no need to clean frequently. Also,

if glass or aluminum curtain wall damages, panels can be replace individually. It can save the

maintenance cost for the building.

Fixing system of curtain wallCurtain wall system is suitable for using in “Langham Place Hotel”. Regarding the report,

“Langham Place Hotel” is situated in density area. It does not recommend using a lot of time to

cast in-situ. It will waste more construction time in “Langham Place Hotel”. On the other hand,

cladding work is the final work of the building construction, so the time is limited for the cladding

work. Therefore, they select the unitized system for installation of curtain wall, which can save

many time of construction on site.

Unitized system in “ Langham Place Hotel ” BSc. (Hon) Building Engineering and Management BRE 32102

P. 21/30


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The exterior cladding is directly attached to the structural with large panels, which span one or more

stories and one or more bays. In this case, “Langham Place Hotel” uses this system at the secondary

part and the upper part, at the front of the building; you can see that bay by bay of the glass panels

form a dome shape. On the other hand, the aluminum panel was used at the room divided section.

Generally speaking, the unitized system is fabricated offsite and it has been prefabricated in the

factory firstly. In the case for “Langham Place Hotel”, a large aluminium panel, usually in

approximate size of 2135mm x 855mm, and a large glass panel, usually in approximate size of

1700mm x 855mm. The installation of curtain wall by using of unitized system, usually starting

from middle. It is usually being installed from middle to left hand side or right hand side until they

meet at the end of side position for easy adjustment.

Fig. 27: The pictures are shown the installation of curtain wall.

DrawingsDrawing is attached at the appendix for reference.



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Case Study 3

Fig. 28 The photo of One Peking

a. Name of Building One Peking

b. Location 1 Peking Road, Tsim Sha Tsui

c. Completion Date 30 April 2003

d. Major Function Commercial

e. No. of Stories 29 stories (160m height)

f. Cladding material / system

Metal panels as feature,

Triple-glazed active wall system with Aluminum sunshading,

Building Integrated Photo Voltaic panels (BIPV panels)

One Peking Road is the first high-rise building in Hong Kong and one of the first in the world to

power majority part of the building with solar energy

The client had support the building as a landmark in Tsim Sha Tsiu. So that the designer Rocco

Design Limited adopt the variation in floor plate dimensions, which suit different tenant's

requirements. Also, the sensible incorporation of hi-tech curtain wall and sun-shading devices,

which provide comfort to the users while maximizing the panoramic harbour view, are adopted.

Moreover, he Building Integrated Photo Voltaic panels (BIPV panels) module was employed to

create environmental friendly -‘green’ building.



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The shape designOne Peking's southern facade is a giant, gently curving glass curtain wall,

which look like a giant sail, culminating in a vast roofline steel screen. The

curved facade is facing south while the flat side is facing north so as to

maximize harbour view with minimal east and west facing facade. As a result,

solar heat gain can be reduced, while light transmission can be increased at the

same time.

The special shape of the superstructure made it worthwhile to carry out a wind

tunnel test in order to determine more accurately data for designing the

cladding elements to be more optimal in terms of safety and economy.

Triple-glazed active wall system with Aluminum sun shading

The Building uses triple-glazed active wall system, which is supported by a

structural steel frame combining three layers of low-E clear glass with a

ventilated cavity that results in high light transmission and a low Overall

Thermal Transfer Value (OTTV)

The triple-glazed active wall system is an environmentally sensitive cladding

system. The cavity within the external sandwich panel (first 2 layers) is

vacuum, which is used for sound insulation, while the cavity in 2nd and the

3rd layer are ventilated by cool air exhausted from floor top inside of the

Building. The cool air passes through the bottom of the cavity and heat is

shunt upwards for dissipation. Thus, the facade can be cooled and this cavity

acts as good heat insulator. As a result, the Building has a high light

transmission and a low (OTTV).

Aluminum sunshading fins are located outside the window to allow better

daylight distribution into rooms which act as reflectors bouncing light up onto

the angled ceiling to transmit more natural light inside the building while

limiting the entry of direct sunlight at the same time. At night, these fins are lit

from below as architectural features.


P e r f o r m a n c e te s ts

f o r c u r ta i n w a l l i n

S i n g a p o r e .

sunlight

South wall

sunlight

East & North wall


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Building Integrated Photo Voltaic panels with Automatic solar bind

Building Integrated Photo Voltaic panels (BIPV panels), which import from Germany, is a double

laminated 8 + 8 mm heat-strengthen glass with 100 * 100 mm silver colour polycrystalline silicon

cell fixed on the surface.

The overall system in 20 m high including totally 144 module (app. 162m2) BIPV panels system

was connected together to form a large PV array and mounted on the steel truss framework at

Southern face on Upper Roof level with an inclined angle of 67 degree. The generated electricity

D.C. power about 10344 kWh/year will be converted to A.C. via the Power Conditioning System

,which incorporated with PV peak power tracker, 3 phase inverter, controller and isolation

transformer, is directly applied to Automatic solar binds system. To maintain the system operate in

a stabilized performance and the grid connection problem, the rest of the absorbed power was

stored into the battery as a buffer to condition unstable solar power generation period, e.g. cloudy

sky. However, large battery system which increases the installation cost of the PV system by one-

third.

Automatic solar blinds, which are housed in a 200mm air gap between external and internal

glazing in the triple-glazed active wall system, operated by the sun sensor or in the specified

schedule via computer programming to control the blind up and down. The photovoltaic panels at

the rooftop provide power for their operation.


Fig. 31:.Steel frame support Fig. 32: PV panels Fig.33: PV panels & battery Fig. 34: Automatic solar blind

Fig. 35: Diagram of automatic solar bind power system Fig. 36: PV panels


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Installation of cladding Special precautions were taken for the installation of the curtain wall, to safeguard workers and

members of the public as well as to overcome storage and traffic constraints. The glass panels were

delivered to site at 7:00 am, to avoid traffic congestion, and immediately hoisted to the designated

floor. A multi-layer protective screen was erected around the building to protect against falling

objects. The tower crane was retained for the installation of the 8 m high glass panels on the

penthouse as well as the steel truss and PV panels on the roof. When the tower crane was finally

dismantled, the PV panels occupying the crane's position was installed with a derrick boom.

Advantage of using above two types cladding system:

1. Energy saving by using natural lighting (PV panels)

2. Power generation by solar energy (PV panels)

3. Environmental friendly by using solar energy (PV panels)

4. Maximum transparence with widest view (Triple-glazed active wall system)

5. Good sound insulation (Triple-glazed active wall system)

6. Good thermal insulation (Triple-glazed active wall system)


Fig. 37: PV panels install by derrick boom Fig. 38: Curtain wall installation Fig. 39: Mmetal cladding installation


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Benefits of Cladding1. Ease of installation

The installation of cladding wall are easy, which results can be reduced construction times and

labour forces. So the overall project cost can save.

2. Less loading bearingCladding wall is non-load bearing exterior wall; it is no need to take up the load of building. It

is transmitted less loading to the bottom, so the smaller supporting units and foundation can be

performed.

3. Consistent QualityThe cladding panels are high quality and uniformity, because it is manufactured in controlled

factory situations.

4. Attractive AppearanceThe cladding wall can provide a good appearance. It is a protective and decorative wall of the

building; it can make variety shape and surface finish.

5. Reduced weather dependencyIncrease construction efficiency because bad weather condition will not delay in production. It

does not affect the installation of panel, allowing the project to progress on schedule.

6. Less wastageLess waste produced during construction, it can be achieved a clean and safe working

environment.

7. Easy to MaintainEasy maintenance of the cladding system after completion of work on site.



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MaintenanceThere are three types of maintenance for cladding on high-rise building

1. Regular cleaning

The most common on glass curtain wall and metal cladding are received on modern buildings.

Many building have cleaning equipment or supports for cleaning equipment designed into the

original building. There are motorized scaffold and cleaning equipment, which are stored on the

roof of building. This equipment move up and down the side of the building on tracks, it possible to

operate without workers, it called wall-washing robots.

2. Preventive maintenance

The inspection should be carry out to locate and repair minor problems before they become major

problem, such as leakage or cladding material falling from the building.

All components of the cladding that are visible should be inspected. Sealant joints, masonry joints,

seals, and supports for the exterior cladding material are the most areas to wear and deterioration.

Regular inspection and repair of minor problems are the most effective methods, it can take to

prevent major problems and expensive repairs in the future.

3. Life-cycle replacement

All materials have a useful life such as sealant joints have a definite life span. Most materials have a

warranty or guarantee period. For most sealants, 10 to 15 years is considered average for a useful

life, and most paints and finishes for metals have from 10 to 20 years of useful life. When the

sealant fails, it must be removed and new sealant installed after the joint has been adequately

cleaned.



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Conclusion

Cladding system is most common adopted in the commercial building in Hong Kong. And the

curtain wall is most popularly material using in high-rise building, it is because it bears no vertical

load so that it can be thin and lightweight regardless of the height of the building. Moreover, the

cladding system are ease to install, it can reduced construction time and required less labour forces.

This will save on a project’s cost and completion time.

In addition, Cladding system is not just a barrier to the external environment; it is crucial to the

image and the perception of a building, the good cladding design with excellent performance is

essential. You con find that curtain wall is the most common type used in Hong Kong, because it is

attractive. However, it will cause large expenditure in future maintenance

However, the choice of Cladding system depends on its labour cost, material supply, need of

standardization, quality of work, structural stability, code requirements, appearance criteria, erection

methods and the convenience for cleaning and maintenance.

In the nut shell, it is quite suitable to use in commercial building and hotel. In fact, many high rise

buildings Hong Kong are using curtain wall as cladding.



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ReferencesWebsite:

http://www.chinachemgroup.com/index.php?option=content&task=view&id=107

http://www.cse.polyu.edu.hk/~civcal/wwwroot/superstr/curtain_wall/content.htm

http://personal.cityu.edu.hk/~bswmwong/pl.html

http://www.sunwaymetal.com/product.htm

http://www.asiaalum.com/EN/MajorProjects_HongKong.asp

http://www.skyscrapercity.com/printthread.php?t=127586&pp=25

http://www.hku.hk/bse/gallery/1pekingroad/1pekingroad.htm

http://www.hku.hk/mech/sbe/case_study/case/hk/pek/conc.htm

http://www.pabhk.com/PVprofile1.htm

http://www.hkie.org.hk/html/publication/Transactions/html/2004/v11n4/v11n4_abstract2a.htm

http://www.hkengineer.org.hk/program/home/articlelist.php?cat=cover&volid=53

http://hkci.org/html/project_intro.asp?pk_project_id=17

http://www.hkpvc.org.hk/main.html

http://www.emporis.com/en/wm/bu/?id=100612

http://www.pbase.com/framewerkz/hkarch

Books:

1. Alan J. Brookes, (1998), Cladding of Buildings, Alden Press. U.K.

2. Alan J. Brookes, (1985), Concepts in Cladding, Longman Group Limited.

3. Wong Wah Sang, (1998), Building Enclosure in Hong Kong, Hong Kong University Press.

4. Schellbach. (1967). Curtain Wall Construction. Lliffe Books Ltd. U.K. Pp. 10-19, 61-93.

5. Michael. Y. L. Chew. (2001). Construction Technology for Tall Building. Singapore University

Press. Singapore.

Others:

1. Catalogue from the Yeung’s Fiberglass Company (http://www.fiberglass.com.hk/index.html)

2. Building Journal. (Jan 1999). China Trend Building Press Ltd. Hong Kong. Pp. 70-75.

3. Building Journal. (Jan 2001). China Trend Building Press Ltd. Hong Kong. Pp. 54-64.

4. Building Journal. (May 2001). China Trend Building Press Ltd. Hong Kong. Pp. 33-36.


https://webmail.polyu.edu.hk/cgi-bin/fetch.cgi?url=http%3A%2F%2Fwww.fiberglass.com.hk%2Findex.html

http://www.pbase.com/framewerkz/hkarch

http://www.emporis.com/en/wm/bu/?id=100612

http://www.hkpvc.org.hk/main.html

http://hkci.org/html/project_intro.asp?pk_project_id=17

http://www.hkengineer.org.hk/program/home/articlelist.php?cat=cover&volid=53

http://www.hkie.org.hk/html/publication/Transactions/html/2004/v11n4/v11n4_abstract2a.htm

http://www.pabhk.com/PVprofile1.htm

http://www.hku.hk/mech/sbe/case_study/case/hk/pek/conc.htm

http://www.hku.hk/bse/gallery/1pekingroad/1pekingroad.htm

http://www.skyscrapercity.com/printthread.php?t=127586&pp=25

http://www.asiaalum.com/EN/MajorProjects_HongKong.asp

http://www.sunwaymetal.com/product.htm

http://personal.cityu.edu.hk/~bswmwong/pl.html

http://www.cse.polyu.edu.hk/~civcal/wwwroot/superstr/curtain_wall/content.htm

http://www.chinachemgroup.com/index.php?option=content&task=view&id=107

cladding report-version 3 (print out)

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