Metal fencing is a generic term that can also encompass metal railings; however, when discussed in the context of schools, this will often mean metal mesh fencing.
Mesh fencing will be found in school premises both as a boundary fence and often as a sports field fence to enclose a playing area.
As boundary fencing, it is not as intimidating as palisade fencing, which would make the school seem more prison-like. Different types of mesh fencing include anti-climb, which has small gaps that prevent a grip for fingers to assist in scaling the wall. However, mesh fencing is a see-through barrier, so it is not an intimidating enclosure.
As a pitch enclosure, it simply helps maintain the ball being used to stay within the pitch. Often an additional wooden board will be fitted along the bottom, inside of the fence, to prevent damage from harder balls such as hockey or cricket balls.