MANGANESE CONTROL FOR PLATFROM AND HANDRAILS

[Gireesh123]

Dears,
Could you please advise whether Mn controlled(0.80% to 1.2%) material is compulsory for fabricating platforms and handrails for a fuel storage tanks or normal material with below 0.80% manganese is acceptable?.
Also pls let me know it has mentioned in API 650 standard, if Manganese controlled material required as said above.
Also pls let me know Grating and stir tread also to be MN controlled as per API650
I am expecting your valuable reply to my query. Thanks

 

[Jay_]

uhh, I don't understand...
Read API 650 scope.
Check section 4 for material requirements.
As far as I'm aware, API 650 section 4 defines tank material, pipes material, bolts, flanges, nuts, washers, couplings, structural elements. why would you care about manganese percentage?? maybe because it plays a role in CE?? not a major role tho, especially for misc. items. did you design the tank?

Detailing is a hobby,

 

[Gireesh123]

Hi Jay,
Thanks for your rply, actually tank has designed by a third party consultant and we are a subcontractor for the fabrication and erection including material procurement. Actually our client is concerned about API650 standards for all material, we have agreed for shell plates and roof&bottom structurals. But as per client that is not enough and they wanted for all materials like the platforms, stairway, walkway. So when I have gone through the API 650 standard, plates and structural (coming under materials section.4 and 4.4 structural shapes) shall be controlled with Manganese in between 0.8% to 1.2% and the client is stick on that section and compelling to fabricate platforms, stairway, walkway with Mn controlled(0.8% to 1.2%)material as per API650. What my understnding that it could not considered as direct material and not be considered under API 650.
so my concern is whether Mn control is compulsory for all materials which all using for platforms, stairway, walkway?. I need to break their arguments with evidence, otherwise, they will not accept
Hope you understood my doubts and will help in this matter soon

 

[Jay_]

Aren’t you talking about table 4.4a? For material A36?
I think this table is only grouping the material for shell, roof, and bottom plates and reinforcements etc.. not structural elements...
Someone else has an opinion?

Detailing is a hobby,

 

[Gireesh123]

Hi Jay,
Yes, As per our Client's QC opinion platforms, stairway, walkway materials also should follow Manganese controlled ratio as per API650, since it is stated under structural shapes.
Do you have any idea how to overcome this or make them to understand?

 

[Jay_]

Choose another material,

Detailing is a hobby,

 

[Gireesh123]

Hi Jay,
Actually it is difficult to get Mn controlled material with ASTM A36 grade from the market. It cannot be get rolled from the factory as well since it is below minimum order quantity.

 

[Jay_]

You can ask for a mill test certificate on which they will state the Mn content in %. Plus why choose A36? Choose another material, like S275

Detailing is a hobby,

 

[Gireesh123]

They accept only ASTM A36

 

[Jay_]

Purchaser of one of a kind

Detailing is a hobby,

 

[Geoff13]

I'm very confused.

The only reference I can find to Mn limited to 08% to 1.2% is in Table 4.4 Note 5. However all the places this Table is referenced are in Section 4.2, which is plates not structural. I wonder if they are assuming that the Table numbering matches the Section numbering it applies to? It doesn't match.

(As a complete aside, since this Table isn't applicable, why do they insist on looking at the Group II A36, which calls for Note 5, rather than the Group I A36 which only requires Note 3?)

As you've noted, structurals are covered in Section 4.4, and there are no restrictions on the A36 chemistry in 4.4.1.a. As a second proof that the Mn limit isn't applicable, you can use plain A36 in AISC, and all materials listed in AISC are permitted under 4.4.1.d.

After 35 years designing tanks I'm still surprised that I can run into new ways for customers to misinterpret the Code. But it keeps life interesting I guess.

 

[Gireesh123]

Hi Geoff13
Thanks for your reply.

There are two tables 4.4a and 4.4b material group coming after section 4.4 structural shapes, what is that means or representing

 

[Geoff13]

Table 4.4 has nothing to do with structural. You must read the Code to find references to Table 4.4.

For instance:
[ul]
[li]Clause 4.2.7.5[/li]
[li]Clause 4.2.10.4[/li]
[li]Figure 4.1[/li]
[/ul]
I will let you search for any others.

The key thing to note is that all these clauses are in Section 4.2 which is plates, and the reference to Figure 4.1 is also in Clause 4.2.

Table 4.4 does not apply to structural, even though is uses the same numbering.

Geoff

 

[Gireesh123]

Thanks Geoff