3 replies to this topic

[J_Leo]

Dear Fellow Engineers,

I am writing to get your opinion on the fire case PSVs on the exchanges with one particular Project. We have AEU type shell & tube exchangers and Compabloc type frame and plate exchanges. Per Client's Standard (attached), exchangers with large gaskets and bolts tend to self-relieve during fire, thus, only fire thermal relief is required. Otherwise, regular fire vapor generation is required.

For AEU type, there are no flanges / gaskets in the rear part. For Combaloc type, the plates are welled and no gaskets between plates. I prefer to use the more conservative fire vapor generation method, which gives larger PSV sizes. My lead insists to use the fire thermal method, which required only a ¾” thermal relief valves.

 

Here is the link to the Compabloc exchanger for your reference:

https://www.alfalava...gers/compabloc/

 

Attached Files

•  Client Standard.pdf   116.7KB   87 downloads

[fallah]

Dear Fellow Engineers,

I am writing to get your opinion on the fire case PSVs on the exchanges with one particular Project. We have AEU type shell & tube exchangers and Compabloc type frame and plate exchanges. Per Client's Standard (attached), exchangers with large gaskets and bolts tend to self-relieve during fire, thus, only fire thermal relief is required. Otherwise, regular fire vapor generation is required.

For AEU type, there are no flanges / gaskets in the rear part. For Combaloc type, the plates are welled and no gaskets between plates. I prefer to use the more conservative fire vapor generation method, which gives larger PSV sizes. My lead insists to use the fire thermal method, which required only a ¾” thermal relief valves.

 

Here is the link to the Compabloc exchanger for your reference:

https://www.alfalava...gers/compabloc/

 

J_Leo,

 

If you have to follow client standard, you should consider vapor relief for the heat exchangers you described in fire case...

[J_Leo]

Fallah,

 

Thank you for being there to help whenever I need help.

I am glad that you are on the same side with me. Can you give a little explanation for your conclusion? 

 

Regards,

Leo

[fallah]

 

Thank you for being there to help whenever I need help.

I am glad that you are on the same side with me. Can you give a little explanation for your conclusion? 

 

 

J_Leo,

 

A 3/4" thermal relieve valve for the exchanger with large gaskets and bolts is to be installed just for code compliance and in fact doesn't much help for exchanger protection against failure in fire case; also cannot help to relieve the over pressure due to fire case in the exchangers without body flange at all.

Hence if there would be a considerable liquid level in the exchanger shell just vapor relief can protect the exchanger in fire case (till all liquid to be vaporized and fire fighting extinguish the fire quickly) and if there would be no liquid level in the exchanger even vapor relief might not protect the exchanger...in fire case...