ASME / ANSI B16.5 Flanged Sight Glass Windows
Select Stock Configurations Below
  • ASME (also know as ANSI) – Industrial, flanged sight glasses
  • Exhibits no outgassing or contamination of most systems*
  • Long working life
  • No maintenance required
  • Tested to high safety factor to insure safety & reliability
  • Exceeds all industry and MIL standards
  • Engineered, Manufactured and tested at the Rayotek U.S. facility

ASME (ANSI) flanged sight glass windows are engineered to endure harsh environments where extreme chemical, thermal, pressure and mechanical conditions are the norm. These flanged sight glasses are workhorses of the industrial world and Rayotek ASME flanged sight windows meet the challenge. The window is fused or bonded to a metal housing creating a hermetically sealed single-piece sight glass unit.

Our ASME flanged sight windows are designed for all B16.5 classes: 150, 300, 400, 600, 900, 1500 and 2500 psi. Custom higher pressures are available, please see Custom and exotic Sight Window page.

Click Configuration for specifications and part numbers.

Temperature Range
General purpose indicator & observation.  NACE MR0175/ISO15156 compliant
-100C - 300C
Optical quality & chemical durability for visible spectrum viewing at lower cost
-100C  - 300C
Optical quality, extreme scratch and chemical resistance for UV, visible & IR viewing
-100C  - 200C
General purpose flat window for imaging and precision optical measurement in chemical and gas environments
-100C  - 200C
Super high temp for UV, IR & visible inspection, pyrometry & indicators; air, gas and vacuum systems where <10-8 bar-CC/sec leakage is acceptable**
-100C  -900C


  • Petroleum & chemical refining, processing, containment & transportation
  • Incinerators, ovens & furnaces
  • Biofuel plants
  • Waste processing & storage
  • Transport vessels such as trucks, trains & ships

Rayotek sight windows can transmit a broad range of wavelengths and are capable of operating under extreme temperature, pressure, chemical and mechanical conditions. The selection of window and housing materials will determine capabilities.

† Alternative materials are available upon request including, but not limited to:
        Housing: duplex, aluminum, Monel, Inconel, plastics and alumina
        Window: borosilicate (Pyrex®), diamond, Zinc Selenide, fused silica, germanium, MgF2, silicon and YAG

*  For systems where purity & cleanliness are critical, Rayotek recommends testing the Sight Window for specific chemical compatibility.
    Call for information.

** Typical leak rate is 10-8 bar-CC/sec. for air at 22C. Actual leak rate TBD based on window size and maximum operating temperature.
    Call for information.

Contact Us with questions or to discuss your requirements and we'll be happy to help