http://www.theuiaa.org/upload_area/Safe ... ILURES.pdf
UIAA has published a dramatic report with the conclusion that 304 stainless steel bolts are a part of a "horror movie" and they should not be used outdoors. This means that all stainless steel 304 bolts should be removed by Titanium or 316 steel bolts and that 99% of all (1 million???) bolts placed at all crags in the world are at risk.
Most critical factors are: “moderate” relative humidity location, areas NOT washed by rain, high temperatures. Limestone/dolomite is generally worse than sandstone or granite (karst rock is the worst case). UIAA says that within months some bolts will only hold few tens of kilograms.
Here are some answers from UIAA, when asked for clarifications of their dramatic but unclear recommendations that Titanium must be used and why the normal stainless steel quality 304 should be avoided also at inland vertical granite crags etc.
"Tests shall start soon to clarify exactly which stainless steels material
will be suitable (and not only titanium) and the standard should be
updated next year.
The UIAA Safety Commission does not find 304 steel bolts/anchors appropriate for outdoor use because 304 anchors are not expected to last 50 years in the outdoor environment."
corrosivi saluti
