Transparent Protective Window Systems

  • >50% reduction in weight & thickness
  • Significant abrasion resistance
  • Improved night vision transmittance
  • Reduced risk of delamination
  • ‘Breaks’ the projectile
  • Chemically inert

SAFirE™ Transparent Protection Solutions address the ever-increasing demands of high-velocity (kinetic energy) projectile protective performance at a reduced weight and thickness. Results from our designs have shown a greater than 50% reduction in weight and thickness at improved kinetic energy protective performance compared to traditional glass solutions. Alternatively, performance can be significantly enhanced without increasing weight and thickness. Sapphire is superior over ALON® and Spinel in optical and stopping power protective performance and is immediately available for high volume, large aperture platforms.

Our SAFirE transparent protective product line incorporates EFG™ Sapphire, the hardest transparent material 2nd only to diamond, which provides an extremely hard and abrasion-resistant strike face that ‘breaks’ the projectile upon impact. SAFirE solutions have been designed to meet a variety of threat levels at reduced weight and thickness while providing improved situational awareness in both the visual and Infra-Red spectra. SAFirE is currently being used in both ground vehicle and rotary-wing platforms.

What we offer is that for whatever the threat protection request may be, a sapphire solution will be half as thick and half the weight of any glass solution meeting the same threat protection. Sapphire is only used for higher levels of protection such as NIJIII-NIJIV and STANG levels.

Choosing the proper material depends on forces experienced by the part, required wavelength range of the optics, overall weight envelope of the platform, and other design constraints.

Material Comparison to Saint-Gobain Synthetic Sapphire Window

Material Type Density g/cc Areal Density
Young's Modulus Gpa Knoop Hardness
Fracture Toughness
Thermal Conductivity
Thermal Expansion
SAPPHIRE Ceramic 3.9 20.2 435 2000 2 32 60
ALON® 3.69 19.2 323 1850 2 9.6 56
Spinell 3.58 18.6 277 1645 1.5 - 2 14.7 60
Soda-Lime Glass Glass 2.52 13.1 69.6 585 0.75 0.9 - 1.3 90
Li-Alumino-Silicate Glass-Ceramic 2.52 13.1 88.5 570 1.1 1.6 - 1.3 0


Uses for Safety Window Sapphire


  • Ground vehicles
  • Rotary wing aircraft
  • Protective shields
  • Personal protection
  • Building/facility security
Armored vehicle with Safety windows

Sapphire (Al2O3) Material Properties Brochure

PDF | 1.21 MB