Sounds like the beginning of a plan. Remember, all the droplets and aerosols don't get tooted out the various apertures of the instrument. There's a lot of time you are sitting there and breathing waiting for a cue. So 100 people in a room, even at distances, is still a lot of exhaled air. The ACH is one thing, but the direction of air flow is also important to know.--- For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at membership**At_Symbol_Here**dchas.org Follow us on Twitter **At_Symbol_Here**acsdchas
It is clear you understand that a single air exchange does not purge a room. But that general formula for "refreshing" the air is misleading. That room is still not completely exchanged. And the amount of air actually replaced is also dependent on the location of the supply and returns. My issue with a lot of stages is that the best exchange is often up in the fly where the supply and/or returns are. The exchange on the stage itself may be poor. That's a problem for removing special effects as well.
And lastly, if the filters in the chiller are less than MERV 13 your supply can be returning the droplets and aerosol. And unless they are MERV 17 or better, the aerosol theoretically (and as one study indicates) may be returning the virus to the room.
So if I was god, the first thing I would require for this plan are the mechanicals for the HVAC and a discussion with the the guy to runs the system.
What do you say to the idea, instead, of making this is the year for the music students to do virtual lessons, tape or web cam their performances at home, sing in virtual choir and ensemble performances, and learn how to do this electronic stuff. It will be extremely useful to them in their careers. I have a young friend studying opera who with a friend has set up zoom "classes" on various individual operas in which they explain the plot, sing the major arias, etc, and make them available to people for free (asking for donations). I think she may be doing more for her career than she would get from taking classes.
Extraordinary times require thinking out of the box. Instead of distancing an orchestra when we know they work best when they really hear and feel each other's sound, lets do something new and different that will accomplish similar ends.
From: Casadonte, Dominick <Dominick.Casadonte**At_Symbol_Here**TTU.EDU>
Sent: Fri, Jul 24, 2020 4:00 pm
Subject: Re: [DCHAS-L] singing and wind instruments indoors
Hi Kristi,If you haven't seen it already, there is some preliminary data from a study of aerosol production for vocalists and brass and woodwind instruments out of the Colorado. The URL is https://www.nfhs.org/media/4029952/preliminary-testing-report-7-13-20.pdf?fbclid=IwAR1QMaQpjx04RQxeExcHekDjDiP82iE4xtDXDk2xN5RDBqAA-iHuaGtNDQA. There are some reasonable recommendations at the end. Two takeaways that I had (I am a musician and a chemist) were that if there were going to be rehearsals with more than one player, they should be 6" apart (9" for trombones) and the horns all need to be masked. Safest would be 36 square feet per person. So for a 100 piece orchestra, 4,000 square feet would be ideal. Could probably get away with less on the sides. Puppy pads are necessary for brass, but then the people picking them up should wear gloves, treat it as biohazardous materials (special bagging) and then wash up after. Another issue is the air exchange rate. Given the example in the slides, I have a chart from which we can extrapolate that it will take about 150 minutes for the air to totally exchange (unless if there are HEPA filters installed) in a large rehearsal hall, so rehearsals with a 10 minute break between rehearsals will not allow for effective clearing of virus that might be aerosolized in a large room. It looks like in the example they worked with 3ACH. With 4 ACH it takes about 117 minutes to refresh the air in a medium-sized clinic, according to my wife, who works in one. Interpolating with a 3ACH rate, it would require over 150 minutes to do the same, assuming a linear relationship (which very well may not be true; others in this list serve will know better than I). The horn mask data looked pretty good, but I'm concerned about aerosolization (which wouldn't necessarily show up in the Schlieren optics). The trombonist's arm movement, for example, will spread the aerosol. I'm also concerned about the cleaning of the nylon, which should be done every day.We are still working out what we are going to do at Texas Tech for anything that is indoors. Maybe chamber ensembles for the fall? Band, orchestras, and choirs? We are looking at large rooms, short rehearsals, no audiences, and masks.I don't know if this helps, other than to say that we are all struggling trying to sort out how to make music and do rehearsals in the time of Corona-Dom CasadonteDominick J. Casadonte, Jr.Minnie Stevens Piper ProfessorFellow, American Chemical SocietyTTU President's Excellence in Teaching ProfessorPresident's Award for Excellence in Science, Mathematics, and Engineering Mentoring (PAESMEM) AwardeeDepartment of Chemistry and BiochemistryTexas Tech UniversityLubbock, TX 79409Hi All,I have a non-chemical safety question for you. This is a talkative bunch with many opinions on many subjects, so I figured it's okay to be off topic. I am particularly interested in your opinion if you are at an institution in MA. Is your institution permitting your music/theater folks to do indoor singing or playing of wind instruments for the Fall? Curious of your or your colleagues opinions on this. Mine is that this is currently not permitted under theatre and performance sector specific MA reopening guidelines (even though those technically apply to only performances and not classes). I think it's splitting hairs to say it's different if they are in front of an audience or not.. What are your thoughts?Thanks,
KristiKristi Ohr, Ph.D. (pronouns: she/her)
Chemical Safety Services ManagerEnvironmental Health and Safety
40 Campus Center Way
Amherst, MA 01003
Office: 413-545-5117Cell: 413-800-4408--- For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at membership**At_Symbol_Here**dchas.org Follow us on Twitter **At_Symbol_Here**acsdchas--- For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at membership**At_Symbol_Here**dchas.org Follow us on Twitter **At_Symbol_Here**acsdchas
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