However, many times such plugs can be the source of moisture leakage. The main problem with this technique is that corrosion under insulation tends to be localized and unless the inspection plug is positions in the right spot the sites of corrosion can be missed. The most serious problem is the system already in service with a know corrosion under insulation problem. This is an area of opportunity. However, long terms performance and efficacy must be proven.
Water proofing to prevent the ingress of water from outside sources is another method.
However, it has been shown that sometimes these techniques tend to lock in moisture which can also increase corrosivity. Careful selection of insulation materials to prevent those that contain high levels of corrosive impurities such as chlorides is critical to reducing corrosion under insulation. One of the best but most expensive options to prevent corrosion under insulation is the use of protective coating systems. Unfortunately, in most cases, coatings that have been successful for atmospheric service are used under insulation with disastrous results. In it often a surprise that under-insulation service is a more severe condition than straight atmospheric service.