NY -- Standard & Poor's CreditWire 3/6/96 -- Standard & Poor's assigns its double-`B'-plus rating to Tanger Properties Ltd. Partnership's $75 million senior unsecured notes due 2001. At the same time, Standard & Poor's affirms its double-`B'-minus rating on the company's $75 million convertible preferred stock, issued by Tanger Factory Outlet Centers Inc. (SKT) Tanger Properties Ltd. Partnership is the operating partnership of SKT. The ratings reflect SKT's diversified portfolio, conservative dividend payout ratio, and good cash flow coverage, which combine to somewhat offset an improved but still moderately encumbered property portfolio. The notes represent a drawdown from a recently filed $200 million mixed shelf. Proceeds will be used mainly to repay existing mortgage debt. Greensboro, N.C.-based SKT is an