Frangible Nozzle 1

[merton]

I have received a bid from an engineering company which is asking for a API 650 tank. This is not a problem, except for the fact that they are asking for some nozzles to be 'frangible'. Has anyone ever heard of this coming up before, and if so where do I look to find design information for this situation.

Thanks in advance.

 

[TD2K]

I haven't heard of that and would question it. Frangible refers to the roof to shell weld and is intended in an emergency relief case that the roof/shell joint fails before the shell/floor joint fails which would result in a release of the tank's contents. API 650 has several design details to ensure a roof/shell joint is frangible.

I can't see why you would want to design a nozzle that way. Let's see if I'm totally wrong when everyone else chimes in.

 

[JoeTank]

I would assume that they want the nozzle to fail before something else fails, hence the term frangible. I am not aware of such a design technique. More detail on the spec requirement would be usedful if you want more input from the forum. For example, what part are they protecting by having the nozzle fail first? Also, what part is supposed to fail?

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com

 

[IFRs]

Could this be like a scored glass diaphragm in foam system piping? As if the tank were Nitrogen blanketed so it needs to be sealed and perhaps too small for a real frangible roof-to-shell joint so the engineer needs a roof nozzle with a frangible diaphragm?

 

[jay165]

The only time I've heard of this is for a filler nozzle at a gas/fuel station. The nozzle is designed to shear away in case the driver leaves the nozzle in the tank and drives away by mistake. Does this tank have hoses for filling vehicles or tank trucks?

 

[chicopee]

Is this frangible nozzle part of a so-called smart hose technology such as the type found on propane storage tank fill connections?