API 650 Std. restrict or not about roof type based on product / services 3

[Muhammad Shoaib Anwar]

Hi,

My question is API 650 guide about restriction of roof type like FIXED ROOF tank can be used for storage of Petroleum or it must need FLOATING ROOF.

Thanks

 

[IFRs]

API does not really care what you put in the tanks. Your environmental agency will tell you if you need a control device like a floating roof, also your risk management department and operations. Floating roofs (internal or external) are good for evaporation control and product contamination. Evaporation control helps with safety, cost, odor, environment.

 

[JStephen]

Internal or external floating roofs are used to prevent product loss and to help avoid explosion/fire hazards from the contained vapor space.
In the US, floating roofs are mandated by environmental concerns by the federal (and perhaps local governments.
Small tanks are exempted. Tanks can use inverting/vapor recovery systems as an alternative.
Some less volatile products are exempted (diesel, fuel oil, asphalt products). Rules are different for oilfield tanks than for refineries or pipelines.

 

[Muhammad Shoaib Anwar]

Dear IFRs thank you for your answer and guidance,
Dear Mr. Stephen, thank you for your answer and guidance,
@Stephen
Regarding "exemption of small tank" so for small tank what size or capacity?
Secondly regarding "less volatile products are exempted", so said tank will construct in bulk storage facility and product fuel oil will be store, so in this case what is common practice?

Thanks

 

[JStephen]

Fuel oil would not normally use a floating roof. The US regulations required a floating roof if over a certain vapor pressure.
I don't remember the minimum size, seems like 40,000 gallons or so is one cut-off.
If you're in the US, this is all in the Code of Federal Regulations.
If you're not in the US, you need to start researching local requirements.

 

[Muhammad Shoaib Anwar]

Thank you Mr. Stephen for reply,
These storage facilities in South Asia and middle east,
Local authorities pushing for floating roof tank, but from owner side plan to construct fixed roof tank.
So going through and getting information any API 650 restriction, operational and safety concerns so finally can answer local authorities concerns.

 

[IFRs]

In the USA it is 40 CFR 60 subpart KB for storage terminals. There are a host of other rules for hazardous liquids Etc. When working on air permits smaller tanks and heavier products sometimes get floating roofs to reduce even further the emissions profile of the facility.

 

[Muhammad Shoaib Anwar]

Dear IFRs, thank you for reply,
Now i go through this document (40CFR 60 Subpar KB)to understand further requirements.

 

[Geoff13]

In Canada the document would be CCME PN-1180. Link

Page 13 has a summary graph relating tank size, product vapour pressure and required vapour control.

You mentioned fuel oil, which has a very low vapour pressure, and thus vapour controls would not be required by this document.

 

[Muhammad Shoaib Anwar]

Dear Geoff13, Thank you for guidance,
What about if store product is Gasoline / Petrol.

 

[JStephen]

Gasoline, ethanol, methanol generally use floating roofs.
Diesel fuel generally not.
Jet fuel tanks generally do- but I think that's for product purity rather than vapor pressure.

 

[Muhammad Shoaib Anwar]

Noted with Thanks,

 

[HTURKAK]

Fixed roof tanks are generally preferred when the product stored does not vaporize at ambient or stored temperature conditions.
In case of fuel oil, it can mean different products depending on country.
Local authorities asking floating roof tank but apparently you prefer fixed roof due to economical reasons . What is the DESIGN TEMPERATURE of the tank? Is the tank insulated ?.

 

[Geoff13]

What about if store product is Gasoline / Petrol.

You know the vapour pressure for the products you want to store, and you know the tank sizes you want to build. You can answer the question yourself.

Please remember this is a Canadian document, and thus you should be looking for any local rules.

 

[IFRs]

To add some more criteria to Geoff13's 100% accurate and to-the-point post, sometimes you put floating roofs in tanks with vapor pressures lower than the required minimum because of odors, product contamination or lack of headroom in your emissions permit.

 

[Dhurjati Sen]

It seems the owner wants to blow up his tank farm. The local authorities should be checking with the health department to assess the owner's mental state!

DHURJATI SEN
Kolkata, India