6-9-06
Help... I Can’t Breathe
So, we’re getting into the heart of our structural planning for the new building. This is the part where highly trained experts tell me how not to fry, freeze, suffocate or electrocute the public.
Clever, no?
One would assume that this is something your architect would do, and in some larger firms, that’s no doubt the case. We are dealing with a very small firm that outsources the permit plans to various subcontractors. This month, we reviewed the mechanical drawings.
“Mechanical” in building-speak, encompasses your building ventilation systems, your electrical systems, sprinklers, etc. It does not include structural issues such as building supports, foundation, roof and so forth. Those are handled by your structural engineer. Finally, there are also landscape designers who do everything from yards to parks. Think you don’t need a landscape designer? Think again. If you have any public-facing store front space or a parking lot you may well require a landscape draft as part of your permitting submission. We will need one to submit a design change for our landlord’s parking lot to put in a small walkway to comply with fire codes. Chicago Jewish Theatre was delayed for weeks and weeks because the local neighborhood ordinances required they put some greenery in front of their old space on Clark. (They opted for a little tree in a concrete pot.)
But those days are still a ways off. We’re trying to make sure that our building is comfortable and safe. Three weeks ago, we had a fair amount of scheduling negotiation to review the HVAC (Heating Ventilation Air Conditioning) plan. I have to admit I thought, “Why do they need me? I want a heating unit and an air-conditioning unit for the two spaces. Don’t bug me with trivia!” (It was a very busy week for me).
It started as a curiously baffling experience. On the one hand, seeing large format drafted plans of my building in 1/2” scale was quite exciting. And yet…it didn’t really look like my building. There are dozens of lines snaking around it, multiple grids overlaid and obscure notes such as “GB 8’0”-VIF.” After 60 minutes of plan review, I was actually none the wiser. My architect and engineer appeared to be reviewing a set of complex plans and I would nod knowledgeably about tonnage and intake vs. exhaust valves. I was mainly struck at how much the conversation resembled two audiophiles discussing high end mixing equipment. It’s full of industry-specific jargon. And it’s the particularly inscrutable jargon, where each definition employs another acronym. Scary.
I was able to piece together some basic information to help y’all. HVAC for buildings is split into zones, where each zone corresponds not to a contiguous area but a space connected by ventilation to a single HVAC unit. Each unit obviously is independently controlled, but linked to a particular thermostat reading. The power of HVAC hardware is measured in tons, where a ton is 12,000 BTU an hour. A BTU stands for “British Thermal Unit,” the energy required to raise the temperature of one pound of water one degree Fahrenheit. Or, 1,055 joules, which is a physics term I vaguely remember from high school but forgot at graduation. Look it up, lazy bones!
There are various technologies that one can employ in building your HVAC, all of which have been reduced in my mind to “burble burble burble water burble” or “burble distilled burble burble.” From a permitting perspective, there are specific BTU ratings required based on expected occupancy and use. In general, the types of units we will need for our spaces are considered “small” by building engineering standards. Which is a good thing because HVAC systems are expensive, heavy and loud. Whenever possible, they are placed outside the building, but you need to be very sensitive about vibrations and structural issues when considering their placement. This is where your structural and acoustical engineers need to review the mechanical plan, but a competent engineer should be able to make some good guesses.
In any case, too much math for me. My recommendation is accept the size recommendation and count yourself lucky.
Of slightly more interest to me was the option of suffocating one’s audience. In ventilation, air is brought in to your theatre which your audience breathes and then exhales. If the exhaust for the space is not equal to its size, everyone can die of oxygen deprivation like being trapped in a car. Exciting! So, each space has vents to bring in the heat and separate vents to allow the used air to escape at the proper rates. These ducts aren’t necessarily too large, but their size and capacity is also dictated by building code and good engineering practice; 10” – 12” are common for public spaces. But where do they go? The art of duct design is not terribly advanced. They come in rectangular and round sizes, while the vents have a few different options to try and reduce sound bleed and control air flow. This was the first point at which I was able to interject/advise. Did I want exposed ducting for a rawer appearance or build in dropped ceilings which were more expensive? If the duct work is exposed, where exactly is it placed in the lobby. We actually spent a fair amount of time reviewing this problem and ended up rerunning a number of ducts to reduce their appearance, provide for more insulation against noise and simplify the paths which reduced the cost.
At this point, I noticed that we had three zones. One for each theatre and one for the public spaces. At this point, I started thinking about daily use and costs. The units are either running or not running. If we will be working in the office during the winter under the current scheme, we would need to heat the entire lobby. Very, very expensive. At the same time, I didn’t want to just bring in little electric space heaters which are semi-expensive in energy terms and a fire hazard. Similar problems existed for the rehearsal rooms and shop.
This is clearly the only reason I was really present. As the only one in the room focused on the practical aspects of operating the space in the future, I was able to help focus attention on our energy consumption problem – a problem that honestly hadn’t occurred to the building engineer. From his perspective, our space was so small for commercial use that the extra energy to heat it was considered just a price of doing business.
Sadly, we work in the theatre. There are no negligible energy costs in our bright and shiny new post-Iraq, pre-Iran invasion world. Natural gas and electricity are at record highs, and a theatre’s cash flow position is, er, poor. So we needed a way to heat more selectively without increasing our construction cost unduly. The industry does make a set of gated ducts that allow adjacent spaces to share a unit while semi-controlling each space’s temperature individually. Unfortunately, most of the spaces I was concerned about were not that closely linked and a lot of extra ducting would be required. Regardless, the HVAC units would still be on. An air conditioner big enough to cool 300 people would be turning on whenever there were three of us in the office.
We finally settled on a combination plan of some air conditioning wall units and electric vents in the office space, and a small unit for the rehearsal space. The cost of the HVAC system will increase by about $10,000 but I think we’ll make up that cost within a few years in energy savings. We also discussed some insulation and conservation issues. Most of those materials and details don’t have to go on the plan for the city, but a little forethought will go a long way to making the space self-sustaining in a few years.
Once the plans are finished, I’ll post them on the Web site, so check in at www.theaterwit.org this month for some downloadable views of HVAC systems. As always, you can post questions on our Web site as well.