What must be done every five years regarding hydrostatic testing?

The correct answer highlights that hydrostatic testing is essential not only as a recommended safety measure but also reflects regulatory requirements established by safety standards affecting equipment like fire hoses and cylinders. Hydrostatic testing ensures that these essential items can withstand pressure and do not pose a safety risk during usage. Regular testing every five years aims to detect deterioration and maintain the reliability of equipment, which is crucial for first responders' safety and effectiveness during emergencies.

By routinely performing hydrostatic tests, organizations can proactively avoid potential failures that could lead to catastrophic incidents. While there may be recommendations for more frequent testing based on usage or manufacturer guidance, the essential aspect here is the regular cycle to ensure equipment safety and compliance with safety standards. Thus, recognizing this procedure as an integral part of the safety protocol ensures the preparedness and operational readiness of firefighting equipment.