Re: Parameters In Standard Of Nfpa68
Originally Posted by joewang
For calculating the vent area of a coal silo, a have some questions on the parameter determination.
In NFPA 68Standard on Explosion Protection by Deflagration Venting2007 Editionfor calculating the venting area, there's some parameters have to be determined.
1) Kst and Pmax : can be find in ANNEX of NFPA68;
Q:The table shows the data for each dust , if the mixure of two or three dusts , how to deal with the data?
Using published data is second best to testing your own dust. So pay the money and get your dust mixture tested
2) Pinitial :
Q: Is that mean the pressure before deflagration? Can I determine it as the silo's inside normal operating pressure?
Yes
3) Pred :
Q: Can I determine it as the silo's design pressure?
It's the maximum pressure that the silo can safely contain
4) Pstat : defined in NFPA68 as "3.3.27.3 Static Activation Pressure (Pstat). Pressure that activates a vent closure when the pressure is increased slowly (with a rate of pressure rise less than 0.1 bar/min =1.5 psi/min).
Q: How to determine it for my coal silo.
Its nothing to do with the silo, it's to do with the vent you are using. It's the pressure at which the vent opens. ■
Re: Parameters In Standard Of Nfpa68
Thank you very much! ■
Untitled
Thanks a lot!!! ■
Parameters in Standard of NFPA68
Definition of the parameters in Standard of NFPA68
For calculating the vent area of a coal silo, a have some questions on the parameter determination.
In NFPA 68Standard on Explosion Protection by Deflagration Venting2007 Editionfor calculating the venting area, there's some parameters have to be determined.
1) Kst and Pmax : can be find in ANNEX of NFPA68;
Q:The table shows the data for each dust , if the mixure of two or three dusts , how to deal with the data?
2) Pinitial :
Q: Is that mean the pressure before deflagration? Can I determine it as the silo's inside normal operating pressure?
3) Pred :
Q: Can I determine it as the silo's design pressure?
4) Pstat : defined in NFPA68 as "3.3.27.3 Static Activation Pressure (Pstat). Pressure that activates a vent closure when the pressure is increased slowly (with a rate of pressure rise less than 0.1 bar/min =1.5 psi/min).
Q: How to determine it for my coal silo. ■