How To Support A Glass Wall On The Ceiling Drawing

Outer not-structural walls of a building

A building project in Wuhan China, visibly demonstrating the human relationship between the inner load-bearing construction and an outside glass drape wall

Drapery walls are besides used on residential structures

A pall wall is an outer covering of a edifice in which the outer walls are non-structural, utilized only to go along the weather out and the occupants in. Since the drape wall is non-structural, it tin exist made of lightweight materials, such as glass, thereby potentially reducing structure costs. An additional advantage of glass is that natural light tin penetrate deeper within the building. The mantle wall façade does not comport whatsoever structural load from the edifice other than its own dead load weight. The wall transfers lateral current of air loads that are incident upon it to the master edifice construction through connections at floors or columns of the building. A drapery wall is designed to resist air and water infiltration, absorb sway induced past wind and seismic forces acting on the building, withstand wind loads, and support its ain weight.

Drape walls may be designed equally "systems" integrating frame, wall panel, and weatherproofing materials. Steel frames take largely given way to aluminum extrusions, typically infilled with glass, which provides an architecturally pleasing wait and benefits such as daylighting. All the same, the effects of low-cal on visual comfort equally well as solar heat gain in a building are more difficult to control when using large amounts of glass infill. Other mutual infills include rock veneer, metal panels, louvres, and operable windows or vents.

Curtain wall systems differ from storefront systems in being designed to span multiple floors, taking into consideration edifice sway and movement in add-on to blueprint requirements such every bit thermal expansion and contraction; seismic requirements, h2o diversion; and thermal efficiency for cost-effective heating, cooling, and interior lighting.

History [edit]

xvi Cook Street, Liverpool, England, 1866. All-encompassing utilize is made of floor-to-ceiling glass, enabling calorie-free to penetrate deeper into the edifice, thus maximizing floor space.

What appears to be an early curtain wall, part of the Curtea Veche Palace in Bucharest, congenital in 1716

Historically, buildings were constructed of timber, masonry, or a combination of both. Their outside walls were load bearing, supporting much or all of the load of the unabridged structure. The nature of the materials resulted in inherent limits to a building'due south height.

The evolution and widespread use of structural steel and afterward reinforced concrete immune relatively small-scale columns to back up large loads. The outside walls could exist non-load bearing, and thus much lighter and more than open up than load-bearing walls of the by. This gave fashion to increased use of glass equally an outside façade, and the modern-day drape wall was born.

Post and beam and balloon framed timber structures effectively had an early version of pall walls, every bit their frames supported loads that allowed the walls themselves to serve other functions, such every bit keeping conditions out and allowing light in. When fe began to exist used extensively in buildings in late 18th-century Britain, such equally at Ditherington Flax Mill, and later when buildings of wrought iron and glass such as The Crystal Palace were built, the building blocks of structural understanding were laid for the development of mantle walls.

Oriel Chambers (1864) and 16 Cook Street (1866), both built in Liverpool, England, by local architect and civil engineer Peter Ellis, are characterised by their extensive use of glass in their facades. Towards the courtyards they even boasted metallic-framed drinking glass curtain walls, which makes them two of the world's first buildings to include this architectural feature. The extensive drinking glass walls immune light to penetrate further into the building, utilizing more floor space and reducing lighting costs. Oriel Chambers comprises 43,000 sq ft (iv,000 m^two) set over five floors without an lift, which had just recently been invented and was non notwithstanding widespread.^[i] The Statue of Liberty (1886) features a sparse, non-load-bearing copper peel.

An early case of an all-steel pall wall used in the classical style is the Kaufhaus Tietz department store on Leipziger Straße , Berlin, congenital in 1901 (since demolished).^[2]

Some of the commencement curtain walls were made with steel mullions, and the polished plate glass was attached to the mullions with asbestos- or fiberglass-modified glazing compound. Eventually silicone sealants or glazing record were substituted for the glazing compound. Some designs included an outer cap to hold the drinking glass in place and to protect the integrity of the seals. The first curtain wall installed in New York City, in the Un Secretariat Edifice (Skidmore, Owings, and Merrill, 1952), was this blazon of structure. Earlier modernist examples are the Bauhaus in Dessau (1926) and the Hallidie Building in San Francisco (1918).

Ludwig Mies van der Rohe's curtain wall is i of the most important aspect of his architectural design. Mies outset began prototyping the drapery wall in his high-rise residential building designs forth Chicago's lakeshore, achieving the await of a drape wall at famed 860-880 Lake Shore Bulldoze Apartments. He finally perfected the drapery wall at 900 910 Lake Shore Drive, where the curtain is an autonomous aluminum and drinking glass peel. After 900 910, Mies' curtain wall appeared on all of his subsequent high-rise building designs including the famed Seagram building in New York.

During the 1970s, the widespread use of aluminium extrusions for mullions began. Aluminum alloys offering the unique advantage of being able to exist easily extruded into nearly any shape required for design and aesthetic purposes. Today, the design complexity and shapes bachelor are most limitless. Custom shapes tin be designed and manufactured with relative ease. The Omni San Diego Hotel mantle wall in California, designed by architectural firm Hornberger and Worstel and adult past JMI Realty, is an example of a unitized curtain-wall organisation with integrated sunshades.^[3]

Systems and principles [edit]

Stick systems [edit]

The vast majority of basis-flooring curtain walls are installed as long pieces (referred to every bit sticks) betwixt floors vertically and between vertical members horizontally. Framing members may exist fabricated in a store, simply installation and glazing is typically performed at the jobsite.

Ladder systems [edit]

Very similar to a stick system, a ladder system has mullions which can be split up and so either snapped or screwed together consisting of a half box and plate. This allows sections of pall wall to be fabricated in a shop, effectively reducing the time spent installing the system on site. The drawbacks of using such a arrangement is reduced structural functioning and visible articulation lines down the length of each mullion.

Unitized systems [edit]

Unitized curtain walls entail factory fabrication and associates of panels and may include manufacturing plant glazing. These completed units are installed on the building construction to class the building enclosure. Unitized curtain wall has the advantages of: speed; lower field installation costs; and quality control within an interior climate-controlled surroundings. The economic benefits are typically realized on large projects or in areas of loftier field labor rates.

Rainscreen principle [edit]

A mutual feature in curtain wall engineering science, the rainscreen principle theorizes that equilibrium of air pressure between the exterior and inside of the "rainscreen" prevents h2o penetration into the edifice. For example, the glass is captured between an inner and an outer gasket in a space chosen the glazing rebate. The glazing rebate is ventilated to the exterior so that the pressure on the inner and outer sides of the outer gasket is the same. When the pressure is equal beyond this gasket, water cannot exist fatigued through joints or defects in the gasket.

Design concerns [edit]

A curtain wall system must be designed to handle all loads imposed on it equally well every bit proceed air and water from penetrating the building envelope.

Loads [edit]

The loads imposed on the curtain wall are transferred to the building construction through the anchors which adhere the mullions to the building.

Dead load

Dead load is defined as the weight of structural elements and the permanent features on the structure.^[4] In the case of curtain walls, this load is made up of the weight of the mullions, anchors and other structural components of the curtain wall, as well equally the weight of the infill fabric. Additional dead loads imposed on the curtain wall may include sunshades or signage fastened to the mantle wall.

Wind load

Wind load is a normal force interim on the building as the result of wind blowing on the edifice.^[v] Wind force per unit area is resisted past the curtain wall system since it envelops and protects the building. Wind loads vary greatly throughout the earth, with the largest wind loads being almost the coast in hurricane-decumbent regions. For each project location, building codes specify the required design wind loads. Often, a wind tunnel study is performed on large or unusually-shaped buildings. A scale model of the edifice and the surrounding vicinity is built and placed in a wind tunnel to determine the wind pressures interim on the structure in question. These studies take into account vortex shedding effectually corners and the effects of surrounding topography and buildings.

Seismic load

Seismic loads in curtain wall arrangement are limited to the interstory migrate induced on the building during an earthquake. In almost situations, the drapery wall is able to naturally withstand seismic and wind induced building sway because of the space provided betwixt the glazing infill and the mullion. In tests, standard curtain wall systems are typically able to withstand up to three inches (75 mm) of relative floor movement without glass breakage or h2o leakage.

Snowfall load

Snow loads and alive loads are not typically an consequence in curtain walls, since curtain walls are designed to be vertical or slightly inclined. If the slope of a wall exceeds xx degrees or so, these loads may demand to be considered.^[6]

Thermal load

Thermal loads are induced in a curtain wall organization because aluminum has a relatively high coefficient of thermal expansion. This means that over the bridge of a couple of floors, the curtain wall will expand and contract some distance, relative to its length and the temperature differential. This expansion and wrinkle is accounted for by cutting horizontal mullions slightly short and assuasive a space between the horizontal and vertical mullions. In unitized drapery wall, a gap is left betwixt units, which is sealed from air and water penetration past gaskets. Vertically, anchors carrying current of air load only (not expressionless load) are slotted to business relationship for movement. Incidentally, this slot likewise accounts for live load deflection and creep in the flooring slabs of the building construction.

Blast load

Accidental explosions and terrorist threats have brought on increased concern for the fragility of a curtain wall arrangement in relation to smash loads. The bombing of the Alfred P. Murrah Federal Building in Oklahoma City, Oklahoma, has spawned much of the current enquiry and mandates in regards to building response to nail loads. Currently, all new federal buildings in the U.Due south. and all U.Southward. embassies congenital on foreign soil must have some provision for resistance to flop blasts.^[7]

Since the curtain wall is at the exterior of the edifice, it becomes the first line of defense in a bomb attack. As such, blast resistant curtain walls are designed to withstand such forces without compromising the interior of the building to protect its occupants. Since nail loads are very high loads with short durations, the pall wall response should be analyzed in a dynamic load analysis, with total-scale mock-up testing performed prior to design completion and installation.

Blast resistant glazing consists of laminated glass, which is meant to break but not carve up from the mullions. Similar engineering science is used in hurricane-prone areas for touch protection from wind-borne debris.

Air Infiltration [edit]

Air infiltration is the air which passes through the curtain wall from the exterior to the interior of the building. The air is infiltrated through the gaskets, through imperfect joinery between the horizontal and vertical mullions, through weep holes, and through imperfect sealing. The American Architectural Manufacturers Clan (AAMA) is an industry trade group in the U.S. that has developed voluntary specifications regarding adequate levels of air infiltration through a drapery wall.^[eight]

H2o penetration [edit]

H2o penetration is defined as h2o passing from the exterior of the edifice to the interior of the drapery wall system. Sometimes, depending on the building specifications, a small amount of controlled water on the interior is deemed acceptable. Controlled water penetration is defined every bit water that penetrates beyond the inner most vertical plane of the test specimen, but has a designed means of drainage back to the outside. AAMA Voluntary Specifications allow for controlled h2o penetration while the underlying ASTM E1105 examination method would ascertain such water penetration as a failure. To test the ability of a curtain wall to withstand water penetration in the field, an ASTM E1105 h2o spray rack arrangement is placed on the exterior side of the test specimen, and a positive air pressure level difference is practical to the organisation. This set simulates a current of air driven rain event on the drape wall to check for field performance of the production and of the installation. Field quality control and balls checks for water penetration has become the norm as builders and installers utilize such quality programs to help reduce the number of h2o damage litigation suits against their piece of work.

Deflection [edit]

1 of the disadvantages of using aluminum for mullions is that its modulus of elasticity is about 1-third that of steel. This translates to three times more deflection in an aluminum mullion compared to a similar steel section under a given load. Building specifications ready deflection limits for perpendicular (wind-induced) and in-plane (dead load-induced) deflections. These deflection limits are not imposed due to strength capacities of the mullions. Rather, they are designed to limit deflection of the glass (which may break nether excessive deflection), and to ensure that the glass does not come out of its pocket in the mullion. Deflection limits are also necessary to command motility at the interior of the curtain wall. Building construction may be such that at that place is a wall located near the mullion, and excessive deflection can crusade the mullion to contact the wall and crusade damage. As well, if deflection of a wall is quite noticeable, public perception may heighten undue business organization that the wall is not strong plenty.

Deflection limits are typically expressed as the distance between anchor points divided by a abiding number. A deflection limit of L/175 is common in curtain wall specifications, based on feel with deflection limits that are unlikely to cause impairment to the glass held by the mullion. Say a given curtain wall is anchored at 12 foot (144 in) flooring heights. The allowable deflection would so be 144/175 = 0.823 inches, which means the wall is allowed to deflect inward or outward a maximum of 0.823 inches at the maximum wind pressure. However, some panels crave stricter movement restrictions, or certainly those that prohibit a torque-similar motility.

Deflection in mullions is controlled by different shapes and depths of drapery wall members. The depth of a given curtain wall system is unremarkably controlled by the surface area moment of inertia required to keep deflection limits under the specification. Another mode to limit deflections in a given section is to add steel reinforcement to the inside tube of the mullion. Since steel deflects at i-3rd the rate of aluminum, the steel will resist much of the load at a lower price or smaller depth.

Force [edit]

Force (or maximum usable stress) available to a item material is not related to its textile stiffness (the material property governing deflection); it is a separate benchmark in curtain wall design and analysis. This often affects the option of materials and sizes for pattern of the system. The allowable bending strength for certain aluminum alloys, such as those typically used in curtain wall framing, approaches the commanded bending strength of steel alloys used in building structure.

Thermal criteria [edit]

Relative to other building components, aluminum has a high rut transfer coefficient, pregnant that aluminum is a very adept conductor of heat. This translates into high oestrus loss through aluminum curtain wall mullions. There are several ways to compensate for this heat loss, the nigh common fashion being the addition of thermal breaks. Thermal breaks are barriers between exterior metallic and interior metal, usually made of polyvinyl chloride (PVC). These breaks provide a meaning subtract in the thermal conductivity of the mantle wall. Withal, since the thermal break interrupts the aluminum mullion, the overall moment of inertia of the mullion is reduced and must be accounted for in the structural analysis and deflection assay of the system.

Thermal conductivity of the curtain wall system is of import because of rut loss through the wall, which affects the heating and cooling costs of the building. On a poorly performing curtain wall, condensation may grade on the interior of the mullions. This could cause damage to adjacent interior trim and walls.

Rigid insulation is provided in spandrel areas to provide a higher R-value at these locations.

Infills [edit]

Infill refers to the large panels that are inserted into the mantle wall between mullions. Infills are typically glass but may exist fabricated up of nearly any exterior edifice element. Some common infills include metal panels, louvers, and photovoltaic panels.

Glass [edit]

Glass curtain wall on the hotel Andaz in Singapore at sunset

Float glass is by far the almost common curtain wall glazing type. It tin be manufactured in an most infinite combination of colour, thickness, and opacity. For commercial construction, the two near common thicknesses are ane/4 inch (6 mm) monolithic and 1 inch (25 mm) insulating glass. ane/4 inch drinking glass is typically used only in spandrel areas, while insulating drinking glass is used for the residue of the building (sometimes spandrel drinking glass is specified as insulating drinking glass every bit well). The one inch insulation drinking glass is typically made upwards of ii one/4-inch lites of glass with a ane/2 inch (12 mm) airspace. The air inside is usually atmospheric air, but some inert gases, such as argon or krypton may be used to offer better thermal transmittance values. In Europe, triple-pane insulating glass infill is now common. In Scandinavia first drapery walls with quadruple-pane have been congenital.

Larger thicknesses are typically employed for buildings or areas with college thermal, relative humidity, or sound transmission requirements, such as laboratory areas or recording studios. In residential structure, thicknesses commonly used are 1/eight inch (3 mm) monolithic and 5/8 inch (xvi mm) insulating glass.

Glass may be used which is transparent, translucent, or opaque, or in varying degrees thereof. Transparent glass usually refers to vision glass in a curtain wall. Spandrel or vision glass may also contain translucent glass, which could be for security or aesthetic purposes. Opaque drinking glass is used in areas to hide a column or spandrel beam or shear wall backside the curtain wall. Another method of hiding spandrel areas is through shadow box construction (providing a night enclosed space behind the transparent or translucent glass). Shadow box construction creates a perception of depth behind the glass that is sometimes desired.

Fabric veneer [edit]

Material is another blazon of material which is common for curtain walls. Fabric is oft much less expensive and serves as a less permanent solution. Dissimilar glass or stone, fabric is much faster to install, less expensive, and frequently much easier to change after it is installed. Because of low density of fabrics total weight of construction is very low then force consideration of construction is not as well important.

Stone veneer [edit]

Thin blocks (3 to 4 inches (75–100 mm)) of stone tin can be inset within a curtain wall arrangement. The type of stone used is express just by the force of the stone and the ability to industry it in the proper shape and size. Common rock types used are: calcium silicate, granite, marble, travertine, limestone, and engineered stone. To reduce weight and amend strength, the natural rock may be fastened to an aluminum honeycomb backing.

Panels [edit]

Metal panels can take diverse forms including stainless steel, aluminum plate; aluminum composite panels consisting of two thin aluminum sheets sandwiching a thin plastic interlayer; copper wall cladding, and panels consisting of metal sheets bonded to rigid insulation, with or without an inner metal sheet to create a sandwich panel. Other opaque console materials include fiber-reinforced plastic (FRP) and terracotta. Terra cotta curtain wall panels were offset used in Europe, merely only a few manufacturers produce high quality mod terracotta curtain wall panels.

Louvers [edit]

A louver is provided in an surface area where mechanical equipment located inside the building requires ventilation or fresh air to operate. They can also serve every bit a means of allowing exterior air to filter into the edifice to take advantage of favorable climatic weather and minimize the usage of free energy-consuming HVAC systems. Curtain wall systems tin can be adapted to have most types of louver systems to maintain the same architectural sightlines and mode while providing desired functionality.

Windows and vents [edit]

Near curtain wall glazing is stock-still, pregnant in that location is no access to the outside of the edifice except through doors. However, windows or vents can be glazed into the curtain wall system equally well, to provide required ventilation or operable windows. Nearly any window type tin can be made to fit into a mantle wall organization.

Fire safety [edit]

Firestopping at the perimeter slab edge, which is a gap betwixt the floor and the mantle wall, is essential to slow the passage of fire and combustion gases between floors. Spandrel areas must have non-combustible insulation at the interior face up of the mantle wall. Some building codes crave the mullion to be wrapped in oestrus-retarding insulation near the ceiling to forbid the mullions from melting and spreading the fire to the floor higher up. The firestop at the perimeter slab edge is considered a continuation of the fire-resistance rating of the flooring slab. The mantle wall itself, even so, is non ordinarily required to have a rating. This causes a quandary as compartmentalization (fire protection) is typically based upon airtight compartments to avert burn down and smoke migrations beyond each engaged compartment. A drapery wall by its very nature prevents the completion of the compartment (or envelope). The use of fire sprinklers has been shown to mitigate this affair. Equally such, unless the edifice is sprinklered, fire may all the same travel up the drape wall, if the glass on the exposed flooring is shattered from heat, causing flames to lick upwards the outside of the building.

Falling glass tin can endanger pedestrians, firefighters and firehoses below. An case of this is the 1988 Starting time Interstate Belfry fire in Los Angeles, California. The fire leapfrogged up the tower by shattering the glass and and then consuming the aluminum framing holding the glass.^[9] Aluminum's melting temperature is 660 °C, whereas building fires tin can reach one,100 °C. The melting bespeak of aluminum is typically reached within minutes of the first of a fire.

Fireman knock-out glazing panels are often required for venting and emergency admission from the exterior. Knock-out panels are generally fully tempered drinking glass to allow full fracturing of the panel into small pieces and relatively safe removal from the opening.

Maintenance and repair [edit]

Drapery walls and perimeter sealants require maintenance to maximize service life. Perimeter sealants, properly designed and installed, have a typical service life of 10 to 15 years. Removal and replacement of perimeter sealants require meticulous surface preparation and proper detailing.

Aluminum frames are by and large painted or anodized. Intendance must be taken when cleaning areas around anodized fabric every bit some cleaning agents will destroy the finish. Factory applied fluoropolymer thermoset coatings have practiced resistance to environmental degradation and require merely periodic cleaning. Recoating with an air-dry fluoropolymer blanket is possible only requires special surface training and is not as durable equally the baked-on original coating. Anodized aluminum frames cannot be "re-anodized" in identify but can be cleaned and protected by proprietary clear coatings to improve appearance and durability.

Stainless steel mantle walls require no coatings, and embossed, equally opposed to abrasively finished, surfaces maintain their original appearance indefinitely without cleaning or other maintenance. Some especially textured matte stainless steel surface finishes are hydrophobic and resist airborne and pelting-borne pollutants.^[x] This has been valuable in the American Southwest and in the Mideast for avoiding dust, as well as avoiding soot and fume staining in polluted urban areas.

Encounter also [edit]

• Mullion wall
• Insulated glazing
• Quadruple glazing
• Copper in architecture

References [edit]

1. ^ "History". Oriel Chambers. Retrieved 27 July 2009.
2. ^ "History". janwillemsen. Baronial 2013. Retrieved 15 March 2014.
3. ^ "Omni San Diego Hotel offers breathtaking Bay views through Wausau's curtainwall", Wausau Press Releases, Retrieved two October 2015
4. ^ 2006 International Building Code, Department 1602.1
5. ^ "Minimum Design Loads for Buildings and Other Structures," American Gild of Civil Engineers, 2005; Chapter six
6. ^ "Minimum Blueprint Loads for Buildings and Other Structures," American Order of Civil Engineers, 2005; Affiliate 7
7. ^ "Blueprint of Buildings to Resist Progressive Plummet," UFC 4-023-03, U.Due south. Department of Defense force, 2009
8. ^ Testing is typically conducted by an independent tertiary political party bureau using the ASTM E-783 standard.
9. ^ "Technical Report, Interstate Banking company Building Fire". U.s. Fire Administration. Archived from the original on 13 July 2010. Retrieved 21 Nov 2009.
10. ^ McGuire, Michael F., "Stainless Steel for Design Engineers", ASM International, 2008.

External links [edit]

• European Commission'due south portal for efficient Curtain Walling Archived 23 September 2015 at the Wayback Machine
• EN 13830: Mantle Walling - Product Standard
• EN 13119: Curtain Walling - Terminology
• Understanding Curtain Wall & Window Wall differences

Source: https://en.wikipedia.org/wiki/Curtain_wall_%28architecture%29

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