AS EN 50069:2013 Welded composite enclosures of cast and wrought aluminium alloys for gas- filled high-voltage switchgear and controlgear
7.4.8 Assessment of imper fections imper fections can be assessed aCCor ding to onc Or the other of the following al ternatives :
(a) if the imperfections do not exceed the acceptance levels speci fied 1n table 7 of EN 50 064，thewe1d ma y be accepted without further action;
(b) part icular imper fections in excess of those permitted in tabie may be accepted after due con- si derat 1 on of the material,stress and env ronment a factors ;
(C) ii acceptance leve1s diiferent from those specified in table7ofEN50064have been es tablished for a parti- cular application and being suitably documented， the y may be adopted.
7.4.9 Repair of we1ds
Unacceptable imperfections shall be rejected or repaired. Repair we lds sha1l be caIr 1ed out to a documented procedure and sub- jected to the same acceptance cr iteria as the or 1ginal work.The whol e of the re palred are as shall be radiographed.
Where imperfections needing repair are pound, the non-destructive testing sha1l be extended for distance of. 10 % of the length of the seam on both sides of the or 1ginal radiograph or ultra soni c test length .
If，in those subsequent non-destructive tests, further imperfec- tions needing repalr are found， the non-destructive testing shal1 be extended to 100 % of the seam length.
The protective devices she11 be constructed, located and instel- led so that they are accessible for inspection and repair.The y sha11 be protected against accidental damage.The devices need not be installed directly on the enclosure . The discharge areas and any connecting ports to or within the enc10- sure shal1 be of adequate size to permit effective relief in the event of overpressure. Pressure rellef devices shall be arranged so as to minimize the danger to an operator during the time he is per forming his normal operating duties, 1f gases vapours are escaping under pressure.