• As I started to write this blog, I noticed the date it’s to be published: 9/11. As a kid, I never understood how Pearl Harbor could move my parents’ and my grandparents’ generations into fighting a war. After 9/11, who could ever question that motivation again? I hope we’ll always remember the price paid that day, and many days since, for our freedoms. God bless the good, great, the fortunate U.S. of A. I’m grateful to live in this good land.

    Okay, back to glass. At one time, anyone who had been in the glazing biz for very long had either worked for Cupples or PPG. Those two companies were responsible for everything from the monster towers of the 1970s in Hong Kong to the Twin Towers in New York to John Hancock and Sears Towers in Chicago. At that time, they were the equivalent to what Harmon, Enclos and Permasteelisa have become today. On the glass side, LOF and PPG were what Cardinal, Guardian and Viracon are now.

    It was with some sorrow I read an article about PPG getting out of the glass business. The story pointed out how much higher the overhead and initial investment is in making raw glass, as opposed to PPG’s chemical and coating product groups, where they will now focus their efforts.

    We all used to want to grow up to be PPG. In our eyes, PPG had the best of several worlds: they had a contract division that probably got a huge price break on glass, and they had an aluminum extrusion business.

    This history was brought into focus this summer reading an article in the June 2014 issue of USGlass about PPG Place’s 30th anniversary. The curtainwall system in that building was pretty interesting, as seen in this mosaic display of the corners and typical verticals (hanging in CDC’s Dallas headquarters).

    Photo courtesy of Charles Clift, Curtain Wall Design and Consulting.

    The PPG Place curtainwall was straightforward, and anyone who worked on it back then could probably pick it back up again tomorrow. It had many benefits:

    1. The basic frame members weren’t finished – so the shop and field could be a little sloppy in the handling of the basic frame components;
    2. The interior covers provided thermal separation from the exterior metals, and only these covers were finished;
    3. It was erected and glazed from the floor, minimizing the need for stage time; and
    4. Reglazing vision lites could be done from the interior.

    Bob Johnston, CDC founder, developed the PPG system “from his standard stick wall with collaboration from Gary McKissick, Bob Wheeler and Lloyd Stokes of PPG,” according to Charles Clift, senior principal at CDC (who was engineer of record for the curtainwall). He also recalls that “Phillip Johnson, the architect, required stiffness criteria that were twice as strict as normal industry standards of L/350 and max 3/8″ deflection” and that there was a need for an “unsymmetrical bending analyses on mullion shapes at corner conditions as wind load vectors did not align with extrusion principle axes.”

    PPG will be missed, if they do get out of the glass business or greatly reduce their role.

    As Bill Swango used to say, “be careful of whom you’re envious.”

    Tags: ,

  • Many of us don’t often think about a building’s exterior skin after it’s installed. But, this set of pictures of eye-catching buildings around the world getting spruced up grabbed my attention, so I had to share them. Image 14, with the workers on the top side of a giant sphere, got me to wondering how close together the tie back buttons are.

    Seeing all those people in high places reminded me of when my grandfather used to tell us kids about the time he jumped off a 100-foot ladder and lived to tell about it. We’d asked him about firemen’s cushions, pools of water, etc. Then, he told us the punch line: he had jumped off the bottom rung. Unfortunately, that’s not an option for people working on hanging window cleaning stages. Another bit of relevant grandfatherly advice he gave me when I helped paint his two-and-a-half story home came to mind: “Don’t step back to admire your work.”

    About the only consideration many building skin design and building pros give to the exterior equipment is the type and placement of tie-back buttons and/or the tracks in the vertical members to accommodate window washing equipment. Such buttons and tracks help keep equipment and crews close to the building during cleaning, for safety. They are NOT meant to support the full weight of people or equipment. Contracting crews might also rely on the buttons and tracks during glazing, including hanging anchors, installing sealants, etc.

    YouTube has some great videos of hanging stages that got away in windy conditions. Tracks or retention buttons would have helped prevent that accident from occurring.

    Just like nearly every other profession, window washers have a trade organization: the International Window Cleaning Association (IWCA). The organization describes itself as the “secratariat of the ANSI/IWCA I-14 Window Cleaning Safety Standard, which is referenced by building owners and property managers as well as the Occupational Safety and Health Administration (OSHA). In addition, it was designed to also be referenced by professional engineers, architects and manufacturers of window cleaning equipment. The I-14.1 Window Cleaning Safety Standard is the only standard of its type that is specifically for those in the window cleaning industry.”

    Designers typically reference the I-14 standard in curtainwall and exterior skin specifications. They also usually include in the performance criteria section of those specs, data on the loads imposed by the window washing equipment that must be accommodated by the curtainwall or windows. Such loads are not more important than wind load or seismic drift, but are equally weighted and tested typically during full-scale performance mockups.

    I’m grateful that I don’t work hundreds of meters off the ground on the exterior skins of a building and instead have a safe desk with four legs on a level floor, no wind gusts and sun only through windows, not directly exposed to it or reflected off the coated glass. I don’t get on one of those window cleaning stages very often, for the same reason I don’t like hanging roller coasters or construction site personnel/material hoists – there’s a great deal of comfort to be found in a solid floor underfoot.

    Did you notice, looking through the extreme window cleaning pictures that many folks were wearing full-body harnesses? And, did you see some weren’t wearing them – are they crazy?

    A bit of (unsanctioned) advice to window cleaners: along with wearing a full-body harness and practicing safe scaffolding, take a hammer with you when you climb on one of those bad boys. If you happen to get caught without the stage underfoot, the hammer is the means by which you can get into the building. A change of clothes is optional. If you’re still alive, it’s all good, right?

    Lastly, kudos to the people who make our walls, windows, and glass look good long after we’re done installing them. Don’t know how you do it, day-in, day-out, but my hat’s off to you.

  • After a recent blog about architecture school and cutting architects some slack, a college classmate, Mike Kadow, principal at Somerville Inc. (Green Bay, Wisc.), dropped me a line asking if I’d heard about the architect who almost died eating a glazed doughnut. Can’t say that I had, Mike. But, next time, would you like a dozen powder coated? We can do that here at TGP. (Note to self: don’t quit day job for a career writing one liners).

    Out of curiosity, how many of you use white boards in your office? And what goes on them? Notes during meetings? To-do lists? I like them for being able to draw closer to scale than on paper, and that they’re much easier to erase and not as messy as chalkboards. I wonder if they still have kids clean the erasers in elementary schools, though.

    After a recent meeting ended, I left the typical clouded “Please Save” note with my initials below it. When I came back, someone had replaced my initials with “Knicker-doodles.” Good for a laugh, right? Thing is, I kind of liked it.

    Recently, one of our sales guys said he gets positive feedback from his customers all the time about this blog (obviously, much appreciated). His comment to our VP of sales was that there are “thousands of Knicker-bloggers out there.” Far be it from me to pin that sort of nickname on anyone without their permission, but if you want a T-shirt, see me…

    I wonder if I can trademark these knick-knacks, though.  If you have other suggestions, I’m open.

    Since this is a blog on a glass industry site, it’s time to get back to business. I recently read an article about a Vancouver, B.C., building that’s the first of 250-plus buildings owned by a single management company to use triple glazing. Several years ago, as the energy issues were starting to take on their growing predominance within the industry, it appeared every job was going to be detailed with 3-pane IGUs. And, it hasn’t happened that way, not even in areas that have severe tropical or winter climates. Maybe this is something we can take up at GANA Technical Committee.

    On a different topic, we sometimes get requests for operable vents to be included in fire-rated glazing applications. Hmmm… Unless the vent hardware can close the opening when a building’s alarm system activates, a vent left open by a building occupant isn’t going to do much to stop a fire.

    Thinking about that reminded me of operable vents in non-rated curtainwalls and windows. The ASCE 7 calculations have a stipulation for “enclosed” or “partially enclosed” buildings. This has to do primarily with residential buildings, where operable vents or sliding glass doors might be present. When considering the partially enclosed buildings, the resulting calculations could result in a 10-25 percent increase in the building wind load, depending on building height, configuration and the wind speed.

    The reason is, when the vent or door is left open, the wind can blow through that opening and create pressure on the interior of the wall opposite the vents, in addition to the normal, exterior wall pressure. Interior partitions might knock some of that down, but in a hurricane, they’re not likely to last very long, and eventually the opposite exterior wall will be doubly exposed to wind loading.

    Which brings up sliders in high-rise residences. If there’s a harder product type to make air- and water-tight, I don’t know what it is. Granted, typical entrance doors might be exposed to some moisture and vapor transmittance, but it’s generally accepted that main entrances aren’t held to the same standard as sliders are, especially on expensive apartments or condos.

    I’ve always preferred swing doors in these applications, as having bulb gaskets with multi-point locks helping to hold the door to the bulbs creates better seals at vulnerable perimeters. But, most architects are not fond of them for high-rise buildings, as most little old ladies (or so the fear expressed by one architect) would be flung off the balcony if they held onto the push/pull if the swing door leaf was ever caught in a wind gust.

    There are some higher performing operable vents, sliders and swing doors out there. Make sure you’re specifying door and vent systems that are suitable for the conditions on a given project. This is one area where you don’t want to undercut the performance specs. I’d call it “Knicker-moronic” if you did that, but that just doesn’t have the same ring as the others.

    And thank you, again, for being a Knickerblogger. I promise never call you that in person. Deal?

USGlass Magazine

USGlass Magazine

Archives