Section 8 - Methods of Inspection

Question 1

Safety precautions dealing with tank entry are discussed in

Answer 1

API 2015 & 2016

Question 2

Prior to entering a tank, be sure to:

Answer 2

Check condition of overhead structures inside the tank

Question 3

Prior to entering a floating roof tank, be sure to

Answer 3

Check that there is not a significant amount of liquid on the roof.

Question 4

Prior to conducting a tank inspection, the inspector should:

Answer 4

read previous inspection reports

Question 5

Which handrail member should be given special attention

Answer 5

Angle Iron
Bars
T-bars
Tubular–

Question 6

Which document provides info concerning the use of tank grounding to prevent static electricity

Answer 6

API 545

Question 7

Which coating problem is the most difficult to detect

Answer 7

Blister
Bonding failure –
Holiday

Question 8

A tank is insulated. Where is a likely spot for external shell corrosion

Answer 8

Shady side of the tank

Question 9

CUI in carbon steel is most aggressive at a temp range of:

Answer 9

120 - 200 F

Question 10

The upper shell of a floating roof tank has the potential for atmospheric corrosion on both sides. On floating roof tanks with uncoated shells, special attention should be given to the shell on the upper:

Answer 10

24”

Question 11

Hydrogen blistering is most common on the tank’s

Answer 11

bottom and shell

Question 12

Hydrogen blistering occurs on the tank’s

Answer 12

external and internal

Question 13

Which of the following is not a cause of tank deformation

Answer 13

Defective vent
Earthquake
Settlement
Wind
Exceeded product fill height--

Question 14

When cracking is suspect in an area of tank deformation, which NDE is preferred?

Answer 14

MT

Question 15

How can rivets be checked for tightness

Answer 15

Light tapping one side and fingering the other side

Question 16

Planks used as a walkway on the roof should span at least

Answer 16

2 rafters

Question 17

A floating roof tank is in a volatile service. When walking on the floating roof, it is advisable that the tank be

Answer 17

High gauged

Question 18

A floating roof is in a volatile service and is 1/2 full. What is a requirement when walking on it?

Answer 18

Must wear respiratory equipment unless the air is tested

Question 19

A floating roof is sitting on it’s legs. A blocked roof drain can cause

Answer 19

Sever roof damage

Question 20

External roof corrosion is most common at

Answer 20

Roof Depressions

Question 21

What should be done if there is significant distortion discovered at a nozzle?

Answer 21

Clean and examine the distorted area for cracks

Question 22

What is a common problem for flame arrestors?

Answer 22

Internal screens get plugged

Question 23

Which of the following is not a common way for flame arrestors to get plugged?

Answer 23

Bees, mud daubers or insects
corrosion build up
solidification of tank vapors
tank over pressure–

Question 24

Which of the following is NOT a problem that can occur if a flame arrestor gets plugged

Answer 24

Tank over pressures
Tank roof-to-shell weld fails
Tank sucks in due to vacuum
Floating roof sucks in–

Question 25

What is a useful method for checking the tank bottom for soil-side corrosion

Answer 25

ROBOTS

Question 26

The owner elects to tunnel under a tank to visually inspect a portion of the soil-side of the tank bottom. What is the primary problem with tunneling?

Answer 26

Difficult to compact the fill

Question 27

When cutting rouf coupons, the coupons must have

Answer 27

rounded corners

Question 28

If there are leaks in a floating roof or the pontoons, what is likely to occur?

Answer 28

The roof may tilt and turn upside down.

Question 29

Which of the following is not commonly installed on a floating roof

Answer 29

Drains Grounding Connections Guides Cathodic Protection--

Question 30

During an outage, the floating roof drain lines should initially be pressure tested for 1/2 hour. The test should normally be conducted at

Answer 30

30 psig

Question 31

If a drain line contains a swing joint, a second 1/2 hour pressure test should be conducted at

Answer 31

5 psig

Question 32

What is the reason for a 2nd pressure test of a drain that has a swing joint?

Answer 32

The joint may be self sealing at high pressures, but leaks at low pressures

Question 33

When walking on an aluminum internal floating roof:

Answer 33

it's best to add planking prior to walking on the tank

Question 34

Aluminum floating roof legs must be:

Answer 34

Electrically isolated from carbon steel to prevent galvanic corrosion

Question 35

Normally internal tank corrosion is least likely to occur

Answer 35

On the bottom At the liquid-level line In the vapor space inside nozzles --

Question 36

Pyrophoric material tends to collect on the

Answer 36

Floor and top side of the rafters

Question 37

Pyrophoric material should be

Answer 37

kept moist until removed

Question 38

In sour services, corrosive vapors are formed when moisture and air mixes with

Answer 38

Hydrogen sulfide

Question 39

In a 98% sulfuric acid tank, corrosion often occurs in the

Answer 39

Vapor-liquid interface

Question 40

In a 98% sulfuric acid tank, corrosion occurs in the vapor-liquid interface, this is because the

Answer 40

water on top of the acid that creates a weaker acid

Question 41

In tanks that are rarely used, like pipeline breakout tanks, corrosion often occurs

Answer 41

behind the tank seal

Question 42

Some incomplete penetration on circ shell welds

Answer 42

was allowed in API 650 prior to the 7th edition

Question 43

Which of the following carbon steels are the most susceptible to hydrogen blistering?

Answer 43

Those with laminations and slag inclusions

Question 44

A statistical method is used to determine the probable minimum remaining thickness of a tank bottom. Typically how much of the bottom is scanned to gather info for the statistical analysis?

Answer 44

0.2-10%

Question 45

A statistical method is used to determine the probably minimum remaining bottom thickness. What part of the floor should be included in the statistical analysis

Answer 45

Outer circumference by the shell

Question 46

When is a statistical analysis of a tank floor effective?

Answer 46

Tanks on pads that have uniform consistency

Question 47

MFL Scanning equipment is useful for finding

Answer 47

Both top-side & bottom-side corrosion on coated & non-coated floors

Question 48

MFL scanning equipment may miss

Answer 48

Sharp small diameter isolated pits

Question 49

On the tank bottom, removing a coupon is an effective method for

Answer 49

determining root cause of soil-side corrosion

Question 50

A method to use when checking for shell cracks is to put penetrant on one side of a the shell and developer on the other. How long might it take to detect a crack?

Answer 50

24 hours

Question 51

What type of lined tanks should be painted on the outside with a unique color or a warning stenciled, that indicates this tank has a special lining?

Answer 51

Glass-lined

Question 52

Steam heating coils should be inspected using either RT or UT to detect:

Answer 52

Condensate Grooving

Question 53

A hydrotest is performed on a tank of high alloy. What is one major concern?

Answer 53

Chloride stress corrosion cracking

Question 54

An air-test is substituted for a tank hydro. The air pressure should not exceed:

Answer 54

2 inches of water

Question 55

Vacuum box testing is being performed on the roof welds. What types of leaks might be missed?

Answer 55

Very small leaks and large leaks.