We report on the design of the Boost interval arithmetic library, a C++ library designed to efficiently handle mathematical intervals in a generic way. The design of the library is unique in that it uses policies to specify the variable behaviors: rounding, checking, comparisons. As a result, with the proper policies, our interval library is able to emulate almost any of the specialized libraries available for interval arithmetic. This library is openly available at http://www.boost.org/ . Using this library, we then examine interval-based filters to compute the sign of a determinant, proposed by Burnikel and two authors of the library, and revisit and extend their experiments. We also illustrate other uses of the library.