Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Confusion
ATC Issue All Types; Airspace Violation All Types; Deviation / Discrepancy - Procedural FAR
Air Traffic Control Provided Assistance; Flight Crew Returned To Clearance
Airspace Structure; Procedure
Shortly before top of descent Oakland Center changed our arrival to the SERFR 1 RNAV arrival. We flew the arrival remaining in VNAV path the entire way and complying  with all restrictions. Upon handoff to NorCal Approach; Oakland Center commented that we had briefly gone below SFO class B duing our descent. Descending below class B while complying with an arrival published for a primary airport is something neither of us would have considered. This appears to be a new procedure and it looks like it still needs to be adjusted. The fact that the path and restrictions allow for you to go below Class B while flying an arrival designed for aircraft landing at the primary airport is counterintuitive. Furthermore; complying with the arrival would not allow for a speed reduction. Crews and ATC should discontiue use of this arrival until the arrival or airspace can be adjusted. Internally our company should consider a NOTAM and/or 10-7 note to discontiue use until this technicality is resolved.
Pilot reports of flying below the Class Bravo while in a descent into SFO on the SERFR1 STAR. Pilot advises there may be something wrong with the arrival that takes the aircraft out of the Class Bravo which is built to protect the aircraft.