Meeting the Standard
The European Standard BS EN12021:1998 became the UK National Standard in June 1999. Clause 6 of this standard supports the essential requirements of the EU Directive 89/686/EEC, in particular clauses 1.2.1.1, 2.8, 3.10.1 and 3.11 of Annex II of the Directive with reference to Breathing Air quality. In so far as the National Standard (BS4275:1997) is in some respects a tighter standard, under clause 6.2.1 the more stringent limits of the National Standard BS4275:1997 will apply.