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blast load

blast load

blast load

(OP)
Anyone here knows how to "rough" calculate the pressure for a ducting/plate 1 meter away from a 5psi blast load.

I have an equipment that may have a blast force of 5 psi and i need to contain it with a duct/plate. Duct is 1 meter away from the blast.

I just need a rough, conservative approach.  

RE: blast load

The figure is from Chapter 7 in the handbook. However front wall pressure is more complicated than what the free field wind pressure of the extracted page suggests.  

RE: blast load

5 psi is 720 psf ... Go from there??

RE: blast load

(OP)
@ishavaag,

i have a copy of ASCE Design of Blast Resistant Bldg.
And based on the formula of front load reflected overpressure is bigger than 5 psi. I was expecting it to be lower than 5psi. I am probably not interpreting this correctly for equivalent static pressure.

RE: blast load

delagina, that's precisely what has refrained me for giving advice, since I am not expert nor trained so I have been looking some resources to see if something could be learnt short term, and if the "free field" pressure results lower than the inciding pressure, the front pressure is shown in the numerical examples in the text be higher than the inciding pressure, as you have also met; this a device of air confinement or whatever, but since not expert I have preferred to refer you to it.

What precisely I haven't understood from the text is that first goes for what in the uploaded page, then goes for a separate case for the front of a building (then sides, rear, roof as well) to find the bigger load you are finding. Now, in my mind that kind of thing seems mainly reasonable if the extent of the obstruction is as big as to produce confinement, other than that, it would make scarce sense to get some evaluation like that in the uploaded page, that would correspond to minor obstructions to the blast unable to show the confinement effects bigger surfaces are able to develop. But whilst I clear the matter better wait for expert advice.

RE: blast load

Still perusing blast effects books.

EXPLOSIVE LOADING OF ENGINEERING STRUCTURES
Philip Bulson
Taylor & Francis e-Library, 2003

makes clear reflected pressure pr goes weel above free field incident overpressure p0. However determining loading, as in the other text is a bit more complicated, depending on the setup, so, again, better go for the reference itself. I muse on what read that a sketch would be useful to those trying to help, making note of if indoors explosion and vents etc
 

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