An inflator assembly (10) for an airbag includes a container (12) with a plurality of exhaust (20) ports positioned about a perimeter (24). A rupturable, non-combustible material covers the perimeter of the container to cover the exhaust ports. A plurality of perforated and rupturable walls (33) define a plurality of chambers (36, 38, 40) concentrically disposed within the container. Within each of the plurality of chambers is a detonator (28) to trigger a gas-producing chemical to inflate an airbag cushion. The detonators disposed in each of the individual chambers can be detonated separately from other detonators in other chambers.
