For more than 15 years, Zalak Purohit has carved out a technical leadership path in the energy sector—from aerospace tooling to rotating equipment on liquefied natural gas (LNG) megaprojects to her current work designing and managing ultrasonic gas-flow measurement systems at Endress+Hauser. A licensed professional engineer based in Houston, Purohit leads complex engineering design projects across the US and Canada, delivering systems that meet exacting standards for accuracy, environmental compliance, and system health monitoring.
In this interview, she explains why ultrasonic technology is rising as a dominant solution for gas-flow applications and how engineering teams can approach measurement as a tool not just for accountability but also for operational excellence.
EW: Zalak, how did your career pivot from rotating equipment engineering on LNG projects to ultrasonic gas measurement systems? When you were pursuing your bachelor’s and master’s degrees in mechanical engineering, did you envision a career in the oil and gas industry? What drew you to specialize in flow measurement, and how have your earlier engineering roles shaped your approach today?
ZP: While pursuing my engineering degree, I was into the research of materials and manufacturing. My alma mater, Texas A&M University, is very close to the energy hub in Houston, which offers many career opportunities for young mechanical engineers. I started my career working on custom design projects in the machine tool industry and moved on to working for a multinational engineering, procurement, and construction (EPC) company, handling engineering responsibilities on LNG projects.
While working on packaged equipment solutions for the oil and gas industry, I earned my professional engineering license in Texas, specializing in fluids and thermals. This drew my interest further into flow measurements and process automation technologies to pursue my next professional role in this field.
EW: In fact, in 2015, your master’s research thesis “On Surface Damage of Polymer Coated Sheet Metals During Forming” was a published technical paper in the Journal of Manufacturing Processes. How do you leverage this knowledge expertise in your current role?
ZP: My published paper evolved from my master’s work as a research assistant in materials and manufacturing, studying the influence of material and manufacturing parameters on the surface damage of precoated sheet metals when they undergo the forming process. Lab experiments and computer simulations using finite element analysis were run to get better insight into the performance of polymer coating on sheet metal.
Now, I continue contributing to the manufacturing community by performing peer reviews for articles to be published in manufacturing and technology journals. This is a win/win, because, as I leverage my professional expertise and volunteer my time to the peer-review process, it enables me to keep abreast of the latest technology in manufacturing and also helps me in my current role when selecting materials and different manufacturing processes.
EW: You have led complex EPC projects from design through fabrication and testing. What are the most overlooked engineering challenges when integrating ultrasonic flow systems into large-scale infrastructure, especially when retrofitting older assets? Are these challenges different for land vs. offshore platform projects?
ZP: My experience working in the EPC industry has given me a solid understanding of customer expectations regarding the design and testing of engineering packages. One of the key aspects, especially when retrofitting into an existing processing unit, is the space constraint. Since ultrasonic flow measurement technologies require a minimum upstream and downstream straight runs, it is not always possible to use standard designed packages for retrofit applications. A careful design solution review is required to assess feasibility before package upgrade can begin. When dealing with offshore packages, the weight of the package is also a constraint which has to be considered in the project design.
EW: Based on your experience, you believe that ultrasonic technology is gaining traction as a future-proof solution for gas-flow measurement. What misconceptions do you still encounter about this technology in the field, and how do you address them when working with your project clients?
ZP: Yes, ultrasonic meters are better than traditional meters, not only in terms of accuracy of the measurements but also in providing real-time data that can be easily integrated into customers’ distributed control systems. One misconception of these meters is that they are expensive. While the upfront cost of these meters can be marginally higher, the long-term savings through reduced maintenance and improved data accuracy leads to lower operational costs and increased utility over time.
EW: In an article you wrote about gas-flow measurement systems, you outlined cases where ultrasonic meters outperformed traditional technologies. Tell us about your decision-making process. What factors lead you to choose ultrasonic solutions over traditional flow meters, such as differential pressure, turbine, Coriolis, or thermal mass flow meters, especially in cost-sensitive scenarios?
ZP: In brief, I worked in a scenario where differential pressure meters were unable to meet the customer’s accuracy requirements for flow measurement and were causing a high pressure drop in the pipeline, which was reducing the gas output of the system. This was causing revenue loss to the customer. Since ultrasonic meters have no moving parts and virtually no pressure drop, we conducted an assessment to check the feasibility of introducing ultrasonic meters in to the existing setup. We were able to provide a solution by tapping into existing connections and replacing the differential meter with ultrasonic meters. The new meters rectified the flow measurement readings and addressed the issue to the client’s satisfaction.
EW: Ultrasonic meters are often considered a premium investment. From your experience, what key data or performance metrics help convince customers that the long-term return on investment (ROI) justifies the upfront cost? When doing feasibility studies for operators and designing projects, what is the value proposition for using ultrasonic technology?
ZP: Ultrasonic meters use ultrasound technology to measure flow by analyzing the transit time of ultrasonic waves between transmitters and receivers. These meters have no moving parts, which reduces their maintenance requirements. In addition, they have virtually no pressure drop and provide smart connectivity to control systems, making them a long-term, cost-effective solution for many application areas. These meters are highly accurate and are versatile in nature, able to handle various gas compositions at different flow rates. I believe that these benefits justify the ROI of ultrasonic meters against their upfront cost.
EW: Flare gas measurement is heavily regulated by the EPA. Is this driving ultrasonic adoption? How has ultrasonic technology helped solve compliance challenges on the ground, and how do you see environmental compliance influencing metering technology choices over the next 5 to 10 years, especially in North America?
ZP: With increased focus on regulatory compliance for the flaring of greenhouse gases into the atmosphere, requirements for intelligent measurement solutions have become indispensable. Due to the technological superiority of ultrasound technology, it can handle fluctuating gas composition and high velocities in the stream. This caters to the basic nature of flare stack, where volume flow and gas composition can vary significantly over short periods of time.
As the US energy sector shifts towards producing cleaner energy, with tighter restrictions around extraction, refining, and packaging, metering technologies will evolve around these norms and ultrasonic measurement systems will be a reliable option for these requirements.
EW: You recently helped achieve Canadian registration number (CRN) certification for Canadian markets. What technical or regulatory differences have you observed between US and Canadian markets, and what engineering insights did you gain from that experience?
ZP: While the Canadian regulation recognizes American [American Society of Mechanical Engineers (ASME)] codes and standards for the design and testing of pressure containing components, under the Technical Standards and Safety Act (Ontario) and similar regulations elsewhere, equipment designs must undergo an engineering review and, once approved, receive a CRN before installation and operation.
The specific piping design that we worked on also required us to submit engineering calculations based on ASME B.31.3, ANSI B.16.5 and other standards that deal with piping design and construction for review with the regulatory body. In addition to these calculations, they also verify quality standards like ISO 9001, followed by design and fabricator firms.
Overall, Canadian firms have more regulatory focus, and achieving the CRN certification for our project helped me gain valuable experience that has shaped my conversations with our Canadian prospects.
EW: Given your background with both rotating equipment and instrumentation, how do you approach the intersection of mechanical design and digital data flow in measurement systems, and how is that skill set evolving with Industry 4.0?
ZP: As global energy demand increases, the need for intelligent systems for driving efficient operations is crucial. Digitalization and automation are the game-changers to meet these challenges.
It is essential to collect, understand, and use the massive amount of data created in the Industrial Internet of Things (IIoT). Integrating measurement systems into heavy rotating equipment skids can transmit real-time output data to the equipment control systems. This data dialog between the equipment and controllers leads to efficient operations where wastage is minimized by preempting the raw material and energy consumption across the production setup. This ecosystem of connected measurement units in the plant is catering to the needs of Industry 4.0.
EW: Your work requires cross-functional collaboration with customers, fabricators, and vendors. How do you align these stakeholders, especially during flare system projects where accuracy and timing are critical?
ZP: Timely collaboration and documentation of design requirements is key to meeting project delivery milestones. As someone who leads the engineering design team, I try to ensure that we receive a clear scope of supply from our sales team. Once that is received, we perform a detailed review of the scope to ensure that a design solution can be provided to meet the project requirements. My team starts creating the design using CAD systems as per the project specifications.
A peer review of these designs ensures that they meet the stringent technical requirements of the customer. Once we have customer sign off for the design, a bill of material is created in the engineering database to source the components and services from vendors and fabricators.
The engineering team coordinates production activities with the shop floor to ensure systems are assembled and tested in a timely manner before delivering the system to the customer. While ERP [enterprise resource planning] systems coordinate the internal departmental handoffs, we have scheduled meetings to keep the external stakeholders aligned on project delivery timelines.
EW: Is building an engineering career in energy—two industries that are traditionally male-dominated—more challenging for women? Did your ASME or ASGMT training shape your confidence in complex technical decisions and managing large EPC projects?
ZP: Yes, unfortunately, you do see very few women in the energy engineering industry; this is something that is changing but will take time. The American Society of Gas Measurement and Technology (ASGMT) is a leader in providing training and networking opportunities to professionals in gas measurement systems. My participation in ASGMT and talking to industry leaders has helped me gain tremendous knowledge and confidence in my field. Following the discussion forums of ASME codes and standards has also contributed towards building my knowledge and keeping abreast of evolving requirements in this dynamic field.
EW: As someone who transitioned from aerospace tooling to oil and gas systems engineering, and a professional engineer involved in mentoring female engineers, what advice would you offer young engineers—especially women—who are exploring unconventional paths within energy technology?
ZP: My assignments across various industry sectors have contributed towards my growth as a mechanical engineer. Indra Nooyi, the CEO of PepsiCo, once said, “If you really want to stand out and contribute in massive ways, you’d better be really, really prepared.”
My advice to young female engineers entering the industry would be to focus on achieving technical excellence and skills.
Building on communication skills is extremely important to confidently share your thoughts and ideas in a professional situation. Lastly, I believe in mentorship programs and social networking; it helps you build a sense of community and confidence.
