SN65C1168: RS422 EMI class B support

Can you give some detail about the system requirement, like conducted or radiated? If you mean adding EMI filter on the bus, this practice is common in the industry. This article might be helpful to you.  

Thanks. we would support RS422 is same as RS485 design?

Product Spec.: EMI: radiated is class-B, ESD: conducted is 4KV, air is 8KV, surge is 1KV. As your experience, do you any suggestion about design?

RS-422 and RS-485 are very similar in many aspects. From my understanding, the EMI challenge mainly comes from the power design such as DC/DC or isolated power. ESD protection can be taken care of external TVS diodes. BTW, SN65C1168E has 8kV contact and air.