×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

API 650 - Frangibility Vs Anchorage

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 !

RE: API 650 - Frangibility Vs Anchorage

An anchored tank can have a frangible roof or nonfrangible roof.
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

(OP)
Ok.. Thank you JStephen
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

These issues are two separate concerns.

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

These two items are [almost] inextricably intertwined when you discuss "Frangible Roof". Without an anchorage system, the strength of a roof with even a large slope may exceed the rupture strength of the "corner joint" of the shell to the floor. To certify a tank as having a Frangible Roof, you have to protect that corner joint somehow. Without anchors, extensive bracing of the floor is required. And that bracing gives problems with being able to drain and clean out that tank. Thus the use of anchorage top protect the corner joint.

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

(OP)
Ok thank you guys !
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 !

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources