Dunk test

The simplest form of compatibility test is to immerse standard ASTM coupons in a liquid or vapor in the lab. Coupons can be installed in the field in a stream. However making a coupon assembly for installation in a pipe or a vessel may be difficult and persuading plant operators even more so. Lab testing is easy to carry out but will not replicate real life conditions such as flow, agitation, stress (compression for gaskets) and one-sided exposure. For this reason, lab dunk tests are usually done for screening reasons. Application temperature is easy to achieve by space heaters. 

Chemical compatibility of the material can be determined by a simple dunk test using either the gasket itself or a generically similar material. The exposure conditions should match the actual application condition. Visual observations and retained mechanical properties should yield useful information. 

Table VI shows the water retained in samples [Dunk-N-Drain test] at zero minute and after oven drying at 100 F at different intervals of time up to 150 minutes. Sample 104 retained 54 g of water vs. 0.15 g in control gauze, after drying for 150 minutes. Since the healthy human body temperature is around 98.6 F, we used a drying temperature of 100 F. The test data have shown that the CM-dressings maintain a moist environment at 100 F.

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