03 Nov 2015 Abrisa Technologies’ preferred glass material for the production of sight glass or sight port windows is SCHOTT® Borofloat®, an optically clear and very versatile borosilicate glass with excellent light transmission and thermal and chemical properties. Borofloat is an excellent choice for operating conditions up to 500ºF. Borofloat glass also provides excellent corrosion, impact, and abrasion resistance.
Soda lime glass can also be selected and provided by Abrisa Technologies for less critical sight glass use in applications up to 300ºF. Soda lime glass does not have the optical clarity of Borofloat.
Used for viewing and monitoring liquid level or flow of a tank, pipeline, or other pressure vessel, sight glass windows can be stepped, flanged, and beveled in either rounds or rectangles and can be tempered if necessary for additional protection and safety. The finished glass disc provided by Abrisa Technologies can be held between two metal frames which are bolted, clamped, or fused to the frame.
Typical sizes are up to 8 inches in diameter and ¾ inches thick. Abrisa technologies does have the capability to provide sight glass as large as 25” in diameter and up to 1inch thick for custom applications. | 
