[MW:587] Re: Annular bottom plates from API-650 Tanks

Gentlemen,

A word to the wise... You could find yourselves in a lot of trouble for copyright infringement, not only with the API but also Google.

As you are well aware, copyright exists in ALL API material: I advise you NEVER to post illegal copies of copyright material in a public chat room. I realise it was done with the best of intentions to help a colleague in need, but please find another way of communicating the information.

 

I'm posting this advice to help you and others stay out of trouble. We have no idea who is monitoring internet traffic! Unfortunately, today Big Brother undoubtedly IS watching us.

 

I'm in Scotland! These emails are read all around the world.

 

Regards to all,

Owen Jenkins.

 

 

 

----- Original Message -----

From: Kannan.Sundaram@Linde-LE.com

To: materials-welding@googlegroups.com

Sent: Thursday, February 21, 2008 8:58 AM

Subject: [MW:586] Re: Annular bottom plates from API-650 Tanks

I think you are missing the copy of API 650......!

A283 Gr.C comes under group I and the following part of API 650 is self explainatory.

5.5 ANNULAR BOTTOM PLATES
5.5.1 When the bottom shell course is designed using the allowable stress for materials in Group IV, IVA, V, or VI, butt-welded
annular bottom plates shall be used (see 5.1.5.6). When the bottom shell course is of a material in Group IV, IVA, V, or VI and the
maximum product stress (see 5.6.2.1) for the first shell course is less than or equal to 160 MPa (23,200 lbf/in.2) or the maximum
hydrostatic test stress (see 5.6.2.2) for the first shell course is less than or equal to 172 MPa (24,900 lbf/in.2), lap-welded bottom
plates (see 5.1.5.4) may be used in lieu of butt-welded annular bottom plates.

M.4.1 Tanks with diameters exceeding 30 m (100 ft) shall have butt-welded annular bottom plates (see 5.1.5.6).

5.1.5.6 Bottom Annular-Plate Joints
Bottom annular-plate radial joints shall be butt-welded in accordance with 5.1.5.5 and shall have complete penetration and complete
fusion. The backing strip, if used, shall be compatible for welding the annular plates together.

5.1.5.5 Butt-Welded Bottom Joints
Butt-welded bottom plates shall have their parallel edges prepared for butt welding with either square or V grooves. Butt-welds shall
be made using an appropriate weld joint configuration that yields a complete penetration weld. Typical permissible bottom buttwelds
without a backing strip are the same as those shown in Figure 5-1. The use of a backing strip at least 3 mm (1/8 in.) thick tack
welded to the underside of the plate is permitted. Butt-welds using a backing strip are shown in Figure 5-3A. If square grooves are
employed, the root openings shall not be less than 6 mm (1/4 in.). A metal spacer shall be used to maintain the root opening between
the adjoining plate edges unless the Manufacturer submits another method of butt-welding the bottom for the Purchaser's approval.
Three-plate joints in the tank bottom shall be at least 300 mm (12 in.) from each other and from the tank shell.



With regards,
Kannan Sundaram.

"saqib gul" <saqibgul@gmail.com> Sent by: materials-welding@googlegroups.com 21/02/2008 07:49 Please respond to materials-welding@googlegroups.com

To materials-welding@googlegroups.com cc Subject [MW:585] Annular bottom plates from API-650 Tanks

Can any body help me out that in which cases we use annular bottom plates for above ground storage tanks? Are there any recommendations in API-650 regarding the use of annular plates? Are the use of annular plates depends on the size of tanks? I am particularly talking about A-283 Gr.C Plates.
 
Regards
Saqib Gul
Design Engineer
Attock Refinery Limited
Pakistan

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