This webinar provided a technical overview of Strobic Air’s laboratory exhaust systems, with a primary focus on life-safety performance, high-plume/high-dilution exhaust design, mechanical configuration, materials of construction, vibration and sound control, and integrated control logic. The discussion centered on the role of Strobic’s SAFE controller in maintaining safe operating conditions and their three primary fan system architectures: TriStack®, DuoStack®, and MonoStack®.
Strobic’s laboratory exhaust systems were originally developed in response to a request from IBM for a dedicated laboratory exhaust solution designed explicitly as a life-safety device, rather than a general-purpose exhaust fan. The design priorities emphasized:
- Prevention of hazardous chemical re-entrainment
- High dilution and effective plume rise
- Reliability and long service life
- Minimal maintenance requirements
The core objective is to safely discharge laboratory exhaust containing corrosive, toxic, or hazardous contaminants without allowing those contaminants to re-enter the building or impact adjacent structures.
A key technical principle discussed is high plume, high dilution exhaust, which differs from traditional tall exhaust stacks. Instead of relying solely on physical stack height to achieve plume dispersion, Strobic systems use induced airflow to increase exhaust mass, velocity profile stability, and plume breadth. This approach increases effective stack height while allowing for a lower physical stack.
Benefits of this approach include:
- Reduced need for tall stacks and guy wires
- Improved architectural integration due to lower profile
- Reduced structural and material requirements
- Improved plume stability under varying wind conditions
Strobic’s TriStack® System
The TriStack® system is Strobic’s flagship, mission-critical laboratory exhaust solution. The “tri” designation refers to three distinct airflow paths:
- Primary inlet airflow from the laboratory exhaust system
- Bypass airflow, used to regulate plenum pressure and modulate system performance
- Induced airflow, drawn through a windband and discharge nozzle
The system uses a bifurcated fan design, which allows a large volume of air to pass through the inlet bell and impeller and then be condensed to achieve a consistent discharge velocity exceeding 3,000 feet per minute at the nozzle. This velocity threshold is critical to maintaining plume integrity and preventing downwash or re-entrainment. The bifurcated design also promotes smooth, uniform airflow through the discharge nozzle, reducing turbulence and improving dispersion consistency.
Strobic places strong emphasis on materials suitable for harsh laboratory exhaust environments:
- FRP (fiberglass reinforced plastic) nozzles are standard, providing high resistance to chemicals and UV exposure.
- Steel plenums and metal components receive zinc-free epoxy coatings, applied at 8–10 mil thickness, with additional UV-resistant coatings as standard.
- For coastal or corrosive environments, systems can achieve salt spray resistance ratings up to 7,000 hours, significantly exceeding typical industry benchmarks.
These construction practices are intended to support long-term durability well beyond typical warranty periods. Across product lines, Strobic systems emphasize direct-drive configurations, eliminating belts and couplings. This reduces maintenance frequency and failure points. Typical maintenance intervals for TriStack systems are approximately 18 months, supporting use in continuous-duty laboratory environments.
Strobic’s DuoStack® System
The DuoStack® system was introduced to address applications that are less mission-critical but still require high performance and reliability. It is a side centrifugal exhaust fan configuration designed for:
- High static pressure applications
- High-temperature exhaust streams
- Airflows containing particulates, with reduced risk of material buildup
While it does not utilize induced flow to the same extent as the TriStack®, the DuoStack® maintains similar quality standards and direct-drive operation. It is positioned as a cost-effective option for facilities where failure would not result in immediate loss of life or critical revenue.
Strobic’s MonoStack® System
The MonoStack® serves applications requiring non-induced flow exhaust fans that meet AMCA 210 certification requirements. It is similar mechanically to the DuoStack® but omits the induction windband (associated with AMCA 260 induced-flow classification). The MonoStack® is designed for wide operating ranges and high static pressure applications while maintaining low maintenance and direct-drive benefits.
The webinar emphasized differentiating applications based on risk:
- Mission-critical applications (where failure could result in loss of life or significant revenue) should use the TriStack® system.
- Non-mission-critical applications may use DuoStack® or MonoStack® systems, depending on certification and airflow requirements.
Strobic’s SAFE Controller
The SAFE controller is an integrated, out-of-the-box control platform designed specifically for critical exhaust applications. Key technical capabilities include:
- Continuous monitoring and control of static pressure setpoints
- Flow measurement and verification
- Modulation of fan speed and bypass dampers for efficiency while maintaining safety
- Automatic detection of failures and activation of redundant fans
- Enforcement of minimum discharge velocity (≥3,000 FPM) at all operating conditions
The controller communicates with system devices via Modbus and integrates with building management systems via IP or MS/TP protocols. While efficiency optimization is supported, the controller’s core logic prioritizes life safety over energy savings.