What physical requirement is stated for the collar protecting the shutoff valves?

The requirement for the collar protecting the shutoff valves to withstand a blow from any direction equivalent to that of a 30 lb weight emphasizes the importance of safety and durability in installations. This specification ensures that the collar can endure physical impacts that could otherwise compromise the integrity of the shutoff valves. By requiring the collar to be able to withstand such forces, it significantly reduces the risk of accidental damage that could lead to leaks or failures, which are critical in maintaining safe operations in plumbing and gas systems. This physical resilience is vital for protecting the shutoff valves from external pressures or impacts that might occur in everyday scenarios, thus ensuring reliable malfunction protection and operational safety.