WET STORAGE
In order to avoid customer complaints and help improve overall quality performance of prepainted products, we would like to offer this friendly reminder. Please alert your customers/end users about the hazards of wet field storage. Moisture and corrosion issues can arise from precipitation if material is not properly stored.
It is recommended by the NCCA that prepainted material be stored in an indoor facility isolated from the elements. If material must be stored outside proper precautions must be taken.
If the bundles are stored on the ground, a plastic cover must be put down under the bundle to minimize condensation of water from the ground onto the panels. The bundles must be then raised off the plastic ground cover to avoid contact with water puddles and allow for air circulation around the bundles to promote drying of condensed water. The panels must be stored at an angle to promote drainage of water off the bundle. Sufficient support must be provided to the raised and angled bundles to avoid excessive bowing, which may result in low spots that could hold water.
The bundle must be completely sheltered with a loose fitting waterproof tarp to protect the bundle during rain or snow events, but allow for air circulation and drying of condensed water.
In addition to water there are other important factors that contribute to the corrosion of stored prepainted panels. These factors are temperature and exposure time. Given enough time, panels will eventually become wet and storage corrosion may occur under most job site conditions. Even in a well protected bundle the natural temperature and humidity variations will cause water to condense on and between the panels. Shipping the bundle from a cold area to a warm area will cause water to condense not only on the bundle but also between the panels.
In conclusion, storage corrosion can be prevented by:
- Decreasing water contact.
- Moderating temperature extremes.
- Immediately drying moisture exposed bundles.
- Reducing site storage time.