Classification of Devices

The range of devices regulated under the general medical device directive, 93/42/EEC, can vary from the simple devices that pose little or no risk to patient or user health to those that are life-critical. It is neither economically feasible, nor justifiable in practice. 

Check Monitor and measure processes and products against policies, objectives and requirements for the product, and report the results. 

1 General Requirements (Implement quality system and continually improve it) 

2 Documentation Requirements (Quality Manual, control of documents and records) 

1 Management Commitment (Show evidence of top management commitment) 

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Definition of a medicai device Risk-based classification of devices Essential principles of safety and performance Labelling... 

As in Europe, the classification of devices plays a central role in the regulation of devices in the US. However, there are a number of differences compared to the European approach. First of all, responsibility for classification rests with the FDA rather than with the manufacturers. When the regulations were introduced, the FDA mandated expert advisory panels (classification panels) to consider the different types of device that existed on the market at that time. The FDA provided classification questionnaires to act as guidelines for the panels when assessing the devices. In determining the safety and effectiveness of a device for purposes of classification, the classification panels had to consider the intended user (not part of EU criteria), the... 

Electiical classification. Article 500 of the National Electric-Code provides for the classification of the hazardous nature of the process area in which the measurement device will be installed. If the measurement device is not inherently compatible with this classification, suitable enclosures must be purchased and included in the installation costs. 

A commonly used basis for classification of level devices is as follows float-ac tuated, displacer, and head devices, and a miscellaneous group that depends mainly on fluid characteristics. 

External control of the process is achieved by devices that are specially designed, selected and configured for the intended process-control application. The text below covers three very common function classifications of process-control devices controllers, final control elements, and regufators. 

Conveyor-Belt Devices The metal-belt type (Fig. 11. 55) is the only device in this classification of material-haudhug equipment that has had serious effort expended on it to adapt it to indirecl heat-transfer seiwice with divided solids. It features a lightweight construction of a large area with a thin metal wall. ludirect-coohiig applications have been made with poor thermal performance, as could be expected with a static layer. Auxihaiy plowlike mixing devices, which are considered an absolute necessity to secure any worthwhile results for this seiwice, restrict applications. 

Electrical switches, relays, and other devices are described for safety reasons by several general categories. Since these devices are potential sources of ignition during normal operation (for example, arcing contacts) or due to malfunction, the area classification limits the types of devices which can be used. 

In Section 13.2, we introduce the materials used in OLEDs. The most obvious classification of the organic materials used in OLEDs is small molecule versus polymer. This distinction relates more to the processing methods used than to the basic principles of operation of the final device. Small molecule materials are typically coated by thermal evaporation in vacuum, whereas polymers are usually spin-coated from solution. Vacuum evaporation lends itself to easy coaling of successive layers. With solution processing, one must consider the compatibility of each layer with the solvents used for coating subsequent layers. Increasingly, multilayered polymer devices arc being described in the literature and, naturally, hybrid devices with layers of both polymer and small molecule have been made. 

Figure 9.5 Relationship between risk and classification of medical devices.

Figure 9.6 Impact of device characteristics on risk classification.

Figure 9.8 Decision chart for classification of non invasive devices (from MEDDEV Guide 2.4).

The previous chapter outlined how device classification and the use of standards provide the basis for effective regulation of medical devices, with particular focus on the application of design control standards to the development of devices. In this chapter we look at the process for evaluation and authorisation of devices, and see how the regulatory requirements vary depending on the perceived risk of the device as indicated by its classification. It will be noted that there is considerable variation between the approaches adopted in Europe and the US and that, compared to dmgs, practical harmonisation of requirements still remains to be adopted. 

MIR techniques have simplified obtaining infrared spectra of many materials important in packaging. These include rubber, plastics, laminations, and components of these materials that find use in pumps, sample packages, and devices. The combination of MIR and computerized pattern recognition techniques can be used for differentiating and classification of flexible packaging polymers such as polyvinyl chloride (PVC), polyvinylidene chloride (PVdC), acrylonitrile (Barex), and CTFE (Aclar) [22]. 

L3. Langer, G., and Radnik, J. L., Development and preliminary testing of a device for the electrostatic classification of submicron airborne particles, J. Appl. Phys. 32, 955 (1961). 

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