Accidental Loads

Definition(s)


Accidental Loads

Accidental loads are loads caused by accidental occurrences. Examples include 1000-yr wave and current loads, operational malfunction, and loads from impacts/collisions.

Source: API Standard 2RD, Dynamic Risers for Floating Production Systems, Second Edition, September 2013. Global Standards

 

Accidental Loads

Loads imposed on the riser system from unplanned conditions/occurrences during a reduced extreme environmental event or by survival environmental events.

EXAMPLE Loads resulting from loss of vessel station-keeping and tensioner lock-up are examples of accidental loads

Source: API Standard 2RD, Dynamic Risers for Floating Production Systems, Second Edition, September 2013. Global Standards

Accidental Loads

Accidental loads are project-specific, and should be verified by a special risk analysis for the actual application. Accidental loads can include dropped objects, snag loads (fishing gear, anchors), abnormal environmental loads (earthquake), etc.

Source: API RP 17A, Design and Operation of Subsea Production Systems—General Requirements and Recommendations, Fourth Edition, Reaffirmed 2011. Global Standards

 

Accidental Loads

Accidental loads (or low probability of occurrence loads) are loads related to abnormal operations or technical failure.

Accidental loads are defined as events with a probability less than 10−2 and larger than 10−4.

EXAMPLES Loads caused by vessel tensioner system failure or motion compensator system failure, e.g. loss of top tension or heave compensator lock-up, loss of dynamic positioning system (drive-off or drift-off) are examples of accidental loads. Loads caused by emergency operation, loss of buoyancy, change in intended pressure difference, unintended change in ballast distribution, fire, explosions, collision impact from infrequent vessel/riser interference, dropped objects and extreme environmental conditions are also accidental.

Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global Standards

 

Accidental Loads

Accidental loads are loads which occur as a direct result of an accident or exceptional circumstances, e.g., loads due to collisions, dropped objects and explosions, etc. See also 4.16.

Source: Rules and Regulations for the Classification of Mobile Offshore Units, Part 4, Steel Unit Structures, June 2013, Lloyd’s Register, Global Standards

 

Accidental Loads

“Accidental loads” means loads which the facility can be subjected to in the event of incorrect use, technical failure or an undesirable external effect.

Source: Petroleum and Natural Gas (Safety in Offshore Operations) Rules, 2008, India, 18th June 2008. Regulations