Tank Peaking/Banding Issue, API 650

[Abdul Wahab]

Dear All,

I am Abdul Wahab working in KSA as QA/QC Inspector, I have an issue
which is confusioning me. Below there is copy of Paragraph of API 650.
Plumbness, peaking, banding & flat spot discussed in this & tolerances
are provided but along with tolerance of API 650, also refering to
ASTM standards, those standards have tolerances aproximately a double
values as compared to API 650 Tolerances. Do we need to follow those
as ASTM is not a tank construction code but provide guidance about
matrial manufacturing,testing & handling etc.

We have Banding Value for 6 mm Plate of 13 mm max, can we consider a
dent as a banding problem in tank shell.

Please see below & advice.

7.5.2 Plumbness

a. The maximum out-of-plumbness of the top of the shell relative to
the bottom of the shell shall not exceed 1/200 of the total
tank height. The out-of-plumbness in one shell course shall not exceed
the permissible variations for flatness and waviness as
specified in ASTM A 6M/A 6, ASTM A 20M/A 20, or ASTM A 480M/A 480,
whichever is applicable.



7.5.4 Local Deviations

c. Flat spots measured in the vertical plane shall not exceed the
appropriate plate flatness and waviness requirements given in
7.5.2.

If there is any confusion to understand, please ask.


Abdul Wahab
Mechanical Inspector
KSA

[Suresh]

Hii Abdul ,

You should follow API 650 for tank consrtuction , not ASME code .

In my best of my knowledge , you need to refer to API 650 and follow
tolarances which was mentioned in API 650 .

Thank you

Suresh

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Thanks & Best Regards,

Suresh

Mobile No: 91-92 92 905 905

[Abdul Wahab]

Dear Sir,

 

Thank you very much for replying, but problem is that API 650 by itself refering to mentioned standard like ASTM A 6M etc.

 

Please advice,

 

Abdul Wahab

[Suresh]

Off course

That code is mentioned for materials(may be at the time of fabrication
) purpose not for construction ...

[ishfaqur rehman]

Respected Wahab,   When you are applying for whole tank height then the criteria will be API 650 i.e., 1/200. Where as if you are going to check plumbness for individual shells the ASTM applicable relevent specification has to be refered. Your interpretation is correct and the tolerence for each individual shell plate based on thickness, height and length will be as per your derived value.   Ishfaq Jubail, KSA

[MM Muthu]

Dear Wahab,

As you are constructing tank as per API 650 you have to follow the 650 tolerances.

SA 6 or 20 doesn't say about plumbness as the scope states it gives a general requirement for certain plates / shapes.

While in 7.5.2 it clearly states that plumbness allowed is 1/200 for the total height and the waviness or flatness on one single course (i.e in one single plate) shall not exceed the values in SA 6 / 20 this is the case for local deviations. For local deviations in one shell course follow SA 6 /20 for tank plumbness follow 1/200.

Peaking and banding talks about local deviations in vertical and horizantal weld joints, and it clearley states that peaking and banding shall not exceed 13mm, so upto and including 13mm is accepted.

Below are the scope of  SA 20 & it states 

"This general requirements specification covers a group of common requirements that, unless otherwise specified

in the applicable product specification, apply to rolled steel plates for pressure vessels covered by each of the

following product specifications issued by ASTM"

As you see the scope of  SA 6 it states 

This general requirements specification covers a group of common requirements that, unless otherwise specified

in the applicable product specification, apply to rolled structural steel bars, plates, shapes, and sheet piling covered

by each of the following product specifications issued by ASTM"

Cheers

MM

[Fitria Rahman]

Dear Abdul

A 6/A 6M indicates the requirements and acceptance criteria when you purchase and receive the material required for project, let say, plate. I have seen A 6 standard is attached on purchase order document in several occasion. The QC shall do inspection upon receipt of material. You still require A 6 on that time.At final inspection, the QC shall issue a "receiving inspection report" which the inspector has decided fulfill the requirement of qualification test and certificates, purchase order document, A 6 standard and whatever you said in PO.
 
After issuance of " receiving inspection report', the the material delivered to fabrication stage. A standard of A6 is not required in here. You have to refer to API 650 during fabrication and installation of the tank.

let this helps

2011/2/26 Abdul Wahab <aweng...@gmail.com>

[AA karandish]

Dear Abdul Wahab,

 

You are right, API 650 referred his users to several ASTM standard specifications, but if you refer to those ASTM, you will find the ASTM dimensional tolerances are related to the individual components (such as a sheet of plate), it means that for raw components and components prefabrication you should refer to relevant ASTM standard specifications, but for the tank fabrication and assembly you should follow the requirements API 650.

  

Hope the above clarification will be useful,

 

Regards,

Karandish

 

---

From: Abdul Wahab <aweng...@gmail.com>
To: material...@googlegroups.com
Sent: Sat, 26 February, 2011 4:42:55 PM

Subject: Re: [MW:10024] Tank Peaking/Banding Issue, API 650

[Adi]

Hi…..
I am agreeing with Mr.Abdul...

A 6 / A 6M for receiving inspection not for after fabrication of the
plate...
After fabrication your should follow API 650

Adi
KSA

On Feb 27, 8:19 am, Fitria Rahman <t.chint...@gmail.com> wrote:
> Dear Abdul
>
> A 6/A 6M indicates the requirements and acceptance criteria when you
> purchase and receive the material required for project, let say, plate. I
> have seen A 6 standard is attached on purchase order document in several
> occasion. The QC shall do inspection upon receipt of material. You still
> require A 6 on that time.At final inspection, the QC shall issue a
> "receiving inspection report" which the inspector has decided fulfill the
> requirement of qualification test and certificates, purchase order document,
> A 6 standard and whatever you said in PO.
>
> After issuance of " receiving inspection report', the the material delivered
> to fabrication stage. A standard of A6 is not required in here. You have to
> refer to API 650 during fabrication and installation of the tank.
>
> let this helps
>

> 2011/2/26 Abdul Wahab <awengin...@gmail.com>

>
>
>
> > Dear Sir,
>
> > Thank you very much for replying, but problem is that API 650 by itself
> > refering to mentioned standard like ASTM A 6M etc.
>
> > Please advice,
>
> > Abdul Wahab
>

> > On Sat, Feb 26, 2011 at 3:24 PM, Suresh <bobsures...@gmail.com> wrote:
>
> >> Hii Abdul ,
>
> >> You should follow API 650 for tank consrtuction , not ASME code .
>
> >> In my best of my knowledge , you need to refer to API 650 and follow
> >> tolarances which was mentioned in API 650 .
>
> >> Thank you
>
> >> Suresh
>

> > w.r.t. applicable code/standard/contract documents.- Hide quoted text -
>
> - Show quoted text -