The solution was to capture at source from the pulleys on three drawing lines which were equipped with capture/enclosed hoods with 4”Ø suction ports. The hoods were installed by the customer after consultation with AST Engineering (www.astengineering.ca) for the design. Each line has twelve 4” ports (thirty-six in total). All the ports are connected to rigid spiral galvanized ductwork by flexible hoses. The ductwork has been designed based on ACGIH and Fire Code by AST. The collected airborne dust is collected at the source via the above-mentioned hood and ductwork system and transported with proper duct velocity as per ACGIH and Fire Code to the dust collector outside of the building. The dust collector has a dual-hopper and is equipped with an explosion protection system as per the details below. The dust collector airflow is rated up to 12,600 CFM. The dust collector has a full VFD control panel which provides constant airflow regardless of the filter condition. The
following are the details of the solution:

• The dust collector is grounded, and the heavy-duty ductwork (between the collector and blowback dampers) is electrically bonded to the collector.
• The collector has two mods, and two hoppers. Each mod has a top-mounted explosion vent with weather cover and Sealed Drum Kit (SDK) for hopper protection.
• Two 16”Ø NRV’s (blowback dampers) are installed on the two inlet ducts as isolation devices.
• A signal from any of the protection equipment will de-energize the fan and create an alarm.
• Transport velocities exceed 3,500 FPM.
• The production line is interlocked to the operation of the dust collector fan.
• The fan is floor mounted and rated for up to 12,600 CFM.
• Clean air is returned to the building through a 2×3 Ultra-Lok (HEPA housing). Note: DFE collector is tested and proven to isolate a deflagration and stop flames or sparks from passing into the clean air plenum.