By Eng. Carlos F Molina

The following article is about API RP 652 for the API 653 certification exam. What do you think is the difference between a lining and a coating? Between a coating and a paint?….. Before you continue reading, share your thoughts in the comment section.

As far as I know,  paint is a liquid or paste that, when applied in a substrate, coats a layer over the surface, protects it and then gets to be known as a coating. Any material applied to the internal surfaces of a tank to serve as a barrier to corrosion and/or product , it is known also as a lining. Right now we are going to study linings. If you are preparing to take the API 653 certification exam, do me a favor an read the 652 RP. (more…)

By Eng. Carlos F Molina

Hi. Following two months and a half of a new job in Panama, I haven´t been so atentive to my website. I am again working for a contractor, meaning I have almost no time at all to update this site. I am usually void of energy because of all of the work that needs to be done.  I hope that changes in the near future. By now, I am trying to retake writing in apiexam.com and to really commit to an schedule. Even when I didn´t write in a long time, the number of people that found value in my content grew (I have 255 suscribers now) in the past 2 and a half months.

Last time, we talked about Ultrasound according to Article 23 Ultrasonic Standards, Section SE–797, only things related to the Body Of Knowledge. This time we will review the use of ultrasound in tanks.

INTRODUCTION

Ultrasonic testing, I think, is going to replace RT as a mean of inspecting welded joints in tanks, because of its many advantages, like reducing hazards and downtime associated with radiography.

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By Carlos F Molina

In the Body Of Knowledge for the API 653 exam, Ultrasonic Testing is one of the smallest parts that needs to be studied. This is what the Body Of Knowledge says you need to get:

E. Article 23, Ultrasonic Standards, Section SE–797 only – Standard practice for measuring thickness by manual ultrasonic pulse-echo contact method:
The inspector should be familiar with and understand;
1. The Scope of Article 23, Section SE-797,
2. The general rules for applying and using the Ultrasonic method
3. The specific procedures for Ultrasonic thickness measurement as contained in paragraph 7.

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By Carlos F Molina

This is my last article about radiology in tanks for readers who are studying for the API 653 exam. We will see

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By Carlos Molina

This time we are going to check radiographic testing for welds in new tanks, an introduction. The BOK for the API 653 exam says:

2. Radiographic Examination:

The inspector should be familiar with and understand:

1. The Scope of Article 2 and general requirements [of ASME V].

2. The rules for radiography as typically applied on butt welded AST horizontal and vertical seams such as, but not limited to:

required marking type.

selection.

number, and placement of IQIs.

allowable density control of backscatter radiation

location markers

3. Records

I will try to simplify this subject as much as posible for the people who is studying for the API 653 exam. (more…)

By Carlos F Molina

TANK SHELL EVALUATION ACCORDING TO API 653

What we are going to do is to dissect the diagram in FIG. 4.1 of API653 until we truly understand it. and there will be no way we fail any of the questions related to this in the exam. First of all we are going to see the following diagram.

average-hoop-stress

Look at the vertical sections drawn in the picture. Remember that hoop stresses (stresses that are tangential to the shell of the tank) are higher in vertical planes than in horizontal planes. (more…)