I would like to correct the number of figure:
Figure 3.4 in FDS Tec Ref. Guide of Revision: 4908.

Figure 3.4: Oxygen-temperature phase space showing 
where combustion is allowed and not allowed to take place.

Sorry, I was looking old Tec Ref. Guide.

Thanks, I'll take a look at it.

Kevin,

Since Jukka seems to be having some good results with the enthalpy calc using actual
gas species, do we want to switch the extinction model in combustion_mf to the one
in
combustion_mf2?  The tech guide figure could be regenerated using the new approach.

Jason

Would this require a minor release, 5.5?

In combustion_mf2, the evaluation of whether combustion can occur in a cell or not 
is based on the gas composition of the cell itself, not the nearest neighbors. In 
combustion_mf, the cell and six nearest neighbors are included by default in this 
evaluation. The parameter SUPPRESSION_SEARCH=T by default. I have little experience

on setting SUPPRESSION_SEARCH=F since pretty soon after this option became 
available, I became aware of combustion_mf2, and I've basically worked with that, 
but with a limited range of cases compared to the diversity of the validation suite.

Also, much of what I've done is outside the current validation suite anyway. To me,

it would seem a good idea to run the validation set if Jason's proposal is 
considered.

Jukka

yes this would be a minor release if it were done.

I changed the critical flame temperature expression to use 20 C rather than the 
ambient temperature. We might eventually replace this routine, but it is easy enough

to make the fix. Thanks.

Thanks, Kevin.
I am interested in extinction criteria now,
and I wanted to modify fig3.4 by myself.
Anyway, new approach by combustion_mf2 is absorbing me too.

I am going to close this Issue.