Volume 48, Issue 10- October 2013
There’s an increasing population of spiders in the glass industry that’s made some people afraid. Spider fittings, that is. This type of hardware, commonly used in the design and installation of point-supported glass applications, has become a quick and easy purchase for just about anyone, anywhere. Of course spider fittings are just one option; there are a variety of hardware types and many are readily available.
“If you have a credit card you can get hardware. You can buy anything on the Internet,” says Mike Nicklas, business development manager with J.E. Berkowitz L.P. in Pedricktown, N.J. Nicklas says the crucial question is, will the hardware be able to handle the application in which it’s to be used?
He’s not alone. A number of companies involved with point-supported applications have seen applications constructed that include hardware from one source, glass from another and engineering from another. Where does the warranty and liability fall? Who will be responsible in the event of a failure? The answers are not clear and it can be frightening to contemplate. When it comes to point-supported glass there is no definitive code or standard to which the industry must adhere. Simply put: it’s not a practice for just anyone. The players are cautious—and advise others to be so as well.
The Apple Effect
“You can look at a structure and see the holes [the fittings] and then try and simply copy and paste it into something similar,” says Marcin March, a senior engineer in the New York offices of Eckersley O'Callaghan & Partners LLC, the structural engineers that have worked on many of the Apple projects. “To an extent you can, but it’s a risk. It’s a risk because you don’t really know what’s going [into it]. If you don’t do it right you can have failures; maybe not during construction but during the lifetime of the building.”
Nicklas agrees and says product accessibility and the interest from architects to design and incorporate it in both exterior and interior applications is growing.
“There is a concern that it all looks simple … but a lot more engineering science involving structural, mechanical, etc., [is involved],” says Nicklas. “Will it withstand the design loads, wind, snow, seismic loads? What are the safety issues? Life safety is a big issue and all that needs to be taken into consideration.”
As a glass fabricator as well as a supplier of a complete point-supported system, Nicklas says there have been instances where people come to them and just want glass. However, he says as they begin to ask questions about glass thickness and drilling holes in the glass, “you start to see they don’t understand fully what’s involved in these applications."
According to Jeff Haber, a managing partner with W&W Glass Systems LLC in Nanuet, N.Y. (the exclusive North American distributor of the Pilkington Planar System), the challenges companies can face have a vast range.
“They include everything from unrealistic budget expectations, glass sizes that are virtually unachievable, spec writers who water down the performance to the point where anyone who has any link to the glass business can be considered an expert,” says Haber. “There can also be a lack of understanding within the industry about how these systems work and why they need to be sold or designed by people who have a track record with complicated systems and or products.”
Beyond the glass and the hardware, another consideration is the structure to which the wall will be attached.
“There are a lot of steps even before we’re involved,” adds Bob Yemola, all glass doors/ engineered products plant manager with JEB. “To what are we attaching? What are the connections? There is a lot to consider even before you get to the glass thickness.”
Nicklas adds, “People think you just hang the glass on the channel and it lines up. But you start adding weight and the structure starts to deflect. It always works on paper but does it really work in reality? You have to design to meet those loads.”
For Haber, and others, the business of point-supported glass is serious—and the implications can be catastrophic.
“Everyone says it’s easy to be in this business. The problem comes when the glass and hardware are not designed to work together, tested together, if you have nothing to back up your analysis,” he says. “A finite element analysis (FEA) is garbage unless you have something to back it up. So considerations such as tempered stress, depth, quality of the holes in the glass … all are critical to the FEA being accurate (see page 49 to learn more about an FEA). Has that [information] been tested, checked against the FEA, etc. We’ve developed our code of practice strictly based on actual empirical testing. Thicknesses, make ups, number of holes, we’ve put pounds per square foot on them, tested them etc., and those points are based on actual elements. It’s output based on input.”
Mic Patterson is the director of strategic development with Enclos Corp., an Eagan, Minn.-based glazing contractor that is heavily involved with complex facades, including point-supported glass. He explains that with most of his company’s projects the glass is part of a system that includes a supporting structure and a mechanical system that fixes the glass to the supporting structure.
“We engineer these three elements as an integral whole. A big part of this is determining the movements of the system under the various loading conditions, and designing the system to accommodate these loads,” he says. “This typically presents much different criteria in a cable net application as opposed to a handrail, for example. This does not mean the considerations with the handrail application are in any way trivial. Exterior balcony handrails, for example, can be subject to thermal expansion and contraction movements that must be accommodated in the system design and installation. Fabrication and installation tolerances are a related consideration that must be factored into the system design.”
Joe Hendrickson is the general manager of Keokuk, Iowa-based Sadev USA, a supplier of hardware and other materials used in point-supported glass structures. When it comes to these applications he says his company provides both hardware and engineering, but does not supply/fabricate glass.
“In some cases we sell directly to the glass supplier/fabricator or we sell directly to the contract glazier,” Hendrickson says. “A lot of times we also work with architects up front.”
Hendrickson says there are advantages when a hardware supplier can get involved with architects early on.
“If we can work with architects to design the system we can look at what needs to happen as far as back-up structure, etc.,” he says. “A lot of times we get a job from the contract glazier asking for a quote and the drawings are incomplete; the drawing doesn’t show how [the structure] is going to [come together].”
Andrew Chatfield, director architectural glass systems and international sales for the Milwaukee-based Wagner Companies, which supplies hardware for point-supported applications, agrees the question of how early to get involved with a project can be a challenge.
“Ideally the optimum entry point is when the architect is first designing the façade/screen as it is extremely important to understand where the project is to be sited, the performance required, its topographical situation, the design of any adjacent support structure in order to provide specification advice and guidance on the correct style of hardware to suit,” says Chatfield, adding that in reality most of the time what they find is the architect indicates some sort of point-support system on the drawing and their involvement starts once the project is sent out for tender. “As point-support systems are still somewhat shrouded in mystery, despite the increasing use in high-profile projects, many of our prospective enquirers require a significant level of support both in design, engineering support and, in some cases, full structural analysis,” he says. “As a hardware manufacturer it is difficult to stand back and just offer an SKU list of parts and pieces for the customer to work out how to build the project. Many companies do this, but by opting for this route invite the incorrect specification of product and all the associated risks and negativity that accompany this stance.”
Chatfield says his company’s philosophy is to support the client, whether an architect, fabricator, glass manufacturer or installer, as much as they can, both in product design, custom fabrication, engineering support, design advice even full drawing and structural analysis.
Hendrickson adds, “This is more than just filling an opening; there has to be a supporting structure. We have to let the glazier know there are other [considerations] that need to happen to make sure the system will work. If we can work with architects in advance we can work to get that sorted out.”
Another option is working with a single-source supplier. “The advantage of a single-source is everything is taken care of and all the elements are covered,” says Nicklas. “When you’re [working with various sources] are all of the proper steps taken to ensure it’s correct? What’s the quality of each piece?”
“We have found people want to go that way, but we’ve also found there can be a lack of knowledge in how it all relates to the structure and the components and the glass,” says Yemola. “A lot struggle with it and we find that those who are lacking that knowledge are the ones trying to value-engineer and do every step by themselves.”
Haber adds, “There have been many instances of a system disconnect between glass and hardware--one doesn't work with the other; hole sizes don't match; load capacities of holes or hardware don't meet the project requirements, etc. How can a system be a system when you have an engineer doing drawings and calculations, a vendor making glass with holes to an often unknown tempering stress and a third-party supplying hardware out of a catalog online which typically has minimal strength calculations available to the end user or designer?”
While a structural engineer can help, this, too, should be approached with caution.
“You can hire a structural engineer but not all of them understand point-supported glass,” says Nicklas. “In the glass industry we have tools and resources on which we can rely for loading etc., but point-supported glass requires an FEA and that’s not something you can just get online. You don’t have the same reference tools as with traditional systems.”
Haber says there can be benefits in working with consultants. “On exotic, complex jobs you see curtainwall consultants 85 percent of the time. And we used to fight it because, for us, it tended to propose propriety, confidential information,” says Haber. “We don’t fight it anymore because we’re confident in what we do and we’re nervous about what competitors don’t know. It only takes one catastrophe to ruin the product. So we work with consultants and we’re open to doing that.”
He continues, “Most of the jobs today are design-assist or design-build. As a specialty contractor you become part of the design team in one way or the other and have to work with consultants and all we look for is a level playing field—the same level of quality everyone has to meet.”
Patterson agrees consultants can be an added benefit, but says, “I feel strongly that the best practice is for the consultant and a qualified facade contractor to work shoulder-to-shoulder from early concept development through schematic design and design development, as opposed to the consultant developing the design solo and then releasing documents for bid.”
From the hardware perspective, Chatfield says they are seeing requests for a single source supply with sole project responsibility, “which, as a hardware manufacturer, is certainly outside of our [responsibility]. Our experience is on projects such as this, the lead company will disseminate the specialties to those who provide the component elements of the whole [system].”
Covering Your Bases
One thing we can risk doing is designing something no one has built before and it becomes an unknown,” says March. “You then have to do back-end material testing, inspection of the [fabrication] plants to [ensure the quality of the] edge details, further research and development, etc. This can also end up being unpredictable [because] until you look at the details you can’t always tell the costs.”
He continues, “Contractors are increasingly better at drawing the details. [These are] visible, structural and closely tied to the quality of workmanship. Close collaboration and working with those with whom you have worked in the past is a bonus because you know each other’s strengths and weakness. It can be difficult to get a good team together at the start.”
From an installation perspective, Patterson says these means and methods become a key consideration when working with advanced facade technology, and should be integral to the design development process.
“The design-assist process allows us the opportunity to provide continuous budgeting and constructability review throughout schematic design and design development. This creates an environment optimal for decision-making; every decision is made in the context of cost and scheduling implications,” says Patterson. “This requires that key field personnel be involved in a project long before the design is complete. We typically involve our field operations people as part of our pre-sale proposal development teams. If we are successful in winning the project they stay involved throughout the design development process.”
And for many companies, having the backing of a “Made in the USA” product is also important.
Chatfield says his company manufacturers its own glass bolts, as well as a unique style of spider fitting, which he says have been tested in the U.S. as individual components but also together.
“We also do source product from the Far East but to our own specifications and tested once again locally in the USA,” he says, adding that they do see clients looking for test results on an entire system, “which, as a hardware manufacturer, is almost impossible for us to comply.
“Even our customers see this as a challenge unless they are of such size that they can control all elements of the system, which then tends to drive them toward sourcing fittings directly from outside of the USA.”
The Game of Risk
“A warranty is only as good or as strong as the company writing/issuing it,” says Haber. “Typically a point-supported system is specified to be sold as a single-source procurement so there is one warranty by the manufacturer and not a series of pass-through warranties by a series of vendors. The latter offers the owner and, in most cases, the glazing contractor little or no recourse if there is a problem.”
From the perspective of one hardware supplier, Hendrickson says his company’s products have a standard warranty. However, in instances where the company also provides the engineering services, that, too, is covered.
“There are a lot of companies that only provide hardware; we can provide engineering [along with] fittings, back-up steel, etc. and in those cases we warranty the entire system.”
But when it comes to any finished application, Nicklas poses the question, “What if there is a case of a catastrophic event?”
“Is it [backed by] a reputable company that can deal with these situations? Who’s behind the warranty if there is not a single-source? Each will likely say it’s not their fault and ultimately question the engineering. So who is responsible and who represents the building owner? Until there is a catastrophic event, the industry is just gliding along.”
Another point Nicklas addresses is the increase in point-supported projects on a smaller scale when compared to large façades.
“Where do you draw the line of what’s point-supported glass? A structural wall? But what about glass hanging on a standoff in an office or hanging glass off a ceiling? Who is looking out for that? How is it being fabricated? To what are they fastening it? That’s what concerns me,” he says.
Yemola adds, “There are also a lot of canopy applications where it’s just bolted to the building. Is it engineered and is a [professional engineer] stamp required?”
On large scale projects it’s so recognizable it’s most likely covered because of the scale and value,” says Nicklas. “It’s the smaller ones where we wonder who is policing it. There are a lot of catalog companies selling hardware and there are a lot of glass companies selling glass with holes and notches and they don’t know where it’s going.”
Speaking of difficulties and problems that may arise, Patterson adds, “It is sometimes challenging, in the instance of a problem, to determine decisively what system component is at fault. Increasingly, in my experience, liability issues tend to diffuse to everyone even remotely involved in the work regardless of culpability,” says Patterson. “The only sure way to avoid this is to avoid the occurrence of a problem to begin with. This is why we are very keen on collaborative delivery strategies where all involved parties are incentivized and empowered to work together very early in the design phase to anticipate and prevent the kind of problems that can occur in procurement, fabrication, and installation, especially when dealing with novel products and materials, and innovative designs.”
To the Core
While such resources can be helpful, March says keeping these systems viable also will require thought, consideration and plenty of time.
“It comes down to [timing]. If you have time to put [the project] together to know what’s achievable and to get people together early on,” he says. “Don’t leave it to the last minute; to move forward you have to be willing to push the envelope. If you want new things you need sufficient time to allow for the unknown costs. New things will never be right the first time so everyone needs to agree to that and be on board. That’s how you push forward.”