DE LA ADMISIÓN TEMPORAL PARA PERFECCIONAMIENTO ACTIVO

10.1 Inspection While Equipment Is Operating 10.1.1 Visual Inspection

10.1.1.1 Leaks

Leaks can be safety or fire hazards, and always result in economic loss. Temporary or permanent repairs can often be made while the lines are in service. Key phrase “leaks”.

10.1.1.2 Misalignment

Piping should be inspected for misalignment. Pipe dislodged from supports, vessel wall deformation, pipe supports out of plumb, excessive replacement of bearings, etc., shifting of baseplates, foundation damage, cracks in connecting flanges, expansion joints not performing properly, are all indications of misalignment. Key phrase “misalignment”.

10.1.1.3 Supports

Supports are shoes, hangers, and braces, and should be visually inspected for problems. Key phrase “supports”.

10.1.1.4 Vibration

Vibrating or swaying piping should be inspected for cracks, at points of restraint, usually in the areas of anchors, or where small bore pipe is attached to the main line. Key phrase

“vibration”.

10.1.1.5 External Corrosion

Defects in the protective coatings and insulation will permit moisture to contact the piping. This can result in corrosion and metal loss. Key phrase “external corrosion”.

10.1.1.6 Accumulations of Corrosive Liquids

Some liquids are corrosive to steel piping, spills should be cleaned up or neutralized. Key phrase “accumulations of

corrosive liquids”.

10.1.1.7 Hot Spots

Operating piping at higher than design limits may cause bulging, even to the point of failure. Investigation of these areas is essential. Key phrase “hot spot”.

10.1.2 Thickness Measurements 10.1.2.1 Ultrasonic Inspection

UT digital thickness gauges are mentioned with emphasis on high temperature readings. Key phrase “UT thickness”.

10.1.2.2 Radiographic Inspection

Wall shot or radiographic profile radiography is discussed in this section, as to the use of the technique, no information about how the technique is performed. Key phrase “radiography”.

10.1.3 Other On-stream Inspections

This section mentions “new” methods of inspection; halogen leak detectors, magnetic induction, real-time radiography, neutron radiography, thermography, etc. Key phrase “methods”.

10.2 Inspection While Equipment Is Shut Down 10.2.1 Visual Inspection

10.2.1.1 Corrosion, Erosion, and Fouling

Borescopes are used to inspect piping internally. Key phrase

10.2.1.2 Cracks

Inspect the susceptible locations, construction tack welds at other than pressure welds, heat affected areas joining welds, and points of restraint or excessive strain. Include locations that are subject to stress-corrosion cracking, hydrogen cracking, and caustic or amine embrittlement, as well as exposed threads. Key

phrase “cracks”.

10.2.1.3 Gasket Faces of Flanges

General inspection. Key phrase “flanges”.

10.2.1.4 Valves

Inspection techniques for gate valves including the valves being dismantled at specified intervals. Key phrase “valves”.

10.2.1.5 Joints, 10.2.1.5.1 Flanged Joints, 10.2.1.5.2 Welded Joints, 10.2.1.5.3 Threaded Joints, 10.2.1.5.4 Clamped Joints

All the listed joints should be inspected, the basic technique is visual examination. Key phrase “joints”.

10.2.1.6 Misalignment

Misalignment is caused by:

a. Inadequate provision for expansion. b. Broken or defective anchors or guides.

c. Excessive friction on sliding saddles, indicating a lack of lubrication or a need for rollers.

d. Broken rollers or rollers that cannot turn because of corrosion or lack of lubrication.

e. Broken or improperly adjusted hangers.

f. Hangers that are too short and thus limit movement or cause lifting of the pipe.

g. Excessive operating temperature.

Key phrase “misalignment”.

10.2.1.7 Vibration

Vibrating or swaying piping should be inspected for cracks, at points of restraint, usually in the areas of anchors, or where small bore pipe is attached to the main line. Key phrase

“vibration”.

10.2.1.8 Hot Spots

A short discussion of areas over heated on piping is discussed. No mention of thermal photography. Key phrase “hot spots”.

10.2.2 Thickness Measurements

UT digital thickness gauges are mentioned with emphasis on high temperature readings and the use of radiography on nipple thickness.

Key phrase “thickness measurement”.

10.2.3 Pressure Tests

Pressure tests are leak tests and may be used on the following: a. Underground lines and other inaccessible piping. b. Water and other non-hazardous utility lines.

c. Long oil transfer lines in areas where a leak or spill would not be

hazardous to personnel or harmful to the environment. d. Complicated manifold systems.

e. Small piping and tubing systems.

f. All systems, after a chemical cleaning operation.

Do not over pressure the system!

Various fluids may be used for pressure testing:

a. Water with or without an inhibitor, freezing-point depressant, or wetting agent.

b. Liquid products normally carried in the system, if non-toxic or flammable.

c. Steam

d. Air, carbon dioxide, nitrogen, helium, or another inert gas. Salt water can create problems like pitting and corrosion.

Pneumatic tests should be conducted strictly in accordance with ASME B 31.3. Key phrase “pressure test”.

10.2.4 Hammer Testing

Hammer testing is an old method of testing piping systems, do not use the hammer on cast iron and stress-relieved lines in caustic and

corrosive service. Key phrase “hammer test”.

10.2.5 Inspection of Piping Welds

Refer to API 570, Section 3.10 which will reference ASME B 31.3 for weld quality. Key phrase “weld quality”.

10.3 Inspection Of Underground Piping

Basic information about buried piping, referencing several NACE documents.

10.3.1 Types and Methods of Inspection and Testing 10.3.1.1 Above-Grade Visual Surveillance

Extremely basic information about leaking underground piping.

10.3.1.2 Close-Interval Potential Survey

This type of survey is used to locate corrosion cells, galvanic anodes, stray currents, coating problems, underground

contacts, areas of low pipe-to-soil potentials and other cathodic protection problems. Key phrase “Close-interval potential

survey”.

10.3.1.3 Holiday Pipe Coating Survey

Basically, a measurement is taken and compared to other areas of the system, coated as opposed to noncoated piping will give different corrosion rates and readings. Key phrase “holiday

pipe coating survey”.

10.3.1.4 Soil Resistivity Testing

The Wenner method, the soil bar and soil box methods are discussed. Basically, each method measures a voltage drop, caused by a known current flow, across a measured volume of soil. The resistance factor is used in a formula to determine the resistivity of the soil. Key phrase “soil resistivity testing”.

10.3.1.5 Cathodic Protection Monitoring

Refer to NACE RP0169 and Section 11 of API Recommended Practice 651. Key phrase “CP monitoring”.

Sections 10.3.2 Inspection Methods, 10.3.21. Intelligent Pigging, 10.3.2.2 Video Cameras, 10.3.2.3 Excavation are all basic with little or no useful information.

10.3.3 Leak Testing

The basic methods of leak testing underground piping are briefly described in this section. The methods are:

a. Pressure decay method.

b. Volume in/volume out method. c. Single-point volumetric methods. d. A marker chemical (tracer) method. e. Acoustic emission method.

10.4 Inspection Of New Construction 10.4.1 General

Must meet the requirements of ASME B 31.3. Key phrase “ASME B

10.4.2 Inspection of Materials

Materials should be checked for conformance with the codes and specifications that are appropriate for the plant. Checks should be made using material test kits or a nuclear alloy analyzer, (PMI)). Key

phrase “ASME B 31.3”.

10.4.3 Deviations

No comment.

11 DETERMINATION OF RETIREMENT THICKNESS