I am trying to gain a clear perspective on the limitations of different f gas certificates. As engineers we have j11 however we have a maintenance engineer who only achieved j13. What does this limit to in real terms. Limited info suggests that he can service, maintain and document small systems (under 3 Kg). However I was under the impression that this is what manufacturers use for their delivery guys. Anyway any opinions and more importantly facts would be appreciated.

Thanks in advance.