270 likes | 482 Views
SafeHull Condition Assessment Program (SH CAP). Presented to INTERTANKO On 24 July 2003 in Miami, FL. ABS SH Condition Assessment Program History. Initiated in 1995, with SH development and VELA requirements for CAP ratings.
E N D
SafeHullCondition Assessment Program (SH CAP) Presented to INTERTANKO On 24 July 2003 in Miami, FL
ABS SH Condition Assessment Program History • Initiated in 1995, with SH development and VELA requirements for CAP ratings. • Has included a fatigue analysis and buckling check since 1995, became mandatory with the BP requirement in 2001. • Has maintained its structure since its inception, assess the whole vessel. • Has adjusted to industry requirements
ABS SH Condition Assessment Program History • Over 250 vessels through program to date. On pace for 65 this year. • More charterer’s initiating CAP requirements, such as STATOIL, and Petronas. • New player’s including Governments such as India’s announcement that foreign flag vessels over 20 years must have CAP 1 or 2 to enter terminals in India.
ABS Condition Assessment Program • Review of Class Records (Only IACS classed vessels) • Fatigue Analysis to inform the owners & surveyors of areas of concern • SafeHull Condition Assessment Survey • Verification of Gaugings • SafeHull Structural Evaluation • Grade assigned by Committee
1. Review of Class Records • Review of Class Records (IACS members)(LR, ABS, DNV, RINA, … ) • Used by surveyors on board. • Used by engineers for fatigue analysis for any modifications / steel renewals / repetitive fractures or lay-up periods. • Not normally a deliverable.
2. Fatigue Analysis • Fatigue assessment of longitudinal stiffener connections. • Fatigue assessment projected for 5 years. • Identification of critical areas for owners and surveyors prior to survey. • Identify areas for increased monitoring or repair.
3. Condition Assessment Survey (Onboard) • Independent of Class survey. But can be done in conjunction with ISH or SSH. • Two “approved” surveyors. • Close-up surveys of hull, machinery, equipment. This includes a close-up of 100% of the ballast and cargo tanks in the cargo block. • Close-up survey of “Hot Spot” areas identified by fatigue analysis. • Survey of vessel on dry-dock or UWILD. • Representative photographs (Over 200).
4. Verification of Gaugings • Three girth belts within the 0.4L (cargo area) for tankers • Surveyors will verify scope and accuracy of gaugings. The gaugings are conducted by client’s contractor (ABS-approved external specialist) • Input for structural (strength) evaluation of current condition
5. SafeHull Structural Evaluation • Strength of current structure compared to SafeHull criteria. Then against the as built requirements. • ‘S’ Curves—renewal requirements vs. as gauged. • Identify areas for increased monitoring or repair. A vessel with substantial corrosion, although OK for Class will not receive a Grade 2 unless repaired within the 120 day survey period for the CAP.
SafeHull Structural Evaluation • Buckling: • Since its inception in 1995 SafeHull has incorporated the t3 minimum thickness (using the as-gauged condition) for buckling as a rule requirement for plates. • Due to an influx of lighter scantling vessels applying for SHCAP a buckling check was added to the program in 2002 to address the deck and bottom longitudinals. This calculation uses the industry standard b/t (h/t) criteria. • We use the h/t requirement as a first indicator and can do additional calculations to determine the minimum web thickness.
SH CAP Structural EvaluationCategories: No special comments or attention • Under Class: Every member is allowed to corrode a certain percentage before it must be replaced. • SafeHull modifies this percentage– it establishes a new as-built requirement for each member. • In Strength: the member properties are greater than 105% of the SafeHull renewal value. • In Fatigue: the connection has a continued life expectancy over the next 5 years. • I.e., no additional requirements or attention beyond the normal Class requirements.
SH CAP Structural EvaluationCategories: Less sensitive • In Strength: the member properties are between 100% and 105% of the SafeHull renewal value (Current ABS rules). • If the member is Category 2 because of corrosion: should be scheduled for replacement during next DD. • In Fatigue: the connection has an increased probability of failure in the next 5 years. Actual probability depends on age of vessel, trading conditions, time spent in DD. • These members require increased monitoring and identified as “must seen” during regular inspections. For ABS-classed vessels: these members may be passed on to ABS Class Document Center.
SH CAP Structural EvaluationCategories: Most sensitive • In Strength: the member is less than 100% of the SafeHull requirement • In Fatigue: the connection has a likely probability of failure in the next 5 years. Actual probability depends on age of vessel, trading conditions, time spent in DD. • These members require replacement or increased monitoring on an annual or more regular basis. • For ABS-classed vessels: These members are passed on to ABS Class Document Center.
What is Critical? i.e., items that will be reported to Class for regular inspection • Category 3 in Section Modulus (the vessel no longer has 90% of the IACS required Section Modulus and MAY be considered for Class removal). • Category 3 in Fatigue (likely probability of failure within the next 5 years). • Category 3 in Strength Analysis - if substantial corrosion exists (less than 100% of SafeHull required renewal value remains). Vessel can not receive Grade 1 or 2 with Substantial corrosioni.e., items in Category 3 in Strength that do not have substantial corrosion may not necessarily require immediate repair (especially if they do not have history of failure)
What is Increased Monitoring? The vessel meets Class requirements but the following items do not meet SafeHull requirements and need to be examined more often than every 5 years: • Category 3 in Fatigue: Repair or Inspect annually. The grading committee determines. • Category 2 in Fatigue: Inspection on an annual or 2.5 years interval (inspections after SEVERE weather, minimum). • Category 3 in Strength Analysis: no substantial corrosion and no history of failures - inspect on an annual basis or 2.5 years along with the Category 2 connections.
6. Condition Assessment Grading Committee is made up of designated survey, engineering, technology and management staff to keep consistent application of the grading process. Each member has a designated alternate to assist in keeping the process moving.
Deliverables for Condition Assessment • Executive Summary • Description of Program and the recap of the vessel grading • Inspection Recommendations for Class Society • Certificate with Grade • Structural/Fatigue Analysis • Condition Assessment Survey Report • Photographs (To be provided electronically)
SHCAP Improvementsduring the last year • ABSC Average Certificate Turnaround Time: 7.0 weeks vs. 14.0 weeks for Competition • Improved Overall Report Format, and include a Table of Recommendations Related to Fatigue Analysis/Structural Evaluation. • Length for SHCAP moved 150 m to 130 m in length. • Reduction in Size of Deliverables.
SHCAP Improvementscoming in 2003 • Clearer presentation of gauging data relative to required. • All deliverable information to be provided on CD • SHCAP to cover LNG vessels