Inspection risk-based inspection

The project "Non-Invasive Inspection within an Asset Risk Management Strategy" is another joint industry project, funded by EC-THERMIE, representing the current trend towards onstream (non-invasive) inspection in combination with risk-based inspection philosophies to establish component condition. In this project, industry and authorities participate aiming at a beneficial use of today s NDT without sacrificing on safety. 

In plant maintenance, the availability of quantitative and non-invasive screening NDT methods will reduce the time needed for shutdowns and increase the intervals between them. Modem NDT methods will become just as important a tool for Risk Based Inspection approaches and maintenance planning as operational parameters and degradation mechanisms already are. 

Risk-Based Inspection. Inspection programs developed using risk analysis methods are becoming increasingly popular (15,16) (see Hazard ANALYSIS AND RISK ASSESSMENT). In this approach, the frequency and type of in-service inspection (IS I) is determined by the probabiUstic risk assessment (PRA) of the inspection results. Here, the results might be a false acceptance of a part that will fail as well as the false rejection of a part that will not fail. Whether a plant or a consumer product, false acceptance of a defective part could lead to catastrophic failure and considerable cost. Also, the false rejection of parts may lead to unjustified, and sometimes exorbitant, costs of operation (2). Risk is defined as follows ... 

In the simplest terms, a fault-tree for risk analysis requires the following information probabiUty of detection of a particular anomaly for an NDE system, repair or replacement decision for an item judged defective, probabiUty of failure of the anomaly, cost of failure, cost of inspection, and cost of repair. Implementation of a risk-based inspection system should lead to an overall improvement in the inspection costs as well as in the safety in operation for a plant, component, or a system. Unless the database is well estabUshed, however, costs may fluctuate considerably. 

ASME Research Task Eorce on Risk-Based Inspection Guidelines, Risk-Based Inspection—Development of Guidelines, CRTD Vol. 20-1, The American Society of Mechanical Engineers, New York, 1991. 

Some companies are now using Risk-Based Inspections (RBI), especially for the costly preparation efforts for internal inspections. RBI is a method that is gaining credibility and... 

Some companies are now using Risk-Based Inspections (RBI), especially for the costly preparation efforts for internal inspections. RBI is a method that is gaining credibility and popularity. Organizations calculate a proposed inspection frequency by considering the consequences of failure (as described previously) and the likelihood of failure based on the anticipated internal corrosion rates. The method employs a risk matrix. 

Visual and other non-intrusive examinations are an essential part of maintenance. This typically begins with an inspection plan that outlines the type and frequency of inspection. The anticipated damage mechanism and the probability determine the type of inspection. The frequency is determined by the consequences associated with the damage. The consequences and the probability together constitute the risk-based inspection (RBI) strategy. 

Determination of the type and frequency of inspection on the risk is what risk-based inspection (RBI) is all about. Risk is quantitatively determined by the probability of failure and the consequences thereof. This implies that the type of failure (blistering, cracking, etc.) and its rate are known through experience, testing, or other information. The owner, on the basis of the contained liquid, its amount, and its hazardous nature, determines the consequences. In almost all cases, fluoropolymers are used for corrosive and hazardous chemicals, and the consequences of failure are quite severe. This has led to the general guidelines for type and frequency of inspections shown in Table 9.1. 

Bertolini, M., Bevilacqua, M., Ciarapica, F. E., Giacchetta, G. (2009). Development of risk-based inspection and maintenance procedures. Journal of Loss Prevention in the Process Industries, 22, 244-253. 

Zhaoyang, T., Jianfeng, L., Zongzhi, W., Weifeng, H. (2011). An evaluation of maintenanee strategy using risk based inspection. Safety Science, 49, 852-860. 

API, Risk-Based Inspection, API Recommended Practice 580, Second Edition, November 2009. 

DNV, Risk Based Inspection of Offshore Topsides Static Mechanical Equipment, DNV Recommended Practice Det Norske Veritas DNV-RP-GlOl, October 2010. 

Inspection (although risk-based inspection may be an exception). 

Adoption of risk-based inspection (RBI) to manage mechanical integrity... 

Recently there are efforts to fix the times between inspections of functionality and integrity on the basis of probabilistic considerations (cf. Chap. 9). This is known as risk-based inspection or risk-based maintenance. 

Chang, Ming-Kuen, Ren-Rong Chang, Chi-Min Shu Kung-Nan Lin 2005. Application of risk based inspection in refinery and processing piping. Journal of Loss Prevention in the Process Industries 18(4-6) 397-402. 

DNV 2002. DNV-RP-GlOl Recommended practice. Risk based inspection of offshore topsides static equipment Det Norske Veritas. 

Sin, Maneesh Tore Markeset 2009. A methodology for risk-based inspection planning of oil and gas pipes based on fuzzy logic fiamework. Engineering FaOure Analysis In Press, Accepted Manuscript. 

Figure 1. Logical scheme of the risk based inspection scheduling. The fuzzy engine is highlighted in gray.

API. 2000. Risk-bases inspection base resource document, API standard 581, 1st ed. Washington, D.C API. Cadwallader, L.C. Herring, J.S. 1999. Safety issues with hydrogen as a vehiclefuel. lNEEL/EXT-99-00522 Report. 

As has been shown above using CATS can deliver the results on which IVW can base a risk base inspection. Some immediately useable results are given above. 

In addition to the development of CIBOCOF, an approach known as value driven maintenance policy (VDMP) was established in order to show the hidden values of maintenance and how organisadmis can benefit from these values [23]. In terms of VDMP, value is defined as the delivery of maximum availability at minimum cost [28]. The approach was developed using principles and concepts from TPM, RCM and risk-based inspection (RBI), and it requires an organisation to concentrate on the dynamic prospects for value creation using appropriate steps/ techniques instead of using a one method fits all approach [29]. The steps used to implement VDMP include [30] ... 

Within the refining industry, the risk-based inspection procedure put forward by the American Petroleum Institute in its Recommended Practices RP-580 (2000) and RP-581 (2000) has been generally adopted and its three levels can be summarised as follows ... 

Qualitative analysis of a process unit is the starting point for any plant- or unit-wide risk based inspection study. It can be carried out while the equipment is in operation and comprises four main steps. To ensure uniformity of treatment and coverage of all aspects, a formal workbook or appropriate software is used to identify, record and analyse the necessary data. 

American Petroleum Institute, Risk based inspection API Recommended Practice 580, First Edition, 2000... 

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