MAWP vs. Vapor Pressure?

[FirstRspndrWriter]

Hi, all. I write training materials for firefighter safety. I am developing text on fuel tank truck incidents. I am having trouble determining the difference between MAWP and vapor pressure. MAWP is a standard, and vapor pressure contributes to the MAWP levels? Looking for some clarification so I can draft clearly. MC 306 tanks used to be at a vapor pressure below 3 psi (I assume the book I am using meant psig...) For the newer tank trucks, the DOT 406, CFR 178.346-1 (b) says the MAWP must be no lower than 2.65 psig and no higher than 4 psig. Is that talking about vapor pressure? Or are they 2 different things? All thoughts welcome, and thank you SO much! I really appreciate it a LOT.

 

[FirstRspndrWriter]

Ah... it looks like the MAWP refers to the CONTAINER and the v.p. refers to the PRODUCT in the container.... yes?

 

[JoeWong88]

I hope the vapor pressure of your product is referring to ambient temperature (min to max.) If so, then operating operating (min - max) will be the vapor pressure.

I hope the following will help you
Definition of Terms Related to PRESSURE

JoeWong
Chemical & Process Technology

 

[FirstRspndrWriter]

Thank you very much - that helps clarify.