GL™(GL™)Glass Lined Piping System

We recommend GL to all customers who have some troubles about pipe
corrosion in finechemical, pharmaceutical, agrichemical, plastic,
textile, petrochemical and papermaking industries.
GL is made of steel pipe and glass with chemical resistant.

  •  GL
  • What is “GL™”
  • GL™ Characteristics
  • GL™ to special order specs
  • Overseas consultation
  • Downloads

GL (GL and GLP) is the registered trademark standing for "Glass Lining". GL is adopted in unique manufacturing technique that glass tube is expanded to the surface inside steel pipe.
GL has got splendid reputations for anti corrosion, anti adhesion, and anti penetration in chemical industry since 1949.

Corrosion-resistant pipes

Charateristics of GL™ (GL™ and GLP™)  Characteristic

  • ●There are no pinholes in glass-lined layer.
  • ●Glass-Lined layer has extremely tough to mechanical and thermal
    properties. GL can be used under high temperature, pressure, and
    full vacuum.
  • ●Glass-lined surface is smooth, so it can inhibit the growth of
    scale and crystal and the adhesion of them.
  • ●Sealing surface of GL flange connection is polished evenly.
    There is less residual liquid in connected pipe area because pipe and
    sealing surface are at right angles to one another.
  • ●Sealing surface is flat, which leads to install with less tolerance.
    Fixed flange makes pipe installation easier.
Diagram of GL™ (GL™ and GLP™) characteristics
  • Zoom in (1)
  • Zoom in (2)
  • Standard

    Straight pipes, short pipes, and spacers

  • Standard

    90° elbows

  • Standard

    45° bends

  • Standard


  • Standard

    Cross joints

  • Standard


  • Standard

    Reducing tees

  • Standard

    Cross view pipe

  • Standard

    Lantern view pipe

  • Standard

    Closure flange

*Above pictures of each GL item are JIS 10K flange type. ANSI standard flange is also available.
*We can provide welded type fitting. In addition, loosen flange pipe and fitting are available. These are made to order. Please contact with us for more details.

We use the solid glass tube as component of glass lining.
At first, we prepare a no pinhole solid glass tube and steel pipe. Then, we insert the glass tube into steel pipe as illustrated below (left), and heat them together. When inserted glass tube is softened, glass tube is expanded with internal pressure. The pressure makes glass adhere completely to steel pipe which has already been expanded at high temperature. Pipe is shrinking while dropping to normal temperature, and outer steel pipe evenly compresses inner glass tube by the difference of expansion coefficient between steel and glass. This compressive stress raises the mechanical strength of GL. Therefore, lined glass inside steel pipe is at same condition as 'toughened glass'. That is the reason why customer can use GL at high temperature and pressure without fear of breakage.
*Glass tube for GL is specially formed and there is no possibility of a pinhole.


History of GL™ GL History

[GL] pipes launched by Iwaki Glass
Changed glass width of GL flange ends to the current expanded type
Renamed Asahi Techno Glass through a merger
Operations transferred from Asahi Techno Glass to Asahi Glass (Current:AGC Inc.)
Change of commercial distribution, to AGC Technology Solutions (wholly-owned subsidiary of AGC Inc.)