V. NIGAM, M. CHOUDHURY, V. BUDAKOTI and S. KUMAR, KBR Technology, Gurgaon, India
What is value engineering for process plant piping? Is it the lowest cost, or is it the maximization of benefit while comparing and evaluating “what we get” versus “what we pay?”
The oil and gas industry today moves at a faster pace than ever before: chemicals become commodities in an instant and high-productivity processes are transformed and upgraded every year. To remain competitive, corporations are forced to constantly evaluate new and diverse technologies and decide where to invest limited resources. Value engineering is a method that evaluates these options and employs them in a way that provides the desired quality performance at the lowest cost. The value engineering process involves studying documentation, generating ideas and then developing them without interrupting the progress of a project.
Sometimes, a decision that appears to be value engineering for a lump sum turnkey (LSTK) contractor may not necessarily be a value engineering decision for the overall project. For example, in a large process plant project in India, the LSTK contractor’s bid specifications did not clearly define the type of steam traps to be used. As a result, the contractor opted for thermodynamic steam traps across all steam circuits, including header drip legs and steam tracer applications.
Value engineering can be defined as a technique that seeks the best functional balance between cost, reliability and performance. However, all available alternatives must be evaluated with long-term functional efficiency in mind. A short-sighted approach can lead to the selection of an alternative that may appear to be cost-effective initially but ends up costing more in the long run.
Thermodynamic traps are less expensive compared to proper thermostatic or bimetallic alternatives, which initially reduced the cost of the traps. However, this decision was not a true value engineering solution. Over time, the use of thermodynamic traps led to significant steam losses in the operating plant, increasing operating costs. Within a few years, the client was forced to replace the thermodynamic traps in the tracer lines with proper thermostatic alternatives to improve efficiency.
VALUE ENGINEERING
Value engineering succeeds by identifying opportunities to eliminate unnecessary costs while maintaining or improving the functionality of the system.
Value engineering for piping begins from the conceptual stage when the process plant package is in the preliminary development stage. Key points include:
The site plan is an important aspect of value engineering. The greater the number of facilities within a complex, the greater the scope for value engineering.
Optimize pipe sizes inside process facilities by ensuring routing that provides the maximum benefit for process hydraulics.
Develop routing concepts that save on exotic and costly material.
Suggest layout concepts that decrease structure height and other structural requirements.
A detailed assessment that considers all aspects among modularization, partial modularization and stick built provides the optimum benefits.
Questioning process philosophies can provide value/benefits.
Material-related value engineering is a significant concern and must be considered.
Pipe stress also contains value engineering, although to a lesser degree (e.g., minimizing piping flexibility and decreasing elbows by studying the layout).
Details of value engineering in piping systems: Site plan. Site plan value engineering is a significant and interesting subject. The potential for value engineering increases with the site plan complexity (logistics of movement and construction, piping connectivity, shortening of piping racks/sleeper paths, shortening of offsite exotic material usage, etc.). Examples include:
In a refinery tank farm, efficiently arranging inputs (e.g., crude), intermediates [e.g., vacuum residue (VR), vacuum gasoil (VGO)], blending areas and product evacuation can lead to substantial value engineering.
A routing study during the site plan development stage plays an important role for value engineering. This was accomplished for the critical lines for an ammonia front-end engineering design (FEED) (revamp) project. Because the layout was proposed after rigorous discussions and a thorough routing study, only 5% of the routing of critical lines was changed during the detailed engineering phase.
An increase in equipment sizes during FEED may pose a challenge for the plot size considered during a project’s basic engineering design (BED) stage. Value engineering for the existing options becomes crucial in such cases. As an example: A conceptual plot plan was prepared with preliminary pump sizes based on past experience for a BED project for the authors’ company’s technologya. The available plot area seemed suitable for equipment placement. However, when the preliminary pump information was received from the vendor during FEED, the pump sizes had increased significantly, which became a challenge when preparing the revised plot plan. A few exchangers were stacked and additional tech structure was added to the plot plan to accommodate the larger size pumps within the available plot area.
Optimizing pipe sizing. The optimization of pipe sizing within process facilities can be aided by ensuring routing that provides the maximum benefit from process hydraulics. Examples include:
For a unit with one inside battery limit (ISBL), process lines and utilities enter from one side only. As an example, consider a petrochemical complex with some 200 pieces of equipment and one battery limit with equipment on both sides of the ISBL pipe rack. After conducting a hydraulic study based on the exit/entry battery limits, it was calculated that a 24-in. cooling water pipe was needed for supply and return. In such a scenario, the location of the main cooling water consumer can be studied. The piping of the underground offsite cooling water network system of the complex can be evaluated, and it can be suggested that the depth of the underground piping decreases near the structure where the specific equipment is located and then goes to the pipe rack. This can substantially decrease the pipe size on the pipe rack. This value engineering comprises both the pipe rack loading and the minimization of the quantity of large diameter piping.
When expanding the capacity for a large refinery unit like a fluid catalytic cracking unit (FCCU), the process team will most likely increase the pipe sizes of many of the piping systems (e.g., the heavy cycle oil circuit header changes from 30 in. to 36 in.), the column overhead line will get changed and the cooling water header size may get changed, in addition to many similar changes. A substantial amount of time will be required by construction teams during a plant shutdown. As an example, let us consider a column overhead line with several safety valve connections that is being changed from 30 in. to 36. In the new process, the total flow quantity increases because the plant capacity has increased. The demolition and replacement during shutdown will impact material costs and extend the shutdown/construction period. In such a scenario, a major shutdown and material cost-saving approach can be the introduction of the header paralleling concept (FIG. 1), with the final tie-ins completed during shutdown. Rather than replacing a 30-in. heavy cycle oil line with a new 36-in. line, a 24-in. line can be laid after a hydraulic study and can be connected to the existing 30-in. line through tie-ins during shutdown to achieve the additional capacity required for expansion. Although this will require piping layout and structural addition/modification skill, such a piping header paralleling concept will provide savings in terms of costly materials and downtime.
A client of the authors’ company required an increase in the capacity of an existing ammonia plant with minimum changes. The company suggested its reforming exchanger systemb. An additional converter and its associated proprietary piping were added to enhance plant capacity without making any major changes to the existing equipment and piping.
Developing routing concepts that save on costly exotic materials. An engineering group was assigned a large vacuum transfer line as part of its detailed engineering work for a large capacity expansion of a crude unit. The 100-in. header was made from exotic material (like P5 alloy), and the furnace connection branches were in segments measuring from 14 in.–26 in. in diameter. The design temperature for this large line was 443°C (829°F). As far as the authors are aware, this was the largest vacuum transfer line of a crude unit being engineered in India. At that time, an Indian engineering company had engineered a 74-in. vacuum transfer line with flexible routing with bends.
The engineering team routed the 100-in. system straight to the header without a single bend and utilized the flexibility of the smaller branches to the furnaces—this qualified the system for all types of stress analyses. The piping was qualified through CAESAR, and the welded nozzle to the 100-inch vacuum column was qualified through ANSYS. The layout was so straight it could have been a 100-in. cooling water system with branches. In a similar case, an ammonia synthesis loop was experiencing an equipment nozzle loading problem that required investigation.1 Along with CAESAR, the NAVIS works model was also used. Over and above the main task of bringing the nozzle loading into an allowable range, the exercise resulted in saving three high-thickness 24-in. size elbows with minor acceptable layout changes.
Suggested layout concepts that reduce structural requirements and height. Consider the case studies and methodologies below.
An air cooler piping layout required a significant time investment to engineer a specific cascade configuration for vapor cooling. Because the piping and instrumentation diagram (P&ID) showed the cascade in a vertical plane, piping engineers often focused their arrangement on the vertical plane; however, a combination of vertical and horizontal cascade piping can often decrease the structural height and cost.
The maximization of an offsite area sleeper and a lower height of the offsite rack are desirable—except in bridge cases—assuming there is no flare on the rack. With a flare on an offsite pipe rack, a thorough study should be conducted, starting from the offsite flare knockout drum. This normally results in some height advantage.
Different techniques are used by all engineers familiar with piping layout. Improvements in column skirt height, internals, vapor space, manhole disposition (during a project’s early design stage) can give some time advantage.
A detailed assessment of modularization, partial modularization and stick-built /dressed construction. To achieve optimum benefits, all aspects must be considered, including those listed below.
Organizations are moving towards maximizing modularization during the quote finalization phase for LSTK projects. However, for certain plants (e.g., a gas processing unit), a detailed evaluation beginning with the equipment layout provided in the invitation to bid (ITB) can indicate that full modularization is effective only in select areas. In most cases, a more traditional "dressed" concept may yield better returns. Factors such as engineering, procurement and construction (EPC), site manpower availability and rates, and the overall project schedule should be considered before finalizing the approach.
A modularization exercise was conducted for a chemical plant. It was concluded that, rather than full modularization, maximizing the use of prefabricated portions that align with trucking dimensions (30 m length x 5 m width x 5 m eight) would be the most cost-effective solution, allowing for efficient final assembly at the project site. A key challenge for the engineering team was accurately marking this approach in the model and producing detailed documentation outlining each step through to full construction completion.
Questioning process philosophy yields value and benefits. Cases studies and methodologies are detailed below.
An air cooler system can function as both a liquid cooler and vapor condenser. However, process engineers often tend to design these systems in a cascade arrangement by default. In some cases, after detailed calculations, a comb or symmetrical rake arrangement may be more efficient. This approach can save on piping and reduce the structure's height. It is worthwhile to raise this query with the process engineers, especially during revamp projects.
Process engineers often provide a conservative design temperature in line lists by adding a generous allowance over the operating temperature. While this may not pose an issue in most cases, it becomes critical when dealing with piping in the creep range. For such systems, excessive design temperature allowances can lead to the selection of more exotic materials, affecting allowable stress values and impacting thermal stress analysis and nozzle loading. In these situations, questioning the design temperature is essential to avoid unnecessary costs and complexities.1
For general liquid systems, process engineers typically limit flow velocities to 3 m/sec. However, this is worth questioning in specific cases. For example, during a revamp project, the process team may propose increasing the bottom liquid nozzle size on a fractionator/column due to increased flowrates from the plant's expanded capacity. This change would complicate the shutdown process. After questioning the necessity of the nozzle size increase, it may be found that although the flow velocity may exceed the design velocity of 3 m/sec, it really poses no harm. As a result, the original nozzle size may be retained, significantly reducing the shutdown effort.
A basic understanding of hydraulics, the 80% erosion velocity rule as per API RP 14E, and two-phase flow can be invaluable. This allows for more informed discussions among process engineers, particularly when optimizing system designs, and avoids unnecessary changes.
In a lithium sulfide project, the client initially opted for a stick-built layout. After reviewing the conceptual plot plan, the client shared concerns about the risk of choking in solid transfer lines based on past experiences. In response, the team questioned the process engineers about incorporating gravity flow into the process flow diagram (PFD)/P&ID. After reviewing the suggestion, the process team revised the design to include gravity flow, which not only solved the potential choking issue but also reduced the overall plot size of the plant.
Material-related value engineering: A major area for optimization. Material-related value engineering plays a critical role in optimizing costs and performance, particularly from a piping perspective. Several key areas where value engineering can be applied effectively are discussed below.
Cooling water and other water systems—In cooling water systems, high-density polyethylene (HDPE) or fiberglass-reinforced plastic (FRP) can be used instead of traditional carbon steel, particularly for underground piping. HDPE and FRP offer advantages such as corrosion resistance, better hydraulics and reduced maintenance costs over time, while carbon steel may be more cost-effective in certain above-ground applications.
Cold box materials: Aluminum vs. stainless steel—For cold box applications, aluminum is often the preferred material due to its lighter weight and lower cost, except in cases where mercury contamination is a concern. In these cases, stainless steel becomes mandatory. For example, in a liquefied natural gas (LNG) plant, switching from stainless steel to aluminum in non-mercury-exposed sections may significantly reduce the project’s overall material costs without compromising performance.
Pipe class optimization for large complexes—In large and complex facilities, creating efficient pipe class systems is essential. Value engineering focuses on selecting the most cost-effective materials for each fluid service, while also aiming for inventory standardization to reduce storage and procurement complexity. For instance, in a petrochemical complex, harmonizing pipe classes across multiple units saves on bulk material orders and simplifies maintenance, resulting in long-term cost savings.
Cladding vs. solid alloy piping—In applications where full corrosion resistance is only required on the interior surface, clad piping (where a corrosion-resistant alloy layer is bonded to a carbon-steel substrate) can offer significant cost savings over solid alloy piping. In a chemical plant, the use of stainless-steel cladding on carbon-steel pipe material reduced costs by 30% compared to solid stainless-steel pipes, while still providing the necessary corrosion protection.
Use of duplex and super-duplex stainless steel—In environments where both strength and corrosion resistance are required, duplex and super duplex stainless steels are increasingly being used rather than traditional austenitic stainless steels. These materials offer higher strength and better corrosion resistance, allowing for thinner walls and smaller pipe sizes. In an offshore oil project, using duplex stainless steel in place of 316L stainless-steel reduced pipe wall thickness and overall material weight by 20%, leading to both material and installation cost savings.
Innovative coatings to extend material life—Applying advanced coatings (e.g., epoxy, ceramic coatings) to carbon steel or other base materials can enhance corrosion resistance and extend material life, avoiding the need for exotic materials. In a water treatment plant, the use of ceramic coatings on carbon-steel pipes extended their life by 10 yr without the need to switch to more expensive materials.
Pipe stress as a minor focus of value engineering. While pipe stress is not typically a major focus of value engineering, there are opportunities for optimization that can provide some tangible benefits. Small but meaningful actions like minimizing piping flexibility, reducing the number of elbows and optimizing layouts can contribute to cost and performance benefits.
Avoiding overly conservative specifications. It is important to ensure that the stress design basis or piping specifications are not excessively conservative. For example:
Some specifications require wind load analysis for very low heights (e.g., 1 m–2 m above ground), which may not be necessary.
In certain cases, it may not be essential to qualify all rotating equipment nozzle loads in the design case. Instead, qualifying them in the operating case could be sufficient.
For flange leakage, is it necessary to apply the pressure-equivalent method with additional safety factors, or will a standard method suffice?
In static seismic design, are the importance factor and response reduction factor being applied conservatively, or are they appropriate for the specific application?
A well-thought-out document that eliminates unnecessary conservatism while maintaining system reliability can lead to cost savings without sacrificing safety or performance.
Reducing unnecessary piping flexibility. Overly flexible layouts can lead to inefficiencies. For instance, while analyzing an ammonia synthesis loop, a stress specialist identified that three large, thick-walled elbows could be eliminated. These elbows were included in the model due to an overly conservative approach to piping flexibility, which did not fully account for the actual nozzle loading conditions. By optimizing the layout, the design became more efficient, and the costs associated with large elbows were avoided (FIG. 2).
Innovative stress solutions. In the case of a major revamp of a large petrochemical offsite facility, there was a requirement for a 24-in. high-pressure, high-temperature (HHP) steam system using P91 material. The run length of the piping was moderately long, and the stress and layout team opted for a 2D expansion loop rather than the more traditional 3D design. This approach required some modifications to the pipe rack but resulted in a simpler layout with fewer elbows and less welding.
Initially, the client engineers were skeptical, as they had never seen a 2D loop used for such a large-diameter HHP system. However, after detailed analysis and justification—including a breakdown of cost savings due to reduced elbow usage, welding and material—the client accepted the design. This change saved approximately $240,000, and the system was successfully engineered, constructed and commissioned without issue.
Takeaways. Various techniques for implementing value engineering in process plant piping have been discussed. The key to executing successful and sustained value engineering lies in strong leadership commitment. While it is possible for an engineering management team to introduce formalized value engineering sessions for a specific project, the real driver of success is cultivating a value engineering mindset across the organization.
To achieve this, leadership must foster a culture where value engineering is an integral part of the decision-making process rather than a “checkbox exercise.” Documented procedures and well-defined approaches, while useful, are not enough on their own. Without a genuine value engineering culture and proactive leadership, the process can devolve into generating superficial or irrelevant suggestions merely to meet a quota of ideas.
Leaders should emphasize quality over quantity, encouraging teams to critically assess designs and propose innovative, cost-effective solutions. This cultural shift, supported by clear documentation and structured approaches, ensures that value engineering becomes a meaningful, ongoing practice that delivers real benefits to the project and the organization. HP
NOTES
KBR’s ROSE technology
KBR’s KRES technology
LITERATURE CITED
Choudhury, M., “Large size transfer lines: Issues which are not always considered in design,” Hydrocarbon Asia, March/April 2006.
Vijita Nigam works as a Piping Engineer at KBR, Gurugram. She has 18 yr of experience in the piping design engineering domain for process plants, petrochemical facilities, refineries, hydrogen plants, chemical plants, etc. Prior to joining KBR, Nigam was associated with Air Liquide (New Delhi) and Reliance Industries Ltd. (Jamnagar Refinery Complex).
Mrinmoy Ghosh Choudhury is an engineering professional with extensive experience in process plant engineering from concept to commissioning, with special emphasis on piping and plant engineering in concept layout, stress and support, or materials. He has been involved in numerous problem-solving projects related to plant startups (vibration, rotary equipment alignment, piping/equipment system failures, etc.) Choudhury has contributed numerous articles and papers to reputed engineering journals like Hydrocarbon Processing, etc. In his professional life, he has been involved with Reliance Engineering, Toyo Engineering India, Chemtex Engineering India, Engineers India Ltd., DCPL and KBR Technology India.
Vikas Budakoti is a piping engineering professional with 19 yr of experience in the piping design engineering domain for process plants, petrochemical facilities, refineries, hydrogen plants, chemical plants, etc. He has worked for KBR Technology India, Gurgaon since June 2017. Budakoti previously held roles at Reliance Industries Ltd., Samsung Engineering India (Noida) and Petrofac Engineering India (Gurugram).
Sushil Kumar is an engineering professional with 27 yr of experience in piping layout and the design engineering domain for process plants, petrochemical facilities, refineries, hydrogen plants, floating production, storage and offloading (FPSO) platforms, etc. He has worked at KBR Technology India, Gurgaon since July 2018. Kumar previously worked for EIL (New Delhi), Triune Project (New Delhi), Lurgi India (New Delhi) and Samsung Engineering India (Noida).