Engineered Architecture

The Ides of July! Beware moisture! It’s not just March with Ides. During the hot summer months, thoughts of condensation are not always with us, but our life giving Aitch to Oh (H2O) can come into view in awkward places where warm moist air comes into contact with cold surfaces. Before we start just a quick commentary on the difference between water and water vapor. We sometimes think that what we see rising off a pond in the morning as water vapor, the white plume from the teapot, or clouds- if you can see it, it is water drops, water vapor is clear. Most important, water vapor does no harm- it is liquid water of which we are to beware.

1. Avoid overall humidity analysis- it is at the exceptions the problems arise- when a channel of uncontrolled air hits the cold surface you have a problem, especially if that cold surface is sheet rock paper. Mold needs three things, spores (which are practically everywhere-note the Kurds in the desert making “sourdough” bread by leaving a pan of flour and water in the open for a few hours), liquid water, present through our poor planning or analysis, and food: cellulose is choice, although good old household dust can be quite nutritious.
2. Remember that heat transfer is orders of magnitude faster during evaporation and condensation: a heat pipe is that because of these phenomona- moisture issues are huge heat highways.
3. If you don’t ventilate you will suffocate and compost your structure. Cooking and bathing are prime culprits. Recirculating stove “vents” are the bane of the building scientist and fodder for forensics!

Happy Bastille Day, also brother Bill’s birthday-big celebrations for him in Paris every year. I was going to call this Concrete Commonsense but it seemed redundant. Concrete, that Roman miracle of burned limestone that enabled the Pantheon to stand with the largest masonry dome in the world for 2000 years is truly gravel superglue. That being said, what more can I add?

1. One never “pours” concrete, one “places” concrete. If it is so soupy that it “pours”, it is too watery to be strong. Adding water has to be precise, because the mixture is one of cement (often used incorrectly to describe, synechdotally, perhaps, the whole compound; and yes it is a compound, not a mixture, where the water has to be precisely enough to hydrate without extra to make it too slippery, or as aforementioned, soupy), water, and washed sand or gravel. If you don’t get the mix right, you will have cracks and breakage. And let it cure properly, usually in a 28 day time frame (there must be a parallel with rehab programs there, but I won’t touch it here!). Sun, rain, and uneven evaporation (particularly caused by those pesky “vapor barriers” of poly under) will curl the final product.
2. Wash your sand or gravel. I have seen large lumps of sod and dirt in finished concrete walls when the forms were stripped, how embarrassing. Avoid cold joints, if you schedule your placement around noon, and the driver for the second load stops for lunch you may spend a lot of time grouting, or worse, re-“placing”. I have seen 40′ gravelly seams across the back of a basement wall- fortunately not a retaining wall. (And if you are using your basement wall as a retaining wall, design it that way! Spend the money on a structural design with all that #5 rebar, counterfort footings, and 30 times the diameter laps.)
3. Formwork is where the money is. I remember Doug Gay, a local hero concrete man discussing having to “get physical” with the formwork in complicated multi faceted designs. Each corner adds a minimum of 3% to the overall cost (and that runs right up through the building, and no, that does not mean that a round building costs 12% less). Rectangular foundations are what is to be expected, everything else is optional- and those 30 degree angles can be the bane of construction progress and commonsense! Allons enfants!

Mark Kelley, a partner at the Hickory Consortium formed under DOE’s “Building America”  program was one of the first mechanical engineers of my ken who started the mantra of “looking at buildings as if they are systems”. As if! Of course they are, as Hafiz pointed out in the 14th century, (paraphrasing), “you will finally understand what every atom and universe understands, when one of us wiggles, we all wiggle.” I used to design jet engines. And yes, today, I am happy to fly with those engines keeping me in the air. Everybody knew that a jet engine was a system, that you could write an equation for the airflow and fuel supply and determine the thrust and then optimize the fuel consumption for a given thrust. But for a building? For the energy related parts a resounding “Yes”; and you could write it so that you could optimize the cost of ownership. Who knew? Better to ask “Who knows?”.

1. Today we call the practice “Building Energy Performance Analysis”, BEPA (gotta love those acronyms). Usually we use some type of spreadsheet to do the dirty work of equation formation, but when we are done we can “simulate” the building performance before we build it.
2. Using this tool, we can make trade offs for insulation thickness, window quality, mechanical system type, fuel, and efficiency; as well as exterior shading (trees!), orientation to the sun, window size and configuration, and so forth and arrive at an “optimized” design.
3. But remember, and this is the commonsense part: The building is not the model, and doesn’t even know about the model- it will perform as it was built. It is up to the construction delivery team to build and verify that the model design intent was executed properly. Henry Gifford has said that the building performance awards so proudly displayed in the lobby should be attached with screws that will allow removal if the building doesn’t perform according to the model predictions. There have been too many examples of buildings not performing as designed, not having equipment as specified, and just plain not even having the equipment installed to corroborate Mr. Gifford’s reservations. For example, we used to think that R-19 insulation in a wooden stud bay gave an R-19 wall. Tests have shown that between the conduction through the wood studs, gaps where the insulation doesn’t touch the studs, and air leakage that we are lucky to get the equivalent of R-11.

Okay. I am a mechanical engineer and had two suffer through four semesters of Thermodynamics and so couldn’t resist that trendy word of the mechanical age: Entropy. All of thermodynamics can be summed up with three propositions: You can’t win. You can’t quit, and finally, You can’t even break even. And that’s where Entropy (I like to use the capital “E” because it makes it look so regal) sneaks in, the property a.k.a. Disordliness has everything to do with why you can’t unscramble an egg. (You could, but it would be way way difficult). So what does this have to do with the construction delivery process? (You can breathe a sigh of relief to know that I am not going to blog about isentropic adiabatic isothermal processes in refrigeration machines). Information is everything! (Great read to, James Gleick’s followup to Chaos, yclept The Information). And where does the information come from in construction projects? Good orderly direction would be great, and one very positive benefit of the LEED process is that early charettes, (design brainstorming sessions), assemble all interested parties to share constraints, issues, and posit approaches to the finished building. So what are the commonsense points for the morning about avoiding entropy in the construction delivery model?

1. Avoid an adversary process. The old model of building was design/build, the master builder was also the architect (in fact “Architect”s are a recent arrival on the scene, having originated in the 18th century as the keepers and assemblers of construction documentation, this was refined to include their role to certify compliance with building codes. There has been an affinity for the profession by those kids who “used to like to draw” and became architects because the fine arts are fickle-that will be a separate morning’s peroration). Back to the point, when the master builder was dissimilated into, in the extreme cases a group including a designer, engineers of many flavors (mechanical, electrical, civil, structural, geotechnical, acoustical, and so forth), a general contractor or two, subcontractors, code officials, regulators who may never see each other in the same room: entropy ensued, (unfortunate verb, because the group is many time reassembled during subsequent lawsuits). Better to assemble a team from the start, difficult, but quite workable, and way better than the alternative.
2. Document with the end in sight, but remember, the plan is not the project. You can’t build those Escher sketches. The building does not give a hoot about the energy simulations you created, (I once worked in the high tech arena of gas turbine engine design. One of my colleagues, Larry Hughes, who was a whiz at computers in the ’60’s had developed a “start to idle engine reliability program” and when I told him one of the real engines he had simulated wouldn’t start, he gave me the “deer in the headlights” stare and said “but the computer says it will”. Nuf said.) One of the beefs I have with some of the new “Energy” award programs is that they are based on simulation. There is a real building there folks.
3. Expect to be surprised. My old architect partner, Clint Sheerr, used to tell clients that they could be guaranteed to have unexpected issues during construction. It is not a perfect process. Smile. Pain is guaranteed, suffering is optional.

Nowhere is material science so necessary as in the Sweet Division 16- electrical. Dominated by copper and aluminum we discover elemental properties as we harness these metals to conduct electricity. Copper is more expensive these days (it wasn’t always so, Napoleon dined with aluminum cutlery, then more expensive than gold- a fascinating book for those geeks among us: Napoleon’s Buttons describing how inferior metal buttons contributed to the defeat of the French attack of Russia), so creative types look to aluminum as a substitute. Reminds me of a conversation with a specifier who adamantly refused to use the words “or equal” since equality meant identical. Good sense. The areas we get into problems:

1. Different thermal expansion can undo mechanical connections.
2. Oxidation increases contact resistance, produces heat and aggravates the thermal expansion effects.
3. Galvanic potential and accelerated corrosion in presence of good old sodium chloride: a.k.a. salt spray and water.

Never use aluminum wiring without planning for it in terms of connectors and corrosion inhibitors. Anything else will cause a fire, sooner or later.

Walking up to a set of buildings with “mechanical issues” is not terribly uncommon. First of all we need to know what the mechanical systems that cause the most problems are, and what common sense lacunae created them. Lacunae are suspenses of sense, or gaps in thinking about plumbing, mostly forgetting basic principles: gravity and materials:

1. Hot on the left, cold on the right and waste goes downhill. Gravity- improperly pitched pipes cause 90% of plumbing blockages, and suprisingly right from the installation, like the architects who forget that 1/4″ per foot is the proper pitch for a “flat roof” that can’t tolerate standing water-1/4″ per foot is de rigeur (and code) except with really large pipes, where the bottom looks flat to the waste in the channel. Let’s not forget to pitch the pipes to a low point drain where winterization is standard operating procedure. I have seen the tell tale low bursts or sawzall improvised drains at low points at the spring startup of cottages by the sea.
2. Be the water. My friend Dan Holohan likes to assume molecular size when describing circulating water systems. When I get to a bull head “T” I don’t know which way to go, so I go both ways- just like traffic, water flows in the direction of least resistance, sometimes in the wrong direction, bad news in a circulating hot water heat or domestic situation. In the big leagues with “primary-secondary-tertiary” pumping, the lack of a common leg has been the downfall of huge campus wide installations. We won’t begin to discuss the life safety and trauma of large scale steam distribution when it gets fouled with air- another chapter.
3. Sometimes water is not just water, in fact usually this is the case unless we go to great lengths to correct its chemistry. And some of those chemistry lessons come to light when acidic water literally eats copper pipe for breakfast: pinholes. The chapter in Florida’s pinhole aversion by means of substituting polybutylene plastic is frought with a digression on improperly designed connexions (as the British like to spell it).

You wouldn’t want to build a home in a place where there was never any rain: life is sustained by water. Life giver that it is, it is also the most pervasive destroyer of building materials with the able assistance of other, simpler forms of life: the wood destroying organisms (WDO’s). Plus it’s just a bother when it drips onto your head when the icemaker pan on the floor above at the hotel where you are staying, leaks; of course, in the middle of the night.

Water intrusion amounts to over half of the immediate needs corrections I have seen in the thousands of buildings I have assessed. (When I arrive on-site, I generally make a comment as to whether it is the roofs or the HVAC systems which need attention. I generally get a “How did you know?”, response). Needless to say, the latter issues of HVAC are generally manifested in the creation of liquid water in the wrong places by condensates which leak, or are created in the wrong places. Same for plumbing: pinholes and sweating leads to destruction by our friend, water, (waste water is water too, just nastier and smellier).

Let’s confine today’s chapter to stormwater: that would be rain, snow, and ice. I have been to seminars given by my colleague, Joe Lstiburek, which have the flavor of an old timey tent revival meeting with a room full of knowledge seekers chanting “All claddings leak!”, “Flash for cash!”, and “Conduct and control the water: down and out! “.

Lots of commonsense here:

1. “All claddings leak!”: the exterior siding on buildings, and even those lovely architectural shingles are there for appearance first but will shed at best 98% of the water impinging upon them. Like the rest of the building, water protection is a system, detailed with backstops to treat the exceptions: penetrations, intersections, and ice dams as minor trifecta.
2. “Flash for cash!”: this is one of the backstops, where two systems or a discontinuity appears, insert solid flashing. I once met a man responsible for the challenges presented in the exterior envelope maintenance of a major hotel chain. He said, “Show me a window system that is not caulk dependent.” At the time, hard to find. If  caulking is applied with 99% perfection, 1% of leaks can cause a world of problems.  
3. “Conduct and control the water: down and out! “. Gravity is with us today, and except for capillarity (which will be a whole other chapter) is our ally in allow our controlled water to reconvene with the ground. The “and out!” emphasis reminds us that if we bring the water into the basement or under the building it is still there to raise havoc. I advised a client on a level lot not to consider a full basement for all the right reasons: level lot, high water table, no adjacent property to give the water to. He insisted. I saw him some years later and said in effect, “You were right, I have two pumps that run all the time and had to put in a generator, because when the power went off for 6 hours, I had four feet of water in my basement.” So much for inexpensive storage for things you should (and now that they are moldy, will) toss.

So water, that nurtured life, when it began, can also work to tear apart, the works of man.

The good news is that we have the brains and creativity to solve our energy, shelter, food, and water challenges in the 21st century. It’s really quite simple, in all areas the Trifecta is Conserve, Combine, and Create. How does this apply?

• With energy, first we conserve the wasted energy that leaves through cracks, windows, and inadequate insulation; then we use the wasted energy we used to reject to the atmosphere while generating something- whether it be domestic hot water that can be reclaimed from a powerplant nearby, or the stack heat from a coffee roasting operation that is heating process water electrically; and finally, create energy from the sun and wind (which is really solar energy in disguise).
• applying this to shelter, first we limit our appetites for size and ostentation (conserve); then we combine function or adaptively reuse existing buildings and land; and then finally we create efficient shelter on a 250-350 sf per occupant model.
• with food, we could feed a nation with the leftovers in our garbage; then we can grow crops that work in combination with the land, for example, soy improves the ground and can provide food or fuel (corn takes more energy to create than it provides); and then diverse crops creating food for a stable population.
• by now I hope you will all be able to see how this applies to water? Don’t use so much, don’t throw it away, don’t irrigate deserts; recycle grey water; and then, we hope we don’t have to create water except on a limited basis from the byproduct of “the hydrogen economy” (whatever happened to that?) or desalinization plants using waste heat from a local power plant.

The planet will be just fine, let’s worry about humankind!

The problem with common sense is that it isn’t common any more. What used to make sense in New England is applied to new homes or buildings in Florida. The reason we used to have “regional architecture” was that the climate was different in different regions. In Florida, we run our pipes on the outside of the buildings. Try doing that in Vermont! Even the bugs know the difference. What is inedible to a termite is a harvest supper for a northern bark beetle. We need to stop homogenizing everything and use the differences for the better. That’s common sense.