For years, fiberglass-reinforced baths and showers have been perceived as commodity products. As with any product, there have always been quality differences between brands. Nevertheless, the manufacturing methods employed and the materials used have roughly been similar.

That has recently changed. Manufacturers of reinforced plastic composites are now required to meet the National Emission Standard for Hazardous Air Pollutant (NESHAP) and follow the guidelines under maximum achievable control technology (MACT) standards as published by the EPA.

The impact of NESHAP on manufacturers of plastic composites was that they either would be required to install new air pollution controls, or they would have to compromise formulations by reducing styrene levels.

Styrene is used for two purposes: 1) as an agent for spraying and 2) as a cross linking agent. Such processing provides hardness and rigidity to items such as bathtubs. A vital component of fiberglass reinforcement technology, the styrene is released into the air during the manufacturing process. While health and environmental concerns have not been confirmed (styrene quickly breaks down in the atmosphere) the EPA's precautionary measures now require manufacturers to capture and control 95 percent of their styrene emissions.

In order to comply with the new MACT standards, a manufacturer has several options:

1. Ignore regulations, face fines and possible plant closures.
2. Reduce the volume of styrene used in the production of its products, resulting in a weaker product.
3. Use lower-emitting, less-effective resins. This option would also require the use of more reinforcing material.
4. Invest in pollution control technologies that will capture and eliminate styrene emissions. This option allows a manufacturer to create products using the formulation of materials resulting in the highest quality products.

Those manufacturers who are able to solve styrene emission control through capital improvements are able to offer a higher-quality fiberglass-reinforced bathing product.

The above cross section provides some operational details.

The concentrator system sitting by the Lasco manufacturing facility.

Aquatic, maker of bath and shower products, Anaheim, Calif., has invested more than $20 million to make MACT-compliant capital improvements and renovate its manufacturing plants. This investment provided several distinct competitive advantages.

1. The investment of more than $2 million in each of its eight United States manufacturing plants allowed the company to exceed the new air quality requirements.
2. By effectively gathering styrene and destroying it in a thermal oxidizer, the company reduced styrene emissions by approximately 250,000 pounds per year per facility. Using the captured and incinerated styrene as a fuel, the company also reduced its dependence on other energy sources.
3. The company's response allowed it to continue using the optimum formulation of styrene in its fiberglass reinforcement process, resulting in the best possible strength, durability and overall quality of the product.
4. The company used the opportunity to install robotic technology in its manufacturing process. This further improved product quality and reliability.

For this project, the Environmental & Energy Systems division of Dürr Systems, Plymouth, Mich., installed their disc concentrator system. The system included a rotary concentrator with a rotary valve RTO. The rotary concentrator, which featured a proprietary material supplied by the company's exclusive supplier, did not allow styrene to polymerize on its surface. As a result, they were able to guarantee a five-year life for this material, which was a major selling point. A high-efficiency filter was installed upstream to remove any particulate matter that might be coming into the airstream. By utilizing the concentrator system, the net cost increase was approximately $2 per unit. Since the fiberglass manufacturer produces more than a million units per year, this represented a significant savings for the company.

According to Syd Pe, project manager at Aquatic, the fuel economy provided by the concentrator system proved to be a major factor in their final decision. "Because of the fuel economy, we were able to increase airflow in the plants without increasing fuel consumption," said Pe. "We haven't had much experience with these types of systems and felt that Durr's size and expertise afforded us the security we were looking for. We wanted a five-year guarantee on the absorbent and that came with the contract."

According to Jason Valia, regional sales manager at Dürr Systems, the air control system was designed to operate without natural gas consumption. The concentrator removes the styrene from the air stream and concentrates it over 10 times, and then feeds it into the RTO for destruction. This provides enough energy to sustain the operation of the RTO without the addition of any external fuel.

"A competitor did propose a less efficient oxidizer, a recuperative system, but there was extremely high fuel consumption for the unit. So, short term, ours wasn't the absolute lowest cost, but long term, ours definitely will be," said Valia. PE