7. The maximum temperature of any surface readily accessible during transport of a package shall not exceed 85°C in the absence of insolation under the ambient condition specified in paragraph 5 of Schedule 12 and the package shall be carried under exclusive use, as specified in paragraph 4 of Schedule 12, if the maximum temperature exceeds 50°C. Account may be taken of barriers or screens to give protection to transport workers without the need for the barriers or screens being subject to any test.