aPI570 chap 5 Flashcards
Thickness measurement shall be obtained by whom?
inspector or the examiner at the director of the inspector
who is responsible that individuals conducting thickness measurement are trained and qualified?
owner/user
What is on stream thickness monitoring good tool for? (2)
- monitoring corrosion and
2. assessing potential damage due to process or operational changes
When is external visual used for? (9)
- condition of outside of the piping
- insulation system
- painting
- coating system
- hardware
- signs of misalignment
- vibration
- leakage
- pipe hangers and support
Types of screen techniques NDE? (2) and what data results it obtain? can be used to locate areas of interest for follow-up inspection using more quantitative NDE techniques
- guided wave testing/EMAT
- Lamb wave inspections
Qualitative
cons of screening techniques? (2)
- may miss significant localized corrosion
2. limited to the qualitative data results
Use screen technique with …
quantitative NDE techniques
what else should they be alert on during External visual? (4)
- bellows expansion joints
- presence of field modification or repairs
- presence of any components that may be unsuitable for long-term operation, such as improper flanges, temporary repairs, valve of improper specification
- weldment of attachments
Vibrating pipes and line movement surveillance at locations where vibrating piping system are restrained to resist dynamic pipe stresses - what should be done? (type of NDE -2)
periodic MT or PT should be considered to check for the onset of fatigue cracking
What is done on supplemental inspection? for fouling/plugging or leaks
- periodic use of RT or thermography to check for fouling or internal plugging.
- acoustic emission, and thermography can be used for remote leak detection
what type of NDE to be done with NPS > 12?
scanning of the areas with UT
of CML on higher CR or localized corrosion?
normally have more CMLs and monitored more frequently
How are thickness measurement made?
4 quadrants on pipe and fitting with special attention to the inside/outside radius of elbows and tees
When can CMLs be eliminated or the number reduce?
- when the expected damage mechanism will not result in a wall loss or other forms of deterioration - may need to consult with CS
Fewer CMLs can be selected for piping systems with any of the following three characteristics:
a) low potential for creating a safety or environmental emergency in the event of a leak;
b) relatively noncorrosive piping systems;
c) long, straight-run piping systems.
CMLs can be eliminated for piping systems with any of the following characteristics: (3)
a) extremely low potential for creating a safety or environmental emergency in the event of a leak;
b) noncorrosive systems, as demonstrated by history or similar service; and
c) systems not subject to changes that could cause corrosion as demonstrated by history and/or periodic reviews.
When is profile RT (PRT) used? (3)
- small bore piping (NPS 1 or less)
- may be used for measuring thicknesses, particularly in insulated systems
- where nonuniform or localized corrosion is suspected.
When ultrasonic measurements are taken above ____ F___instruments, couplants, and procedures should be used that will result in accurate measurements at the higher temperatures
150 F
When to use UT angle Beam examiners? (2)
a) detection of interior surface (ID) breaking flaws when inspecting from the external surface (OD); or
b) detection, characterization, and/or through-wall sizing of defects
Inspection for CUI shall be considered for externally-insulated carbon and low alloy piping operating between
10 °F
–12 °C) and 350 °F (175 °C
What NDE can help to determine if any scale is present behind the insulation without removal.
Non-intrusive techniques such as real time radiography
Mixing points? definition
locations in piping systems where two or more different streams meet.
the preferred methods of inspecting mixing points include; (2) - NDE
- radiography and
- ultrasonics (straight beam and/or angle beam) to determine the minimum measured thickness and/or the presence of other susceptible damage mechanisms
Mixing points may be treated as separate inspection circuits, and these areas may need to be inspected differently, using (3)
1 . special techniques,
- different scope,
- and at more frequent intervals when compared to the inspection plan for the parent/contributing piping stream(s).
Injection points are sometimes subject to ________ or _______ corrosion
accelerated or localized
When designing an injection point circuit for the purposes of inspection, the inspection (2) upstream/downstream
- upstream limit of the injection point circuit is a minimum of 12 in. (300 mm) or three pipe diameters upstream of the injection point,
- downstream limit of the injection point circuit is the second change in flow direction past the injection point, or 25 ft (7.6 m) beyond the first change in flow direction, whichever is less.
preferred methods of inspecting injection points (3) (NDE)
- radiography and/or
- UT scanning or
- closely spaced UT grid inspection
During periodic scheduled inspections, more extensive inspection should be applied where at the IP? upstream/downstream
to an area beginning 12 in. (300 mm) upstream of the injection nozzle and continuing for at least ten pipe diameters downstream of the injection
point.
The potential for localized corrosion can occur at the junction where the injection point enters_______ . The use of profile radiography at the junction and UT manual scanning of the primary pipe (surrounding and downstream of the junction) is recommended
into the primary pipe