Earl and the Aboveground Storage Tank Forum for fuel tanks, plastic tanks, fuel oil storage tanksWelcome to the aboveground storage tank forum, a bulletin board dedicated to tanks, fuel tanks, plastic tanks, fuel storage tanks, and above ground storage tanks (AST) API650, API653 & UL142 aboveground storage tanks (AST) and chemical plastic tanks. Remember the forum is made up of volunteers from experts to beginners. Unfortunately, we cannot allow free commercialism that promotes products, services, or sites.
Sponsored by:
Contact us about advertising
Earl   AST Forum  

Need help to explain Dimension tolerances Item 7.5

Sunday, December 24, 2017   By: Ho chi minh [1902] 0 Stars
Dear Gentlemen
I found that Dimension tolerances as follow API 650 consists: Plumbness, roundness, banding, and peaking. Please help me explained that How the dimension tolerances affected to the tank each per Plumbness, roundness, banding and peaking

Many thanks for sharing your experience
Best regards

Post a Reply...
Viewed 589 times

Monday, December 25, 2017   By: karsadi [652] 4 Stars
Sorry what the purpose of your question is?
If you are a tank designer and refer to the API 650 standard, then it is absolutely necessary that you follow all API 650 requirements from start up to finish as required including following dimensional tank tolerances and if each tolerance of Plumbness, roundness, banding and peaking does not follow provision of API 650, it meaning you are creating a tank not compliant with API 650.
Sorry if it is do not answer to the intent and purpose of you and if necessary you try to be clarified, please.

Post a Reply...
Viewed 552 times

Monday, December 25, 2017   By: Ho chi minh [1902] 0 Stars
Dear Mr Karsadi

Thank you for your kind support
Actually, i wonder the affection of plumbness, roundness, banding and peaking.
For example: when the plumbness has not met the standard so I wonder what is happened? and roundness, banding and peaking also?

Thank you
Best regard

Post a Reply...
Viewed 540 times

Tuesday, December 26, 2017   By: karsadi [652] 4 Stars
It is clear that API 650 specifies The purpose of the tolerances given in 7.5.2 through 7. 5.7 is to produce a tank of acceptable appearance and to permit the proper functioning of floating roofs. For this purpose and objectives all tolerances must be met and if they occur deviations must be corrected until entered at a predetermined tolerance limit.
If there is a deviation must be made procedure to fix it.
I try to explain with my own mind, there may be other friends who are ordinary and can provide feedback and suggestions.
If not satisfied please to issue some things that you have not satisfied

Post a Reply...
Viewed 533 times

Tuesday, December 26, 2017   By: DavidR@Fast.net [39] 5 Stars
when the plumbness has not met the standard so I wonder what is happened? and roundness, banding and peaking also?

It could be some or all of those you mentioned roundness, banding, peaking, plumbness that has been measured. These can be from material, fabrication or erection issues. For an existing tank It could also be from foundation settlement, wind or seismic overload, excessive pressure or vacuum, etc.

Post a Reply...
Viewed 535 times

Thursday, December 28, 2017   By: BABRTs 973 [53] 5 Stars
Roundness can affect the operation of a floating roof.
Being plumb affects the operation of floating roof and applies uneven pressure to the foundation. This can cause stress to the piping and shell attachments.
Peaking and Banding can cause issues with the operation of floating roof seals.
You forgot flat spots which can cause issues with floating roofs.
These are all workmanship issues. If a tank is designed to API 650 and you are paying for a tank Engineered, Fabricated and Erected to API 650 then the allowables must be met. There are tanks having been in service for 50 years or more which were built to these tolerances. And they did not have access to the tools and technology available today. There is no reason in todays world there should ever be acceptance of anything close to these allowables. But it comes down to the level of workmanship the owner is willing to accept.

Post a Reply...
Viewed 526 times

Thursday, December 28, 2017   By: ITS [1678] 4 Stars
Well said!

Post a Reply...
Viewed 532 times

Published on ast-forum.com


Atmospheric Design Pressure
By: Fathi [46]

The whole story is to avoid brittle fracture=

Test temperature shall be equal or warmer than Minimum Metal Design temperature at Test pressure.

I would limit my minimum testing temperature for a tank (or even for a vessel or a piping system) by the =

Temp = maximum of [ Min(lower shell) , Min(shell# 2) ....Min (Upper shell) ]

For a Shell# i the minimum is function ( of shell tickness , Material group ) and this can be found in API 650 , Fig 2-1

A similar a....   Read All

It's hard not to look at this ad at least once, then you go to the next page an notice it again. Maybe you will not read the message, but you will be thinking about the brand and we call that brand impressions.

About 2/3 of internet traffic is useless traffic and consist mostly of malicous-bad-robots.  However, there are good robots too.  We block bad-robots, and allow the good one's through, but we just do not count the good one's.  We want good straight-brand impressions for our advertisers with human impressions.

Imagine your static or animated display advertisement placed here, and if that is not enough you can include text too to expound on the virtues of your services and or products.    In addition, you can benefit by using our new advertisement feature to have your video included in your ad space.  Wow, make an infomerical with text and a display by combining all features to enhance the readers or audience's experience using your brand.  Ads can be much more than a static display ad. Here is an example of how your video could be used or position in this ad space


Caption: Public domain video showing a CB&I (Chicago Bridge and Iron) aboveground tank being built on-site. The author of the video is not an advertiser and is being used to show how the video ad can be of value to the reader since you have already being viewing the video.  It is hard not to think about the authors brand after viewing the video ad.  This is the benefit of Branding.

 - Ask for our Media Kit -



A Long-game that Earns Tomorrow's Sales

 Click on this Promotional Advertisement to Contact Us Today!

Good Branding Puts Your Brand or Company in the Front of a Decision-Maker’s Mind for a Purchase either Months from Now or Five-Years in the Future.

Good branding makes your brand or company the leader in a crowded field of other brands or companies vying for your potential or existing client's attention. 

An invitation to the buyer's table to negotiate potential sales from $thousands to $millions of dollars in any of these: Systems sale, Capital Equipment, Upgrades & Modifications,  Repairs, or Capital Project becomes easier now with a recognized brand that thinks forward by brand advertising.

Your advertising will cost you an unbelievable low amount, so ask for our Media Kit that has Specs and Rates. 

Below is some of our demographic data for ast-forum users will speak for itself:

Bus Sector Percent   Education Percent
Manufacturing 18%   College+ 70%
Power Gen 2%      
Chemical 4%      
Petroleum 40%      
A&E 6%      
Construction 12%      

Our network works hard for you with placements for full coverage on part of the network, or full network placement.  Brand yourself today and don’t miss-out on being invited to your client or future client's table because they forgot you.  Be the leader they will remember and be part of their capital project.  Tomorrow’s clients are your future.


Advertising and Marketing Agency for the ast-forum
PE Marketing, LLCBranding.jpg
Industrial Training School - Basic Electricity
ITS - Maintenance
Industrial Training School - Steel Making Tutorial
Steel Maiking Tutorial
Industrial Training School - Instrumentation
5% Off Enter TV0901
Confidentiality, Disclaimer & Policy
© 2001 to AST (Aboveground Storage Tank) Forum, All Rights Reserved.
PE Marketing LLC is representing the steamforum for advertising and marketing
Valid XHTML 1.0 Transitional