As noted earlier in Sections 2.2, 2.3 and 2.5, the load/action factors are similar in 2A LRFD and

ISO 19902. It is our understanding that the API document was utilized as a starting point for the

ISO standards development that started in the 1990s. Therefore the ISO document have improved considerably on the 2A LRFD document not only in providing more guidance to the

designer but also in correcting and clarifying several issues that existed in 2A LRFD such as the

separation of the inertia component of the load with different load factor and the definition of an

operating environmental condition.

Table 2-12 Annual Pf in API Sec. 17 and NORSOK for unmanned and manned platforms

Table 2-13 ISO 19906

Reliability Targets for ULS

and ALS Exposure Level

Maximum Acceptable Annual

Failure Probability

L1* 1.0 x 10-5

L2* 1.0 x 10-4

L3* 1.0 x 10-3