Hi Maria Grazia,
the Jin's correlation is not the only correlation for relating extinction coefficients and walking speeds. I recently wrote a paper about this issue together with Steve Gwynne and Dave Purser when we described the differences between Jin´s correlation and another data-set that was collected at Lund University and the way they are employed by evacuation models.
The paper is:
E. Ronchi, S. Gwynne, D. Purser (2011). The impact of default settings on evacuation model results: a study of visibility conditions vs occupant walking speeds. Advanced Research Workshop Evacuation and Human Behaviour in Emergency Situations EVAC11, Santander (Spain) – 2011.
and you can donwload the paper here:
and my presentation is here:
An extended version of the paper with more evacuation models (6 in total) will be out soon.
This has also been discussed in one chapter of Hui Xie's Phd thesis, which analysed in total four data-sets on this issue:
Xie Hui (2011). "Investigation into the interaction of people with signage systems and its implementation within evacuation models". Phd thesis. Fire Safety Engineering Group. University of Greenwich.
I am not aware of any explicit correlation between temperature/radiation and walking speeds/behaviours. I remember a discussion in the FDS+Evac forum some time ago about an "away from the fire" function (some users were trying to model temperature/radiation effects on people using Evac). The problem of modelling this aspect is mainly due to the difficulties of collecting data (both real data and experiments). I am also not aware of any evacuation model that explicitly model this. I know instead many models that represent the effects of fire implicitly, i.e. they can model the agent's route choice in relation to the environmental conditions, e.g., smoke, emissions, etc.