Security bars (also called burglar bars or window grilles) are metal bars or grilles fitted in front of or inside a window, light well or cellar opening to prevent forced entry. They form a physical barrier that makes it impossible — or at least very slow — for an intruder to access the interior of a building.
Forms and execution
Security bars come in many configurations:
- Vertical bars — usually solid round or square steel, 16–25 mm
- Wrought-iron grilles — decorative and protective at the same time
- Grates — cross-welded or rolled grates for light wells and cellar openings
- Removable bars — released with a key or latch (important for fire safety)
- Bedded into masonry — bars with split ends are mortared deep into the wall on both sides
Application
Security bars are mainly used on vulnerable openings:
- Basement and souterrain windows — low-level windows that are easy to reach
- Light wells and area entries — interrupting an open shaft to the basement
- Ground-floor shops and offices — often combined with roller shutters
- Heritage buildings — wrought-iron grilles are frequently part of the original architecture
- Skylights and roof lights — fitted under the glazing to deter roof entry
Codes and regulations
In the UK and EU, the relevant standards are BS EN 1627–1630 (resistance classes RC 1 to RC 6). When bars are fitted on an escape route, they must be openable from inside without a key or tools — otherwise an unacceptable fire risk arises.
Key considerations
- Anchoring — bars are only effective when firmly fixed into masonry or concrete (at least 75 mm deep)
- Corrosion resistance — galvanised or powder-coated steel for outdoor use
- Appearance — wrought-iron work can enhance a facade; industrial bars often look harsh
- Fire safety — combine with an inside-release model on escape windows
Related terms
- Burglar-resistant hardware
- Cellar window
- Light well
- Security glazing
- Roller shutter
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