Case Study: First to market — engineering, testing and certifying a B100 shutoff valve

Regional and state-level initiatives in the northeastern United States are accelerating the adoption of biodiesel in heating systems to reduce greenhouse gas emissions. To support safe and compliant burner designs, Underwriters Laboratories (UL) updated its UL296 standard to include biodiesel blends from 20% (B20) to 100% (B100). In markets such as New York City and Massachusetts, where UL listings are required, burner manufacturers quickly faced a gap: no UL-certified, high-pressure safety shutoff valve was available for B100.

To address this challenge, Preferred Utilities Manufacturing Corporation partnered with Emerson to bring a compliant solution to market.

Modern shutoff valves are critical components in burner fuel trains, regulating fuel flow between the supply and the burner and ensuring safe, reliable operation. Their ability to move quickly between fully open and fully closed positions is essential for minimizing combustion risk, particularly as fuel characteristics change.

A longtime developer of commercial and industrial combustion systems, Preferred Utilities turned to Emerson to adapt its existing API burner to meet the new B100 requirements. While Preferred Utilities’ products had previously supported up to B20, the shift to higher biodiesel blends created an urgent need for a new certified solution.

Collaborating for speed

Preferred Utilities and Emerson have worked together for many years on burner system innovation and validation, including extensive in-house testing at Preferred Utilities’ Danbury, Connecticut, facility. During a collaborative test program for a new Emerson pressure regulator, Preferred Utilities asked Emerson’s engineering team to help develop a safety shutoff valve capable of reliable operation with B100 fuel — an option that did not yet exist in the market.

Emerson had already launched its first biodiesel-rated safety shutoff valves in 2023 and had a B100-certified version of its ASCO Series 148/149 valves in development. Recognizing the urgency of the market need, Emerson reprioritized the project and accelerated development and UL certification.

The ASCO Series 148/149 is a compact, high-flow, high-pressure safety shutoff valve designed for industrial burner applications that require fast, reliable fuel isolation. A motorized actuator shuts off fuel in less than one second, while built-in redundancy helps prevent overpressure, leakage and system faults that could lead to safety incidents. In addition to improving safety, modern shutoff valves also help stabilize pressure, reduce emissions and improve burner efficiency.

Because the valve was originally designed for a wide range of fuel oils, it already featured a rugged construction, motorized actuator and a temperature rating from -40°F to 150°F. Emerson engineers adapted the internal materials and elastomers to ensure compatibility with B100’s more corrosive chemical properties.

Testing and certifying in parallel

To validate the design, Emerson analyzed all wetted materials and worked closely with elastomer suppliers to source UL-approved O-rings suitable for B100. Production-intent samples were delivered to Preferred Utilities, which installed them on its in-house test burner.

For nine months, the updated burner supplied hot water and heat to the Danbury facility without issue, proving long-term performance and reliability. At the same time, Emerson submitted the valve design to UL, completed the required testing and supported on-site witness inspections at Preferred Utilities.

By running development, testing and certification in parallel, the companies reduced the overall timeline dramatically. In less than a year, the ASCO Series 148/149 valves were fully certified and ready for commercial release.

Gaining benefits beyond compliance

In addition to B100 compatibility, the new ASCO Series 148/149 valve offers higher flow rates, improved pressure handling and more stable burner operation. Fewer start-stop cycles reduce wear and improve efficiency. Its modular design allows flexible in-field configuration for different port sizes and two- or three-way operation.

The Preferred Utilities burner system also incorporates ASCO 8266 two-way and three-way oil shutoff valves, which Emerson recently upgraded for B100 compatibility.

Outpacing the competition

This project marked the second time Preferred Utilities and Emerson brought B100-compatible products to market ahead of competitors. Earlier collaborations included B100 versions of the ASCO 8266 and ASCO 8262 valves.

By aligning engineering priorities with customer needs and regulatory trends, Emerson delivered compliant, environmentally focused solutions at speed — helping customers meet evolving energy and safety requirements without delay.

Customer perspective

“Moving toward a lower-carbon future takes collaboration between industry leaders to develop practical, real-world solutions for alternative fuels,” said Gustavo Sanclemente, engineering manager at Preferred Utilities Manufacturing. “In cities like New York, where regulations demand decarbonization as well as strict adherence to safety standards and certification requirements, Preferred Utilities Manufacturing is pleased to offer UL-listed solutions to meet those challenges. Our partnership with Emerson, a company that matches our commitment to advancing the biodiesel and renewable diesel industries, has been essential. We look forward to continuing our progress together.”

Fueling the future of combustion

The collaboration between Emerson and Preferred Utilities demonstrates how engineering agility and trusted partnerships can accelerate innovation in clean combustion. Faced with a critical need for a UL-certified B100 shutoff valve, Emerson delivered a production-ready solution that met both performance and compliance requirements.

As demand grows for lower-carbon fuels, modular valve platforms, rapid certification and close customer collaboration will remain key to meeting the next generation of safety and sustainability standards.