Coatings that are applied to the exteriors of transit buses and railcars are subject to governmental regulation, especially in regard to their impact on the environment. Limiting emissions of volatile organic compounds (VOC), in particular, is a key factor as transit agencies consider the types of primers and topcoats that they’ll apply to their rolling stock.
The Department of Buses at New York City Transit (NYCT) recently switched to an environmentally friendly line of paints for bus exteriors manufactured by Deft Coatings Inc. Its experience with the products has been positive and is worth further explanation.
Key reduction in VOC
Previously, NYCT had used PPG and Dupont paint products. Before switching to Deft Coatings two years ago, the department had used Dupont’s Imron 5000 paints, according to David Chen of NYCT’s maintenance department. He said the VOC was 3.6 lbs./gallon, a relatively large concentration compared to the Deft products.
NYCT began testing and evaluation of Deft’s polyester polyurethane primer and acrylic polyurethane topcoats in 2001. In late 2002, the department began applying Deft’s paints with 1.7 lbs./gallon VOC. That’s a 53% reduction in solvent emissions. In December 2003, NYCT approved Deft paints that contain 0 VOC.
“In 2003, about 800 buses were painted with Deft’s 1.7 VOC and 10 buses with 0 VOC paints,” Chen said. “We expect to completely switch from 1.7 to 0 VOC Deft paints this year.”
The switch to the Deft product was not based on environmental impact alone, however. “We chose the Deft paints because Deft is a 60-year-old manufacturer with a full line of high quality wood finishes as well as aerospace, industrial and military-specification coatings,” Chen said.
This was not NYCT’s first experience with Deft. It has been using Deft polyurethane paints on bus interiors for about 15 years.
Although it’s too early for NYCT to draw any conclusions about the long-term, on-the-street performance of the Deft products, the agency has been impressed with results of laboratory and field tests. “They show excellent performance, durability and resistance to chemicals and weatherability,” Chen said.
Reduction in cost, too
In addition, the 1.7 VOC Deft paints also reduced the cost of paint per bus by about 60% for the 1.7 VOC and 40% for the 0 VOC compared to the 3.6 VOC Dupont Imron 5000 products. “Most importantly, using 1.7 and 0 VOC Deft paints will allow NYCT to sharply reduce its total VOC emission,” Chen said. “This in turn permits the Department of Buses to paint more buses without violating VOC emission caps set by the New York State Department of Environmental Conservation, thus increasing overall operating efficiency.”
As with all products, especially those that are new to the operation, the vendor’s customer support level plays a crucial role in the overall experience.
Chen said Deft representatives have provided timely and excellent technical support. “We feel strongly that Deft representatives are extremely knowledgeable and professional in helping us achieve our goal of implementing a cost-effective and environmentally friendly painting system,” he said.