This is probably the worst connection in the whole terminal, if not the whole airport. Takes around 10-15 minutes walking at a brisk pace from the gate to security. The transfer centre is rarely busy in T1 so that shouldn't take too long. The transfer centre takes you into the departure lounge at the wrong end of the building; continue through to the opposite end towards the 70s gates and gates 2, 5 and 7 and follow the signs to the Irish pier. I think its another 10 minute walk from here!