From the BRU Airport site:
Terminal
At Brussels airport there is a Main Terminal divided in two areas: Concourse A (Pier) and Concourse B (Pier).
Passengers can reach these two piers from Arrivals and Departures Level.
In total, Brussels Airport has 109 gates.
You’ll likely arrive here:
Concourse B
It is only used for non-Schengen flights. The pier links directly with the Main Departure Hall through. On Level 3 there are gates from B1 to B40. On Level 0 there are gates from B80 to B98.
This Concourse is divided between Departures and Arrivals.
From Level 0 passengers can pick up the transfer bus that links with Concourse A (A and T gates).
On Level 4 there are most of the shops, bars, restaurants and services.
Transfer between concourses
The airport terminals are integrated buildings. The connection is done through the connector building, which links the ground level with Concourses A and B.
You’ll likely depart here:
Concourse A
Is the newest one at the airport and handles Schengen flights and some Schengen flights to Africa and New York.
Concourse A has the following levels:
- Ground level: Food, drink and retail concessions and access to boarding gates A28-A39.
- First level: Food, drink and retail conceccions ans access to boarding gates A40-A72 and gates T61-T72.
Other services: Baggage reclaim hall, security screening and border control. From this level it is possible to connect direcly to both Concourses A and B.