The purpose of barrier[/controls/safeguards] management is to make the kind of implicit controls explicit:  to be clear about exactly

1. what controls are relied on to prevent incidents,
2. to understand their characteristics,
3. to have an understanding of how reliable they can be expected to be, and
4. to know what needs to be done to ensure the controls are implemented and continue to function throughout their expected operational lifetime.

Source: Human Factors in Barrier Management, Prepared by a CIEHF Working Group comprising: Ron McLeod, Ian Randle, Rob Miles, Ian Hamilton, John Wilkinson, Christine Tomlinson, Gyuchan Thomas Jun, Tony Wynn. December 2016