Propane storage tanks

[chicopee]

Under the current ASME code VIII, division 1 are propane storage tanks still design w/ a maximum allowable temperature of 125 deg. Farhenheit(d.F) for a MAWP of 250 psig or were the MAT and MAWP raised? The reason that I am asking is because commercial propane has a vapor pressure nearly at 250 psig for a temperature of 125 d.F.and it would not take much to come close to that temperature on a sunny day in hot climates. Relief valves would obviously vent but it seems such a waste of a good product.

 

[JoeTank]

The ASME Code does not set pressures and temperatures for vessel design. That is the responsibility of the owner or the owner's agent. The 250 psig design pressure you cite is very typical of propane vessels designed for ambient storage temperatures. I probably couldnot find it, but I sure thought that there was another safety related standard out there that required 250 psig for propane storage vessels.

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com

 

[chicopee]

Steve Braune,I dont have a copy of ASME code VIII but I do remember the power boiler code having tables on tensile strength vs. temperatures. Wouldn't code VIII have similar tables? and if so what is the smallest design temp. in those tables? Also I am quite confident tanks are stamped w/ MAWP and MAT by the fabricators, therefore how do the fabricators select the MAT's? Is it possible that MAT is based on commercial propane vapor temperature for the stamped design pressure of 250psig and not based the ASME design temperature of the metal?

 

[CRG]

Take a look at the Compressed Gas Association, “Handbook of Compressed Gases.” It gives a lot of information and references about storage tanks for propane. Typically shipping tanks must comply with the appropriate TC/DOT regulation. 49 CFR 173.315 has design pressures for cargo tanks. Also see NFPA 58 and 59 for recommendations for LP-gas installations.

 

[GenB]

The tanks must be built per the Jurisdictions requirements,
(depending of where you are going to send the vessel),
most of the jurisdictions will ask for ASME + construction.
on top of that if in the US, you must comply with other requirement as DOT. So the vessel must meet ASME Code requirements and the service requirements.
When you say that the basic design is because of the vapor
temperature against the ASME Code, it is not true.
You must meet both, the material will be chosen to meet the ASME design criteria and secundary, other Codes, and the proposed service.
ER