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Class 1 Division 1 Design

Class 1 Division 1 Design

Class 1 Division 1 Design

(OP)
Our company is looking to design equipment for class 1 division 1 areas.  I understand that the purpose of a Div1 enclosure is to contain the gases until they cool enough to escape into the surrounding area, and depending on the group going for that gas is different.  I've read through a ton of information on required flame paths etc but the one thing I cannot seem to find any information on is how to calculate the expected ignition pressure.
  
What would be the process to solve something like the following. If you have a dia cylinder 24" long filled with hydrogen/air mixture (5% hydrogen) at 25deg C and 1 ATM
what is the maximum pressure that would be generated inside the cylinder?

Can someone recommend a book/reference?

Or is the common practice to build something and try and blow it up and then adjust the design so it doesn't fail?  

Thank you in advance for any useful comments.

RE: Class 1 Division 1 Design

The adiabatic combustion pressure ("explosion pressure") is generally about 150 psi, or ten times the initial pressure. It is limited by the amount of oxygen available. Going lean or rich will just lower the pressure. The way to calculate it is to figure out how many moles of gas you start with and room temp. and how many moles you end with. Use heats of formation to calculate the heat release and heat capacities to calculate temperature rise.

RE: Class 1 Division 1 Design

(OP)
Thank you.
Are there circumstances where I should be concerned with detonation vs deflagration? ( I hope I've got the terms correct, burning vs exploding).
 

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