The philosophy of two means of protection has not changed from 2nd to 3rd edition. It still relies on the concept that if a person has two levels of protection and one fails that person is still safe due to the 2nd level. Now the standard breaks down the equipment into Operator Protection and Patient Protection. The patient protection carries slightly more stringent requirements, but both continue the use of two levels. The equipment manufacturer decides whether a devices is Operator or Patient Protection and that becomes part of the Risk Management File.