• The ASHRAE folks keep stirring the pot, and it doesn’t bode well for the glass industry. I’m left wondering: How do they get away with writing proscriptive qualifications for glazing that would result in a black/white reduction in the amount of vision glass in a building, when glazing can be more effectively addressed with a little forethought and integrated design?

    I get that walls, by means of their thermal performance, directly impact the amount of heating and cooling required for a building. It doesn’t matter if the wall is glass, insulating glass, metal panels, stucco, precast or any other material, if heat can travel through it, then the HVAC systems are impacted, and ASHRAE by rights weighs in.

    But, how can they proscribe the amount of glass on a building? This would be like GANA or the precast industry proscribing what the building frames have to be in order to carry the weight and loading of the curtainwall materials being anchored to them, and then professional engineers have to design building structures to those limits. We could require A50 Steel and 5,000 psi concrete, claiming it could reduce the size of embeds and anchors. I know it’s not a well reasoned argument, but neither is ASHRAE’s claim about the need to limit vision glass.

    Besides, did it occur to ASHRAE that more HVAC capacity is required when artificial lighting loads go up? There is a correlation between increasing daylight (read: increasing glass) and reducing the amount of artificial lighting required. How has ASHRAE responded to that? How would the lighting folks respond if they had ASHRAE come in and say, “We want fewer lights, as it reduces the capacity of the HVAC equipment.”

    Limiting vision glass also reduces the human comfort factor of daylighting. That’s sometimes hard to put dollars on, but there are studies about improved productivity of workers and students occupying spaces with abundant natural light.

    One more argument: ASHRAE does not limit the area of the structure that bridges the exterior wall and is exposed to exterior conditions. All those balconies on condos are really just radiator fins. Talk about an ice maker on a cold December day in Chicago.

    Okay, enough crying: Who’s going to save us from the abyss?

    We need the architects to take a stand. An architect friend of mine said he’d be surprised if a lot of architects know what ASHRAE is, let alone what the organization’s proposed standard 90.1 related to glass requires. His office is looking into indigenous architecture for clues on how to design for the location, rather than relying on any one standard. The point is, architects have to design for the whole, and balance all types of needs from human comfort to energy usage, as they relate to HVAC and lighting. One discipline can’t outweigh any of the others. Good design is most evident when all components are molded, kneaded and coalesced into a cohesive whole: Structure, human comfort, circulation, HVAC, exterior walls, all blended together so that no one element takes precedence over the others.

    I see a lot of pleas from industry publications that now’s the time to weigh in. And, I get that. Unfortunately, many of the little guys don’t have the time or resources to devote to this fight. So they look to the industry big boys to carry the fight for them.

    Look at BEC, for example. Sure a lot of the contractors go to Vegas every spring for the BEC conference, but look at the people serving on the BEC committees. There’s a lot of representation from the manufacturers, but not a lot from the CONTRACTORS. It’s because the resources aren’t there. What about the big glazing contractors, can they step it up a bit for the industry?

    I will pass my comments onto ASHRAE. Who else will step up to the plate? Everybody remembers how Mighty Casey ended his day. Let there be joy in Glassville, instead. Hopefully, there are those among us who will not only make a plate appearance, but will smack it outta the park.

     

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  • 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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  • I’ve been picking up some vibes that USGBC’s LEED program might be coming under additional scrutiny. Namely, that the credits aren’t delivering the intended performance, or that some of the rating system needs to be revised.  Third parties such as the Dept. of Energy are looking into how buildings perform compared to their design.  Since LEED certification is basically developed during the design, the actual performance is not considered.  I couldn’t agree more with looking into the final results, since the design is only half the battle.  If the design and credits don’t lead to actual performance, what’s the point?

    The preacher will tell his flock, “The road to hell is paved with good intentions.”  The point is, the battle is won in “walk the talk.” This is where LEED falls short.  In some ways,  it’s too short-sighted, especially when it comes to life cycle issues.  I get that credits like the use of regional materials obtained within 500 miles of the job site are good, but what about longer-term things, such as what happens to the glass when the building eventually comes down, or is replaced?  Shouldn’t the ability to recycle a product at its end of life be taken into account also?

    Presently, tinted or insulating glass units aren’t recycled; they go to the landfill.  The reflective film on low-E glass isn’t easily removed, and spacers on IGUs are a bugger to unconstruct to recycle the glass.  I saw a building in Dallas not too many years ago imploded with glass still on the façade.  It was cheaper to leave it there and send it to the landfill than to pull it off and recycle it.  Even the curtainwall aluminum could be pulled out of the rubble and recycled with the steel and concrete, but not the glass.

    In a different industry, I recently heard about a newspaper that donated its unused paper stock to an animal shelter that used it to line kennels.  Okay, I get that paper is a renewable resource.  The question, though, is how much energy is expended making new paper compared to recycling it?  Because, once that donated paper is finished in its second life as kennel liner, I gotta believe it’s NOT going to be recycled, but will instead be headed to the landfill.  The point is, let’s think the whole life cycle out, not just between any two points somewhere on the time line.  In some respects, I don’t think LEED does that.

    What about requiring buildings to work as intended in the credits taken in the LEED certification?  Makes sense,  the building ought to “walk the talk.”   It can’t be a bad thing to ensure that happens.

    Maybe the LEED rating ought to include an evaluation period after the Certificate of Occupancy is issued, and the building be judged on how well the intended LEED credits and solutions actually perform before a rating is given.

    College Hoops Musings

    I didn’t know what I was in for.  Go! If you ever think about attending the college basketball championships, even for a second, just GO!  I don’t know if it was because it was the 75th championship, or that the games were all good.  But, my oh my, what an experience!  Kudos to the folks in Atlanta, they ran a classy, southern hospitality, no-holds-barred operation.  If you’re a fan of the game, you cannot miss an experience like this.

    A guy across the aisle from us was a Wichita State fan who brought his 10-year-old twin sons.  What an experience, and they stayed until Monday night, even after their team lost on Saturday.  All the fans sitting around us were just fun; they were there representing every team.

    And if ever a team I want to see win gets in, I’ll definitely go back.  I’d miss the Super Bowl, even if the Eagles make it, just to go to one of these again.  The heartache if your team loses, so be it, but what a ride!  Maybe not having a team at the dance made it enjoyable.  But if you have a chance, do NOT hesitate; like the Nike ads say, “JUST DO IT!!!”  So a big thanks to Jeremy for taking me.

    P.S. Trivia:  do you know the only team to win both the NIT and NCAA in the same year?  Hint: 1950.