A Risk-Informed Approach to Performance Assurance - Structural Integrity of Offshore Wind Turbines - page 66

BOX 4-3
Performance-Based Standards and Innovation
As generally understood, a performance-based standard specifies
the outcome required but allows each regulated entity to decide
how to meet it. Performance standards give firms flexibility and
make it possible for them to seek the lowest-cost means to achieve
the stated level of performance (Coglianese et al. 2003).
By focusing on outcomes, performance-based standards accom-
modate technological change and innovation, which can be key
to lowering costs. To the extent that they reduce the costs of
power generated by using offshore wind, they increase the abil-
ity of this source to compete with other sources of electricity.
See Box 4-4 on the International Maritime Organization's goal-
based standards for an example.
in the Gulf of Mexico (GOM). This was at a time when there were no
data on the response of frame structures to hurricane forces. Land-based
steel design codes, principally the American Institute of Steel Construc-
tion (AISC) Manual of Steel Construction, were the standards most
closely aligned with offshore design and construction materials. Offshore
developments progressed over roughly 20 years in the GOM under a
variety of operator-specific design approaches and criteria. Design con-
ditions (conditions that the structure must be designed to withstand)
were specified probabilistically, where the probability of an event occur-
ring is expressed in terms of the percentage chance that it will occur in
any given year.
The most common design condition was a 25-year return period,
though other operators used return periods of up to 100 years according
to their appetite for risk (MMS 2004). Data to develop the design criteria
were collected on an ad hoc basis with limited cooperation between oper-
ators (MMS 2004).