Tubular Gage Glass

Made using SCHOTT DURAN® glass, our high quality Tubular Gage (or Gauge) Glasses go beyond the technical requirements for industrial and commercial liquid measurement. Thermal shock resistance, chemical resistance, pressure resistance, and high transparency combine with a range of design options for a unique solution.

Designed to perform in the most demanding conditions

Excellent thermal shock resistance

The exceptional thermal shock resistance of SCHOTT Tubular Gage Glasses enable them to withstand high temperatures and heat fluctuations, ensuring optimum performance in challenging environments.

Robust chemical resistance

The DURAN® borosilicate glass tubing used in our Tubular Gage Glasses offers outstanding chemical and hydrolytic resistance, ensuring minimal deterioration and reliable long-term performance.

Pressure resistance in the harshest environments

SCHOTT offers customers Tubular Gage Glass designed to resist the highest pressures in boiler and tank systems. With pressure ratings from 90-600 psi depending on the end finish, diameter and length required, our gage glasses can perform effectively in both high and low pressure boiler systems.

Wide choice of end finishes

SCHOTT prides itself on working with customers to develop bespoke products tailored closely to their requirements, and end finishes can be cut, ground or fire polished depending on the final application.
Use and Care


Examine the gage glass regularly for any signs of clouding, scratching, erosion, or corrosion. In new processes, the glass should be inspected daily until the need for replacement becomes apparent. This will help establish the routine inspection and routine replacement cycles.


Keep gage glass clean using non-abrasive commercial glass cleaners. Where regular cleaners do not seem to work, use diluted acids such as muriatic acid. Always observe the safety rules when handling hazardous cleaning solutions. Never use wire brushes, metal scrapers, or harsh abrasives, which could scratch the glass.


Scratches, corrosion, chips, surface flaws, or nicks on the surface or edges weaken the gage glass. To examine for these, shine a very bright concentrated light ('Burton Lite' or powerful flashlight) at about a 45˚ angle. Anything that glistens and catches the fingernail or any star-shaped or crescent-shaped mark that glistens, is cause for replacement. Any gage glass that appears cloudy or roughened and will not respond to cleaning procedures should be replaced.


Keep gage glasses in original packaging until ready to install.


Avoid bumping, chipping, or scratching gage glass.

Do's and Don'ts

Warning: Failure to observe the following Do’s and Don’ts can result in glass breakage and an explosive release of pressurized system contents and flying glass particles.


  • DO inspect the gage glass daily, keeping maintenance records, and conduct routine replacements.
  • DO install protective guards where necessary to protect personnel.
  • DO protect the outside of the gage glass from sudden temperature changes, such as drafts, water spray, etc.
  • DO remove all deposits from the seal areas, the glands nuts, glands (where used) and use new packing before installing a tubular gage glass.
  • DO examine gage glass for damage and seals for hard deposits and tears.
  • DO verify that the tubular gage glass, gland, nuts, packing, etc. are the correct size and type before installing.
  • DO ensure that system is protected by safety shut-off system (e.g. safety ball, check).


  • DO NOT work on any gage until you have carefully read these warnings and instructions.
  • DO NOT reuse any tubular glass, packing, or seals.
  • DO NOT use glass that is scratched, chipped, or otherwise damaged. Used glasses may contain damage and are poor safety risks.
  • DO NOT exceed the glass or gage manufacturer’s recommended working pressures or maximum recommended gage glass length.
  • DO NOT bump, impact, or scratch the glass.
  • DO NOT tighten gland nut and packing beyond gage manufacturer’s recommendations.
  • DO NOT operate gages unless gage valve sets are equipped with drain vent and safety ball check.
  • DO NOT attempt to clean glass while the unit is in operation. Cleaning should be done without removing the gage glass.
  • DO NOT attempt to inspect the glass, adjust tie rods, packing nuts or glands, inspect or tighten other fittings without isolating the gage from the pressure vessel and opening the drain vent.
  • DO NOT weld, impact, or sandblast in the gage glass area without protecting the glass.
  • DO NOT have glass-to-metal contact.
  • DO NOT subject gage glass to bending or twisting stress.
  • DO NOT allow the gage glass to contact the bottom of the packing gland.

Want to know more? Let's talk

Whether you need more information, samples, a quote, or advice for a project, we would be delighted to talk to you.

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