Atmospheric exposure tests indoor atmospheres

The first three authors were concerned with the rusting of motorcar bodies. They found that the rusts formed on steel under sheltered and exposed conditions, respectively, differed markedly in chemical composition, structure and protective properties. The second paper gives the results of exposure tests in many different indoor atmospheres, from which the following representative rates of rusting over one year are taken. 

Some carbonation tests have been reported on plain and air-entrained concretes using two aggregate types, where the depth of carbonation on indoor and atmospheric exposure for 5 years have been measured [40]. The results are given in Table 3.24. In all cases, the air-entrained mixes have shown less carbonation than similar controls, suggesting that air-entrained concrete should provide a better reinforcement protection in the long term. 

A recent standardization project is for Swedish Standard SS 11 72 11 Corrosion Tests in Artificial Atmosphere— Accelerated Outdoor Test. Strom et al. (1992) at Volvo are devising four indoor tests. These developments are still in progress but already show that the 12-month outdoor scab tests can be simulated (in 12 weeks). The outdoor tests show that the distance of blistering of painted coatings from a scribe mark is inversely proportional to zinc coating thickness. Johannson and Rendahl (1991) have evaluated a range of zinc and zinc alloy coatings but find correlation with marine exposure rather low. 

Because connectors and contacts are usually exposed without protection to the environment during operation, testing typically has been performed in the context of atmospheric corrosion [113]. Various forms of accelerated tests for indoor office environments have been developed for this pimpose [26,114-117]. For example, procedmes have been developed at IBM (the G1(T) test) [26,114,117], Battelle Institute (Flowing Mixed Gas Class II or FMGII) [23,115,116], and in Europe by the International Electrotechnical Commission (lEC Test 68-2-60) [118] for simulating an indoor office environment. These techniques vary slightly but involve exposure to an atmosphere containing a combination of dilute pollutants such... 

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