Specifies the response modification coefficient, R. This coefficient reflects system ductility. The calculated spectrum accelerations are divided by this value to generate the horizontal shock spectrum. Values range from 3.0 to 8.0 for most plant structures. A value of 3.5 for piping is common.
ASCE 7
R is defined in Table 12.2-1 and applied according to paragraph 12.9.2.
IBC
R is defined in Table 1617.6 and used according to equation 16-53.