What is the value of process piping design?

Process piping insights

• The value of process piping design lies in the ability to identify specific project drivers, meet the specific needs of the industrial process while ensuring safety, compliance and reliability.
• Thorough planning and attention to detail during the design phase contribute to the success of the project and longevity of the piping system while meeting all needs of operation, construction, maintenance, accessibility and safety.

Process piping design is a critical aspect of engineering in various industries, including chemical processing, oil and gas, power generation, food and beverage and others. Designing an effective process piping system involves careful consideration of several factors to ensure safety, efficiency and compliance with industry standards.

Proper piping design is fundamental to ensuring the safe transport of fluids within a facility. Despite the critical nature of piping design to health, safety, well-being, the environment, profitability, better operations and minimization of maintenance, piping system design is often discounted, sometimes even overlooked altogether.

The investment in design can yield returns as early as installation — reduction in material volume and in fabrication costs — and lifetimes later by way of decreased inspection and maintenance cost, both of piping and connected equipment.

Piping designers need to understand the specific requirements of the industrial process, including the type of fluids (liquids or gases), flow rates, pressures, temperatures and any special handling or treatment requirements. This information forms the basis for designing the piping system. They choose materials for pipes and fittings based on compatibility with the transported fluids, corrosion, environmental conditions, durability and cost.

A streamlined system design can minimize operational costs and contribute to the effectiveness of the entire production cycle. A well-designed piping system allows for flexibility in accommodating future changes, expansions or modifications, thus leading to lower costs down the road. This adaptability reduces the need for extensive overhauls and facilitates cost-effective adjustments to meet evolving operational needs.

Proper piping design also minimizes the risk of equipment failures and unplanned downtime. By ensuring the integrity of the piping system, industrial facilities can operate reliably, meeting production schedules and avoiding costly disruptions. This reliability is critical in industries where continuous operation is essential to profitability.

One example of this is pump reliability and the relationship with pump nozzle stresses. A piping design that has flexibility built in, rather than the shortest route from A to B will reduce nozzle stresses resulting in increased impeller life, fewer pump seal failures, decreased vibration and overall, longer pump life leading to monetary savings that are typically not quantified in this way.

Thoughtful piping design considers the total cost of the system, including initial installation costs, maintenance costs, inspections and energy consumption. By optimizing the piping design for cost-effectiveness, industries can achieve long-term savings and enhance their competitive edge versus looking to save on engineering by “just hooking up the lines.”

Process piping design and engineering

The piping engineer should work with process engineers to properly size pipes to ensure optimal fluid flow by providing preliminary sketches on routing options. Consider factors like velocity, pressure drop and friction losses. Plan the routing of pipes to minimize bends, elbows and obstacles that could impede flow and create pressure drops.

Efficient pipe routing can also facilitate maintenance and accessibility. Account for the pressure and temperature conditions that the pipes will experience. Select materials and design features capable of withstanding these conditions. Ensure that pressure relief devices and thermal expansion considerations are integrated into the design.

Further, access to devices, valves, control valves, expansions joints, can lower future expenses for operations, maintenance, inspection and replacement.

Figure 1: Proper piping design focuses on the equipment layout and all connections for optimal access for operation and maintenance. Courtesy: Matrix Technologies Inc.

Adhere to industry standards and codes to ensure the design meets safety, quality and regulatory requirements. Compliance with these standards is essential for obtaining necessary approvals and certifications. Conduct a thorough safety analysis to identify potential hazards associated with the transported fluids. Implement safety measures, such as relief systems and isolation valves, to mitigate risks. Consider the consequences of leaks or spills and design with safety in mind.

The piping engineer should work with the structural team to design appropriate supports and restraints to prevent excessive movement or vibration of pipes. Proper support is essential for preventing stress on the piping system and ensuring its long-term integrity.

Design the system to facilitate ease of maintenance and inspection. Consider accessibility for maintenance personnel and incorporate features such as isolation valves and spacers for easy removal or replacement of components. Integrate instrumentation and control devices into the piping system to monitor and regulate the flow of fluids. This includes valves, flow meters, pressure gauges and other instruments essential for process control and safety.

Maintain thorough documentation of material specifications used in the piping system. This traceability is crucial for quality control and ensures that materials meet specified standards.

Consider budgetary constraints and optimize the design for cost-effectiveness. Balance the upfront costs with long-term operational efficiency and maintenance considerations, for example, layout equipment to minimize pipe runs in designs with high-cost materials when possible.

Three types of process piping project drivers

1. Cost driven: Cost-driven design is an approach in engineering where cost considerations play a central role in shaping design decisions. The primary focus is on optimizing the design to minimize design, fabrication and installation costs while meeting minimum specified performance and quality requirements. This approach is particularly relevant in industries where lower upfront costs are a critical factor, such as manufacturing, construction and food and beverage industries as opposed to long-term, overall costs.

Long-term maintenance costs or superior materials are often traded for reduced upfront costs. “Nice-to-have” features are often eliminated early. Reduction in automation and a heavier operator presence are often seen with cost-driven projects.

Process piping designers have options on approach to cost driven projects, starting with developing the quality plan and evaluating the risks, then adjusting the project level of detail and design to meet project needs, without over or under delivering. The level of design refers to the amount of detail in the 3D model and the level of detail refers to the amount of detail in the construction drawings. This is broken down into four levels with one being very low detail and four being highest level of detail.

Many times, there are embedded contractors that continually work in the plant. They are very familiar with the plant’s details, preferences and need minimum guidance with low level detail sketches and drawings. This level of detail needs to align with the construction team, providing direction without any extras. This approach dials in level of engineering effort to support the field contractors’ expectations to construct the project.

Figure 2: Process pipe designers allow for flexibility in their designs, like adding stress loops, pipe guides and anchors when needed to absorb or control pipe movement. Courtesy: Matrix Technologies Inc.

Routing and layout designs are scalable and can range from basic sketches to detailed fabrication drawings, the latter typically being scaled back to save on capital expenditures upfront. This can be effective but does expose the owner to risk of cost overruns during construction. The higher risks of requests for information to clarify gray areas while constructing, so planning for post issued for construction site assistance is typically warranted.

2. Schedule driven: Conversely, schedule-driven design refers to an engineering approach where the schedule is the primary driver for decision-making during the design process. In other words, the design process is structured and guided by the need to meet specific deadlines or milestones. In some cases, this may necessitate larger than typical engineering or construction teams resulting in lower efficiencies to meet those dates. Obviously, those lower efficiencies come with higher design costs, higher construction costs and increased contingency.

These projects have tight deadlines that are daisy chained with minimal relief. Planning work packages in strategic order, usually timed with construction planning is paramount. Laying out the process units, along with equipment placement and orientation, focusing on the first areas to be built, can be an effective strategy for shortening timelines. Staging is a popular design and construction technique where installations such as deep foundations can be constructed, while detailed piping design finishes and long lead items await arrival.

Figure 3: Plant or unit layout focus will minimize distance between tethered process and equipment, with consideration for minimizing long runs of costly high alloy pipe. Courtesy: Matrix Technologies Inc.

Where shutdowns are necessary for installations, process piping designers can separate packages into pre- and post-turnaround designs. This allows for small, accelerated work packages to be demolished and installed in short windows of a swoop down or shut down if needed. The remaining work can be connected to the pre-turnaround design and installed without affecting the operation of the existing facility. This is done with careful planning in the design process for minimal components to be installed in a minimal construction window, while creating a bolt-up connection between the two phases for quicker install.

Another approach is modular/prefabrication design. Design predetermined shippable units and skids to minimize field time and reduce construction costs. This is favorable in remote work sites or where there is limited skilled labor and in schedule-constrained projects. Built in a shop within a controlled environment with high level of accuracy, these skids and pipe spools can be bolted up in the field or at least minimize field welds. This also allows for clear project scheduling, repeatable construction that lends itself to duplication and being easily replaceable. This method typically extends engineering design to allow for a well-thought-out plan to construct during a compressed outage.

There can be design sacrifices when executing a schedule driven project plan. Because of the project pace there are higher risks for design or construction conflicts to arise. The right quality planning needs to take place for proper focus on the high-risk items versus lower acceptable risks. Understanding the owner’s goals is key to preparation and preparation is key to successful construction.

3. Design driven: Design-driven projects refers to where the design process takes a central role in shaping the project’s goals, decisions and outcomes.

When the project requires an optimal output, is targeting a firm operational threshold or needs to consider multiple options, the design-driven engineering approach is typically employed. An example of this might be a very specific product in the spirits distillation industry where there is also a visual centerpiece to the project such as the façade and the shiny process equipment. These projects tend to have finite engineering, while needing more schedule to work through and consider all project drivers.

Figure 4: The acronym “LOD” can be used in different ways throughout the industries we serve and needs clarification when discussing. Level of design refers to the amount of detail in the 3D model. Level of detail refers to the amount of detail in the deliverable drawings. Thes are both common scales used to dial into project expectations. Courtesy: Matrix Technologies Inc.

These types of projects typically have very defined details and code-driven parameters. This could be cleanroom design, food and beverage or semiconductor projects that require specific design practices and adherence to codes. Other common examples would be cryogenic or super-heated lines that require strict finite element analysis to account for all stress needs of contraction and expansion of piping systems without overloading equipment connections while containing the process fluids safely.

In summary, the value of process piping design lies in the ability to identify specific project drivers, meet the specific needs of the industrial process while ensuring safety, compliance and reliability. This value extends to operational efficiency, compliance with standards, cost-effectiveness, adaptability and the overall integrity of industrial processes.

Thorough planning and attention to detail during the design phase via piping system engineering and design contribute to the success of the project and longevity of the piping system while meeting all needs of operation, construction, maintenance, accessibility and safety.

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