This part of EN ISO 11254 describes a test procedure for assurance of power density (energy density) handling capability of optical surfaces, both coated and uncoated. This part of EN ISO 11254 specifies this procedure by providing two test methods for assurance of the power density (energy density) handling capability of optical surfaces. The first method provides a rigorous test that fulfils requirements at a specified confidence level in the knowledge of potential defects. The second method provides a simple test for an empirically derived test level, allowing an inexpensive test.