• Layout Issues – Coming to a Robot Near You

    Uncategorized 30.04.2013 No Comments

    Robots build your car and computer, and now they’re laying out interior walls. What are the implications for other building components, including curtainwalls? Read on, or be assimilated …

    We’ve all seen interior partition subs marking floors with chalk lines for metal stud and gypsum walls.  The 4/22/13 issue of ENR had an article about a robot used to lay these out to an accuracy of +/- 1/8”.  The CAD or BIM information is entered into the “laybot” robot, which then moves around the floor at 1.8 – 2.2 feet/minute, even around corners, laying out curved or straight walls.  I wonder if it can be adapted for layout of curtainwall? Some challenges come to mind.

    In any curtainwall job, one of the first tasks the field crews undertake is layout of the wall in relation to the structure.  On taller buildings, the forming of the upper floors is proceeding above, while the curtainwall layout, starting on the first floor, has to predict where the building is going to be long before it’s completed.

    The biggest challenge is that a continuous, full-height curtainwall is not on the slab, it’s off the slab, hanging out in thin air.  So, putting a layout line where the wall will be is not feasible (after all this isn’t drywall we’re talking about) except maybe at the base of the wall.   But curbs and overhanging walls can complicate that.  Additionally, perimeter columns get in the way of putting the layout lines right at the edge of the floor.  That location is further complicated as slab edges  often are not straight.

    So, layout crews tend to “cheat” the line to miss the columns, moving back in on the floor slab to miss the columns.  One of the things the field crews usually discuss with the GC when they first hit the job is:  How much room are we going to need for layout and material storage around the perimeter of the floor?

    Layout in plan is one facet of this, but the layout crew also has to deal with vertical tolerance.  If you’ve ever stood at the base of a tall curtainwall and looked up, it’s surprising to see how straight the wall is (it’s a perspective you can’t get when standing away from the building, taking in the whole of it).  The in/out plumb of the wall can only be seen from that vantage point, or possibly from the other end, on the roof looking down.  It’s a sign of how good the layout crew was.  Specifications often limit plumb deviations to less than 1/8 inch per floor.  That’s a lot.

    It’s always been a minor miracle to me that more buildings and curtainwalls don’t crash into each other.  BIM can help model this prior to start of the work, but when the building actually starts, theory becomes reality, or should, anyway.  Granted, tolerances and designed-in allowances accommodate that, but when a steel structure is erected with tolerances of +/-2” or more, and curtainwalls being built to +/-1/32”, why don’t they bump into each other more often?

    And concrete’s even more challenging than steel in this regard.  At least with steel, you can work from fixed dimensions every time, but concrete’s formwork is repeated over and over again for the height of the building, allowing just a small mistake to have serious repercussions.

    And the horror stories about having to chip concrete to allow a mullion to go by are out there.  In one project I heard about, crews had to chip the concrete floor beam so far back, they had to cut through the rebar, also.  I’ll bet the project structural engineer loved hearing that.

    Typically the 1 ½- to 2-inch tolerance between face of slab and back of wall system is cheap insurance.  It gives the general contractor (GC) some flexibility with the edge of the slab, and allows the curtainwall to accommodate any variance without having to notch slabs.  Anything smaller than 1 ½” ends up with notching requirements later.   Architects don’t like it, as they don’t like to think about how to close off the gap.  But it’s a necessary “evil” which permits an easier installation of the wall.

    Having the discussion with the GC prior to work starting, usually as part of the pre-installation conference, is a good place to get all this figured out.  For example, what the structure erection tolerances are, what the curtainwall anchors can reasonably expect to accommodate for the structure tolerance, and what to do when the inevitable clash occurs.  It may be beneficial to have this discussion as soon as possible after contract award so that everyone, GC, framing sub and glazing sub all get off on the right foot, knowing where everybody’s supposed to be when the wall starts to go up.

    It will be interesting to see who among the curtainwall subs will be the first to set up a robot to do layout work…

    Answer to previous trivia:  CCNY, 1950. They beat the same school both times, and since I know some Bradley grads, I won’t mention who it was that lost both tourney championship games in the same year.    

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  • Fighting for Glass

    Uncategorized 03.04.2013 2 Comments

    The Glass Association of North America’s (GANA) Building Envelope Contractors (BEC) Conference has come and gone, with some good ground covered. A high point was when Guardian’s Scott Thomsen gave a strong call to action for our industry in his presentation the “Battle for the Wall.”  The key takeaway was if we don’t fight for the role of glass in energy-efficient construction (thermal performance and daylighting), then ASHRAE will force us to the sidelines. Do you want to go to work for the stud wall, stucco and masonry contractors, because ASHRAE’s current emphasis is to greatly downsize the percentage of glass in exterior walls?

    We as a glazing industry should be showing architects  there are many glazing products that WILL increase thermal performance.  Architects will help us win this war, but only if we get smarter about educating them on the newest, most innovative glass and framing products now available.

    We should also be assertive with noting the other construction types have as many problems, as well, that are now coming to light in this energy-conscious age.  As ATI’s John Runkle noted in his presentation on building commissioning, these are things the glazing industry has dealt with for years.

    Notably, when the surrounding wall systems – cavity walls behind masonry or panels, precast panels, or whatever construction –  have to start meeting the same water and air penetration requirements as windows and curtainwall presently do on a regular basis, then that bodes well for the exterior skin, as a whole.

    But there are some down-sides, too.  For example, testing the weatherproofing/air barrier to the AAMA and ASTM standards for water penetration  aren’t  realistic since it never sees that amount of rain in the finished condition if a brick or panel wall is placed over it.  Air test it, yes. But a full-blown, 5-gallon/hour/square-foot water test ON THAT SURFACE isn’t real-world.  Some of this is still in the developmental stage, but I expect it will catch on in one form or another.

    Does commissioning make sense for a total glass curtainwall? Probably not with the current regimen of pre-construction and in-field testing required in curtainwall and window specifications.  There are some that would argue the call for increased testing is an effort by the labs to create more work for themselves.  Yes, I can see that, but what good is it having an air- and water-tight window or curtainwall if the wall around it doesn’t perform equally as well?

    Another high point at BEC was the presentation on Chinese tariffs. Some of the USGNN.com newsfeed had comments from the Chinese manufacturers’ side of the fence that felt the presentation didn’t accurately present both sides of the argument.  That wasn’t likely to occur given the fact the person making the presentation was the plaintiff’s attorney.  When’s the last time a lawyer led a fair, objective and balanced viewpoint on something his clients were paying him to have just the opposite opinion on in order to properly argue their case?  But, the tariff issue is going to be in the news quite a bit going forward.

    One last note:  Having turned the odometer over on my age this year, my brother bought me opening day tickets in Philly next Friday.  And, my no. 1 son bought us Final Four tickets.  Only one drawback to the venue:  basketball was not meant to be played in a football arena, unless they put the court in the end zone.  When watching the game, the Philly Phanatic sitting down the right field line in the KU garb, or in the corner of the end zone in Atlanta with the biggest pair of binoculars known to man will be yours truly.  This is one thing I’ll be able to cross off the ol’ bucket list.  As I review this blog post one last time Monday morning, I hope Wichita can shock the world.

    Here’s hoping the Easter season, with the accompanying onset of spring weather, brings renewal of faith, hope and charity to you and yours.

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  • Life Apprenticeship

    Uncategorized 21.03.2012 No Comments

    I attended the Building Envelope Contractors (BEC) Conference in Las Vegas this week. One thing I picked up was about the new turtle codes for glass. I’m told this has been all over the industry publications, but I’m having a hard time believing we have to now design glass for turtle safety. I guess I shouldn’t be surprised. We’re using glass to create electricity, protect occupants during storms and bomb blasts, etc. But I think I have now heard it all. It’s true that learning is a lifelong process.

    This got to me to thinking about all I have learned over the years. Bill Swango hired me straight out of college and told me it would take five years to teach me everything I needed to learn about this business—to know what glass strength is; how annealed, heat-strengthened, and tempered glass respond in loads; and their relative strengths, along with all the thousands of things about aluminum, gaskets, sealants, fasteners, and other components that go into curtainwall. I had to learn about finishes, coatings on glass, compatibility and adhesion, building movements—all of it in those first formative years.

    And then came the other side of the coin: it would take another five years to see if I could properly apply what I had learned the first five years before it could be determined if I was going to be a “keeper.” The “apprenticeship” was going to last ten years. And that’s why, in hindsight, I wasn’t going to be getting paid the same as the guys who had done their time. As young as I was, I thought I could do anything they could, and should be paid the same. Ah, the folly of youth. I was wrong, but I had to get older (which, by the way, also takes time) before I learned how wrong I was.

    It has also occurred to me that the “apprenticeship” program is probably true of any profession. College can teach you how to think like a (fill your major in here), or you can learn it by jumping right into it as a glazier or ironworker. But the time has to be spent. There’s no way to go from kindergarten to graduation immediately, the time has to be put in. Some may be better/faster learners, but time must pass in some quantity before you can learn a subject in depth.

    How do we pass this information on? If you’ve got a keeper in your organization, send them to BEC to interact with others in the profession and see how much knowledge and expertise is out there. Mentor someone in your organization.

    Where do you draw your talent from? Here are a couple of ideas:

    There are a lot of good college programs teaching project management and/or construction. Seek recruits from their ranks of graduates. Bringing them in after graduation, they can learn it without the “habits” of having already worked in the industry.

    Speaking from personal experience, I learned in school I wasn’t going to be an architect, but completed my degree and sort of fell into something related. Fortunately, I’ve never regretted working in the glazing profession, and have not looked back once.

    There have got to be people with that same background in the architectural schools who could be involved in the one construction trade that deals everyday with what they learned in school. Plus, the draw that the glazing biz pays better than architecture has to have at least some attraction, right?

    And get involved in the trade. One of the technical issues we dealt with at BEC this week was to try to determine how clearance distances between glass and metal came about as listed in an industry standard. Some of this has been around longer than the “long-in-the-tooth” guys can remember. And there doesn’t appear to be anyone who sat down and put all their notes in a form that someone can use all these years later.

    Because of the time taken to teach me the business, and for the joy and happiness being involved in it has brought me, I’m going to take this on as a passion, to take what I know and pass it on, somehow. I know I can do that participating in the technical committees, but there are probably other ways, too.

    I learned about having passion for our work this week, too, at BEC. It hasn’t all been turtle codes and Vegas stucco. Plus, there was golf yesterday afternoon, and that doesn’t happen very often in Seattle this time of year …

    In your own career, what actions do you take to keep learning, and to share your expertise with others?

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