Metallic flange to Non- mettalic pipe like FRP

can we use mettalic flanges to the non metallic pipe connections especially in case of equipments nozzles when the equipment is FRP? Please recommend which is the best/ Either using non metallic flanges to non metallic pipes or metallic flanges?

Well if you’re changing specs then there's no way around it. I've connected FRP flanges to steel flanges a number of times, only issue is the steel flange has to be flat faced and use an appropriate gasket! Also I suggest using steel washers on the studs, FRP side only.