oh, you've got it already
I have it, and I have just built Excel spreadsheet about this RP-581
now I am going to make real Software, but there are several things that I am still confused

Why Furnace Tube module (which exist in 581 BRD year 2000) is deleted in RP-281 year 2008?
how can I built calculation logic of Cloud Dispersion Analysis (Consequences Level 2) ? Is there any of you can share it? I need SLAB or DEGADIS logic calculation (not the software)
and also is there any of you know any calculation logic of any Fluid Property Solver (also for Consequences Level 2)?

Please let me know
thanx..

Regards,
Christian Sembiring
Materials Engineer & RBI Software Developer
Indonesia