Greg, I will answer them as best I can

greggorbett Wrote:
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> Dan,
>
> Like Doug, I was extremely interested in your
> findings. I have a few additional questions.
>
> How did each student analyze the scene, alone or
> within a group?

Due to time constraints the class was broken down into two groups. We encouraged them to work independently, but they did discuss it with each other. Based on the results, however, one can summise that they final decision, more often than not was independent based on the written conclusions.
>

> Did group dynamics play a role in the
> investigations/determinations? Meaning, was the
> group members allowed to talk with each other?

Yes, and like in the real world, we observed people get talked out of correct calls and talked into correct calls as well.
>
> If so, were a higher percentage of incorrect
> origin determinations found within certain
> groups?

That would have been a very interesting dynamic to study.....damn.....Didn't think of tracking that at the time. Oh well next time.

> Here’s the big one – Pat’s earlier question…what
> patterns change from a compartment transitioning
> through flashover? What research are you basing
> your findings on? Did you perform an identical
> burn that did not transition through flashover to
> analyze what patterns exists in a pre-flashover
> compartment?

No, we did not perform an identical burn that did not transition through flashover, although we have done it in the past. Didn't have access to a second cell this time.

The big one. I will not give my personal opinion, because I don't wish to debate it. However, according to 921 and I agree with it, (uh oh, that is my personal opinion....fire away) it states.

6.2.3.4.1 The ventilation of the room of fire origin has a great effect on the growth and heat release rate of a fire, and for this reason greatly affects pattern formation. In limited, full scale testing, it was found that patterns that indicated area of the tense burning remote from the point of origin were observed and appeared to be from ventilation effects only. This result was observed in rooms that had flashover conditions where clean burn areas were produced under a window that had been broken during the fire, away from the origin. It was observed as areas of intense burning on furniture items near a door opening as truncated cone patterns on walls opposite door openings.

Now 921 goes into a lot more detail, but I got you started, read the rest for yourself cause my fingers are getting tired.

How long after “flashover” was the compartment
> allowed to burn before extinguishment?

approximately 2 minutes.

What was your indicator that flashover occurred?

I know what it is and when the room transitioned I started my stop watch.


>
> Did the students use any analysis techniques to
> aid in the patterns analysis? (i.e. depth of
> calcination, depth of char)

Some did and some did not. No real statistics to quote on that since it was a training exercise more than a scientific experiment.

>
> How long were the students allowed to analyze the
> scenes before making a determination? As long as they wanted. All in all I guestimate that they took about an hour to analyze a single room that was 12'x 12' x 8'.
>
> Gregory E. Gorbett, CFEI, IAAI-CFI, CFPS, MIFireE


Dan Hebert