API 650 ROOF PLATES

[engrdcb]

Hello, may I know if I can use less than 5mm minimum of roof plate stated in API 650, is there any rules or section that can I used less than the minimum?
thak you for your answer, im new in API 650. thanks

Tank details
Dia.= 6.85m
Ht. = 6m

 

[JStephen]

See 5.3.5 of the 13th Edition which allows 4.8mm in lieu of 5 mm with purchaser approval. Otherwise, it's 5mm per 5.10.2.2.

 

[engrdcb]

Planning to use 3mm instead for the roof plates. So, this is not possible, since the code is allowing 4.8mm or 5mm only.

 

[HTURKAK]

The mentioned thickness 3 mm implies subject tank is small size. If the tank will be constructed as per API 650, shall comply with the requirements of API 650 and ( 5.10.2.2 Roof Plate Thickness: Roof plates shall have a minimum nominal thickness of 5 mm (3/16 in.) or 7-gauge sheet) as mentioned by JStephen .

If the tank is stainless steel, EN 14015 allows 3 mm for stainless steels.

 

[LittleInch]

There is a storage tank forum under mechanical Engineers where this really belongs....

Also next time please add relevant details such as height, diameter, roof material, location etc.

But 3mm seems very thin to me.

People have a tendency to walk on tank roofs to repair and maintain vents etc. Think there would be a lot of bending and some brown trousers if you use 3mm...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Geoff13]

I expect this would be a false saving. Many API 650 limits are for constructability rather than strength. I expect 3 mm plate to be very difficult to work with (extra manhours spent).

You would also need more rafters to meet clause 5.10.4.4 (extra material and manhours spent).

Of course this won't be an API 650 tank if you don't follow the requirements.

As already noted by LittleInch, the forum1452 or forum809 would be better locations for this posting.

 

[dik]

Interesting thread... if placed in forum 1452... I'd have missed it. One of the problems with questions... structure OK, I think.



Dik