Abstract: A foam generating apparatus includes a manifold defined by a rectangular metal block, into which a liquid and surfactant is introduced under very high pressure via a first longitudinally extending passage, and air is introduced via a second longitudinally extending passage parallel to the first passage. The liquid passes through restricted orifices into the narrow ends of a plurality of venturi outlet passages, which are perpendicular to the liquid inlet passage. The velocity of the liquid/surfactant mixture exiting the restricted orifices is maintained sufficiently high to cause flashing to take place to initiate foam generation. Air is injected into the venturi through small diameter ports extending from the second inlet passage to the venturi. The foam and liquid/gas mixture is discharged from the venturis through fittings which may contain vaned inserts for promoting turbulence and thus foaming. Foam production continues in the foam carrying lines downstream of the discharge bushings.