One reason is that stainless steels, when they corrode, do not corrode in a general fashion but moreso in a localized fashion. They are susceptible to microscopic galvanic action inherent to the material, sometimes exacerbated by the soil environment interaction. [sig][/sig]
In addition stainless steel is highly corrosive when in the presence of chlorides. (stress cracking). If you indeed needed to bury SS pipe, I would use a duplex type stainless such as 2205 or 2507. [sig]<p>Mroz<br><a href=mailto:dan@mroz.com>dan@mroz.com</a><br>[/sig]