Using Tank Inspection Services for Risk-Based Inspections (RBI)

tank inspection

Risk-based inspection (RBI) is an advanced approach in industrial asset management that focuses on assessing the risk associated with equipment failure to optimize inspection schedules and prioritize maintenance tasks. In the context of above-ground storage tanks (ASTs), RBI provides a more strategic inspection framework compared to traditional time-based inspections. By utilizing tank inspection services for risk-based inspections, tank inspection services companies can significantly improve safety, reduce operational costs, and extend the lifespan of storage assets. Here’s a comprehensive look at how tank inspection services can be effectively used for RBI.

What is Risk-Based Inspection (RBI)?

Risk-based inspection is a methodology that integrates risk assessment with the inspection planning process. Instead of performing inspections at fixed intervals, RBI evaluates the likelihood of failure and the potential consequences to prioritize inspection activities. The risk is calculated as a combination of the probability of failure (PoF) and the consequence of failure (CoF). This approach allows facility operators to allocate resources more effectively, focusing on areas where the risk is higher.

RBI has become a widely recognized method in the oil, gas, and chemical industries. According to the American Petroleum Institute (API), implementing RBI can lead to up to a 50% reduction in inspection costs while maintaining or improving safety levels.

How Tank Inspection Services Integrate with RBI

Tank inspection services are crucial for gathering the data needed to perform an RBI analysis. Here’s how these services support the process:

  1. Data Collection for Risk Assessment

Tank inspection services involve various methods, including visual inspections, ultrasonic thickness (UT) measurements, magnetic flux leakage (MFL) testing, and corrosion monitoring. These methods collect detailed information on the tank’s structural integrity, including wall and floor thickness, corrosion rates, weld conditions, and settlement.

The gathered data is essential for calculating the probability of failure, which takes into account factors such as corrosion rates, operational conditions, and historical inspection records. For example, data showing significant corrosion in the tank bottom may indicate a higher probability of failure, necessitating more frequent inspections.

  1. Evaluating Consequence of Failure

Besides assessing the probability of failure, RBI also considers the consequence of failure, which involves evaluating the potential impact of a leak, spill, or structural failure. This assessment by water tank inspection services professionals takes into account factors such as the stored material’s toxicity, flammability, and environmental impact. Tank inspection services help identify tanks with higher risk profiles, such as those storing hazardous chemicals or located near sensitive environments.

A study conducted by the American Society of Mechanical Engineers (ASME) found that tanks located near water sources had 30% higher consequence ratings due to the potential for environmental contamination, emphasizing the importance of considering location in the risk assessment.

  1. Establishing Inspection Intervals Based on Risk

One of the main advantages of RBI is its ability to adjust inspection intervals based on risk levels. Tanks with higher risk scores will require more frequent inspections, while those with lower risk scores may have extended intervals between inspections. This flexibility helps optimize maintenance schedules, reduce downtime, and allocate resources where they are most needed.

The National Association of Corrosion Engineers (NACE) indicates that implementing RBI for tank inspections can increase inspection intervals by 20-40% for low-risk assets without compromising safety. This reduction in unnecessary inspections results in significant cost savings over the asset’s lifecycle.

Common Inspection Techniques Used in RBI for Tanks

The effectiveness of RBI relies on the quality and accuracy of the inspection techniques used. Here are some common inspection methods that tank inspection services employ:

  • Ultrasonic Thickness Testing (UT): Measures the remaining wall thickness of the tank shell and floor to monitor corrosion rates.
  • Magnetic Flux Leakage (MFL): Detects corrosion and pitting in the tank floor, especially in inaccessible areas, by measuring magnetic field disturbances.
  • Acoustic Emission Testing (AET): Identifies active corrosion and crack formation by detecting sound waves produced by structural changes.
  • Visual Inspections: Provide an overall assessment of the tank’s condition, including weld integrity, settlement, and external corrosion.

Each of these techniques contributes valuable data to the RBI process, enabling more accurate risk assessments and targeted maintenance.

Advantages of Using Tank Inspection Services for RBI

  1. Cost-Effective Maintenance

By prioritizing inspections based on risk, RBI helps reduce inspection frequency for low-risk assets, leading to cost savings. Additionally, fewer inspections mean less downtime for equipment, enhancing operational efficiency. Companies can also avoid costly emergency repairs by identifying and addressing potential issues early.

  1. Improved Safety and Compliance

RBI ensures that tanks with the highest risks are inspected and maintained more frequently, thus reducing the likelihood of catastrophic failures. This proactive approach aligns with industry standards like API 653 and API 580, which emphasize the importance of risk-based strategies for inspection and maintenance. Adhering to these standards helps companies stay compliant with regulatory requirements, avoiding fines and penalties.

  1. Extended Asset Life

Regular inspections based on RBI can help detect early signs of deterioration, such as corrosion, settlement, or weld defects. Addressing these issues promptly extends the lifespan of storage tanks by up to 30%, according to industry experts. The early detection of potential problems also enables more planned maintenance, avoiding costly unplanned shutdowns.

Challenges in Implementing RBI for Tank Inspections

While the benefits of RBI are clear, there are challenges associated with its implementation:

  • Initial Data Collection Requirements: Gathering the necessary data for an accurate risk assessment requires comprehensive inspections, which may involve high upfront costs.
  • Expertise Needed: Implementing RBI effectively requires expertise in risk assessment methodologies, corrosion science, and tank inspection standards.
  • Continuous Monitoring: Risk levels may change over time due to factors like process changes or environmental conditions. Continuous monitoring is essential for updating the risk assessments accordingly.

Conclusion

Using tank inspection services for risk-based inspections (RBI) represents a smart, strategic approach to managing the maintenance of above-ground storage tanks. By focusing on risk, companies can optimize their inspection schedules, improve safety, and achieve significant cost savings. As industries increasingly adopt RBI methodologies, the importance of high-quality inspection services and accurate data collection cannot be overstated. When applied correctly, RBI can help industrial facilities reduce risks, …

Key Considerations for Water and Wastewater Tank Fabrication

Tank inspection services

The fabrication of water and wastewater tanks is a critical aspect of ensuring reliable water storage and treatment systems. Whether for municipal water supplies, industrial processes, or wastewater treatment plants, the quality and durability of tanks play a pivotal role in the overall efficiency of these systems. Here, water tank inspection services play a crucial role in ensuring the tanks are in working condition.

In this blog post, we will explore key considerations that are crucial during the fabrication process of water and wastewater tanks.


Material Selection
Choosing the right materials for tank fabrication is paramount to its performance and longevity. The selected materials must be resistant to corrosion, chemicals, and other environmental factors. Common materials for water and wastewater tanks include stainless steel, carbon steel, and fiberglass-reinforced plastic (FRP). Each material has its advantages and limitations, and the choice depends on the specific requirements of the application.

Stainless Steel: 
Stainless steel is known for its corrosion resistance and durability, so it is a popular choice for water tanks. It is suitable for both potable water and wastewater applications, providing a robust solution with a long lifespan.

tank inspection service

Carbon Steel: This material is often chosen for its strength and cost-effectiveness. However, carbon steel may be susceptible to corrosion, so proper coating and maintenance are essential to enhance its durability, particularly in wastewater applications.

Fiberglass Reinforced Plastic (FRP): FRP tanks are corrosion-resistant, lightweight, and have a high strength-to-weight ratio. They are suitable for various water and wastewater applications and are known for their resistance to harsh chemicals.


Tank Design and Configuration
The design of water and wastewater tanks should align with the specific needs of the application. Factors to consider include tank size, shape, and configuration. Tanks must be designed to withstand the load they will bear, whether it’s the weight of the stored water, external environmental forces, or seismic activity in earthquake-prone areas.

Tank Size: Assess the required storage capacity based on the anticipated water or wastewater demand. Oversized tanks may incur unnecessary costs, while undersized tanks can lead to operational inefficiencies.

Tank Shape: The shape of the tank can impact its structural integrity and the efficiency of water or wastewater treatment processes. Consider the available space, required storage volume, and the nature of the liquids being stored when determining the tank shape.

Tank Configuration: Some applications may require specialized tank configurations, such as elevated or ground-level tanks. The choice depends on factors like topography, available space, and the desired water distribution system.

Compliance with Standards and Regulations
Adherence to industry standards and regulations is non-negotiable when fabricating water and wastewater tanks. Standards such as those set by the American Water Works Association (AWWA) or the American Society of Civil Engineers (ASCE) provide design, fabrication, and installation guidelines. Compliance ensures that the tanks meet safety, quality, and performance standards.

AWWA D100: AWWA D100 is a widely recognized standard for designing and constructing welded steel water storage tanks. It covers various aspects, including materials, design considerations, fabrication, and testing.

ASCE 7: ASCE 7 provides guidelines for assessing and designing structures to withstand natural forces like wind, snow, and seismic activity. Compliance with ASCE 7 is crucial to ensure the structural integrity of water and wastewater tanks.

Coating and Lining
Protecting the interior and exterior surfaces of water and wastewater tanks is essential to prevent corrosion and contamination. Coatings and linings act as a barrier between the tank material and the stored liquid, preserving water quality and extending the tank’s lifespan. Thus, tank facility owners and operators should engage with tank inspection services providers.

Interior Coatings: For potable water storage tanks, interior coatings must comply with regulations to ensure water safety. Epoxy coatings are commonly used due to their resistance to corrosion and ability to comply with health and safety standards.

Exterior Coatings: The exterior of the tank is exposed to weather conditions, making corrosion protection crucial. Weather-resistant coatings and proper surface preparation are necessary to prevent deterioration over time.

Construction Method
The chosen construction method can significantly impact water and wastewater tank fabrication’s cost, timeline, and quality. Common construction methods include field-welded construction, bolted steel tanks, and precast concrete tanks.

Field-Welded Construction: Tanks constructed on-site through field welding offer flexibility in terms of size and configuration. This method is suitable for large tanks but may require longer construction timelines.

Bolted Steel Tanks: Bolted steel tanks are fabricated off-site and assembled on-site, reducing construction time. They are cost-effective and provide versatility in terms of size and customization.

Precast Concrete Tanks: Concrete tanks are precast off-site and transported for installation. They are durable and resistant to environmental factors but may have limitations in terms of customization.

Conclusion

The fabrication of water and wastewater tanks demands a meticulous approach to ensure the reliability, longevity, and safety of these critical components in water treatment systems. From material selection and tank design to compliance with standards and construction methods, each consideration contributes to the overall quality of the fabricated tank. By prioritizing these key aspects, industries can confidently invest in water and wastewater tanks that meet their specific needs, adhere to regulatory requirements, and contribute to the efficient and sustainable management of water resources.…