14 replies to this topic

[sadia]

Dear All,

 

If our ambient temp is 50 Deg.C, then is there requirement of cooling of LOG bullets in summer.Please share any NFPA, API etc code reference, which support this.

[fallah]

 

If our ambient temp is 50 Deg.C, then is there requirement of cooling of LOG bullets in summer.Please share any NFPA, API etc code reference, which support this.

 

sadia,

 

What is the specified pressure under which the LPG is to be stored inside the bullets?
 

[sadia]

Dear Sir,

 

Our system operating pressure is 100 to 150 Psig. I have tried to find any authentic source of reference but did not find.NFPA 58 is supporting showering system in case of fire not for cooling.

[Bobby Strain]

Are these already in service? Hopefully the vessels are designed for the pressure at 50 C.

 

Bobby

[breizh]

Sadia,

Consider this resource , you will find pointers ( references /Codes) :

http://www.firehouse...ions-the-basics .

 

Note :1- Consider Sun shields to mitigate the temperature rise .  

 

         2- http://www.tcetoday....VI-Paper-15.pdf

 

Hope this helps

 

Breizh 

Edited by breizh, 30 May 2016 - 12:13 AM.

[fallah]

 

Our system operating pressure is 100 to 150 Psig. I have tried to find any authentic source of reference but did not find.NFPA 58 is supporting showering system in case of fire not for cooling.

 

sadia,

 

You should arrange the operating pressure to be the value equal to saturation pressure of LPG at 50 C. Anyway, you can consider cold insulation on the tank or if it's spherical a sun shade to isolate from sunshine...

[sadia]

Dear All,

 

We have already considered wet type fire sprinklers which will be used in case of fire. LPG Bullets are also made of cast iron with design temperature range upto 80-90 Deg.C as per ASME II.

 

Dear Sir breizh,

 

The provided link is for LPG system fire protection not cooling.

 

My question is cooling of LPG bullets in case of temp rise in summers not in case of fire.

 

Thanks

[sadia]

Dear Sir Bobby Strain,

 

This is green field project. The vessels are design for 250 psig at design temp 80 Dec C.

[sadia]

Dear Sir fallah, 

 

For large storage vessel shelter seems not practice & economical.

[Bobby Strain]

Paint them white to reflect radiation. Check the LPG vapor pressure at 50 C and see if it is less than 235 - 240 psig. If so, then you should have no problem with the high temperature. I have used earth covered bullets for fire protection in Saudi Arabia.
This also keeps the tanks cooler.

[breizh]

Hi Sadia ,

I'm still thinking that spraying water could be an option to cool down the bullet . I've seen similar set up on monomers storage tanks .

At least your equipment should have Sun shield and painted in white as stated in other posts .

 

Breizh

[sadia]

Dear Sir,

 

NFPA 58 not allowed to used fire water resource in some other purpose e.g cooling. However mounding will also add the cost.

[breizh]

Sadia ,

Did I mention to use the fire water resource ? I just indicated the possibility to spray water on the vessel to cool it down . In the set up I was refering the water was recovered in a sump for recirculation .

 

 

Breizh

[breizh]

Hi Sadia ,

 

You may find good  info in this pamphlet , not restricitive to your query .

 

Hope this is of some help.

Breizh

Edited by breizh, 02 June 2016 - 07:12 AM.

[S.AHMAD]

Hi Sadia

1. Please let me know the LPG composition.

2  Normally LPG  is 100% propane, or 100% butane or mixed LPG that contains 60% propane and 40% butane.

3. Assuming 100% propane, the vapor pressure at 122 ^oF (50 ^oC) is about 250 psia or 235 psig.

2. That means if the maximum expected temperature is 50 ^oC then the design pressure of 250 psig is NOT sufficient since the design pressure should be 2235 + 25 psig = 260 npsig. However, if the bullet is existing then what is the MAWP specified by the fabricator? If the MAWP is equal` or greater than 260 psig then the bullet is inherently safer designed.

4. If assuming 100% n-butane then the corresponding vapor pressure is 70 psia or 55 psig so no over pressure issue.

5. If storing mixed LPG then limit the propane composition not more then  90%.

 

Hope the above short comment helps.

 

S.ahmad