Experience the unparalleled leak resistance, ease of maintenance, and safety in our Model L flange industrial sight window. You will discover that sight glasses that experience high temperature and pressure cycles do not have to leak or be difficult to maintain! Our Model L sight glass features a proprietary sidewall seal that makes it the safest, most user-friendly ASME B16.5 flanged sight glass available. With this unique seal, window re-sealing is safe and easy. Simply torque down the flange bolts to re-seal the window; it is essentially impossible to damage the glass by over-torquing the bolts. Our laminated glass options ensure total safety even when one of the glass layers is cracked; the remaining layer is capable of holding maximum rated conditions indefinitely with full design margin of safety. 

The Model L is available in configurations that will withstand temperatures from cryogenic to 450F, and full vacuum to 150 PSI. It really shines in high temperature and pressure conditions; it does not spring leaks like typical gasket sealed windows. Flange bodies can be supplied with carbon steel or stainless steel, and mill test reports are included. The glass pane can be made of tempered soda lime, tempered borosilicate or fused quartz. Laminated glass is available in tempered borosilicate and tempered soda lime. We stock our Model L industrial sight glass for ASME B16.5 flange sizes of 2, 3, 4, 6, and 8 inches.