API 650 - Frangibility Vs Anchorage
API 650 - Frangibility Vs Anchorage
(OP)
Hello everyone,
I have a simple ask for you, do i have design a frangible roof with an anchored tank ?
Thank you !
I have a simple ask for you, do i have design a frangible roof with an anchored tank ?
Thank you !





RE: API 650 - Frangibility Vs Anchorage
A frangible-roof tank can be anchored or unanchored.
The rules vary, but either combination can be used.
If the roof is not frangible, it would generally have an emergency vent.
RE: API 650 - Frangibility Vs Anchorage
I'll try to explain easier, i had a tank no-anchored with emergency vent on the roof to make the frangibility available, calculated with API 650 and API 620.
Now, my tank is anchored with 1'' but my nozzles to guarantee frangibility of roof aren't correct, i have some comments " the roof have to be frangible withotu these nozzles "...
Im looking for a solution..
RE: API 650 - Frangibility Vs Anchorage
The tank must not be exposed to internal pressure that exceeds its design capacity. One of the pressures is what may happen during an emergency. A frangible roof-to-shell junction can serve as emergency venting, or vents can do this.
Anchors are required to maintain stability in high wind or earthquake conditions and also if the internal pressure could exceed the weight of the tank and result in net uplift. If uplift occurs for any reason, the corner weld will experience stresses and strains that may cause a failure.
RE: API 650 - Frangibility Vs Anchorage
FYI, look at the cost of putting something like a ProtectoSeal 53300-series Emergency Vent hatch cover in the roof manway. Pretty cheap compared to the structural requirements, like anchors, to protect the corner joint enough to declare the roof "Frangible".
RE: API 650 - Frangibility Vs Anchorage
Last thing, because there are several differents answers with my ask so i change my way to ask :
How to calculate the frangibility for an anchored tank ?
I dont find the chapter in API 650...
Thanks again !