Chlorides can cause various types of localized corrosion in austenitic stainless steels like 316L. Factors that influence chloride induced corrosion include the composition of the alloy, chloride ion concentration, oxygen concentration, stress level, temperature, and pH. Even ppm levels of chlorides can be problematic depending on the environment so it is difficult to set a maximum chloride content that is "safe." If chlorides are implicated in corrosion of an austenitic stainless steel, a more resistant alloy like a duplex stainless steel should be used. Since 316L is most always attacked by a form of localized corrosion (pitting, crevice corrosion, SCC, etc.), a corrosion allowance is not helpful. Corrosion allowances are only used when one is trying to deal with alloys that tend to corrode uniformly such as carbon steel.