According to ASME B30.3, how often should a periodic inspection be conducted in normal service conditions?

Periodic inspections are crucial for maintaining the safety and functionality of tower cranes as outlined in the ASME B30.3 standards. These inspections are to ensure that any wear, damage, or potential hazards are identified and addressed before they lead to malfunction or accidents. Under normal service conditions, the standard specifies that these inspections should occur semi-annually, which translates to at least twice a year, or annually. This frequency strikes a balance between ensuring safety and practicality for operators and owners, allowing enough time for preventive maintenance while minimizing operational downtime.

In contrast, monthly or weekly inspections would be excessive for normal service conditions and might overwhelm operators with administrative and operational burdens. Quarterly inspections do not align with the ASME B30.3 recommendations either, as they fall short of the required semi-annual standard. Thus, semi-annually to annually remains the correct answer, reflecting established industry practices for maintaining safe operating conditions.