The Manatee County Water Treatment Lab is a multi-lab building used to test water quality for customers serviced by Manatee County. The lab is located on the western end of Bradenton, FL, about three miles from the Gulf of Mexico. The lab collects water samples throughout the county to ensure all distribution systems meet the Safe Drinking Water Act regulations. This involves utilizing various concentrations of chloramines (chlorine + ammonia) as a disinfectant.

The lab contains multiple fume hoods and general exhaust which are served by high plume lab fans mounted at the top of the building. Due to the critical tests the lab performs, the fans are designed with N+1 redundancy. With the close proximity to the salt water of the Gulf and the nature of the tests being run in the lab, the existing high plume fan suffered significant corrosion. As a result of the corrosion, the steel fans did not meet the original design airflow, which caused room pressurization issues.

A team from Manatee County Government (Owner), and Advanced System Engineering (Mechanical Engineer), worked with Tom Barrow Company to solve this problem. The owner wanted a fan that could hold up to both the environment and various lab chemical tests. The constraint was to fit the existing curb of the steel fan and avoid upgrading any electrical.

Tom Barrow Company partnered with MK Plastics to develop a solution. An inline high plume lab fan and plenum were proposed. The entire fan assembly and plenum were constructed of FRP. This included the casing, impeller, and velocity cone. The new fan was able to meet the design airflow and static requirements without increasing the motor size from the existing fan. This also allowed the fans to be connected to the existing VFDs.

The FRP inline fan was mounted on a plenum that was custom sized to the fit the existing curb. The final assembly was 30% lighter than the existing, thus no additional structural modifications were needed. A FL PE stamped, high-wind load analysis was conducted based on the latest Florida Building Code. This provided the contractor with details on how to properly secure the fan to the structure.

“We were able to provide the end user a product that will last and perform in a lab that plays a critical role for water in Manatee County,” shared Cyril John, Sales Engineer – Tom Barrow Company, Tampa.

MK Plastics was founded in 1963, and they are the global leader in the production of corrosion resistant industrial and commercial blowers. The fans manufactured are AMCA certified for both air and sound performance.



  • Design and replace an existing steel lab fan that had corroded in under 10 years due to the proximity to salt water (<3 miles) and the chemicals being exhausted through it.
  • New fan needed to be designed to fit the existing footprint and have exceptional corrosion resistance to both the environment and lab experiment chemicals.


  • Design an inline direct drive Fiberglass Reinforced Plastic (FRP) fan and plenum provided by MK Plastics, to be mounted on the existing curb/structure.
  • New fan was designed with 10’ stack height from the roof deck with a FRP velocity cone to maintain 3000 fpm nozzle velocity.
  • Final shipped product was 30% lighter than the existing steel fan and matched the existing electrical.
  • MK Plastics AXCL FRP with K-Kore Plenum was used as the basis of design and provided the end user the flexibility to test various chemicals on the lab side.