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European standardization of compressed gas cylinders
Does my compressed air breathing apparatus count as pressure equipment? Why does my apparatus come marked with so many CE markings? Can I start using my respiratory protective device as soon as it has been delivered? These are the questions which are asked time and time again, by our readers, customers and users. Those responsible for drawing up the European standards have also left room for interpretation when it comes down to such details, so this article will attempt to shed some light on the issue of European standardization and its treatment of compressed gas cylinders. Compressed gas cylinders, first and foremost, are pressure vessels which, if they are fitted with a valve, are known as pressure equipment. This is the definition contained in the European Pressure Equipment Directive 97/23/EC, the PED. And pressure equipment designed for operating pressures in excess of 0.5 bar, regardless of type, must be approved before being placed on the European market. By approval is meant that Notified Bodies in Europe check that the equipment submitted by the manufacturer conforms to the requirements contained in the Directive and then approve the equipment specimens. They are then issued with a certificate testifying that they can be placed on the market.

Different directives
The equipment is marked with the CE number of the respective certification authority, which distinguishes it as an approved product that has been manufactured to achieve the required quality and performance characteristics. This is the aim of the Pressure Equipment Directive, which entered into force on 29 May 2002. The Directive also covers pressure equipment that is used in respiratory protective devices (Article 3, 1.1), which means that compressed air breathing apparatuses, in the widest sense, can also be regarded as pressure equipment. All components of pressure equipment must be subjected to a conformity assessment by the manufacturer and, depending on their operating pressure and volume, are assigned to different categories. If this is applied to those state-of-the-art compressed air breathing apparatuses currently on the market, only pressure vessels fitted with valves are placed in a category which is subject to marking in accordance with the PED. All the other components of the compressed air breathing apparatus which conduct compressed air do not require marking on account of their design. However, compressed air breathing apparatuses also and not least count as personal protective equipment (PPE) and, as such, must comply with European Directive 89/686/EC. Here too, the general approval requirements apply before PPE can be placed on the market, and once again a CE mark is issued once all conditions have been met. If certain types of PPE – such as compressed air breathing apparatuses – are to be used on ships, yet another specific European Directive applies, the Marine Equipment Directive (MED), according to which the equipment must be approved and marked. And if particular types of PPE are intended for use in explosive atmospheres, the ATEX directive comes into play. However, not all Notified Bodies across Europe are equally authorized to verify the proper implementation of the various directives. As a result, a device may well end up with several different CE marks. But now back to the pressure equipment. Pressure vessels themselves are generally approved and CE marked as individual components, and the same is true of the valves. If these components are subsequently combined to form an assembly, the PED says that pressure equipment requiring approval has been created, so naturally it must be issued with a CE mark. If this assembly is now used in a compressed air breathing apparatus marked as PPE, the outcome is a compressed air breathing apparatus that is regarded as pressure equipment. In other words, there are already four distinct types of CE marking – confusing? Not really, if one is familiar with the background, and yet the situation can be misleading because not everyone can work their way through all the details. According to the European Directives, a single CE mark would be more than sufficient, because one basic principle that all directives share is that all other applicable directives have to be taken into account during testing. In an ideal situation this could work if all Notified Bodies in Europe were authorized to deal with all directives. However, for as long as this ideal situation does not exist, Dräger Safety has made it its job to give consideration to national differences and to approve and make available pressure equipment of all kinds of different types – with pressure vessels made of steel, aluminium or carbon fibre-reinforced composite material – in its Dräger compressed air breathing apparatus series. A correlation matrix (see Appendix B01001) shows the current range of Dräger pressure vessels with their respective valves, including those used in diving apparatus. This matrix is constantly changing as new types of pressure equipment are included to widen the range of Europe-wide approved Dräger pressure equipment.

Occupational Safety Ordinance
In Germany, another piece of legislation exists in connection with the Pressure Equipment Directive, namely the Occupational Safety Ordinance (Betriebssicherheitsverordnung, or BetrSichV). This ordinance requires approved and CE-marked pressure equipment to be checked by an authorized body for compliance with all requirements prior to being put into service for the first time. This check is performed by the German Technical Inspectorates (TÜV). Dräger Safety also offers this check as an optional service, meaning that compressed air breathing apparatuses and pressure equipment – i.e. compressed gas cylinders with valve – supplied by Dräger can be put into service immediately upon delivery. Dräger Safety is also able to carry out the repeat tests for pressure vessels which are required by the German ordinance. At European level, manufacturers' associations, among them Dräger Safety, have joined forces with user groups to bring about the harmonization of the different directives. Although this process is time-consuming, there is certainly a chance, as far as the device-specific standards are concerned, to prove points of similarity between at least two directives, the PPE and PED. Consequently, just one CE mark affixed to a device would be sufficient to demonstrate compliance with a Europe-wide quality standard – the ideal of every directive author.

Wolfgang Drews
Dräger Safety AG & Co. KGaA

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