Vessels classification

Classification Societies exist to promote the safe construction of ships and to protect that condition throughout the life of the vessel. One of the tools available to shipbuilders, shipowners and surveyors that can be used to achieve these aims is Non-Destructive Examination (NDE). The intent of this presentation is to describe the application of NDE to hull structure during construction and also during periodic surveys as seen from the viewpoint of the Classification Surveyor. 

Appendix 4 gives definitions and rules for stress analysis for shells, flat and formed heads, and tube sheets, layered vessels, and nozzles including discontinuity stresses. Of particular importance are Table 4-120.1, Classification of Stresses for Some Typical Cases, and Fig. 4-130.1, Stress Categories and Limits of Stress Intensity. These are veiy useful in that they clarify a number of paragraphs and simphfy stress analysis. 

Another classification refers to the shape of the vessel. In the case of the laboratory vessel installed with a stirrer, the composition and temperature of die reaction is homogeneous in all parts of die vessel. This type of vessel is classified as a stiiTcd tank or well mixed reactor. Where there is no mixing in the direction of flow as in the cylindrical vessel, it is classified as a plug flow or tubular flow reactor. 

A runaway reaction occurs when an exothermic system becomes uncontrollable. The reaction leads to a rapid increase in the temperature and pressure, which if not relieved can rupture the containing vessel. A runaway reaction occurs because the rate of reaction, and therefore the rate of heat generation, increases exponentially with temperature. In contrast, the rate of cooling increases only linearly with temperature. Once the rate of heat generation exceeds available cooling, the rate of temperature increase becomes progressively faster. Runaway reactions nearly always result in two-phase flow reliefs. In reactor venting, reactions essentially fall into three classifications ... 

The European philosophy on area classification varies from that of the United. States and Canada. Specifically, in Europe and most other inter national areas, the Zone concept is utilized. An area in which an expio sive gas-air mixture is continuously present, or present for long perioiK of time, is referred to as Zone 0. The vapor space of a closed, but vented, process vessel or storage tank is an example. An area in which an explosive gas-air mixture is likely to occur in normal operations is designated Zone 1. An area in which an explosive gas-air mixture is less likely to occur, and if it does occur will exist only for a short time, is designated Zone 2. Zone 0 and Zone 1 correspond to Division 1 in the U.S. and Canada System. Zone 2 is equivalent to Division 2. 

Although several approaches to stroke classification have been described, the most common mechanism-based classification in current use is the system described by the TOAST investigators." This classification describes five major subtypes of ischemic stroke based on the results of neuroimaging and other medical investigations, namely (1) LAA, (2) cardioembolism, (3) small-vessel occlusion, (4) stroke of other determined etiology, and (5) stroke of undetermined etiology. Inter-rater reliability of the TOAST scheme has been reported as moderate-to-substantial K 0.5-0.7). 

Process plants are categorized into different hazard classifications, according to the potential explosion energy available from vessel rupture, condensed-phase explosion, confined vapor (building) explosion, or VCE. 

Process Facilities 15 Area electrical classification 16 Accessibility for mechanical integrity (sampling, maintenance, repairs) 17 Protection of piping and vessels from vehicles and forklifts 18 Protection of small-bore lines, fittings from external impact, personnel 19 Routing of process piping, critical controls cable trays, critical utilities 20 Vent, drain, and relief valve discharge locations... 

The basis for a classification is shown in Figure 21.5, and control volumes are shown in Figure 21.6 for axial flow. These diagrams could apply to catalyst packed inside a vessel or inside a tube in a multitubular arrangement (but not outside the tubes without modification-see Section 21.5.4.2). 

Charters, S., Evershed, R. P., Goad, L. J., et al. (1993). Quantification and distribution of lipid in archaeological ceramics implications for sampling potsherds for organic residue analysis and the classification of vessel use. Archaeometry 35 211-223. 

Classification Results of the Glass Vessels Data Using LDA... 

Chemical Compatibility Classification — The U.S. Coast Guard defines 43 cargo groups listed in Navigation and Vessel Inspection Circular No. 4-75, "Guide to Compatibility of Chemicals."... 

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