TECHNICAL ADVICE

PVB vs SGP Glazing Interlayers

What is a glazing interlayer?

Laminated glass is a type of safety glass where two or more panes are bonded together to form a unit.

Interlayers are used in this process to bond the two panes together when manufacturing this type of glass.

Using a security interlayer has many advantages, more information on these benefits can be found here.

This interlayer is often made from PVB (Poly Vinyl Butyral), but there are many other interlayers available.

PVB is one of the oldest interlayers used in laminated glass, with its use dating back to the 1930s. It is used widely to laminate glass used in the automotive industry.

SGP (SentryGlas Plus) is another popular security interlayer used in laminated glass, with increased strength and security.

Heat soaked and toughened glass can be incorporated into the laminated glazing to create a secure pane that will be tough to break and even tougher to break through.

sieger frameless glass balustrade internal on stairs

What is a PVB interlayer?

Poly Vinyl Butyral is a tough plastic resin that is used in between two panes of glass to bond them together.

It’s made from polyvinyl alcohol through reacting it with butyraldehyde.

This resin is placed in between glass panes then a combination of heat and pressure is applied to create one laminated pane.

Sieger often use a PVB interlayer for internal glass balustrades and an SGP interlayer for external frameless glass balustrades.

 

What is an SGP interlayer?

SentryGlas Plus is an ionoplast interlayer that when used to laminate glass boasts extremely high weather resistance and strength levels.

The two are usually manufactured using the same process of applying heat and pressure to the glass to melt the layer in between which then acts as a glue, bonding the panes together.

Glass that uses this tough plastic interlayer is more costly than glass that uses PVB, however it has many advantages such as greater clarity.

sieger thermally broken floorlight with laminated outer pane
sieger thermally broken flush glass floorlight with laminated outer pane

What are the main differences between the two?

Both interlayers provide strength and security in the event of breakage, however there are significant differences in their performance levels.

SGP reportedly has 5 times the strength and 100 times the rigidity of standard PVB.

For external glazing systems that use low iron glass or glazing with exposed edges like frameless glass balustrades, SGP is clearer than PVB making it an ideal interlayer for these systems.

If a glazing system has exposed edges, such as a frameless glass balustrade, as PVB is susceptible to absorbing moisture it may start to decay after a year or two. This can be avoided by using a metal capping along the balustrade.

When an internal glazing system has exposed edges, such as the Sieger Frameless Glass Balustrade System, PVB is commonly used as it is not exposed to the weather elements and does not need to be waterproof.

In a glass unit with a PVB interlayer, if one side of the unit is damaged the glass will stay in place, however if both sides are broken then the glass may fall out of the unit.

With an SGP interlayer, even if the glass on both sides of the pane are damaged,  it will usually stay in place.

Which one is right for my project?

We recommend using PVB for internal glazing as SGP can be more costly and the higher performance levels are not required.

For external glazing with exposed edges, SGP should be used to avoid discolouration and disintegration from weathering.

Here at Sieger we use toughened and laminated glass as standard for the outer panes of floorlights and inner panes of our rooflight systems.

This protects people in the event of breakage from injuries from shattered glass.

 

For more information contact our technical team or book a showroom visit where you can discuss your project in person and get advice on which interlayer is right for you.

Speak to the team today to book a showroom visit or for more information. Call 01494 722 882 or email sales@siegersystems.co.uk

sieger lantern rooflight with pvb interlayer on inner pane

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