IACS UR Z13 - Hull Condition Monitoring
UR Z13 thickness measurement intervals and allowable diminutions for steel scantling survey - the schedule that governs ship-age surveys.
UTM coverage
Comprehensive - all suspect + representative
Max interval
2.5years
Formula, assumptions, and limits
Allowable diminution depends on structural member and corrosion category - typically 15–25 % of as-built thickness. Substantial corrosion (> 75 % diminution allowance) triggers re-survey in 6-12 months.
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| Ship age from keel laying | years | class certificate |