• 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?

  • When the company I was working for in the early ’80s bought a mainframe drafting computer, before networked PCs were the norm, the IBM sales people told us that their stock answers to most questions they received were:

    1. “That’s a known problem, and our best people are working on finding a solution,”
    2. “That is NOT a problem, that’s a feature, we did it that way on purpose,” and
    3. In response to whether the system could be made to do this, that or the other thing: “it depends,” which meant if there was enough money and time to accomplish it.

    These responses are relevant not only to computers, but also in some cases to curtainwall and glazing.  Over the years, I’ve used these responses when answering questions from customers – architects, general contractors and glazing subcontractors – regardless of the system and whether I was working as a manufacturer, glazing subcontractor or consultant.

    Here’s an example, at one extreme, of the challenges faced in estimating architectural products. A certain wall design looked to be about $400 per square foot installed, taking into account that the framing was all custom shapes and detailing, with the verticals set at 45” centers, 2’-0” wide glass fins set at 15” on center canted at a 45 degree to the main plane of glass, across the entire façade (+/-120’) for the better part of two stories for most of the full length, and stretching to three stories at both ends.

    The GC had asked a glazing sub who they had worked with before what a curtainwall installed number was for that part of the country.  The glazier’s stock answer: $80 per square foot, which obviously was for a generic curtainwall and didn’t come close to covering the cost of the highly detailed wall described above.

    What was really surprising was that the wall’s designer hadn’t questioned the $80-per-square-foot figure. A compromise was made, and the owner spent more than the $80-per-square-foot-“guess,” but nowhere close to the more realistic cost that was about five times as much.

    In another example, my employer at the time lost a job when the square foot budget increased in the time between the preliminary review of the drawings and the bid for construction.  The problem was the total square footage of the wall had been reduced by half of what it was when the original budget was established, with no consideration given as to how that might impact the budget.

    Budgets being budgets, everyone likes to stick with them throughout the project cycle.  But as drawings progress from design development, and greater clarity gets added as the design matures, how can an early budget estimate realistically be maintained?

    It has always seemed prudent to me to be up front and honest about the realistic costs of a wall at all stages of the design process.  Yes, it’s easy to cover what is normally furnished, but that’s not always going to be sufficient for whatever surprising little idiosyncrasies get added later than can increase the cost.

    Does it (should it?) matter how you qualify the bids, regardless of when the estimates are prepared? Does it make it easier on the customer to understand the changes?  It didn’t on the above project. Even though we tried to explain the situation, the designer ended up looking at another wall systems.

    When I lived in Texas, I picked up all sorts of quirky sayings like, ‘that dog won’t hunt’ and ‘that’s slicker than snot on a doorknob.’  Trust me, sometimes you have to live there to understand some of these. Applicable to estimating, here’s some Texas wisdom FDR received. The president had asked his VP, Texan John Nance Garner, for his thoughts on a proposal to add six associate judges to the Supreme Court. Garner replied: “Mr. President, you want it with the bark on [the version you want to hear], or the bark off [the answer you’re not going to like]?”

    When it comes to providing an architectural estimate, sooner or later the bark will have to come off, and the final number will be what it is, regardless of the initial budget. In all likelihood, each estimator has his own viewpoint on this.

    I strive to be a bark-off estimator. The challenge for many of us in the glass biz, of course, is to provide a realistic estimate, but not price ourselves out of the running. Estimating a standard system and standard application is one thing.  But, with a highly detailed system, say one where there are glass plane changes, highly ornamental detailed caps, louver or sunshade systems, etc., the estimator really earns their pay with trying to predict where the architect will take a custom wall system from one stage of development to the next.

USGlass Magazine

USGlass Magazine

Archives