3.4u Day 4 Homework

Question 1

Which of the following would not be included in a video survey?

Answer 1

Flux indicator

Question 1

If you change the f-stop from f-8 to f-16, which of the following would result?

Answer 1

The depth of field would increase

Question 2

Which ultrasonic probe would be suitable for a FMD inspection?

Answer 2

O.5MHz Compression probe

Question 3

How often must risers be inspected

Answer 3

Every year

Question 4

What cleaning standard is required to conduct an ACPD inspection?

Answer 4

SA2.5

Note ACPD - (D for Depth)

Question 5

What items should be included in a good commentary introduction to a video survey?

Answer 5

There are four elements to a video introduction:

1 Who?
Who am I?
Who is the contractor?
Who is the client?

2 What?
What am I doing?
For example ‘Performing a general visual inspection…’.

3 Where?
Where am I?
For example ‘On the Charlie-1 leg of North Cormorant platform between zero and minus 20m elevation…’.

4 When?
Time and date.
For example ‘The date is the 1st of January, 2013. The time is 16:30 hours’.

Question 6

List the advantages and disadvantages of ROV deployed video.

Answer 6

**Advantages **
* Exceptional endurance.
* The vehicle is not limited by decompression or fatigue.
* Deployed in higher water currents.
* The vehicle is usually equipped with powerful lights giving excellent illumination.
* multiple cameras
* Multiple sensors may provide detailed telemetry. For example depth, heading, CP, etc.

Disadvantages
* Vehicle access may be restricted, eg by penetration into the structure or debris.
* Poor stability when operating in shallow water in rough sea conditions.
* ROV s are less versatile than divers.
* No human eyes on the subject – the view is limited by the quality of the video system.

Question 7

Explain, with the aid of sketches, how Eddy Current works.

Answer 7

Eddy current works by inducing a circular (eddy) current to flow in the surface of the material. Any surface discontinuity will upset the symmetry of the eddy current and be detected by the equipment.

Eddy current technique will detect the presence of a surface-breaking crack, but will not give any indication of its depth.

Clean SA2

Question 8

With the aid of a diagram explain how a Box Matrix numbering system works and choose an example component and correctly identify it.