After any structural repair or modification during proof testing, the platform must be tested at what percentage of its rating?

The correct answer is based on industry standards and safety protocols that dictate the testing requirements for platforms after structural repairs or modifications. Following any repairs or modifications, it is essential to verify the integrity and safety of the platform. Testing at 150% of its rated capacity ensures that the platform can withstand conditions beyond its typical use and verifies that the repairs or modifications have been executed properly.

This percentage allows for a margin of safety, addressing potential weaknesses introduced during the repair process. Testing at this level helps identify any structural deficiencies or issues that could arise under normal or excessive load conditions. It is a precautionary measure to ensure the platform's safety before it is put back into service.

In contrast, testing at lower percentages would not adequately verify the strength and safety of the platform post-repair, potentially leading to unsafe operating conditions.