Part B - Certificates and approval requirements 
19 
The current versions of the technical codes of practice listed below (the list is not complete) can be used 
as an additional basis where DIN 1054 [19] does not define any regulations or cannot be used or cannot 
be used practically due to the special features of offshore foundations in general or offshore wind farms in 
particular: 
f61 GL Guideline for the Certification of Offshore Wind Turbines 
IZ1 DNV OS-J-101 
f211 DIBt-RIU WEA 
122] API RP 2A-WSD 
]5] API RP 2A-LRFD 
3.2.4.4 Material designations and parameters 
The material parameters used for the soil types shall in all cases be determined and designated accord 
ing to the relevant DIN regulations. Deviating or supplementary processes and designations shall be 
indicated as such and comprehensively documented. 
3.2.4.5 Soil model and characteristic soil parameters 
• The „Standard for Geotechnical Site and Route Surveys“ ]1] of the BSH shall be used in its current 
version as the minimum requirement for soil surveys. 
• For each site of offshore wind turbines, the set of available survey results shall be used for deriving 
an individual geotechnical soil model for the site that shall be used as the basis of the certificates. 
For this purpose (at least) one suitable calculation profile (soil profile) shall be specified with the 
required characteristic soil parameters of its soil layers. If the soil is non-homogenous, it may be 
necessary to formulate a more complex soil model for each offshore wind farm site with several 
calculation profiles. 
• The characteristic values and their probable bandwidths of all soil characteristics that are relevant 
for certification shall be defined and specified for the soil model. This data shall be based on the 
evaluation of a bandwidth of investigation results and on an expert's opinion based on experience, 
correlation and/or interpretation of direct and indirect information and investigations on the site. 
• Design values of the soil parameters shall, if necessary, be derived from the bandwidth of charac 
teristic values with regard to their significance in whichever calculation model is used. Variations in 
model calculations shall be provided to an appropriate extent. 
• Lower and upper limits for the relevant soil parameters shall be varied in an unfavourable combina 
tion for the purposes of natural frequency analyses as well as for the load capacity and serviceabil 
ity certificates. 
3.2.4.6 Boundary conditions for certificates 
The following boundary conditions for certificates shall be differentiated: 
• Ultimate limit state (ULS) 
• Fatigue limit state (FLS) 
• Serviceability limit state (SLS) 
• Accidental limit state (ALS), to the extent given. 
3.2.4.7 Required certificates 
3.2.4.7.1 Certificate of stability of the seabed 
Demonstration shall be given that the soil system on which the certificates for the foundation and load 
calculations for the support structure are based is stable.