LZ Parameter for Rafter of Clear Span Gabled Building

Dear All,

             Can anybody suggest what will be the LZ Value for the Rafter of a Clear Span Building. For Example, there is a Clear Span building 30m wide , Slope - 1:10 , Gable at 15m  . In this case what will be the LZ Value for Roof Rafter . If possible please provide any relevant thesis for better understanding.

Regards,

SURAJ PILLAI