Security Fences are traditionally, but not exclusively, used around factories, schools and parks.
Being a tubular type fence they consist of two rails with connecting vertical rods. There are several different types, mainly indicating their strength:
Light
weight -- 38x25 rail with 16mm tubes. (round) Light
supreme -- 40x40 rail with 16mm tubes. Medium
duty -- 40x40 rail with 19mm tubes. (round) Heavy
duty -- 40x40 rails 25mm tubes. (square)
An example
of factory fence: Please note the sliding gate closing the yard.
With fences come gates.
Above left a personal access gate. Right a motorized vehicle access
sliding gate.
Light
weight -- 38x25 rail with 16mm tubes. (round) 
