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280 Cha pte r Se v e n

Defects Codes Defects Codes
Brick gone BG Tile broken TB
Brick loose BL Tile cracked TC
Crown gone CG Tile gone TG
Peeling T-lock PTL Tile loose TL

TABLE 7.2 Sample Defect Codes used in Sewer Pipes

There are several ways to categorize and classify pipelines defects.
Table 7.2 presents sample defect codes that may be used in sewer pipes.
Similar codes can be used for different types of pipes. Table 7.3 presents
a six category pipeline condition assessment system.
The defects listed in the “Condition Description” column of
Table 7.4 include only the most common/critical defects affecting
the structural integrity of a pipeline. Also, in this column, “light,”

Action/ Response
Category Sample Defects Response Period
• Severe corrosion throughout
• Few areas with tile remaining Renewal or
I Immediate
• Exposed rebar replacement
• Soil voids visible
• Heavy to severe corrosion
Renewal or
II • Large areas with tile missing 2–3 months
replacement
• Some rebar corrosion
• Moderate to heavy corrosion
Follow-up
III • Many large areas with tile 1 year
investigation
missing
• Light to moderate corrosion
Follow-up
IV • Some large areas with all the 3–5 years
investigation
tile missing
• Slight corrosion in some areas Follow-up
V 5 years
• Patches of tile missing investigation
• No corrosion visible Follow-up
VI 5–10 years
• Some individual tiles missing investigation

a Overlapping of categories can occur as a result of the six categories lending themselves
to subjective interpretations.
TABLE 7.3 Six Category Pipeline Condition Assessment System a