SFO Controller voiced concern regarding the Local Controller and Supervisors non-action during a heavy over take situation on the final for Runway 28; adding the heavy aircraft elected to go around when ATC should have initiated the action.

Narrative

A B747 was on final for Runway 28L; an A319 was on final for Runway 28R. The B747 was about one mile behind the A319 and showing 40 KTS overtake on speed. The Local Controller told the B747 not to pass the A319 for the parallel runway or they would have to be sent around. The B747 complained that NCT had given them 180 KTS to 4DME. The B747 was about 8 DME when he was given the instructions not to pass the A319. The Local Controller pointed the situation out to the Supervisor and asked the Supervisor if he (the Local Controller) should take corrective action and send one of the aircraft around. The Supervisor watched what was happening and when the B747 was abeam the A319 and still showing 20 KTS faster; the Supervisor said; 'Let them land. It will be alright.' Shortly after that the B747 went around on his own because he was about to pass the A319. I recommend retraining for the Local Controller and Supervisor on wake turbulence rules and taking corrective action to prevent this happening in the future.