National standardization and approvals

In most industrial countries and those at the threshold of industrialization, the field of explosion protection for electrical apparatus and systems is subject to legislation. The usual procedure, that a manufacturer declares the conformity of a product with a given standard under his own responsibility, is altered in such a way that an administrative body nominated by the government of a state, or, in states with a federal structure, nominated by the authority of a land, issues an approval which declares the compliance with a standard and with legislative acts in parallel. On this basis, the apparatus may be commissioned and put into service. 

The administration body often refers to an expert s appraisement and renounces for type testing and inspection. These activities are carried out by certifying bodies, state-owned facilities or privately owned companies. 

As an example of such a practice, there may be the situation in Germany before transformating the European Directives 76/117/EEC, concerning explosion protection, and 82/130/EEC, concerning firedamp protection into national legislation. The relevant standard was VDE 0170/0171/1961-02, with amendment VDE 0170/0171 d/1965-02 and with amendment VDE 0170 f/0171 f/ 1969-01, quoted simply as VDE 0170/0171/1969-01 throughout this book. 

Until ElexV [8] and EIZulBergV [9] came into force - ElexV dated 1980-07-01 and EIZulBergV 1984-01-01 - firedamp-proof and explosion protected electrical apparatus had to pass a two-step procedure in order to come into operation  

many apparatus complying with VDE 0170/0171/1969-01 are still in operation. Therefore, this standard shall be considered more in detail. Table 3.1 summarizes the different types of protection, and Table 3.2 demonstrates the 

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