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The Professional Services Perspective: Industry Potpourri

With the end of the year approaching, my final blog of 2018 is a collection of random thoughts and experiences. Hopefully some will resonate with you.


Let’s discuss terms.

I love the technical terms we use in our industry. “Chicken head” may be the best. Most of us know that term to define the upturned stack-joint leg on an expansion horizontal mullion. In profile, it looks like a “chicken head” when some types of gaskets are applied over top. I first heard the term in 1989, and it has been used since. Can’t we find a better naming convention?

Yes, Mr. Owner, you are buying a high-performance curtain wall with a chicken-head in it. Don’t ask questions. Just smile and nod. “Single leg stack and double leg stack” refer to the type of stack joint typology. One or both can be “chicken heads.” Your stack joint will have one leg or two. Depends on which design-camp you’re in. Both options work just fine. Yes, Mr. Owner, you’re getting a single leg stack that looks like a chicken head. You’ll be okay.

There are many more interesting terms we use: jumbo glass, bellows gasket, bulb gasket; sponge gasket (I have a good story about that one I’ll share another time), V-groove, nub, hook anchor, condensation trough, weep tubes, baffles, peening and more. I’d love to hear your favorite terms in the comment section below.


Let’s move on to the building code.

“Yeah, John, but you guys are designing and engineering to CODE. You are being conservative.” Um, let’s remember that the building code is defined as the “Minimum Requirements” for buildings. Thankfully, we have standards, since most things are “sticky downward” if not defined and benchmarked prescriptively. Being “conservative” or perhaps “wise” in some instances would be designing and engineering to MORE than the codified standard, such as with Factory Mutual specifications.

I am not advocating for conservatism, I am just making the point not to misrepresent the standard. So many of us see the code as the maximum, but it is not. We can design for more egress, better redundancy, better light, ventilation, daylighting, air and water infiltration resistance, and other attributes if owners want a better building product. As design-professionals, we are working and starting with the standard and needing to meet certain requirements. How we interpret and apply our craft within those standards is where we provide value to clients. More on that in a future post.


Next up, U-values and thermal analysis.

We have gotten this comment recently on two different jobs, one from a general contractor and one from a curtain wall consultant (perish at the thought): “Don’t give me standard NFRC boundary conditions. We need the U-values to be calculated based on the local conditions, not the standard.” That’s not right. U-values are based on the standard NFRC boundary conditions. In this way, they are all comparable to the same standard. Dew points can be run for the specific local boundary conditions. This will give insight into condensation issues and whether or not moisture will form on various surfaces. 

Thanks for all that you, the readers, pour into this industry. Thanks to Glass Magazine for this platform and for your advocacy. Thanks to AAMA and NGA technical committee members for your efforts and investments. Thanks to all of you for working together to make the built-world a better place. I count it a privilege to be a part of this meaningful and purposeful work. Make it a wonderful holiday, and I look forward to future connectivity and collaboration.

John Wheaton is the founder & co-owner of Wheaton & Sprague Engineering, Inc., also known as Wheaton Sprague Building Envelope. The firm provides full service design, engineering and consulting services for the curtain wall/building envelope/building enclosure industry, and works at “Creating Structure” for clients. He can be reached at and on Twitter, @JohnLWheaton1.

The opinions expressed here are those of the individual author and do not necessarily reflect those of the National Glass Association, Glass Magazine editors, or other glassblog contributors.


John Wheaton headshot

John Wheaton

John Wheaton is the founder and co-owner of Wheaton Sprague Building Envelope, He can be reached at and on Twitter, @JohnLWheaton1.