Employees shall be required to pass a written rules examination every __________ years.

The requirement for employees to pass a written rules examination every two years is rooted in the need for regular reinforcement of safety protocols, procedures, and technical knowledge essential to the practice of thermite welding. This biannual testing ensures that employees remain current with industry standards and best practices, helping to mitigate risks associated with the operation.

By mandating this frequency, organizations can also effectively address any updates or changes in regulations, technology, or safety practices that may have emerged since the last examination. Regular assessments facilitate a culture of continuous learning and awareness, which is crucial in maintaining high safety standards and operational efficiency in a potentially hazardous work environment.

The other options suggest a longer interval for examination, which may not ensure the same level of compliance, knowledge retention, and safety awareness necessary for effective thermite welding operations.