# Orchestra Pit Ventilation



## TMPTechDir (Oct 18, 2012)

So, we are well into the design process for a significant remodel of our space that will give us an orchestra pit. The proposed pit is roughly 24'x14' with an 8' ceiling. Since we are strictly a musical theatre company, no pit covers are going to be used and there will be a 5'6" opening that runs the full 24' width of the pit. The question is this: do we need a dedicated hvac system to control the temperature in the pit and provide ventilation, or will the 132 sqft opening be sufficient. The Music Director has spent the last show up on stage on top of an 8' platform for the last 3 weeks of our current production and has suddenly become concerned with the comfort of the performers and musicians and is thus convinced that the pit needs to be climate controlled. Thoughts?


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## Footer (Oct 18, 2012)

It is not a bad idea. I have been in several places that the return vents for the whole space are in the pit. If you have union musicians, plan for it. You can't add it later. If it was totally open air it would not be as big of a deal, but with a cantilever you should have something.


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## TMPTechDir (Oct 18, 2012)

The difficult part is that it sounds like tying into the existing roof systems will be cost-prohibitive. The talk right now is converting one of the small storage spaces on the orchestra pit level into a small furnace room. The thought is it would be utilized primarily for moving air around and occasionally for warming the pit in the winter months.


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## JohnD (Oct 18, 2012)

I would start interviewing local HVAC contractors and get their assistance.
I wonder if something like a ducted mini-split system would be a good choice.
Or perhaps a HVLP system.
Small Duct Central Heating & Air Conditioning
The system can't take up a lot of space, and it needs to be quiet.


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## ruinexplorer (Oct 18, 2012)

You also have to consider the productions. Should you try to do a production like Phantom of the Opera, utilizing heavy amounts of low-lying fog, you may need the ventilation due to high density gasses like CO2. Otherwise you _could _make the pit a toxic gas dump (watch this Mythbuster's clip at about 1 minute in for a visual of high density gasses being trapped). This is why you don't have someone lying down in ground fog. 

Anyhow, instruments stay in tune better if at a constant temperature and humidity, which this could provide.


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## lwinters630 (Oct 18, 2012)

Cold air falls and is dense, with out a way to vent the cold air out it will prevent heat from flowing in and during A/C will be even colder. (how cold is your catwalk?) Big ducts with sound dampening will reduce noise.

Definitely get an HVAC consultant.


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## kiwitechgirl (Oct 18, 2012)

I work for an orchestra which lives in a pit (opera and ballet orchestra). If we didn't have dedicated air con, I'm pretty sure there would be nights when we wouldn't have an orchestra. If we have different sized orchestras in there (we work in rep and often will go from an orchestra of less than 40 to one of more than 65) then we have to adjust the air con accordingly to stop them either freezing or overheating. Wind players, in particular, do need specific conditions for optimum performance - otherwise they have reeds drying out or water bubbles forming under keys. I'd say you should definitely be considering dedicated air con, even though your pit is a good deal smaller than ours is....


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## FMEng (Oct 19, 2012)

Contractor designed HVAC systems for situations that are not typical usually fail. It isn't a house or an office and definitely not typical. The system has to be quiet, maintain temperature and humidity fairly well, and the installation situation sounds tricky. I have yet to find an HVAC contractor that knows how to achieve quiet from their own design. If you want it to work in the end, have a mechanical engineer do the design. In Tacoma, I recommend Rick Hultz, at Hultz/BHU. Maybe he would donate some efforts to the arts.


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## MPowers (Oct 19, 2012)

I can't help you with the pit question other than what others have already mentioned, but I DO have a nagging question.

Do you ever work with a designer named Cary Wong? When I was TD for the Wildwood Opera for 10 years, he was the "resident" designer.


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## TMPTechDir (Oct 19, 2012)

Can't say that I have worked with Cary Wong. We had a resident designer here for the first half of my first season here. When her "regular" job became too demanding, the designing fell to me. I've been serving as the TD, resident designer and scenic artist ever since. Though I wouldn't mind sharing the load...it can get to be a bit much.


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## museav (Oct 19, 2012)

TMPTechDir said:


> So, we are well into the design process for a significant remodel of our space that will give us an orchestra pit. The proposed pit is roughly 24'x14' with an 8' ceiling. Since we are strictly a musical theatre company, no pit covers are going to be used and there will be a 5'6" opening that runs the full 24' width of the pit. The question is this: do we need a dedicated hvac system to control the temperature in the pit and provide ventilation, or will the 132 sqft opening be sufficient. The Music Director has spent the last show up on stage on top of an 8' platform for the last 3 weeks of our current production and has suddenly become concerned with the comfort of the performers and musicians and is thus convinced that the pit needs to be climate controlled. Thoughts?


A pit is occupied space so it would have to be heated and cooled or at least ventilated as required by any applicable codes. If the pit is existing or completely new will likely impact how it relates to the existing HVAC system and what may already have been considered in the design work to date. It may be important to find out what is required and what is already planned to address that.

As Kyle noted, it is fairly common to use a pit or the area under the stage as part of the return air path for the audience chamber. If that is the case then it may be very difficult to treat the pit as a separate environment with its own climate control. Imagine someone cranking up the pit air conditioning and that resulting in the audience chamber HVAC controls seeing cooler return air and thus turning down the A/C for the audience chamber. You would have to somewhat segregate the two 'zones' to prevent their interacting. And that then also relates to how changes in temperature and humidity, be it changes to the pit environment or between the pit and other environments, may affect instruments and making sure your Mechanical Engineer recognizes the related implications.


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## JohnD (Oct 19, 2012)

ruinexplorer said:


> Should you try to do a production like Phantom of the Opera, utilizing heavy amounts of low-lying fog, you may need the ventilation due to high density gasses like CO2. Otherwise you _could _make the pit a toxic gas dump (watch this Mythbuster's clip at about 1 minute in for a visual of high density gasses being trapped). This is why you don't have someone lying down in ground fog.


This post reminded me of the scene in "Sing Faster".


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