Abstract: A parallel-walled ventilation duct assembly with integrated low-profile subducts, and/or methods of manufacturing the assembly are provided. The assembly of embodiments includes a main shaft body defined by at least one wall surrounding an interior cavity and at least one low-profile subduct disposed within the interior cavity. The cross-sectional area of the main shaft body has a rectangular or an obround shape. The low-profile subduct includes an interior channel defined by a plurality of walls. The low-profile subduct is integrated into at least one wall of the main shaft body such that at least one wall of the plurality of walls of the low-profile subduct includes at least a portion of an interior surface of the at least one wall of the main shaft body, and the portion of the interior surface of the at least one wall includes a flat portion of the interior surface.

Abstract: An active stairwell compensation system includes air injection points at different elevations in a stairwell; a fan for providing airflow to the air injection points; sensors; air injection dampers; and a controller in data communication with the fan, the sensors, and the air injection dampers. At least some of the sensors are located inside the stairwell, and at least some of the sensors are located outside the stairwell. A respective air injection damper is located between each air injection point and the fan. The controller has programming to utilize data from the sensors to adjust an amount of air provided by the fan and independently adjust the air injection dampers to maintain a desirable amount of air pressure at the air injection points. The desirable amount of air pressure is selected to prevent smoke from entering the stairwell while allowing stairwell doors to open for egress.

Abstract: Reversible draft controllers and exhaust systems incorporating reversible draft controllers are disclosed. One system for controlling draft in a chimney includes a sensor for determining condition data, an axial fan blade, an electronically commutated motor (ECM), and a controller. The ECM is configured to rotate the fan blade in a first direction to increase draft in the chimney and in a second, opposite direction to decrease draft. The controller has a processor and a program of instructions executable by the processor to perform steps for controlling draft in the chimney with the fan blade. The steps include: comparing condition data from the sensor to set point data to determine if an intervention is required; addressing insufficient draft by actuating the ECM to rotate the axial fan blade in the first direction; and addressing excessive draft by actuating the ECM to rotate the fan blade in the second direction.

Abstract: Draft inducers are set forth herein. According to one embodiment, a draft inducer for use with corrosive and high temperature gas includes an inline tubular housing, an impeller inside the housing, and a motor outside the housing. A drive shaft couples the motor to the impeller to rotate the impeller with force from the motor. According to another embodiment, an inline shaft driven draft inducer includes an inline tubular housing, a rotating member, a motor, and a drive shaft. The housing has an external perimeter, and the motor is outside the housing external perimeter. The rotating member is inside the housing, and the drive shaft couples the motor to the rotating member to spin the rotating member with force from the motor.

Abstract: Reversible draft controllers and exhaust systems incorporating reversible draft controllers are disclosed. One system for controlling draft in a chimney includes a sensor for determining condition data, an axial fan blade, an electronically commutated motor (ECM), and a controller. The ECM is configured to rotate the fan blade in a first direction to increase draft in the chimney and in a second, opposite direction to decrease draft. The controller has a processor and a program of instructions executable by the processor to perform steps for controlling draft in the chimney with the fan blade. The steps include: comparing condition data from the sensor to set point data to determine if an intervention is required; addressing insufficient draft by actuating the ECM to rotate the axial fan blade in the first direction; and addressing excessive draft by actuating the ECM to rotate the fan blade in the second direction.

Abstract: Sub-ducts and methods of exhausting into a generally rectangular and vertical main shaft are disclosed herein. A sub-duct of one embodiment includes hollow first and second portions. The first portion presents a generally flat attaching wall, a top side that defines an opening, and a bottom side that has an aerodynamic configuration; the second portion defines an intake opening, meets with the first portion attaching wall at approximately a ninety degree angle, and has a configuration complementary to a configuration of an exhaust duct. The first and second portions collectively define a continuous channel between the intake opening and the top side opening. The first portion may have a section of generally constant cross section extending from adjacent the second portion to the top side opening, and the second portion may have a generally constant cross section extending from the intake opening to the first portion.