Materials degradation damage

The chemical and physical compatibility of decontamination solutions or other decontamination materials must be determined before use. Any decontamination method that permeates, degrades, damages, or otherwise impairs the functioning of the personal protective equipment (PPE) is incompatible with such PPE and should not be used. If a decontamination method does pose a direct health hazard, measures must be taken to protect both decontamination personnel and the workers being decontaminated. Figure 16.22 presents a decision aid for the evaluation of health and safety aspects of decontamination methods. 

Materials Degradation Effects. Virtually all of the effects of S02 on materials are associated with its dissolution in surface moisture as the primary mechanism of deposition (19). Thus an appropriate environmental index for materials damage should include not only the average ambient S02 concentration but also a measure of the portion of time that the material surfaces are wet and thus receptive to S02 deposition. Sulfur in the atmosphere has an additional adverse affect on some materials through acidification of precipitation however, for both "dry" deposition of S02 and impact by acid precipitation, the primary damage mode is attack by dilute acids. 

Thermal damage to the base material Degradation of metaUization adhesion Warping of the thermoplastic device... 

Corrosion-related failures constitute over 25% of the failures experienced in the oil and gas industries. More than half of these failures are associated with sweet (COj) and sour (H2S) produced fluids. An analysis of failures assessed during the 2000s in a very limited industrywide survey showed a high degree of damage caused by corrosion and other types of material degradation. 

As with radiation damage, wear is generally a physical rather than chemical form of material degradation. Specifically, wear can be defined as the removal of surface material as a result of mechanical action. The amount of wear need not be great to be relatively devastating. Although the systematic study of wear has largely been confined to the last few decades, several key aspects of this phenomenon are now well characterized. Four main forms of wear have been identified ... 

Graner and della Rocca [83] conducted a condition survey of 74 US Navy boats of 21 different classes from 5-15 years old (the median hull, fabricated in 1958, was 10 years old). Defects were classified into 17 categories, most of which were the result of impact damage or abuse. The laminates were generally in excellent condition, regardless of the age of the boats, with material degradation limited to minor, surface skin delaminations, skin/ core separation in sandwich panels and deterioration of the paper honey-... 

The effect of water absorption must be taken into consideration when designing with water-absorbent plastics. In many cases, water absorption in plastics follows Pick s law (Eq. 5.2), so that the mass of absorbed water increases linearly with the root of time until equilibrium is reached. If the material does not follow Pick s law, surface damage or material degradation has taken place [596]. 

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