The present invention is directed to a modular roll-up partition assembly, such as a rolling protective shutter, implementing an improved tension adjustment mechanism for torsion springs used in roll-up partition assemblies. In one embodiment, the roll-up partition assembly of the present invention includes a tension adjustment mechanism to adjust the tension of a torsion spring connected between a support rod and the partition support member. The tension adjustment mechanism rotates the support rod to move the end of the torsion spring connected to the rod relative to the end of the torsion spring connected to the partition support member. Unlike previous roll-up partition assemblies which permitted adjustment of the torsion spring tension only in increments of a full rotation of the support member, the tension adjustment mechanism facilitates fine adjustment of the torsion spring in increments of less than a full rotation of the partition support member.