NFPA12 declearation

[arshiatabrizian]

hello all.
the storage temperature of co2 cylinder is mentioned -18 to 54 in nfpa12.
on the other hand the calculation in nfpa12 is based on 21C (750psi). also nfpa says:
" this pressure has therefore been selected for calculations involving high pressure systems"
is it mean that all calculation should done at 21C?
or in other words if we have a room for cylinder with temperature of 48C how shold we calculate the system according to nfpa12?

 

[stookeyfpe]

Google Boyles Law andCharles Law

 

[arshiatabrizian]

Thanks for your answer.
I know about that 2 rules. But I have another question.
I just want to know about the calculation basis at temperature other than 21C.
Should I use other y and z than what mentioned in nfpa?
I think if we change the storage pressure the average discharge pressure is changed accordingly. Does nfpa approve the new parameters regarding to the above mentiond sentence?!
Waiting for your help!!

 

[arshiatabrizian]

dear friends,
I`m in urgent need for the answer.
no body has any idea?!?

 

[cdafd]

You got the best answer you are going to get


If you have a manufacture supplying this equipment, you might ask them the question

 

[chicopee]

what is the scope of NFPA 12 and is that scope within your objective? if not within your objective, there may be another NFPA code more appropriate.

 

[anggiES]

helo experts,
I would like to discuss about O2 Content while doing tank cleaning an purging.
we have 700 MT Spherical Tank for LPG and we want to clean it first time. what we do is push all Vapor and liquid out from tank. rest of it need to be pushed by N2. all i need to know is how much in MOC(Minimum Oxygen Content) that allowed inside the tank before LPG vapour injected to the tank ? and do you have standard about tank leak test since i know we cant use Hydrostatic test for LPG/Shpericl tank.

 

[arshiatabrizian]

Hi checopi
Im working on a high pressure co2 extinguishing system and nfpa 12 is its standard. Im sure about the standard but i could not to find out the standard meaning in that matter mentioned above.

 

[zxc12345]

Arshi, waiting.

CO2 is not particularly cold sensitive. At cylinder pressures your storage concern is over 37C. Resulting increases in storage pressure will vent the containers. As cylinder pressure is never monitored, this venting can result in an ugly surprise, should a time of need arise.

z

 

[arshiatabrizian]

Dear zxc
Im not afraid of venting the gas. Because cylinder's burst disk performs at 190 bars. I want to know how should I hydraulically calculate a system stored in higher temperatures like 40, etc. according to nfpa graphs or should I generates new graphs regarding new temp.
all the best
Arshia