Architectural Glazing Glossary

Architectural Glazing Glossary

 

 

The world of contract glazing is extremely technologically advanced and, as a result, can sometimes be confusing. We’ve taken the time to craft an industry glossary in order to assist designers, project architects, fellow glaziers, architecture students, engineers and anyone else interested in learning more about some industry terminology. We’d like our readers to fully understand our featured content and projects and truly hope this glossary assists on that front.

 

901 Fitting: A Pilkington Planar™ countersunk bolt fitting designed to transfer glass loads. It can be connected to spring plates or spider fittings without access the back of the fitting. Also known as a “blind” fitting.

 

902 Fitting: A Pilkington Planar™ bolt fitting with a countersunk, flush head designed to transfer glass loads. It directly fixes to a back-up structure by means of stainless steel spring plate bracket or a spider casting. In addition to vertical walls, this fitting can accommodate any slope making it the perfect choice for use on roofs, canopies, and skylights.

 

905 Fitting: A Pilkington Planar™ bolt fitting with a countersunk, flush head designed to transfer glass loads. It attaches to a stainless steel rod connected to a back-up structure. This fitting can be articulated to create faceted facades. This fitting can be used on vertical and sloped walls, canopies, roofs, and skylights.

 

Adjustable Jaw Turnbuckle: A termination assembly that can be used on the end of tension cable or rod that had a telescoping end concealing threads. Aside from adjustability, this provides an aesthetically pleasing machined termination for vision areas in lieu of a much larger steel assembly.

 

Bow: The amount of curve over the length of glass to greatest deviation of flatness.

 

Cable Net Wall: A tension facade system that uses both vertical and horizontal cables or one-way vertical stainless steel tension cables or rods that are pre-tensioned from the boundary structure to act as support for bolted glass panels to be be hung off of. A simplistic way of thinking of this is that of stringing a tennis racket. A surrounding frame is built with cables brought across it and those cables are pulled tight and locked in place.

 

Clevis: See spelter, swage stud, adjustable jaw turnbuckle, and fixed jaw assembly.

 

Component Warranty: A manufacturer’s warranty on a specific product that is used in an assembly only. This is not the same as a single source “system” warranty.  

 

Edge-Dip: The amount of deviation at the edge of the glass from the tempering process.

 

Fixed Jaw Assembly: A termination assembly that can be used on the end of tension cable or rod that is fixed in place. This provides an aesthetically pleasing machined termination for vision areas in lieu of a much larger steel assembly.

 

Glass Fin Wall: A type of point-supported structural glass system that uses vertical, tempered glass mullions also know as “fins” as a structural support. These glass fins can be ¾-inch (19mm) tempered or multi-ply laminated glass make-ups. Fins are generally suspended from structure above in most applications above 26-feet or in high seismic zones.

 

Gusset: A steel plate with that is bolted or welded to steel to accept a Pilkington Planar™ fitting or spring plate.

 

Heat Soaking: A process of reheating fully tempered glass in a chamber and holding it at a constant temperature for a duration of time then cooling back down. This process can be 2-8 hours depending on the manufacturer and standard. It helps to reduce the probability of spontaneous breakage due to a nickel sulfide inclusion. Glass that may have inclusions has more of a propensity to break in the heat soak chamber than in service from this process. See Spontaneous Breakage.

 

Hybrid Tension Structure Facade: A kind of tension facade system that often utilizes 1”-2” thick horizontal steel plate beams, that can vary in depth, to brace the system for wind load behind the horizontal joints. These plates beams are combined with vertical stainless steel sag rods/cables to support the dead load of the glass and pick up some of weight of the beam between attachment points at the building columns. The resulting structure helps to spread out the forces put on the building into both the columns and the head of the wall, while keeping the sightlines very clean inside and out. 

 

Infill: A type of material glazed directly into unitized curtain panels. Infill materials can be any material that is inserted into the curtain wall panel between extruded aluminum support mullions. Traditionally, they have typically been composed of vision glass or spandrel glass, but can also be made of metal, terracotta, and stone. Infills can also be operable and automated. 

 

Iridescence/Leopard Spots: When heat strengthened or tempered glass is viewed in polarized light, stress patterns called “leopard spots” or “iridescence” may become visible. This phenomenon is unavoidable and can be present from the tempering process.

 

Longhorn Fitting: A custom machined Pilkington Planar™ 905 rod fitting that is clamped to a cable or rod. 

 

Mullion: A support member anchored vertically or horizontally to be a rigid support to transfer loads of a material back to structure. See Stick-built System,  Structural Glazing System, and Unitized Curtain Wall.

 

Patch Fitting: A fitting that clamps face glass to a structural element to hold it in place. This can be connected to another piece of glass, a tension cable/rod, or a steel mullion.

 

Point-Supported Structural Glass System: A structural glass system that consists of tempered glass with holes allowing for attachment to a structural member by using bolted or clamped fittings. The structural glass is hung off of a back-up support structure in most cases. These structures can be tempered glass fins, steel members, or stainless steel tension cable structures. See The Pilkington Planar™ System.

 

Portal Frame: An entrance frame constructed to separate a suspended structural glass wall from the base loaded entrance doors. These frames can be made of hollow tube steel sections clad in stainless steel or painted steel/stainless steel custom fabricated plate beams or shapes. Depths will vary on each application.

 

The Pilkington Planar™ System: A type of custom point-supported structural glass system developed by Pilkington Architectural that is manufactured in St. Helens, United Kingdom. W&W Glass, LLC is the exclusive distributor for Pilkington Planar™ structural glass systems throughout North America. This product comes with a system warranty for twelve years from date of production/shipment on design, engineering, materials, and installation. It also features one of best roller-wave flatness tolerances on tempered glass in the industry at 0.0007-inches per foot or 0.02-millimeters per meter peak to valley.

 

Roller-wave Distortion: The deformation of glass on the rollers due to the tempering process where the glass is heated and cooled. It is measured from peak to valley per foot or meter taking the average of the high and low point deviations using a zebra board or electronic scanning device. There is no industry standard to quantify roller-wave distortion tolerance, just a general recommendation of no more than .006” peak to valley per foot. However, this deformation can be specified and controlled with better processing techniques and equipment. The Pilkington Planar™ System has an average peak to valley roller-wave distortion of 0.0007” per foot (.02mm per meter) on all tempered glass, which is the best in the structural glass industry.  

 

Single Source System Warranty: A comprehensive single source manufacturer warranty on the design, engineering, components, and installation by a single product manufacturer. This is not the same as a component warranty. See Pilkington Planar™ System.

 

Sloped (Overhead) Glazing: A type glazing that is horizontal or sloped to form a skylight or canopy. These must use laminated glass or insulated laminated glass units with the laminated glass facing the occupant side for fallout protection. Sloped or overhead glazing is subject to permanent gravity load from its self-weight and depending on the location, long-term gravity load from snow drift.

 

Sotawall® HYBRID-WALL®: A versatile, proprietary curtain wall system developed by Sotawall®. These HYBRID-WALL® systems can have integrated vision and spandrel materials combined inside a single unitized panel, which may be a preferred choice over window wall and slab edge cover systems due to better air and water penetration performance and less potential for leaks between systems on mid to high-rise construction.

 

Spelter: A termination for tension cables that may be closed or open depending on connection details. These are generally used in applications for larger diameter cables where the cable termination can be hidden from view.

 

Spider Fittings: A cast stainless steel fitting with armatures to accept bolt fittings to connect back to a back-up structure. These fittings can accept Pilkington Planar™ 902 or 901 fittings. See 902 Fitting and 901 Fitting.

 

Spontaneous Breakage: A phenomenon that causes fully tempered glass to break spontaneously due to the expansion of a nickel sulfide (NiS) stone (particle inclusion) trapped inside the tension layer of glass. When the stone expands due to a phase transformation from in-service temperature exposure (from alpha to beta phase), the glass can spontaneously break. See Heat Soaking. 

 

Spring Plate: A stainless steel angle that is connected to a back-up structure to accept fittings. These are most often used with Pilkington Planar™ 902 or 901 fittings.

 

Stainless Steel Cable: A tension cable comprised of stainless steel strands in a wire rope or structural strand configuration. 

 

Stick-built System: A curtain wall where long vertical pieces of aluminum (hence the name stick) are anchored between floors and horizontal mullions are set between vertical members to support and transfer the loads of the glass or infill material back to structure. Most of the erection and glazing for a stick-built system is done on site.

 

Structural Glazing System: A structural glazing system, in its simplest form, is a type of curtain wall system that consists of glass that is bonded or anchored back to a structure without the use of continuously gasketed aluminum pressure plates or caps.

 

Swage Stud: A threaded stud termination at the end of a cable. This allows for locking the cable in place with a nut on the end using mechanical engagement.

 

Tension Box Assembly: A galvanized steel box that a cable end will pass through and be locked in place. A hydraulic jack tensioning device will then pull the cable tight against the tension box assembly.

 

Tension Cable: A cable constructed of wire strands twisted around a core that is used in tension in structural applications. Cables can be constructed of stainless steel or galvanized steel with wire rope, structural strand, or fully locked configurations depending on the application. For structural elements, structural strand and fully locked are the most commonly used. Since each construction has it’s specific uses and limitations, it is recommend that a system supplier is consulted for selection. 

 

Tension Facade System: A point-supported system that uses high tension cables or stainless steel rods to impose the loads of the facade onto main structure. This decreases the amount of solid structural elements visible on the project and in many cases depth of the support structure, therefore increasing the transparency of the facade.

 

Unitized Curtain Wall: A curtain wall system that is composed of large panel assemblies that are fabricated into aluminum frames and pre-glazed within a factory with infill materials (fixed glass, operable windows, metal panels, terracotta, etc.) and then sent to the construction site for weathertight installation. Once on site, the units can then be hoisted onto anchors connected to the building.

 

Vertical Glazing: Any curtain wall/structural glass panel that is oriented vertically on the facade. This glazing may be comprised of monolithic, laminated, insulating glass units, or insulated laminated units. The glass can be tinted, annealed, heat-strengthened, tempered, low-e coated or even painted with colored silk-screened ceramic frit patterns. 

 

Vestibule: A vestibule is a small space or entranceway most often employed in all commercial and institutional buildings to provide a passage to connect the exterior and interior environments. These entryways serve to act as a transitional barrier from the weather outside.

 

Warp: The amount of twist or curve diagonally from corner to corner.

 

Do you have any questions about any of the included terms? Do you have a term you’d like to see added to the list?

 

Please comment below and we’ll respond as soon as we can.

Top 5 Structural Glass Misconceptions

There are a lot of misconceptions about point-supported structural glass systems out there. Having over 30 years experience in the structural glass business, we’ve heard a lot of reasons why structural glass systems are “value engineered” out of a project early on in the design phase from architects and contractors alike. If you’re a designer or a building owner interested in using structural glass systems, you’ve probably heard a few of these concerns yourself during project discussions. In this blog, we’ll have a look at the top five misconceptions about structural glass systems (counting down to the biggest misconception) to help put your mind at ease. This perspective is taken from the system manufacturer/installer’s point of view… someone that provides budgets for these every day. Experience says, “Ask more questions to become more knowledgeable. Don’t always believe the hype.”

 

5. Structural Glass Systems are Too Expensive!

 

How often have we heard this one? Cost is one of the first things that comes to mind when a consultant, general contractor, or construction manager looks at a potential component for the building. It can be tempting to throw out a square foot number on something that scares off the architect/client from using a particular type of system. However, it is important to understand that there are many factors that determine the price of a structural glass system. The module width and height, number of points of support, glass make-up (thickness and performance) required, back-up structure, etc. are all important factors to understand. These factors should be considered based on project requirements like wind load, live load deflections, seismic criteria, maximum snow drift load (if a canopy or skylight), acoustics, and any impact or blast resistance criteria before any budget pricing takes place. Many of these items can be quickly vetted out by a structural glass systems engineer before an arbitrary number is put on the table. Be sure to speak with a point-supported structural system manufacturer on approximate rough budget costs before going too far down the road with details. They can best advise you of potential cost savings measures by modifications in design if there is a budget range in mind. System pricing can vary greatly depending on requirements. We can help advise of the best solution within a prescribed budget.

 

Additionally, glass types and make-ups are rated at different optical and thermal performance levels. Finding the one that is right for your project depends on the unique requirements of the building. For example, the type of glass you choose can strike a balance with visible light transmittance, thermal performance, and the type/size of HVAC mechanical heating and cooling systems used. This trade-off may provide a cost savings in building overhead and maintenance by downsizing the HVAC system by using a slightly more expensive high-performance coated structural glass make-up. It also depends on the amount of glass. A project that uses a larger amount of structural glass area will have a better economy of scale on a cost per square foot basis. It’s all a balancing act.

 

This is why it’s important to have a system supplier on board early in the design process. At the very least, making a call or exchanging an email with some sketches with a supplier to discuss up front budgets can put to rest many fears about the cost of these systems.

 

4. I’ll Just Spec the Same Glass I Have in the Aluminum-Framed Curtain Wall for the Point-Supported Structural Glass in the 088000 Specification Section to Match.

 

It can be tempting to use the same glass that you’ve already specified elsewhere, but it is important to understand that structural glazing components are inherently more expensive than standard curtain walls. The rigors put on point-supported glass to limit deflection and stress at specific points without risking breakage at the holes or fittings are much higher than the edge loads of that on a continuously supported unit backed up with aluminum mullions. Structural glass requires much heavier make-ups than typical one-inch insulating glass units. Often the outer lite needs to be stiffened using ⅜” or ½” glass and there are special “bosses” that transfer the load through the holes. The whole unit needs to be flexible to a certain degree while maintaining the air seal. In the event of over deflection, the PIB sealant shears allowing condensation to form inside; this is also known as a seal failure. It’s very important to make sure the glass and fittings are manufactured and engineered together to help prevent these types of issues.  

 

 

 

Above: Photo of Pilkington Planar “boss” in an insulating glass unit.

 

Each project requires different kinds of glass. Coating and size availability, required thicknesses, product sourcing, roller-wave flatness (optical distortion), fabrication tolerances, interactions with fittings, and system warranties are all important aspects of structural glass that you have to take into consideration. We recommend using a separate spec section. Section 089700 can be used for the structural glass wall system specification, which should include glass type and make-ups as it is integral to a complete system warranty. The Pilkington Planar System™ carries a 12-year complete system warranty covering design, engineering, materials and labor. It’s one of the most comprehensive in the industry. Other manufacturers may offer only component warranties on glass, fittings and engineering separately or offer other coverage durations. Be sure to ask to get a sample warranty to better understand exactly what is covered by the vendor.

 

Again, you won’t know the kind of glass your project requires until you speak with a structural glass system supplier. This will prevent major problems later in the bid phase due to increased glass thicknesses and system costs. Each vendor will do their own calculations in most cases, but it is important to get an idea going in from a budget and design standpoint.

 

3. I Don’t Want to Draw in Anyone’s System Details. The Details Will Show the Intent Only.

 

Point-supported systems like Pilkington Planar™ are designed specifically on a case by case basis to be tailored to individual project requirements. Therefore, not all projects use the same fittings. They are customized as required, but work off of a similar design concept. Without discussing the project with a structural glass vendor, it is entirely possible that your design may not be possible as envisioned.

The design principles for the Pilkington Planar™ are proven through in-house and independent laboratory testing. Be sure you review test reports from structural glass system manufacturers to verify these systems meet or exceed the design criteria for your project. If these reports are not satisfactory or readily available, be sure to require that specific tests be performed in the specifications. This will ensure you are receiving the highest quality product to limit potential liabilities down the road.

 
  

2. I Want a Competitive Bid. I Need to Include Multiple Glass Suppliers in the Spec.

 

A common line of thinking is that you choose a company to do all the design work and budgeting, and then pick three or four other structural glass suppliers as alternates that meet specifications. The problem with this thinking is that the vendors may not always be qualified to meet all of the same system requirements specified. More often than not, they don’t meet all of the requirements, so be sure to do some research to check them out. There are many companies that only make components (glass, fittings, structure) and then subcontract out engineering services or vice versa. If this is the case, how can you know who is really responsible for manufacturing the “system” if there is an issue? Is it the glass manufacturer, the fitting supplier, the engineer or the installer?  

 

Do your homework to make sure the quality level of the bill of goods expected to be installed on the project is what they actually get. Make sure the list of approved manufacturers specified meet all of the criteria of the basis of design. This isn’t as easy as picking names out of a directory or performing a Google search for “structural glass”.

 

When glaziers bid a specified structural glass system, they are usually looking to have a fully fabricated and engineered package to install. There is a high degree of risk in attempting to bid an unspecified product, let alone the additional time it takes to cobble together a system and get it tested to pass to meet spec in most cases. If a substitute was proposed and rejected or the quality level installed was not acceptable, they may not get paid until approved or replaced with an acceptable product. They bear the ultimate risk being accountable for providing systems per the bid contract construction documents. Their livelihood is based on providing a properly warranted product installation that meets owner expectations to help them to secure the next project.

 

Unfortunately, in this day and age, we have seen glaziers come and go. Even long-term businesses have closed their doors due to tough economic conditions. A structural glass system warranty from a glazier, usually covering only a few years, will certainly not suffice in most cases. You want to make sure the system is warrantied by a reputable manufacturer that can stand behind it for many years to come.

 

1. Glass is Glass and Structurally Glazed Systems Look Pretty Similar.

 

This is one of the biggest misconceptions in the glass industry that is shared by many people inside and outside of the architectural community. In essence, yes, all glass products act as a translucent enclosure or cladding to keep the weather out. However, there are many differences in quality, performance, and perceived value. A great reference point in understanding these differences in fabricated glass products is by comparing two brands of cars like Kia versus  Cadillac. A Kia comes with many standard features. It can get you from point A to point B and comes with a warranty, but would you say it’s interchangeable for a Cadillac? Do they look and perform identical? Most people would say that they are not the same level of quality and performance. Even if some of the visual cues look similar from a distance, up close there are measurable differences. If you had said that they are identical, then you may be accepting any car someone can manufacture with a warranty.

 

The same can be said of fabricated glass. When looking at a feature glazing area of a building, do you want your clients to perceive a Kia… or a Cadillac. How about a Mercedes? There are many price points within the realm of structural glass that are heavily influenced by the design, back-up structure required, and budget. The quality level, however, must be specified so that you get that Cadillac or Mercedes perception. You get what you pay for in this regard, and it all depends on how you want to differentiate your building from the rest.

 

Structural glass is used almost exclusively for feature areas of projects where clients want a more transparent look from inside out and outside in. They don’t want large aluminum vertical mullions and horizontals, or additional steel supports coming across to break up spans. It’s an inherently more expensive option due to the face glass and back-up structure doing all of the work as mentioned above. These systems may look similar from a distance at night, but that’s not when most people are viewing these feature areas. Most are looking to utilize the atrium and lobby spaces during business hours. That’s where these transparent structural glass systems really shine.

Interior structural glass fin wall atrium at the AMC Theater in Los Angeles, CA (left). Interior curtain wall in the Overture lobby (right). Photo credit: Zane Williams Photography.
 

It needs to be visually appealing, distortion-free as possible, and crisply reflect the surroundings while providing a clear view inside and out. Since these systems use tempered glass for added strength, there will be roller-wave distortion that is inherent in the process. This can be controlled with the proper equipment and processing techniques.

 
 

 

 

Pilkington Planar structural glass at the Beverly Center in Los Angeles, CA (left). Structural glass system with high visual distortion in NJ (right).

 

 

The fittings need to be kept as small as possible to minimize detection and should be spread out as far as possible to keep things light. Not all fittings from manufacturers are created equal and not all glass is tempered the same. We generally use ¾” exterior countersunk, flush bolts with the Pilkington Planar™ system to keep the fittings as small and unobtrusive as possible. Others may use larger disks and caps. Each manufacturer has its own design parameters and tolerances to be aware of.

 
 

 
 

Pilkington Planar system with flush countersunk bolt 905 fittings in Manhattan (left). Another structural glass system in Manhattan with spider castings and caps (right).

 

There is no doubt that there is a difference when it comes to the design and fabrication of standard glass in aluminum curtain wall versus custom tempered structural glass and fittings for point-supported glass systems. That’s why it is always important to discuss your options with a system supplier from the beginning. They can clear up any misconceptions about structural glass early on for your next project, and ensure you are receiving the highest quality product that meets the exact project requirements. If you have any other questions about structural glass systems or are looking for help on starting a project, feel free to contact us and we’d be glad to assist.

 

W&W Glass LLC is a family owned business with a 70-year history in the metal and glass industry, one of the largest metal and glass companies in the New York metropolitan area and the largest supplier of structural glass systems in the country. We have over two decades of experience in the design and installation of various building enclosure systems, including stick-built curtain walls, pre-glazed unitized curtain walls, Pilkington Planar™  structural glass facades, and custom metal and glass enclosure systems. We install all of our work with our own dedicated union labor force. W&W is consistently the largest employer of glaziers in the NY metropolitan area.

 

What is a Facade Retrofit?

Building facades don’t always age gracefully. Over the years cracks can appear in concrete, leaks can arise due to damaged silicone joints and glazing gaskets, metals rust, and building maintenance can become much more expensive due to rising operating costs and poor energy efficiency of outdated systems. More often than not, some of this energy inefficiency can be attributed to old non-thermally broken steel or aluminum curtain wall systems. The same can be said for older glazing that may be monolithic or insulating glass without high performance low-e coatings. If these aren’t enough reasons for building owners to consider their options of facade replacement or complete demolition and building new, there is also the pressure to try to attract new tenants or to increase rent by modernization of an antiquated looking exterior (in addition to adding amenities and interior upgrades) to meet current design trends and client needs. If the rest of the project’s structure is sound and intact, it may be a prime candidate for a facade retrofit. In this blog, we will look at the reasons to consider a retrofit for office buildings and the process behind it.

 

 
 
330 Madison Ave. before the façade retrofit.
 
There are a few main reasons why a building might benefit from a facade retrofit. These retrofits can provide new life to a building as shown in the before and after photos of 330 Madison Avenue. In most cases, fixing the current facade is not an option. The systems are obsolete and beyond repair. The building may have air and moisture leakage issues and may not have acceptable thermal or acoustical performance that meets today’s standards. This could cost more money in operating/maintenance costs to the owner and tenants. A reclad will not only fix these problems, but also allow the building to still be fully operational with minimal disruption to tenants. This ensures that the owner can still keep the space occupied, bringing in revenue while the update is taking place, without having to shut down for a long period of time. 
 
 

 
 
Left: 330 Madison Ave. façade retrofit in progress. Right: Completion of the retrofit.
 
 
Full building demolition can be costly and very difficult with larger buildings in major cities. The demolition process can be slow and potentially dangerous when dismantling the entire structure in a tight lot. Also, the timeline to build new can be two to four years from concept design until the new project is complete for occupancy. This means that the owner can’t make income from the property for a long time. Recladding can be a great alternative solution.

 

Sometimes an older building just needs a new look in order to attract new clients or catch up with the times. Retrofitting allows old projects to look brand new to attract higher-paying tenants willing to sign a long-term lease. Our work at 100 Park Avenue in New York City is a great example of a commercial building reclad that used a high performance unitized curtain wall system to do just that.

 

 

 

 

Facade retrofits allow for a wide range of materials and visual design language to be incorporated into the new exterior enclosure. Many times, owners or development teams are required to file for a zoning variance to allow for the new façade to encroach further out over the property line. This variance can be helpful in the creation of a more prominent, deep facade or due to the fact that the old facade may need to remain in place during the installation of the new building skin over top. The unitized curtain walls installed during the reclad can often include infills such as terracotta, stone, custom insulated panels, or metal plate in various finishes to completely change the look of the building. 

 

Architectural designs for facade retrofits are developed based on the premise of fitting new high performance curtain wall and window systems within existing building conditions. Sometimes old architectural and structural drawings aren’t always accurate, so some demolition probes are done to find the exact locations of main structural components. Retrofits require close coordination between the design team and the glazing subcontractor to make sure the system can be installed and sufficiently anchored off the current structure.     

 

Unitized curtain wall system panels for the reclad will include fire-rated spandrel or shadow box assemblies. Panels are shop fabricated to control quality and expedite installation time on site. Meanwhile, holes are demoed back to structure through the current façade for new anchors to be attached. The building will then be reclad top to bottom or bottom to top depending on the installation sequence required for the panels.

 
 
 
 
Once the building reclad is weathertight, the interior demolition can begin. In this stage, the contractor either takes out vision area glazing and curtain wall or puts in new operable windows depending on the type of system. Fire safing of areas at each slab level must be put in between the systems, and interior closure metal may be installed to cover the space between the old and new facade head and sill at each floor slab.

Again, all of this demolition and installation can often be completed while the building is still fully or partially occupied. The goal is to be as accommodating as possible to limit disruption during normal working hours of the current tenants. This often means most of the work is done during the early morning or at night.

 

It’s also important to understand the logistics and structural design tolerances of a facade reclad on a project to project basis. For example, a site like 655 Madison Avenue may be more difficult to work on if there are other buildings and roads within close proximity. They can make it difficult for deliveries to be made and material to be staged for installation. Accommodating higher live load slab deflections can also be problematic depending on when the building was designed due to the added weight of another facade on the columns and beams.

 

Facade retrofits are a great choice for projects that need renovation due to energy performance or simply need a new look to draw in new businesses. They are an efficient solution that can keep your building operational and can make your building look great without the expenditures of complete demolition and reconstruction. If you think your next project could be a facade retrofit, feel free to contact us and we’d be glad to help you out! 

 

NEW FAÇADE RETROFIT PROJECT ANNOUNCEMENT!

 

Recently, W&W Glass was awarded the reclad/repositioning of the iconic Time-Life Building at 1271 Avenue of the Americas at Rockefeller Center by Turner Construction Company. The 48-story building, previously designed by Harrison, Abramovitz, & Harris, was built in 1959. World-renowned architect Pei Cobb Freed is the design architect for this complete renovation. World-renowned architect Pei Cobb Freed & Partners is the design architect for this complete renovation.

 

Our installation scope will include 430,000 square foot of Sotawall® unitized curtain wall, Erie Architectural Products Enviro/Facades™ custom-fabricated storefront systems and new all glass entrances. More info is to come, so please stay tuned for future updates.

 

 
 
 
 
W&W Glass LLC is a family owned business with a 70-year history in the metal and glass industry, one of the largest metal and glass companies in the New York metropolitan area and the largest supplier of structural glass systems in the country. We have over two decades of experience in the design and installation of various building enclosure systems, including stick-built curtain walls, pre-glazed unitized curtain walls, Pilkington Planar structural glass facades, and custom metal and glass enclosure systems. We install all of our work with our own dedicated union labor force. W&W is consistently the largest employer of glaziers in the NY metropolitan area.

Laminated Glass Fins vs. Tempered Monolithic Fins: Guidelines for Point Supported Glass Applications

If high transparency is a goal for a feature glazing area on your next project, odds are you’ve started looking at point supported glass fin walls as a potential solution. They offer a highly transparent, modern look to any building. With new technology currently available in the market, these systems have the ability to reach new heights with far less mechanical connections. Latest advances in engineering, and improvements in glass fabrication processes and equipment have allowed designers to push the boundaries of what structural glass systems could previously do, making them an excellent choice for your next tall, unsupported span curtain wall area.

 

 
 
In the 1990s and 2000s, most glass fin wall systems utilized ¾” tempered, monolithic vertical glass fins, hung from structure above, with mechanical bolt fitting connections like Pilkington 905 fittings or spider castings to anchor the face glass to the fins at every vertical joint. These Pilkington Planar™ systems performed well for high-span applications, having been fail-safe tested up to 40’-50’ tall without any progressive collapse issues. However, these fins required the use of anti-buckling cables to limit twist at greater heights. They also tended to be extremely deep, taking up over two to three foot of precious lobby/retail space at the base. Architects were looking for a solution for this design issue… they found it with Dupont SentryGlas interlayer laminated, tempered glass fins.
 
 
 
 

The main advantage of using Dupont SentryGlas interlayer laminated glass fins over tempered fins is to add the composite strength of two or three laminated glass lites in lieu of only a ¾” monolithic lite. It allows for shallower fin depths and additional resistance to buckling on spans greater than fifty feet tall without the use of the anti-buckling cables that would otherwise be required. The newest laminated tempered glass fin technology even allows for laminated fins by the European manufacturer Sedak to be produced over 40 feet tall in one piece without using mechanical stainless steel splices to connect smaller fins together! This technology does not come without it’s own set of challenges, however. Procurement, installation, and replacement can often be cost prohibitive on many projects. We recommend that you reach out to prospective vendors to check on manufacturers’ maximum fabrication sizing available, roller-wave distortion tolerances for flatness, bow and warp, edge finishing quality, and glass alignment tolerance to be certain the glass can be produced to the clients specified quality control levels and verify associated system costs to assure product expectations are met within budget.

 
 
 
 

There are a few potential concerns to be aware of when using laminated glass fins. These systems may seem thicker than monolithic fins when viewed from the inside on an angle or from directly behind…even with ultra-clear, low-iron glass. This perception can be attributed to the exposed edges of the laminate, which may not match up cleanly between multiple laminated plies and may have some offset. There may even be a slight noticeable color visible at the interlayer edge between the lites. During laminated glass processing, the interlayer fills the gap between laminated glass lites, often appearing closer to ⅜” instead of ¼” actual thickness. While the interlayer is clear, it will still be somewhat visible when exposed vertically on the back edge of the fin unless a cap is used to obscure the back edge. Hole sizes may also be oversized to allow for tolerance, which could be considered a visual imperfection in some cases.

 

In some low-rise structurally glazed glass mullion systems, additional silicone adhesion surface is required to bond the face glass to the fins that are being used instead of mechanical fasteners through holes. These often require triple-ply glass fins that create much larger visible silicone joints from the exterior that could be as thick 1.5” or more; that’s almost double the size of a typical monolithic fin joint. This may or may not be acceptable to the client, so we always recommend making visits to projects that have a similar designs to ensure overall system quality and visual aesthetics.  

 

Still not sure about what may be the best option? W&W Glass is here to help with free design consultation and specification assistance to make sure you have exactly the right customized Pilkington Planar™ system for your next project. Be sure to visit our Pilkington Planar™ system website for our latest completed projects and stay connected on new projects and industry trends by joining our LinkedIn or signing up for our W&W Glass Facades e-newsletter.

 

W&W Glass LLC is a family owned business with a 70-year history in the metal and glass industry, one of the largest metal and glass companies in the New York metropolitan area and the largest supplier of structural glass systems in the country. W&W is the exclusive distributor of Pilkington Planar structural glass systems throughout North America to a network of qualified glazing partners for installation. We have over two decades of experience in the design and installation of various building enclosure systems, including stick-built curtain walls, pre-glazed unitized curtain walls, Pilkington Planar structural glass facades, and custom metal and glass enclosure systems. We install all of our work with our own dedicated union labor force. W&W is consistently the largest employer of glaziers in the NY metropolitan area.

Leveling the Playing Field: How Do You Know You Are Getting a Tested Point Supported Glazing System or Just Components?

Recent developments in point supported structural glass systems have afforded a wealth of options when it comes to designing feature areas of your building. However, as designs become more complex and buildings become increasingly more transparent, the technology behind the systems becomes more complex as well. The increasingly complex nature of point supported glazing systems makes it all the more important to understand if your system is fully tested to meet all of the specific criteria for your project.

 

 
 

Point supported glazing systems are made up of exterior face glass, stainless steel fittings, and a backup member/structure all working together to create a uniform assembly. Throughout the entire process, W&W Glass makes certain each component is rigorously tested and meets very high testing requirements. Heat Soak Testing helps to limit the statistical probability that glass with nickel impurities (also known as nickel sulphide inclusions) which can cause spontaneous breakage when the glass is in service, are broken in a test chamber instead of on the jobsite. Strain Gauge tests make sure that the countersunk holes drilled into the glass are capable of holding both vertical dead load, horizontal wind loads and even accommodating seismic movement. The Uniform Load test stresses the glass beyond its breaking point and ensures that the laminate layer and system will support the weight of the broken glass so that it can be safely braced to be changed. Finite Element Analysis shows how the glass will react to loading from anticipated stress conditions. The glass system then goes for various other tests for wind conditions, seismic resistance, water penetration performance and so on. A system manufacturer should have all of this information available for review from previous projects to ensure the system meets all project criteria.

 

There are also hardware and structural back-up system tests in place to ensure the whole system is structurally sound. “Spiders”, “patches”, or “905” type fitting systems are the most common in the industry and adhere to rigorous specifications based on the requirements of the building design. Various supporting structures are also tested and versatile enough to meet the desired aesthetics. Structural glass fins undergo buckling analysis to make sure they can support the proper load, especially for taller façades. Steel and tension supported structures allow for very high-tech innovative designs.

 
 

 
 

W&W Glass and Pilkington ensure that each component included in the Pilkington Planar point supported glazing system design is fully tested and fail-safe against progressive collapse (which is extremely important for glass fin walls). Pilkington never supplies hardware or glass produced by another company to ensure sole-source responsibility which allows them to offer a 12-year furnish and install warranty on the project to the Owner. Every part of the system is meant to work together to create the safest and most structurally sound design possible. With W&W Glass, you know you are getting the true Pilkington Planar system, and not separate glass and hardware components coupled with some engineering that may not work together from a firm that does not actually have a hand in manufacturing anything. Be sure to check specifications to ensure the quality levels and system testing required for your point supported glass system are being reached. Otherwise, buyer beware.

 

W&W Glass LLC is a family owned business with a 70-year history in the metal and glass industry, one of the largest metal and glass companies in the New York metropolitan area and the largest supplier of structural glass systems in the country. We have over two decades of experience in the design and installation of various building enclosure systems, including stick-built curtain walls, pre-glazed unitized curtain walls, Pilkington Planar structural glass facades and custom metal and glass enclosure systems. We install all of our work with our own dedicated union labor force. W&W is consistently the largest employer of glaziers in the NY metropolitan area.

The Latest Trends in Unitized Curtain Walls

The commercial glass and glazing industry is constantly evolving, and different trends are always entering the marketplace. Here, we’ll talk about some of the latest trends in unitized curtain walls.

 

One current trend is focused on the integration of multiple “infill” materials glazed directly into unitized curtain panels. Infill materials can be any material that is inserted into the curtain wall panel between extruded aluminum support mullions. Traditionally, they have typically been vision glass and spandrel glass (back-painted glazing with fire-resistant insulation materials behind that is located in front of floor slabs) to give the building a homogenous, fully-glazed “all glass box” look, but recently some other facade materials have been coming more into fashion like stone, metal, and terracotta.

 
 

 
 

Stone infills can be used for a unique flavor and design. Thin-cut stone panels are inserted within the same areas glass ones would normally go. The integration of this material not only offers a seamless look, but also a single source responsibility for a weather barrier within the same system, thereby limiting possibilities of leaks between trade areas. Some new stone materials being used are arriscraft, granite, marble, travertine, and limestone.

 

Another infill we have seen a rise in popularity with over the years is the use of metal panels. Metal panels can have various material compositions like aluminum plate, aluminum composite panel, stainless steel, copper, and zinc. They also create unique design feature opportunities through fabulous finishes, textures, and shapes available. Some of these options include: high or low visual reflectance of different materials, weathering of copper and zinc, brake formed shape designs of aluminum plate, and the full palette of flat or exotic metallic paint color finishes for aluminum panels available.

 

Terracotta Infills have also found a unique niche as an infill panel. These panels are light-weight and can create an interesting texture or rhythm to the façade. They are available in an array of colors, patterns, shapes, and sizes.

 

Sloping and undulating facades have become very en vogue on many high-end facades to set them apart from the traditional glass box shaped towers. The visual perception from the outside can be considered nothing less than a work of art.

 

 
 

Twin-skin or double-skin facades, a facade concept quite commonplace in Europe over the past decade due to the high cost of energy, have also been gaining more popularity in North America with the advent of the green building movement and higher LEED Certification goals for building sustainability. These building envelopes are bespoke systems built with an interior and exterior facade constructed in a way in which air is allowed to flow through the intermediate cavity. In cool climates the solar gain within this cavity can be used to offset heating requirements while in hotter climates, it can be used to decrease the cooling load making these systems functional and very visually distinctive.

 

Building in a sunny area? Custom sunshades are a great functional option. The design resources with these are truly limitless and give a very distinctive look to your building. Choosing automated sunshades, which is a modern feature, allows these shades to automatically move in order to afford shading and glare protection in specific areas of the building. Add sunshade louvers for an attractive look to your building that can be enjoyed from the inside and out. Some examples of sunshades are aluminum extrusion shapes, terracotta baguettes, mesh screening, formed mesh panels, formed metal panels, and glass louver blades.

 

Are you considering a unitized curtain wall as part of your next project? Contact us today to speak with a professional!

 

W&W Glass LLC is a family owned business with a 70-year history in the metal and glass industry, one of the largest metal and glass companies in the New York metropolitan area and the largest supplier of structural glass systems in the country. We have over two decades of experience in the design and installation of various building enclosure systems, including stick-built curtain walls, pre-glazed unitized curtain walls, Pilkington Planar structural glass facades, and custom metal and glass enclosure systems. We install all of our work with our own dedicated union labor force. W&W is consistently the largest employer of glaziers in the NY metropolitan area.

Should I Use a Unitized Curtain Wall or Stick-Built System?

Curtain walls can be defined as non-structural aluminum-framed walls, containing infills of glass, thin stone, or metal panels that are connected back to the building structure. There are two main categories of curtain walls: unitized curtain walls and stick-built systems. So how do you know which one is right for your building? 

 

 

Unitized curtain systems are composed of large glass units that are created and glazed within a factory and then sent to the construction site. Once on site, the units can then be hoisted onto anchors connected to the building. High quality, due to tight tolerances of fabrication in a climate-controlled environment, is only one hallmark of this type of system. Since there is no on-site glazing, another major benefit of using a unitized system is the speed of installation. The system can be installed in a third of the time of a stick-built system. This system is well suited for cases where there is a large volume of prefabricated unitized panels required, where there are higher field labor costs (thereby shifting the labor to a more cost-effective factory work force), where higher performance is needed (for wind loads, air/moisture protection, seismic/blast performance), for taller structures, and more regular conditions for panel optimization.

 

 

If your project doesn’t suit most of the criteria for a unitized system, your other option is to use a stick-built system. The vast majority of low to mid-rise curtain walls are installed in this way. Long pieces of aluminum (hence the name stick) are inserted between floors vertically and horizontally between vertical members to support and transfer the load of the glass back to structure. Most of the erection and glazing for a stick-built system is done on site. One of the benefits of stick-built systems is its economic friendliness for facades that have lower required volumes and many complicated conditions. The lead times for these types of systems are often much shorter for fabricated materials to be delivered to the site and allow for less up front staging. This is shorter in comparison to a unitized system, where six months to a year can be required for this process. However, the trade-off is that the installation takes longer to complete on-site. You also need a significant amount of space for installation and storage of material on the site, which can be difficult in many high-traffic cities with tight job sites.

 

Do you have questions regarding which type of system to use? Contact us today to speak with a professional!

 

W&W Glass LLC is a family owned business with a 70-year history in the metal and glass industry, one of the largest metal and glass companies in the New York metropolitan area and the largest supplier of structural glass systems in the country. We have over two decades of experience in the design and installation of various building enclosure systems including, stick-built curtain walls, pre-glazed unitized curtain walls, Pilkington Planar structural glass facades and custom metal and glass enclosure systems. We install all of our work with our own dedicated union labor force. W&W consistently is the largest employer of glaziers in the NY metropolitan area.

What is Structural Glazing?

Need a brilliant and cost-effective solution for contemporary glass design? Structural Glazing is your answer, systems that W&W Glass specialize in!

 

Structural glazing systems, in their simplest form, are types of curtain wall systems consisting of glass that is bonded or anchored back to a structure without the use of continuously gasketed aluminum pressure plates or caps. The glass can be comprised of monolithic, laminated, dual-glazed or even triple-glazed insulating glass units (IGUs). The back-up structure may use horizontal and/or vertical aluminum mullions or be a glass mullion, steel blade, cable or stainless steel rod. The interior and exterior may use extruded silicone/EPDM gaskets, or a wet sealed silicone depending on the system. This system creates a completely clean, flush exterior appearance while the interior members have many different options depending on design and budget.

 

So why would you want to go with a structural glazing system? Structurally glazed systems create a greater transparency than traditional captured systems. There are less visual interruptions due to the lack of metal on the exterior (and potentially the interior), creating a seamless, continuous glass look. Traditional captured curtain wall systems have pressure plates and caps that can conduct large amounts of heat in or out of the façade depending on the season. Since there is little to no exposed exterior metal, there is also less thermal bridging with structural glazing, saving on energy consumption costs. Now, let’s take a look at some of the different types of structural glazing systems in the market today.

 

 

A stick-built structural glazing system is one of the oldest and most conventional curtain wall types. It is assembled from similar components to that of a captured system, with the exception of an exterior aluminum pressure plate and cap with gaskets to hold the glass in place. It is either siliconed or toggle fastened in place on site depending on the manufacturer’s system. The toggled system glazing is predominantly shop fabricated to have either a channel bonded to the back of the glass with silicone, or to have the insulating glass spacer frame with a reveal to fasten to internally. These methods allow for dry fixing of the units on site to eliminate curing time. Otherwise, the systems that are wet sealed on site must have the glass temporarily clamped in place for 1-2 weeks to assure the silicone is fully cured before the exterior silicone weather seal is applied. Besides an exterior wet silicone/gasket seal, air and moisture control is achieved through what is called pressure equalization. Pressure equalization is a means by which air within the system located between the glass and aluminum mullions helps to drain water at each lite of glass (zone drainage) or at the base of the system (overall system drainage). These systems are often used for low-rise projects less than 15,000 sq. ft. of area, projects where the labor is less expensive, and projects with low repetition.

 

A unitized structural glazing system is a pre-assembled glazing system. Multiple glazing types and materials can be combined into one “unit” in a quality controlled shop environment. The glazing materials are siliconed in place and allowed to fully cure to give a similar flush exterior appearance to that of the stick-built system, without the concerns for weather conditions on site (as you should not silicone below 40 degrees Fahrenheit) and quality of sealant application on site by the tradesmen.  These units can be installed one panel tall and one panel wide or at times, two panels tall or two panels wide.  After the glass, spandrel materials, and anchors are glazed into unit frames within the shop, they are loaded onto flatbed trucks to be installed “just in time” at the job site. The units receive additional silicone/EPDM gaskets after they are set by crane from the outside, or from each floor to create the “stack joint”. The stack joint acts as the complete air and moisture barrier of the system allowing a weep at each floor. Unitized systems handle movement much better than most others because each panel is gasketed together to be able to move independently with the structure, and the additional movement capacity of the anchors. Generally, these systems are used on mid-rise to high-rise structures that are 20,000 sq. ft. and up where there is high repetition, tight job site access, and high installation labor costs.

 

 
 

Point supported glass systems are the most transparent structurally glazed systems available on the market today. They can be custom engineered to fit any opening. From the exterior, they have silicone sealants between the joints like other structurally glazed systems, but have far less obstructed views looking from the inside out and vice versa due to the elimination of vertical and/or horizontal aluminum mullions. When using glass fins as a vertical back-up structure, the whole façade can appear to be virtually transparent! Glass is held in at specific points using stainless steel fittings to transfer deadload and wind loads back to the structure. Most glass types are available for point supported glazing, including: insulating glass units, low-e coated glass, laminated glass, monolithic, etc. These glasses can be paired with a host of back-up structures to create vertical walls, roofs and skylights, canopies, elevator enclosures, or windscreens. There are many options available depending on design aesthetics, structure and budget constraints.

 

Vertical cable tension walls (sometimes also known as cable nets) are the thinnest point supported glass system structures that can make the tallest unsupported spans, but require the largest amount of load on the boundary structure and are usually the most expensive. There are also stainless steel tension structure systems that are deeper, but put less loads on the boundary structure; however, these systems have similar costs to that of vertical cable walls.  There can even be hybrid combinations of horizontal steel and cables/tension rods as well. Glass fin walls and glass on steel systems (steel tubes, plate beams, or pipes) are usually the least expensive option and put far less loading on the boundary structure. They do, however, require greater depth of the vertical members to resist loads. The depths can range from around one to four feet on average depending on spans and module widths. These custom designed systems allow for a lot of artistic creativity and flexibility from the design aspect. They are a great fit for an all glass entrance, lobby, atrium, cafeteria, or any other feature area of a building.

 

Are you ready to have a discussion about your project? Contact us today to speak with a professional!

 

W&W Glass, LLC is a family owned business with a 70-year history in the metal and glass industry, one of the largest metal and glass companies in the New York metropolitan area and the largest supplier of structural glass systems in the country. We have over two decades of experience in the design and installation of various building enclosure systems, including stick-built curtain walls, pre-glazed unitized curtain walls, Pilkington Planar structural glass facades, and custom metal and glass enclosure systems. We install all of our work with our own dedicated union labor force. W&W is consistently the largest employer of glaziers in the NY metropolitan area.

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