These are sad situations. It’s important for engineers and architects to double check the shop drawings to be sure the door glass is tempered.
Let’s work together for good and communicate well for everyone’s best. Here are some great comments from our social networking posts.
Widow to Sue Architects for Alleged Negligent Glass Design - (Thoughts from the Industry)
Freelance Consultant presso Enzo Ciccarone
Unfortunately, many times the security is not considered
Marketing & Continuing Education Coordinator, & Web Designer
I remember this incident. It is very unfortunate. I wonder how many public establishments aren’t up to code? Seems like simple measures could have been taken to avoid this tragic event.
Senior Project Manager at Thermal Windows Inc
How does something like this get past the G.C., the Glazing Contractor and the Building Inspector? What happens now? Does the Architect point to the general notes where He/She points out, in the design, that it was specified all glass and glazing to meet local building codes and point the finger down the line?
JEI Structural Engineering – Glazing Design Calcs
In every industry there are companies that push bad information through the system and those that take the harder road of doing it right. Weather situations are accidental or avoidable, technology and social networks are making it harder to hide.
I think it’s time for high quality companies and people with integrity to take over in every aspect of living.
Project Estimator/Manager in Memphis
It might matter in legal terms what the specifications and drawings stated but ethically the glazing contractor is to blame. Every glazier whether they are in the field or office knows that door glass needs to be “safety” rated.
This is an example of the G.C. going with the lowest bidder on every project. Top glazing firms can’t afford to be the lowest bidder on every project as the overhead is too high. It’s time to start respecting “quality” of work instead of leaping for the lowest bid number out there.
I’ve been called out to numerous buildings that have recently been built to replace door glass with tempered or sloped glazing with a laminate.
National Account Executive at Management Recruiters of Davidson / Glass & Glazing / Facade Industry
You tell it, Tyler……
Owner at Vern’s Glass
We just priced a repair job last week (and lost) because someone needed new pivots for the door. Neither the door or the side lite next to the door were tempered so we naturally included changing the glass into our price.
Well guess what? The owner of the “smoke shop” went with another guy who only repaired the door and went on his way. The building is 30 plus years old but I REFUSE to walk away from these situations. I think I’ll mail a copy of the article to the owner of the shop.
JEI Structural Engineering – Glazing Design Calcs
You hang in there Vicki. I have to believe the internet is going to help quality service providers thrive as consumers have more access to good education and poor customer service reviews.
It’s always harder for those of us who choose to do things right. Leadership isn’t easy, but it’s a worthwhile endeavor.
Project Estimator/Manager in Memphis
Vicki, you did the right thing. The “grandfather” rule doesn’t imply in this situation. I remember going to a local business that had damaged glass due to gunfire. There were two pieces that were damaged out of a row of thirty. This was a slope-glazed frame with insulated glass. However, the inboard lite wasn’t laminated as required for the degree of slope.
I was required by law to change out the entire row of glass if we removed the two damaged pieces because they were technically in the same frame. Needless to say the local business still has two damaged lites.
Marketing & sales professional at GARWARE POLYESTER LTD.
whether door glass tempered or not dosn’t matter for safety purpose, one can use safety film on door glass which is light weight
Project Estimator/Manager in Memphis
You are correct, safety film is an alternative. However, many manufacturers void the warranty when any film is placed on an insulated unit. In some situations the warranty may not mean much and it might be more cost effective to install the film on existing pieces. My preference is to install tempered the first time and be done with it.
Business Development Manager at Facade Solutions L.L.C
@ Rajeev the door glass if frameless needs to be tempered atleast HS depending on size and the argument is of safety. Depending on what safety film you would use, it still cannot safe guard from injury as you never know what is the force of impact and how it happens. Risk is risk after all it is human life. Cost of safety implication is far too less than compared to human life and the litigation. I’d rather prefer a laminated tempered glass for an external shop front facing main roads and parking lots.
Marketing & sales professional at GARWARE POLYESTER LTD.
laminated glass is good for safety on roadside area or where traffic movement is high and yes of-course toughened glass is twice stronger than HS & 4-5 times stronger than annealed glass, but laminated toughened glass is not advisable in safety or security purpose due to USP of toughened glass which turns negative in laminated glass i.e. it breaking pattern, if a toughened glass breaks it breaks(by applying force or due to impurity NiS) in small pieces, in case of toughened laminated glass , if glass breaks toughened glass as per it nature will break in small pieces & these small pieces will have own strength & adhere to pvb film(a soft film) which now start sagging toward gravitational force or any one can make entry by applying force, also the same is not advisable in skylights or domes due to this.
Using Centry PVB in toughened laminated glass combination may solve the purpose of safety & security but again cost will further escalate.
The rational option is using polyester based safety film of 175 micron with any glass combination. Polyester is very tough material ,neutral to fire and adhesion is very high and suitable to prevent from injury to nearby traffic .
for further demo just visit you tube & type Safety Films or Garware safety films,
The Glass Labyrinth, a sculpture by legendary Kansas City artist Robert Morris, is now open to the public at the Nelson-Atkins Museum. Nearly one million pounds of one-inch-thick plate glass went into the sculpture, which was built to commemorate the 25th anniversary of the Donald J. Hall Sculpture Park.
A unique combination of high art meets glass engineering. The glass labyrinth expands the parks idea of creating an outdoor museum—a place for people of all ages to experience the relationship between art, architecture and nature.
JEI Structural Engineering provided the calculations and glazing system design. The clear glass labyrinth is heavier than it appears; the 62-foot by 62-foot by 62-foot, 7-foot-tall labyrinth weighs more than 400 tons.
Stewart Jeske, P.E. said it was challenging because the artist wanted clear glass without the distortion waves that you get in tempered glass. “We utilized annealed Starphire glass (low iron) for visibility with SentryGlas interlayer for strength.”
Another obstacle was the bronze cap. It was a experiment getting the bronze cap to act as a structural member with hidden joinery needed for artistic appeal. JEI had over site review of the bronze cap to assure its structural capacity, working closely with the fabricator, the artist, the glazing contractor, and the Nelson team.
A lockable glass door was considered for security purposes but ultimately omitted because of the difficulty in designing stability for wind and pedestrians in addition to difficulties for design of supports off of the brass rail and surrounding glass. Video surveillance was used, instead.
Jan Schall, the museum’s curator of modern art, says “while most of her museum’s outdoor pieces are hands-off, this one welcomes the viewer to walk right through. It’s a completely new dimension for us that is experiential that way,” Schall said. “That lets you move in and through it. I think it will be a powerful experience for people and a moving and aesthetic experience.”
It’s what one museum official is calling a visual “Tour de force.”
Steve Waterman, the museum’s director of presentations, says, “Mr. Morris is a big deal and has been a big deal in the art world,” He’s the Kansas City native who has spent his artistic life building similar labyrinths out of glass and chain link fences, like this one in Brazil. Waterman says this seven-foot-high labyrinth will challenge the participant as if they’re in a hall of mirrors.
In the late 1960s, Morris helped start the Process Art movement and began using industrial materials for sculptural works. He used aluminum, steel, felt, string, mirrors and dirt to create transient works of art like Continuous Project Altered Daily, 1969. His felt series is a stunning example of the beauty he found in these unexpected and unconventional media.
Morris, who has credited childhood visits to the Nelson-Atkins museum as a formative experience for his art, progressed naturally into the art of sculpture because of its interactive possibilities. His continued curiosity for the opportunities of viewer participation led to the creation of his Labyrinth series. Glass Labyrinth is the first permanent Robert Morris labyrinth installed in the U.S.
- A Maze of double-paned glass to life.
- 53 pieces of large glass panels.
- The largest panel weighs about 600lb.
- Utilizes annealed Starphireglass (low iron) for visibility with SentryGlasinterlayer for strength
- All glass in the US is designed/engineered for probability of breakage – this is designed with a low probability of breakage less than 1/1000 under an extreme wind event.
- All of the glass pieces are tied together at the top with a continuous structural bronze cap which adds to the visually appealing design.
The Nelson-Atkins in Kansas City is recognized nationally and internationally as one of America’s finest art museums. A bright orange ribbon surrounds the newly installed glass labyrinth for the Grand Opening. JEI Structural Engineering can be contacted at www.JEIstructural.com .
Client: The Nelson-Atkins Museum of Art
Structural Engineer: JEI Structural Engineering, Stewart Jeske, P.E,
Contract Glazier: W. Carter & Associates (cc above) Bill Carter, president of sales
Architect: BNIM Architects, Greg Sheldon
Artist: Robert E. Morris and his representative Eric Bloom.
Fabrication: Oldcastle Glass, Perrysburg Ohio. Special equipment bought for this project from Italy to provide exactly perfect edges polished on a the1 1/16” laminated glass. The Sentry Glass interlayer is structural and very difficult to trim after the glass is laminated.
Bronze cap Design / Fabrication: Oversight for the design was provided by JEI Structural, who reviewed and approved the design. Fabricated by Livers Bronze, installed by W Carter Glazing.
April 10-11, 2014 Wyndham San Antonio Riverwalk Hotel San Antonio, Texas
Meet JEI Structural Engineering in person in Booth 14.
We offer FREE project consulting on site with Professional Engineer (P.E.) licensed in the state of Texas (TX).
FREE pass to Glass Tec Tx 2014 from JEI structural engineering for glazing system, complements of JEI Structural Engineering Design Calculations for Glazing systems.
We serve the glass industry exclusively and are up to date on all the latest issues, codes and manufacture systems.
We are Glazing Engineers, Façade Engineers, Curtain Wall Engineers, Storefront Engineers and anything metal.
Serving Glazing contractors, window manufactures and skylight installers.
We provide Glazing engineering, façade engineering, curtain wall engineering, storefront engineering and more.
1) Must design for 2 times the glazing resistance now. Previous 2007 UFC 4-010-01 requirements allowed for frame design for the static 3 sec load and the connections for 2 x the 3 sec load.
2) Most Manufactures systems have been tested to previous 2007 UFC stand-off distances. The 2012 UFC allows for stand-off distances much less which can create very large blast loads that systems have not been tested for – so check this out before selecting the systems as engineering, fabrication and installation cost may be greatly affected.
CALL 816-734-8345 for a FREE Consultation.
For a quote, email elevations and specifications to us.
Two-sided Structural Glazing is popular in skylight design due to its water infiltration performance. In this construction type, the two sloping edges of the glass unit are supported by the rafters and retained by glazing caps. The two horizontal edges are secured to the purlins using a structural silicone joint, typically applied from the exterior. This flush purlin detail minimizes water and dirt retention on the skylight. The exterior joint is typically thought of as just a weather seal. However, these edges must also be structurally retained to the purlins.
Per the GANA Glazing Manual, 50th Anniversary Edition, insulated glass units must be structurally retained on all four sides. Ideally, the horizontal edges would have two sealant joints. The weather seal would be on the edge of the unit, and the structural joint would be at the base, connecting the inboard light to the purlin.
In some cases, it’s possible to use a single joint as both the weather seal, and the structural joint. However, this option offers many challenges. The joint must be ¼” deep minimum, it must remain at a depth to width ratio of one to one, and it must support the glass unit under wind uplift pressure. Depending on the situation, this joint may become unreasonably large to support the load. Other challenges with this setup include issues with the load path. Large joints have the possibility of coming in contact with the insulated unit’s edge seal, this leads to compatibility issues between sealants. Also, as the load must travel from the IG unit to the purlin, there must be a flush glaze cap and retainer assembly fastened to the purlin for the sealant to adhere to.
Designers should be conscience of this topic in the design of their skylight. If you have any questions about your skylight design, please give us a call.
Matt Gorny, E.I.
JEI Structural Engineering Glazing Systems
Matt Gorny serves clients at JEI Structural Engineering, a Kansas City, Missouri based company focused on providing professional engineering P.E. calculations and consulting in the United States.
The wind design criteria are usually given on the contract structural drawings. Sometimes design wind pressures for components and cladding are given as well. However, the changes with the 2012 IBC have created much confusion regarding the actual design pressures to be used.
Many times the components and cladding pressures listed on the structural drawings are given in terms of “Ultimate strength design”, which is not used in any of the wind load charts given by manufactures. Using these pressures will ultimately lead to overly conservative design.
Designers need to be able to calculate the allowable strength design loads from the information given off of the structural drawings.
If you have a question about what is on a structural drawing, give us a call.
UFC 2012 criteria now requires the inner glass doors and side lights for inside elevations of vestibules to be blast resistant.
We keep an eye out early on to reduce headaches on the back end.
|Seems to be a large gap between what architects require to accommodate vertical movement of the building system, interfacing with glazed systems and what the manufacture provides to accommodate for those movements.
Connect with JEI Structural Engineering online.
Get a free project quote
The gap between Architects and Manufactures in Vertical Movement?
Carrie JeskeJEI Structural Engineering – Glazing Design Calcs
Seems to be a large gap between what architects require to accommodate vertical movement of the building system, interfacing with glazed systems and what the manufacture provides to accommodate for those movements. Any answers?
reyad abu diab TECHNICAL MANAGER at ALHAMAD
Many senior consultant architects they know nothings about the glazing and aluminum systems , So we suggest to be the specialist consultant for glazing and aluminum works in the area. Chuck Knickerbocker Curtain Wall Manager at Technical Glass Products
Define vertical movement: Are we talking about thermal, or building frame movements (including column foreshortening, concrete shrinkage, and drift, either from wind or seismic)? Or all of the above? The more sophisticated designs / manufacturers are often left to educate the architect through the shop drawing process. Certainly, if / when the specs lay out all these performance requirements, the framing has to address them. The specs are often the first clue that the architects understand the design issues. Their details ought to reflect those constraints, and how they envision the curtain wall system being able to absorb or work within those parameters. If the drawings and specs don’t address all of those issues, then let the c/wall provider beware – or “caveat emptor” in reverse: The architect probably doesn’t have a clue as to what’s coming.
Richard Araw, Façade Design Supervisor at ALT Cladding Inc.
Commonly, the vertical movement are accommodated by the STACK JOINT – ranging from 25mm to 45mm. But most architects prefer 25mm to 30mm. You do not want to see thick black line across their building. Or , if thick line is necessary, this can be hidden by an aluminum capture instead of the trim on the glass.
And that is where the Curtain wall consultant and curtain wall manufacturer comes in. We need to educate the architects how important vertical movement to the façade.
Stewart Jeske President at JEI Structural Engineering
On virtually all of the small and medium jobs it is a major issue. A general CW or storefront manufacturer is selected by the glazing contractor after receiving quotes. The architect has specified that the system must accommodate the building structural movement. The building structural engineer has designed perimeter/ spandrel beams for L/360 LL (typically between 1/2″ to 3/4″ vertical movement). So, for instance, if it is a head joint, thermal movement (say 1/4″) and the vertical live load (say 3/4″) adds up to a joint required at the head of 2″ (for sealant properly designed). Its ridiculous. The manufacturer’s don’t design standard anchors or receptors for this type of movement.
The breakdown is on the part of the building code – We need something standardized that requires the structural engineer designing the buildings to design for something reasonable that the manufacturer’s can accommodate – Say 1/4″ vertical LL movement at the perimeter beams. Then, everyone would be on the same page.
Chuck Knickerbocker Curtain Wall Manager at Technical Glass Products
if they did a masonry wall instead of curtain wall, wouldn’t there also be a “thick black line across their building” for the very same reason? The floor carrying the dead load deflects, the exterior skin has to accommodate the deflection somehow and / or somewhere, right? Granted the size of the joint may vary, but that’s often (or should be) driven by the movement capacity of the sealant. In unitized walls, there’s a little more forgiveness, in that the gaskets can compress, and the joints can often be smaller, not having to account for sealant capacity to take movement.
Peter Karsai Associate Director at AECOM
This is a complex issue, and is probably one of the area’s most at risk of poor performance, dispute, and litigation. It is not an issue that can be addressed by a simple “rule of thumb” approach. Coordination between cladding and structure needs to address 3 key aspects:
1) Location of any movement joints in the superstructure (usually vertical joints in long buildings). Cladding needs to mirror a joint over the building joints (common sense, but I’ve often seen cladding installed without joint, always with disastrous results).
2) Deflection of structure at cladding fixing points at time of installation (most cladding is installed level, most structures are not level, cladding brackets need to make up the mis-match).
3) Deflection of the structure after the cladding has been installed (live load deflections, wind load/sway, and creep/settlement movements).
After this, the cladding contractor still has to accommodate his fabrication and erection tolerances.
So, quite complex, and it gets worse if the structure has long spans or cantilevers. Many projects (large and small) have tripped on this issue.
This is not something that can safely be covered by the architect’s specification. It is also beyond the understanding of the structural engineer (structural people and cladding people speak a different “language”, and need an middle-man to help them understand each other). It really needs a specialist cladding consultant to sort it all out, either during the design stage (for a small fee), or during the dispute/rectification/litigation stage (for a very BIG fee). From an industry perspective, the first approach is obviously better.
David Altenhofen East Coast Director at The Facade Group
Good architects figure this out with their structural engineers all of the time. A good consultants can also help but is far from essential on every job. Good structural engineers will frequently bring up the topic just from their own experience.
It is not that big of a deal to ask the structural engineer to limit live load deflection to 1/4″ at the spandrel. On projects with masonry veneers the beams supporting the veneer is frequently designed for L/600 or less and maximum 3/16″ live load deflection (half of a typical joint width). On large buildings the live load can be a small amount of the total load, so perimeter beams might only have to get a bit bigger. That L/360 criteria is usually for total load. Sometimes we have introduced extra columns on the perimeter to keep live load deflection down. Sometimes we introduce an extra beam or HSS at the window head to carry only the dead load of the wall and then there is no live load deflection at the head at all. Sometime the spandrel panel is designed to act like a truss and that reduces the deflection. I have worked with many architects over the years who were aware of how to do this coordination.
Peter Karsai Associate Director at AECOM
20 years ago (when I was a structural engineer) I would have agreed. Life has become much more complex since then, with a multitude of different cladding systems, innovative structural systems, and the desire to constantly push things to the limit. As a result, today we often need a 3-way dialogue (architect/structural engineer/cladding contractor), and a cladding consultant is well placed to facilitate that conversation. Lastly, if the status quo was satisfactory, then this discussion thread wouldn’t be taking place
Bruce Keeler, PE Principal at Drafting & Engineering
Well stated Stewart. We run up against this issue day in and day out. I don’t know the answer, but it does take multiple conversations during the shop drawing and architectural review process, along with some RFI’s to get everyone comfortable with the specific requirements on any given project, large or small.
Stewart Jeske President at JEI Structural Engineering
Agree, Agree and Agree. Peter, you point out that there is definitely a need for the cladding consultant in the middle. I think this is essential also, to help bring the limitations of the manufactured systems in to the reality of the design. I think this will be needed well into the future. David, I agree with you too. If only there were more projects where the Architect would do this with the Structural Engineer – Too many of them do not.
Again, I’m hammering on the Building Code. This is the central area where information and restriction can be communicated. Limitations for spandrel deflections at curtain walls and glazing systems need to be small to work with current off the self manufactured glazing systems.
Fluelenne Duenas Structural Engineer at Vistawall International/ Oldcastle Building Envelope
I agree with you Peter, a curtain wall consultant would resolve these issues before commencing the cladding design and construction phase. But before agreeing with everything the cladding consultant’s figure, a discussion between consultant, manufacturer, Architect and main contractors Structural Engineers should still take place. They need to resolve the floor to floor design vertical movement. The most common mistake happen during the design stage is catering the maximum vertical movement the cladding consultant issued. This is not correct. Intermediate floors should only be design to differential floor slab/beam movement. Its floor having vertical movement depending on live load. All parties must agree on a common figure, rather than designing the frames/systems to huge movement which in reality not needed at all.
Carrie Jeske JEI Structural Engineering – Glazing Design Calculations
Discussions on the front end of the design process between all parties are rare. It’s not till after a project is awarded to a glazing contractor that the problem is found, forcing everyone into scramble mode.
Our goal is to save glazing contractors money and add value to manufactures designs. It’s conversations like these, with people like each of us, that have to lead the way to better communication and higher quality outcomes. Good leadership requires making tough decisions early on for the good of everyone. Let’s start in our own circle of influence and move out from there.
To jump into this conversation, join the LinkedIn tread.
The Future of Glass Series
|Location: Westfield Shopping Centre, Australia. We found this great video on YouTube and wanted to share it in our Future of Class category. Technology is moving so fast. The future holds a vast array of changes to our everyday lives using new composites and materials. JEI Structural Engineering is committed to being a key player in the glazing industry future.
Application: Switchable Glass Privacy Glass.
Switchglass Privacy Glass is a laminated glass panel composed of polymer dispersed liquid crystal film (PDLC). By applying a small electrical current, users can change its state from opaque to transparent, and vice versa. As you can see on the Demo video various Switchglass Privacy Glass can be joined together forming one large panel controlled by a single switch, ultimately creating a privacy glass wall.
What’s the difference between PDLC and Electrochromic Glass?
Polymer Dispersed Liquid Crystal Glass (known as switchable glass) functions by the application of an electrical current that aligns the randomly scattered crystals within the laminated film to create transparency. Electrochromic Glass has a thin transparent coating on the protected inside glass surface which becomes increasingly dark grey tinted with the application of a low voltage electric current, but it does not prevent transparency as does PDLC Switchable glass. They can be combined.
For more cool videos, see our YOUTUBE channel Future of Glass playlist.