1. What are the reasons for replacing OHSAS 18001?
2. Which approach is perfect for the implementation of 45001, functional or systematic? Why that approach?
1. OHSAS 18001 was not an international ISO standard, but was instead maintained by BSI. As such it was not agreed upon by the member countries of ISO as the internationally recognized benchmark for an OH&SMS. With the release of ISO 45001 this is now the case, and in the near future you should expect to see BSI stop updating OHSAS 18001 and then making it obsolete.
2. As ISO 45001 is a management system then the approach of looking at your implementation as a system is important. This does not mean that understanding what certain functions need to do is unimportant, and assigning the roles and responsibilities of functions needs to be done. If you already have your management system in place, it does help to look at how the requirements for the system have changed, and then focus on how each functional responsibility needs to change within your system to meet the new requirements.