Final answer:
The minimum nominal thickness for isolated hollow masonry piers can vary, but it is generally recommended to be at least 8 inches according to the National Concrete Masonry Association; local building codes and engineering analysis will provide specific requirements.
Step-by-step explanation:
The question pertains to the structural requirements of isolated hollow masonry piers which are crucial in architecture and civil engineering. When designing isolated hollow masonry piers, which support significant weight from structures like stone vaulting, a minimum nominal thickness is required to ensure structural integrity and safety. Beth's commentary on the pressure exerted by stone vaulting necessitates very strong walls and piers to manage the load, while Steven's observation remarks on the delicate appearance through the use of mullions despite this need for strength.
The actual minimum nominal thickness for isolated hollow masonry piers can vary based on local building codes, the materials used, the height of the pier, and the load it must support. As a general recommendation, the National Concrete Masonry Association (NCMA) suggests walls made of concrete masonry units (CMUs) have a minimum nominal thickness of at least 8-inches, which would likely apply to isolated hollow masonry piers as well. However, for an accurate specification, one should consult the relevant local building codes or a structural engineer.