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 been roughly similar.

Or at least they used to be. As of April 21, 2006, manufacturers of reinforced plastic composites are required to meet hazardous air pollutant emissions under new maximum achievable control technology (MACT) standards published by the EPA.

Federal control of styrene

The impact MACT had on manufacturers of plastic composites was that either they would be required to install new controls or they would have to compromise product formulations by reducing styrene levels.

Styrene is used for two purposes: as an agent for spraying, and as a cross-linking agent. This gives the hardness and rigidity to items such as bathtubs. A vital component of the fiberglass reinforcement technology, styrene is released into the air during the manufacturing process.

According to the EPA, inhalation of styrene causes irritation to respiratory process, and the chemical is a central nervous system depressant. The International Agency for Research on Cancer classifies styrene as a potential human carcinogen.

However, many in the composites industry have maintained that styrene quickly breaks down in the atmosphere, and consider federal control a precautionary measure. On exposure to light and air, styrene slowly undergoes polymerization and oxidation to form peroxides. Either way, the MACT 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, and face fines and possibly plant closures.
2. Reduce the amount of styrene used in the creation of its products, resulting in a weaker product.
3. Use lower-emitting, less-effective resins. This option requires the use of more reinforcing material.
4. Invest in pollution control technologies that will capture and eliminate styrene. This option allows a manufacturer to create products using the most effective and strongest formulation of materials, resulting in the highest quality products.

Essentially, manufacturers who do not install sophisticated capture-and-control emissions equipment must reduce the level of styrene they use in their resin formula. Those manufacturers who are able to solve this problem through capital improvements are able to offer a higher-quality fiberglass reinforced bathing product.

Case study

Lasco Bathware, Anaheim, Calif., has invested more than $20 million to install MACT-compliant capital improvements and renovate its manufacturing plants. The company’s investment of more than $2 million in each of its eight U.S. manufacturing plants not only met but exceeded the new clean air standards. By effectively gathering styrene and burning it in a thermal oxidizer, the company has reduced its emissions of the chemical by approximately 250,000 tons per year. Using the captured and incinerated styrene as a fuel, the company also reduced its dependence on other energy sources.

The new control systems have allowed the company to use the optimum formulation of styrene in its fiberglass reinforcement process, resulting in the greatest possible strength, durability and overall quality of its products.

To accomplish this, the Environmental & Energy Systems division of Dürr Systems, Plymouth, Mich., installed its Disc Concentrator System. The system included a rotary concentrator with a rotary valve regenerative thermal oxidizer (RTO).

The rotary concentrator featured a proprietary material supplied by the manufacturer, which would not allow styrene to polymerize on its surface. The manufacturer was able to guarantee a five-year life of this material, which was a major selling point.

A high-efficiency filter was installed upstream to remove any particulate matter from the air stream. By utilizing the concentrator system, the net cost increase was approximately $2 per unit. Since the plastics company produced over a million units per year, this represented a significant savings to the company.

According to the plastics company’s project manager, Syd Pe, the fuel economy provided by the disc system proved to be a major factor in the 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 Dürr’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,” he added.

According to Jason Valia, the control system manufacturer’s regional sales manager, the system can operate with no 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 external fuel.

“A competitor did propose a less efficient oxidizer, a recuperative system, but there was an extremely high fuel consumption for the unit,” said Valia. “So, short-term, ours wasn’t the absolute lowest cost, but long-term ours definitely will be. Overall, the cost of ownership was much lower than the systems offered by other companies.” PE