There is not a specific requirement from OSHA regarding storage racks. However, in terms of general storage safety, OSHA requires under 1910.176(b) that, “Storage of material shall not create a hazard. Bags, containers, bundles, etc., stored in tiers shall be stacked, blocked, interlocked and limited in height so that they are stable and secure against sliding or collapse.”
OSHA also requires at 1910.159(c)(10) regarding sprinkler clearance that when stacking items, “The minimum vertical clearance between sprinklers and material below shall be 18 inches (45.7 cm).”