Three- and four-pass dry-back design accommodates moderate BTUH/CF (Mcal/m³) volumetric furnace heat release rates in comparison to competitive dry-back configurations. The centerline furnace construction reduces vessel thermal stresses.

Three- and four-pass water-back design accommodates lower BTUH/CF (Mcal/m³) volumetric furnace heat release rates in comparison to competitive water-back configurations. The intermediate tubesheet design reduces vessel thermal stresses.