Steel-cored security.
Conservation areas to data centres.
Bulletproof glazing for data centres, Accoya sash for Grade II listed terraces. Same welded steel section inside every one.
What an architect specifies as a window isn’t quite what we manufacture. We manufacture a welded steel section – sealed, rated, with the glazing channels engineered into the steel itself. That’s the window. The exterior framing – timber for heritage, aluminium for commercial, bare steel for industrial – is what gets fitted to it after.
Sash Vault uses our steel cores wrapped in Accoya or Tricoya timber, profiled to match Victorian, Georgian, or Edwardian originals. Magnificent uses them in concealed installations behind plaster reveals in HNW London residences. Fort Security Doors uses them in bare powder-coated industrial framings. Same steel. Different jobs.
We don’t sell direct. The four customer brands further down handle the four audiences – residential, HNW London, heritage and conservation, commercial. The steel is ours. The brand you buy from depends on where the window’s going.
FE / 09
Placeholder – steel window section mid-fabrication. Before glazing and exterior framing. Replace before launch.
What we manufacture
Four variants. One core.
Every variant uses the same welded steel section, the same engineered glazing channels, the same security rating. What changes is the framing and the glazing performance.
01 / Variant
Fixed security
Single-light or multi-pane fixed installations. Steel section, weather-sealed. The baseline security window for buildings that don’t need ventilation through the opening.
LPS 1175 SR1-SR2
PAS 24
02 / Variant
Operable
Tilt-turn or casement opening windows. Maintains security rating when locked. For occupied buildings that need ventilation without losing the rating.
LPS 1175 SR2-SR3
PAS 24
03 / Variant
Heritage sash
Steel-core sliding sash in Accoya or Tricoya timber. Looks unchanged from the street. Built for Grade-listed buildings and conservation areas.
LPS 1175
PAS 24
04 / Variant
Bulletproof
EN 1063 BR1-BR7 ballistic glazing. Reinforced steel framing. The window equivalent of an SR4 door, for the same kinds of projects.
LPS 1175 SR3-SR4
EN 1063
What’s inside
Manufacturing specifications.
The numbers a specifier actually needs. Drawn straight from the production line, not the brochure.
Steel
Frame
Welded steel section
Source
British, certified mills
Welding
Coded welders, to standard
Construction
Welded throughout, no bolted joints
Framing + cladding
Heritage timber
Accoya, Tricoya – engineered, weatherproof
Commercial
Aluminium, any RAL
Industrial
Bare steel, powder coat or galvanise
Profiles
Period replica or modern flush
Glazing
Anti-bandit (standard)
Laminated, double-glazed
Anti-bandit (enhanced)
Triple-glazed
Ballistic
EN 1063 BR1-BR7
Acoustic
Laminated acoustic, project-specific
Locking + hardware
Locking
Multipoint espagnolette, sash bolts
Operation
Tilt-turn, casement, fixed, sash
Handles
Brushed stainless, brass, chrome, matte black
Restrictors
Where required (child safety, MoD)
Performance
Security rating
LPS 1175 SR1-SR4
Acoustic attenuation
Up to 45dB
Thermal U-value
Project-specific (timber lower than aluminium)
Weather rating
BS 6375
Tested at
BRE, independent labs
Lead time
Bespoke, project-by-project
Independently certified to UK security standards.
Manufactured to the standards specifiers actually require – not the ones we like the sound of.
Manufacturing process
How we manufacture.
01
Steel intake
British-sourced steel sheets and structural members arrive at the factory. Quality-checked on receipt.
02
Cutting + forming
Laser cutting and CNC bending to project specification. Tolerances measured in tenths of a millimetre.
03
Welding + assembly
Coded welders join components to certified standards. Frame, leaf, hardware fixings.
04
Finishing
Galvanising, powder coating, painting. Hardware fitted. Glazing units installed where applicable.
05
Testing + cert
Each product batch independently tested. Certificates issued. Then shipped to the customer brand.
– 07 / 08
Resources
For architects and specifiers.
Specification files, drawings, and samples. Pull what you need straight into your spec.
Four brands. One for conservation areas.
Fort Engineering manufactures these windows. You buy them from one of our four customer brands – one for heritage and conservation work, three for everything else. Find the right one for your project.