Hello everyone. I would appreciate if anyone could help me. Does anyone know how can I calculate the impulse arc pressure that takes place in a confined structure (low vented). I have read that the waves reflect when the arc occurs in a confined area beacuse of the reflections, but I can not find a find a formula to estimate the impulse reflected pressure.

Thanks in advance.

Eugenio

Ralph Lee's theoretical calculation indicates pressures developed by an arc but does not consider a confined condition, and worse, the current ongoing studies by the joint IEEE/NFPA group seem to suggest that the pressure calculation is grossly higher than reality.

There isn't much information available. The current IEEE-NFPA Arc Flash Collaboration Project was supposed to provide some new information on arc blast pressure, but I haven't seen anything released to date.

Dr. Ralph Lee's work from tthe 1980s pioneered work on arc flash blast pressure. There may be others that have reviewed and commented.

There is some information in the IEEE Yellow Book which is now a 3007.X Standard, three documents.

Regards;
Terry

If you calculate the blast pressure, what do you do with it?

There is an ACARP study that may be able to assist your inquiry.
ACARP - Australian Coal Association Research Program
'C4032: Safety Aspects of IP55 Enclosures used in High Fault Level Underground Coal Mines'

Has Arc Energy -> Pressure calculation that can then be used to calculate required venting area of an IP enclosure so as to avoid catastrophic failure of enclosure under fault condition.

Hope this helps.