Hi Oscar, the flares I have seen here, usually have a loop before the flare nozzle, by the way, in a recent project the manufacturer give us the allowable loads for a flare and the axial loads were so low that we have to add a large loop to reduce axial loads. Allowable loads shall be given by vendor.
Maybe Superpiper thinks loads is responsibility of vendor, but you have to check design in order to get reasonable loads on equipment. 22 mts of the last support seem to be a little far, i think that at the end you may need another one closer (you have to ask vendor for loads). By the way, it is detail engineering? do you already have purchase orders putted? or you still dont have any vendor approved? If you dont have any vendor yet, try comparing with API code for furnaces (it does not apply directly, i think, but i have found some allowable loads from stack vendors that are exactly the same loads given by that code, maybe is casual, but someone i know thinks that it really is the applicable code)

Regards,
Hector