API 570 Chap 8 Flashcards
ASME 31.3 is written for
design and construction of piping systems.
design, welding, examination, and materials also can be applied in the (4)
inspection, rerating, repair, and alteration of operating piping systems.
When ASME B31.3 cannot be followed because of its new construction coverage the piping engineer or inspector shall be guided by
API 570 in lieu of strict conformity
to ASME B31.3.
All repair and alteration work shall be done by a ______ and shall be authorized by the _______
repair organization / inspector prior to its commencement
The inspector will designate any inspection hold points required during _____
the repair or alteration sequence.
All proposed methods of design, execution, materials, welding procedures, examination, and testing shall be approved by the (2)
inspector or by the piping engineer
approval of on-stream welding is required from
owner/user
Welding repairs of cracks that occurred in-service should not be attempted without prior consultation with the piping engineer in order to
identify and correct the cause of the cracking.
The inspector shall approve all repair and alteration work at …..
designated hold points and after the repairs and alterations have been satisfactorily completed in accordance with the requirements of API 570
The design of temporary enclosures and repairs shall be approved
by the piping engineer.
Longitudinal cracks shall not be repaired with a sleeve unless
the piping engineer has determined that cracks would not be expected to propagate from under the sleeve.
what are consider temporary repairs? (3)
- on-stream, a full encirclement welded split sleeve
- box-type enclosure
- fillet patch
when can a temporary repair may be made by fillet welding a properly designed split coupling or plate patch over the pitted or locally thinned area (2)
If the repair area is localized and the SMYS (Specified Minimum Yield Strength) of the pipe is not more than 40,000 psi (275,800 kPa), and a Fitness-for-Service analysis shows it is acceptable
A fillet-welded patch shall not be installed
on top of an existing fillet-welded patch.
when installing a fillet-welded patch adjacent to an existing fillet-welded patch, the minimum distance between the toe of the fillet weld shall not be less than
d = 4 (Rt)^.5
d is the minimum distance between the toes of fillet welds of adjacent fillet weld attachments, in inches
(millimeters);
R is the inside radius in inches (millimeters);
t is the minimum required thickness of the fillet-welded patch in inches (millimeters).
Temporary repairs should be removed and replaced with a suitable permanent repair at the next available maintenance opportunity. Temporary repairs may remain in place for a longer period of time only if approved and documented by who?
piping engineer.
Any leak in a Class 1 service or where a risk ranking is determined to be high, shall be first reviewed
by a piping engineer to determine if the work can be safely performed while the system remains on stream.
For minor leaks and thinning below Tmin, properly designed enclosures may be welded over the leak or thin piping while the piping system is in-service provided…..
the inspector is satisfied that adequate thickness remains in the actual location of the proposed weld and HAZ
Permanent repairs types?(2)
- flush/insert patches
2. overlay/metal
steps to perform overlay/metal build up? (2 steps)
Surface irregularities and contamination shall be removed and Appropriate NDE methods shall be applied afterwards
Insert patches (flush patches) may be used to repair damaged or corroded areas if the following requirements are met: (3)
a) full-penetration groove welds are provided;
b) for Class 1 and Class 2 piping systems, the welds shall be 100 % radiographed or ultrasonically tested
c) patches may be any shape but shall have rounded corners [1 in. (25 mm) minimum radius]
injection fittings on valves to seal fugitive (LDAR) emissions from valve stem seal are consider as temp repairs? (Y/N)
No, they are not considered to be temporary repairs. Their removal or valve replacement is at the discretion of the owner operator
Temporary repairs of locally thinned sections or circumferential linear defects may be made on-stream by installing a
properly designed and applied enclosure (e.g. bolted clamp, nonmetallic composite wrap, metallic and epoxy wraps, or other non-welded applied temporary repair).
Temp repairs design shall consider what type of loads?
of axial thrust loads of the piping
Procedures that include leak sealing fluids “pumping”) for process piping should be reviewed for acceptance by who?
by the inspector or piping engineer.
What consideration to be made for sealing fluids? (4
- consideration the compatibility of the sealant with the leaking material;
- the pumping pressure on the clamp (especially when re-pumping) and any resulting crushing forces;
- and; the risk of sealant affecting downstream flow meters, pressure relieving devices, or machinery; the risk of subsequent leakage at bolt threads causing corrosion or stress corrosion cracking of bolts;
- and the number of times the seal area is repumped
All repair and alteration welding shall be done in accordance with the principles of
ASME B31.3 or the code to which the piping system was built.
Any welding conducted on piping components in operation shall be done in accordance with what code
with API 2201. (Hot tapping)
The repair organization shall use welders and welding procedures qualified in
ASME B31.3 or the code to which the piping system was built.
PWHT of piping system repairs or alterations should be made using the applicable requirements of
ASME B31.3 or the code to which the piping system was built.
Re-rating piping systems by changing the temperature rating or the MAWP may be done only after all of the following requirements are met (10)
a) Calculations are performed by the piping engineer or the inspector.
b) All re-ratings shall be established in accordance with the requirements of the code to which the piping system was built or by computation using the appropriate methods in the latest edition of the applicable code or other industry standards approved by a SDO (e.g. API 579-1/ASME FFS-1).
c) Current inspection records verify that the piping system is satisfactory for the proposed service conditions and that the appropriate corrosion allowance is provided.
d) Re-rated piping systems shall be leak tested in accordance with the code to which the piping system was built or the latest edition of the applicable code for the new service conditions, unless one of the following is true.
1) Documented records indicate a previous leak test was performed at greater than or equal to the test pressure for the new condition.
2) The re-rate is an increase in the rating temperature that does not affect allowable tensile stress.
3) The piping integrity is confirmed by appropriate nondestructive inspection techniques in lieu of testing after
consultation with the inspector and piping engineer.
e) The piping system is checked to affirm that the required pressure relieving devices are present, are set at the
appropriate pressure, and have the appropriate capacity at set pressure.
f) The piping system re-rating is acceptable to the inspector or piping engineer.
g) All piping components in the system (such as valves, flanges, bolts, gaskets, packing, and expansion joints) are adequate for the new combination of pressure and temperature.
h) Piping flexibility is adequate for design temperature changes.
i) Appropriate engineering records are updated.
j) A decrease in minimum operating temperature is justified by impact test results, if required by the applicable code
Pressure tests are normally required
after alterations and major repairs.
When a pressure test is not necessary or practical, _______, and only after consulting with______(2)__
NDE shall be utilized in lieu of a pressure test, with the inspector and the piping engineer
For existing insulated lines that are being pressure tested after repairs, re-rating, or alterations, it is not necessary to
strip insulation on all existing welds.
What test can be substituted for insulation stripping when the risks associated with leak under the insulation are acceptable.
Pressure tests with longer hold times and observations of pressure gauges can
be
When it is NOT practical to perform a pressure test of a final closure weld that joins a new or replacement section of piping to an existing system, all of the following requirements shall be satisfied (4)
a)welds are examined with appropriate NDE, as specified by the authorized piping inspector.
b) The closure weld is a weld between any pipe or standard piping component of equal diameter and thickness, axially aligned (not miter cut), and of equivalent materials. Where slip-on flanges or socket weld fittings are permitted by the specification for the piping system, they may be used within the limitations of that specification.
Acceptable alternatives are:
1) slip-on flanges for design cases up to Class 150 and 500 °F (260 °C); and
2) socket-welded fittings for sizes NPS 2 or less and design cases up to 500 °F (260 °C). A spacer designed for socket welding or some other means shall be used to establish a minimum 1/16 in. (1.6 mm) gap. Socket welds shall be per ASME B31.3 and shall be a minimum of two passes.
c) Any final closure butt weld shall be of 100 % RT; or angle beam ultrasonic flaw detection may be used, provided the appropriate acceptance criteria have been established.
d) MT or PT shall be performed on the root pass and the completed weld for butt welds and on the completed weld for fillet welds.
Fillet-welded patches shall be designed by who?
by the piping engineer
Different components in the same piping system or circuit may have different design temperatures. In establishing the design temperature, consideration shall be given to (4)
to process fluid temperatures, ambient temperatures, heating and cooling media temperatures, and insulation
A patch may be applied to the external surfaces of piping, meets either of the following requirements: (2)
a) the proposed patch provides design strength equivalent to a reinforced opening designed
b) the proposed patch is designed to absorb the membrane strain of the part in a manner that is in accordance with the principles of the applicable code, if the following criteria are met:
1) the allowable membrane stress is not exceeded in the piping part or the patch,
2) the strain in the patch does not result in fillet weld stresses exceeding allowable stresses for such welds,
3) an overlay patch shall have rounded corners (see Annex C)
8.23
not finished
A preheat of ____F_or higher is maintained during welding
300F
