Chapter 7

Question 1

What is point to point method?

Answer 1

CR (LT) and CR(ST)

Question 2

What are the 2 method to determine corrosion rates?

Answer 2

1. point to point

2. statistical analysis

Question 3

What is the statistical analysis?

Answer 3

probability plots or related tools to establish a representative corrosion, remaining life estimate and/or re-inspection date

Question 4

Statistical analysis employing point measurements is NOT applicable to piping circuits with

Answer 4

significant localized unpredictable corrosion mechanisms

Question 5

What is required to be done if newly pipe or change of service? (3)

Answer 5

1. use CR of similar service
2. use CR of owner/user experience or published data if #1 is not available
3. initial thickness measure shall be made no more than 3 months. Corrosion monitoring devices, such as corrosion coupons or corrosion probes, may be useful in establishing the timing of these thickness measurements. Subsequent measurements shall be made after appropriate intervals until the corrosion rate is established

Question 6

What method to be done for existing pipe?(2)

Answer 6

use point to point or statistical analysis

Question 7

The MAWP for the continued use of piping systems shall be established using ________code

Answer 7

using the applicable code

Question 8

MAWP computations may be made for known materials if all the following essential details are known (5)

Answer 8

a) upper and/or lower temperature limits for specific materials,
b) quality of materials and workmanship,
c) inspection requirements,
d) reinforcement of openings,
e) any cyclical service requirements.

Question 9

For unknown materials, MAWP computations may be made assuming (2)

Answer 9

the lowest grade material and joint efficiency

Question 10

When the MAWP is recalculated, the wall thickness used in these computations shall be ….

Answer 10

Estimated actual thickness minus twice the estimated corrosion loss

Question 11

MAWP formula

Answer 11

2SEt/D , t = Estimated actual thickness minus twice the estimated corrosion loss

Question 12

The required thickness of a pipe shall be the greater(2)

Answer 12

1. of the pressure design thickness

2. the structural minimum thickness.

Question 13

For services with high risk, the piping engineer should consider increasing the required thickness to
provide for …..

Answer 13

unanticipated or unknown loadings, or undiscovered metal loss

Question 14

Piping shall be supported and guided so that: (4)

Answer 14

a) its weight is carried safely,
b) it has sufficient flexibility for thermal expansion or contraction, and
c) it does not vibrate excessively, and
d) accounts for other loads (e.g. those included in the original code of construction).

Question 15

Piping flexibility is of increasing concern (2) for what kind of specs on pipe

Answer 15

1. the larger the diameter of the piping

2. the greater the difference between ambient and operating temperature conditions

Question 16

Piping stress analysis can identify the …? (3)

Answer 16

1. highly stressed components in a piping system
2. predict the thermal movement of the system when it is placed in operation.
3. vibration

Question 17

When is a piping stress analysis performed?

Answer 17

When unexpected movement of a piping system is observed, such as during an external visual inspection

Question 18

What does a Piping stress analysis to assess? (2)

Answer 18

system flexibility and support adequacy

Question 19

What records should be maintained and what duration? and who?

Answer 19

1. piping systems/PRD
2. throughout the service life of each piping system
3. owners/users

Question 20

Piping system and pressure-relieving device records shall contain four types of information pertinent to mechanical integrity as follows.

Answer 20

1. Fabrication, Construction and Design Information to the Extent Available
2. Inspection History
3. Repair, Alteration, and Re-rating Information
4. Fitness-for-Service assessment documentation requirements

Question 21

Site operating and maintenance records, such as operating conditions, including process upsets that may affect mechanical integrity, changes in service, mechanical damage from maintenance should also be available to the

Answer 21

inspector.

Question 22

The primary purpose of inspection ISOs is to

Answer 22

identify the location of CMLs and to identify the location of any recommended maintenance

Question 23

when documenting inspection results A combination of (2)

Answer 23

checklist and narrative record keeping is recommended

Question 24

A deferral procedure shall be in place that defines a risk-based deferral process, including a (3)

Answer 24

corrective action plan and deferral date, plus necessary approvals

Question 25

If inspection of a piping circuit is to be deferred beyond the established interval. that procedure should include: (4)

Answer 25

a) concurrence with the appropriate piping personnel including the inspector and appropriate owner/user
management representative;
b) any required operating controls needed to make the extended run;
c) need for appropriate nonintrusive inspection with NDE, if any, as needed to justify the temporary extension; and
d) proper documentation of the deferral in the piping or PRD records.

Question 26

an inspection or pressure relieving device servicing interval may be deferred by the
inspector, without other approvals, based

Answer 26

on a satisfactory review of the equipment history and appropriate risk analysis, when the period of time for which the item is to be deferred does not exceed 10 % of the inspection/servicing interval or six months, whichever is less

Question 27

initial thickness measure shall be made no more than

Answer 27

3 months