curtain wall

Acoustic

When adjacent to highways, rail tracks, airports or other noise sources, acoustic design of curtainwall systems is vital.

Finite Element Thermal Modeling Software

Widely used to predict thermal performance of untested or custom systems, or to estimate the performance of specific frame-glass combinations.

pipe spacer

(Part of "Double Angle" Mullion Anchor). Allows for thermal and side-to-side building movement of mullions, even when anchor bolts are securely tightened.

jack screw

(Part of Three-Way Adjustable Anchors) Stops the movement of a "saddle plate" attached to the side of the mullion, thus allowing the hoist to unhook and pick another unit, while the curtainwall is being set to its final position.

exterior glass/aluminum façade and enclosure systems have three important and primary functions

1. Water Management (keep water and moisture outside) 2. Air Infiltration Resistance 3. Thermal Insulation/Performance

Ideal splice location

20-22% of mullion span, at the zero moment point, where flexural stresses reverse from compression to tension at mullion flanges.

Condensation Resistance Factor (CRF)

A dimensionless ratio of surface temperature to ambient temperature difference.

Solar Heat Gain Coefficient (SHGC)

A dimensionless ratio of the total visible, infrared and ultraviolet energy flowing through glazing, divided by incident energy.

Thermal Transmittance

A measure of heat flow per unit time, area and temperature difference. - U-Value (or U-Factor) is measure in Inch Pound Units as BTU/hr.sqft.degF.

Blast Hazard Mitigation

A vital design criterion in many government and institutional buildings.

Three-Way Adjustable Anchors

Allow for in-and-out, up-and-down,as well as side-to-side adjustmentduring installation, and feature a "jack screw" for fine adjustment.

Solar Heat Gain Coefficient (SHGC)

Center-of-glass is always worse than "whole window", but requires no modeling

Visible Light Transmittance (VT)

Center-of-glass is always worse than "whole window", but requires no modeling

Simply Supported

Curtainwall members anchored only at their ends

Wind Load

Determining wind loads is the job of the building design team's engineer of record, not the curtainwall manufacturer. - Criteria should be listed on the first sheet of the structural drawings.

CRF 80

Highest performing curtainwalls

U= .20 BTU/hr.sqft.°F

Highest performing curtainwalls

Seismic Design

Specifications for projects in many areas of the U.S. dictate minimum movements and/or clearances determined by analysis of seismic design criteria. - One such criterion, "drift"

U= .60 BTU/hr.sqft.°F

Standard uncoated, insulating glass

CRF 52

Standard, uncoated, insulating glass

"Double Angle" Mullion Anchor

Straddles both sides of the vertical mullion, secured with a through-bolt and pipe spacer. - Typically attached to the face ofthe slab using insert weld plates,channel-shaped embeds, or expansion bolts drilled into thefloor slab.

Continuous Span

System's vertical mullions spliced at zero moment (inflection points).

Dead Load

Transferred from horizontal framing members to vertical mullions, and down to anchor points, where it is transferred to the building structure.

Curtain walls rely on two _____ at every lite to evacuate water. This allows the Curtain Wall to handle more water per lite.

weep holes

drift

the amount of inter-story building movement anticipated during a seismic event.

Storefronts rely on ________ to direct water down the vertical members to a sill flashing.

water deflectors

Store fronts

- Typically include commercial aluminum entrances - The Sill flashing must be able to accommodate the anticipated amount of water. - anchored at the head and sill allowing the jambs to move vertically in thermal expansion.

how many field seals do unitized curtain wall have

one

Shadow Box Spandrels

Incorporating a shadow box into the building design can give spandrel areas some transparency. -Shadow box's air cavity must be sealed nearly air tight relative to interior air in cold climates

Inter-story Movements

Live load movements result from all occupants, materials, equipment, construction or other elements of weight supported in, on, or by structural element that will or are likely to be moved or changed during the life of the structure.

Sun Shades

Louvers, blades, catwalk grids, and solid panels are used to meet aesthetic and daylight control goals.

Pressure Wall/Stick Wall

Many stick curtain walls are called "pressure walls," because exterior extruded aluminum plates are screwed applied to compress glass between interior and exterior bedding gaskets

Twin Span

Members spanning two floors and anchoring at the intermediate floor or other structure.

CRF 29

Non-thermal single glazed

U= 1.20 BTU/hr.sqft.°F

Non-thermal single glazed

unitized system

Only one unit-to-unit splice (usually a silicone sheet or patch) needs to be field-sealed, and only one anchor per jamb needs to be attached to the face of the floor slab.

Stick/Pressure Curtain Walls

Performance of any field-assembled or field-glazed curtain wall is only as good as field workmanship allows, limited by variables such as weather, access, and job site dirt and dust. - All stick curtain walls are field-glazed