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Author Topic: Tenability within Means of Escape  (Read 422 times)

Gary

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Tenability within Means of Escape
« on: November 11, 2018, 12:38:08 pm »

I have a scenario where I am trying to measure the radiative heat transfer and subsequent tenability within an open plan apartment and the relationship between cooking facilities and the means of escape.

I have inserted a slice file within Pyrosim which measures radiation loss however the units at Kw/m3 and not Kw/m2 therefore perhaps I am measuring the wrong parameter.

I am considering using a hand calculation where:

q=Stefan-boltzman constant x T(absolute temp in Kelvin) x A (area of emitting body)

Would the forum agree this is the correct formula or is there another formula to prove that the radiative heat does not exceed 2.5Kw/m2?

If anyone has used this formula, is the temperature measured at the source of at the various points along the MoE?
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Timo

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Re: Tenability within Means of Escape
« Reply #1 on: November 12, 2018, 04:54:37 am »

Hi Gary,

from what I gather you are interested in the radiation received at a certain point in space (target) at a certain distance from the heat source (emitter). 'Radiation Loss' is the wrong parameter for this. I suggest you set up a device (or an array of multiple devices) along the egress route, measuring the parameter 'Radiative heat flux gas'. The results will be plotted in a spreadsheet file.

The tenability limit of 2,5 kW/m² is commonly referenced in literature and should be reasonable, especially for short duration of exposure.

In regards to hand calculation your formula doesn't look right. The radiation received by a target is depending (among other things such as temperature and emissivity of the heat source) by the distance and angle from the source, typically described by a configuration factor. You may want to refer to literature on this topic, e. g. D. Drysdale, An Introduction to Fire Dynamics

Good luck
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