For more than 30 years, TRAX has provided first principles-based furnace draft studies to the power industry. Utilities and design engineers consistently choose TRAX analyses to validate their own designs and performance predictions. With TRAX’s capabilities and expertise, analysts can evaluate alternative strategies to mitigate transient events, such as trips, load rejections, runbacks, and failures of critical components.

What is a furnace draft analysis?

To perform an analysis, TRAX engineers use the ProTRAX simulation software system to develop high-performance, high-fidelity models to solve even the most complex plant problems. ProTRAX is comprised of an extensive library of over 200 components, or modules. These modules are configured to exactly match a site component, and the individual modules are tailored to match the specific plant, resulting in a high-fidelity model that truly represents plant operation. The method is described in more detail here:  "How is an Analysis Conducted?".

These system models are powerful analytic tools that allow a variety of potential solutions to be tested and refined. With our software, TRAX can provide studies developed with dynamic models to verify NFPA85 compliance, optimize plant operation, and predict plant dynamics for a plant or facility. We can test control logic across the load range, tuning the controls as necessary to avoid nuisance trips while providing protection against catastrophic failures. Conducting a dynamic analysis during an equipment or controls upgrade is an important part of ensuring the safety and reliability of the plant with new configurations.


A furnace draft analysis begins with building a dynamic model of the existing plant, replicating both the plant process and control system. After verifying the model performance closely matches the plant function, TRAX can test new fan configurations, piping designs, duct changes, or any other proposed scenarios you may want to examine.

Step-by-Step Process

When is a draft analysis Helpful?

When is a draft analysis helpful?

  • Coal to gas conversion
  • Carbon capture additions
  • Draft fan economic optimization
  • Addition or removal of pollution control equipment
  • Control system design and modification
  • Design verification
  • Equipment specification
  • NFPA 85 compliance

Coal To Gas Conversion

Conversion of fuel to natural gas brings several challenges to operating the furnace air-gas system.

Find out more

As part of every analysis, TRAX assesses plant controls for compliance with NFPA-85 industry code for the prevention of fire, explosion, and implosion. In addition, we explore controls strategies to optimize plant operation and mitigation strategies for explosion and implosion protection. These strategies are tested on the plant model and tuned for optimal performance while avoiding nuisance trips. Conducting a furnace draft study during an equipment or controls upgrade is an important part of ensuring the safety and reliability of the plant with new configurations. It can help a plant achieve NFPA 85 compliance while avoiding nuisance trips and implosion of equipment that will improve plant safety, reliability and efficiency.



Prevent furnace implosion

Prevent ductwork and equipment pressures from exceeding design limits during abnormal operation

Reduce or eliminate positive furnace pressure excursions for operator safety


Potential insurance savings

Reduce cost by using tested controls mitigations compared to boiler strengthening ($500K vs $10M savings potential)


Ensure compliance with current NFPA 85 code

Tune to prevent nuisance trips

Retune controls for more effective responses


Ensure that new equipment is properly sized

Increase operation efficiency

Investigate actuator stroke times