No barrier on the list that accompanies the question does that.
Safety goggles form a barrier between your eyes and something that might damage them.
A Zener barrier is an intrinsic safety equipment. It allows short circuiting of cables to each other or to metallic parts connected to ground without danger.
safety Gate
safety Gate
So that you, yourself, do not end up needing first aid.
for safety purposes
Usually in the bays. Bays act as a natural barrier from rough seas.
There are many companies that offer online employee safety training classes. The benefit of an online class is that it is available on demand when it is convenient for your employees to participate and would be available for subsequent new hires without needing to bring back a trainer for a one or two person class.
On Nov 7, 1916 the drawbridge was opened and the safety barrier lowered but the motorman failed to see the barrier. It was claimed that the red lantern had not been placed on the barrier. The trolley dropped into the Fort Point Channel killing 47 people.
Without the Aid of a Safety Net was created on 1993-12-29.
This is called safety aid