Heat release rate

[VishwanathMg]

Hello Guys,

Hope you are well.

I am currently working on a project involving CFD modelling of a naturally ventilated cave. The organisers are proposing to host a gig within the space; however, I am seeking guidance on the appropriate heat release rate (HRR) to adopt for a basic, steady-state CFD analysis.

I would be grateful for any suggestions on suitable HRR values to consider for this type of scenario. Additionally, if you could advise on any relevant guidance documents or references that may be used to justify the selected HRR, that would be very helpful.

Thank you in advance.

[johodges]

That is an interesting scenario. Do you have more information on what they are planning for this gig? The answer will depend significantly on the transient fuels that they are bringing with them to support.

[VishwanathMg]

Hello,
Thank you for the response,

It is anticipated that the setup will comprise temporary staging, lighting, and audio-visual equipment, with limited scenic dressing. The majority of the combustible fuel load is therefore expected to be concentrated at the stage area. The cave itself is formed entirely of natural stone, with no proposed linings or alterations, and is therefore considered non-combustible. A bar is located at one corner of the cave; however, it is anticipated that beverages will be sold in cans only, and the associated fuel load is expected to be relatively low in comparison to that present at the stage.

[johodges]

Are they planning to have any props on stage or just the band and equipment? Theater props may be made of expanded foams which will burn pretty well and generate a lot of soot.

[VishwanathMg]

Yes, I understand, but the stage includes just the band and their equipments.

[johodges]

The Fire Protection Research Foundation funded a study on theaters back in 2009. You can find the final report on the website at the link below. The authors used an assumed 500 kW/m2 with a fast growth rate. The basis of the design fire on the stage itself is not the strongest, but it is a reasonable starting point.

https://nfpa.access.preservica.com/uncategorized/IO_d4e7010a-a295-41d8-93a8-c7b5886a1c6c/

[drjfloyd]

Drinking, dim lighting because of a concert, unfamiliar and unsual egress paths, loud music that might interfere with notification, limited ventilation, large crowd -- this is sounding like the setup for what just happened in Switzerland on New Year's Eve. While a design fire is an important consideration, this seems like something where very strong adminstrative controls keeping the venue as sterile as possible in terms of fuel load may be warranted.

[rmcdermo]

My guess is that your first task is to estimate the mass of combustible material.

[mcgratta]

Are we all assuming that this is a musical concert of some kind?

[VishwanathMg]

Hello,

Thank you for the response,

Yes, this is a musical concert, with the stage representing the primary potential fuel load, and an anticipated occupancy of approximately 500 persons. The cave is formed entirely of natural stone, with no proposed linings or alterations. I am seeking guidance on the selection of an appropriate heat release rate (HRR) for the purposes of the CFD analysis.

[famousstages]

I'd recommend basing the HRR on the planned occupancy and the actual stage setup rather than using a generic value. The stage truss itself doesn't generate heat, but the lighting, speakers, LED panels, and other equipment mounted on the truss can contribute significantly to the overall heat load. At Famous Stages, we've seen how different stage truss configurations support varying equipment loads, so using the planned production layout will give you a more realistic CFD model.