Factors Impacting the Cost of Pipeline Condition Assessment
Water and wastewater utilities face the challenge of maintaining infrastructure that has served for decades. Buried pipeline infrastructure poses accessibility challenges from physical limitations and operational constraints. Consequently, utilities must strategize effectively to plan for potential rehabilitation initiatives. The optimal approach involves conducting a comprehensive field-based condition assessment, ensuring the availability of up-to-date and precise data for informed decision-making. However, the logistics of gathering condition data can be challenging, impacting the pipeline condition assessment cost.
Replacement vs. Assessment
When considering infrastructure replacement versus condition assessment costs, several factors should be taken into consideration. These include the age and perceived condition of the pipeline, the potential likelihood and consequence of failure, and the available funding and resources.
Replacing infrastructure can be very expensive, especially if it involves critical pipelines. In some cases, replacement may be necessary if the pipeline is old, deteriorating, and can no longer serve its intended purpose, or the assessment cost outweighs the replacement cost. The replacement cost should be balanced against the potential benefits, including improved reliability, increased capacity, and reduced risk of failure.
On the other hand, condition assessment can help identify areas of the infrastructure that may need repair or maintenance and prioritize those repairs based on the severity of the issues. This can be a cost-effective way to extend the life of pipeline infrastructure, especially if it is not yet at the end of its useful life.
As the length and diameter of a pipeline asset increases, it generally more cost effective to perform condition assessment and rehabilitate rather than replace the asset.
Factors Impacting the Cost of Pipeline Condition Assessment
The cost of pipeline condition assessment can vary significantly depending on several factors. Understanding these factors helps utilities estimate and manage the overall cost of pipeline assessment projects. Some key factors that impact cost are:
Pipeline Length and Diameter - The pipeline's size and length will directly impact the cost. Longer and larger-diameter pipelines typically require more resources and equipment for assessment and usually more advanced inspection technologies to obtain accurate condition data. The data from advanced inspection technologies can be voluminous and complex, and analyzing and interpreting this data may require more sophisticated software and skilled engineers, which can impact cost.
Pipeline Material - Different pipe materials require different inspection methods and technologies. For example, the methods used to assess asbestos cement (AC) pipelines vary significantly from those used to evaluate metallic pipes. Corrosion is a significant concern for metallic pipelines, especially in environments with corrosive elements. Assessing the extent of corrosion involves corrosivity surveys and advanced tools for measuring pipe wall thickness to identify potential weak points. These methods can be time-consuming and require advanced equipment, contributing to higher costs. While non-metallic pipelines resist corrosion, they can still experience degradation due to UV exposure, soil movements, or manufacturing defects. For AC pipelines, pipe samples or coupons are required to accurately assess the true extent of material degradation that affects its structural integrity. Assessing the condition of non-metallic pipelines may involve technologies specific to these materials and condition issues, impacting the overall cost.
Pipeline Depth and Accessibility - The depth at which a pipeline is buried, and its accessibility can affect costs. Deeper, hard-to-reach or inaccessible pipelines typically require more access-enabling efforts, e.g., deeper excavations, bypassing, dewatering, and installation of access manways or tool launching ports. Sometimes, complex and expensive assessment methods are the only viable option to assess pipelines with challenging access. The availability of access manholes or inspection ports along the alignment of a pipeline can significantly reduce the cost of deploying in-line inspection tools.
Pipeline Scale and Scope - The scale and scope of the assessment project, including the number of pipelines to be assessed and the level of detail required, will impact costs. An economy of scale typically applies, and the cost of performing condition assessments on multiple pipelines or longer lengths during one project or a single mobilization will have a lower cost per foot or cost per pipeline. High-resolution assessments using advanced in-pipe methods will be more expensive than general screening assessments.
Assessment Method - Both indirect and direct assessment methods vary in cost based on the complexity of implementation and the quantity and quality of data collected. Indirect methods, such as desktop data analysis and performance monitoring, can identify potential areas of concern or estimate the general condition of the pipeline. These methods are less costly and time-consuming than direct methods yet provide valuable insights into the overall health and performance of the pipe. Direct methods, such as visual inspection, testing, and sampling, can provide more detailed information about the condition. These methods are often more accurate than indirect methods and can help to identify specific issues that may require repair or replacement.
Environmental Conditions - The location of the pipeline and its surrounding environment can affect the cost of assessment. Assessing a pipeline in an environmentally sensitive habitat will require additional resources and equipment. It may trigger the need to apply for state and federal permits before mobilizing for field-based condition assessment. Environmental permitting can be a lengthy and costly process for utility owners. Compliance with permit requirements may increase assessment costs due to restrictions for on-site access or the need for reporting and monitoring while performing fieldwork.
Geographic Location - The physical location of a pipeline asset affects costs due to factors such as transportation of equipment and personnel, permitting, and local labor rates. Some states, like California, have contracting regulations that require public utility owners to pay prevailing wages for field-based condition assessment activities. Pipelines located in remote areas or rugged terrain with access difficulties will have increased costs associated with the mobilization and demobilization of equipment and resources.
Safety Measures - Ensuring the safety of personnel during the assessment process is essential. Safety measures can add to the overall cost, especially for high-risk and critical pipelines. Larger pipelines may also present more significant safety challenges during inspections if shutdown and confined space entry are needed as part of the condition assessment work plan.
Emergency Assessments - If the condition assessment is conducted as part of an emergency response, the cost may be higher due to the need for rapid deployment and specialized equipment required to gather critical information to inform emergency response decisions.
Surface penetrating radar is performed on the interior of a large-diameter concrete pipeline to determine the wall thickness and spacing of reinforcement.
Pipeline owners and operators need to evaluate and balance the cost of condition assessment, repair, or replacement against the potential risks associated with pipeline failure. New technologies and innovative tools have led to major advancements in pipeline condition assessment; however, the challenge of removing a pipeline from service for inspection and the costs to assess the pipeline for tool deployment can be overwhelming for some public agencies. It's essential to carefully consider these factors when planning and budgeting for pipeline condition assessment to ensure that the assessment is conducted effectively and within budget constraints. A thorough cost-benefit analysis can also help determine the most cost-effective approach to assessing the pipeline condition.
At V&A, we are passionate about condition assessment. Our field-based engineers assist water and wastewater clients nationwide in evaluating pipeline conditions and developing cost-effective solutions to mitigate damage caused by corrosion or degradation. We welcome your condition assessment questions in the comment section below.