Specification
PVB thickness guide: 0.38, 0.76, 1.14 or 1.52 mm?
PVB interlayer comes in multiples of a single 0.38 mm ply: 0.38, 0.76, 1.14 and 1.52 mm. Standard architectural glazing uses 0.76 mm. Balustrades, overhead glazing and walkable floors typically move to 1.52 mm. Automotive windscreens standardise on 0.76 mm. Security glazing uses multiple plies above that.
ImageFour strips of clear interlayer film of increasing thickness stacked on a pale surface
Why the ladder is in steps of 0.38 mm
PVB is manufactured at a nominal 0.38 mm ply — 15 thousandths of an inch, a legacy of the imperial origins of the flat glass industry. Every other standard thickness is a multiple of it: two plies give 0.76 mm, three give 1.14 mm, four give 1.52 mm.
This matters practically, because it means a processor can build an intermediate specification by stacking plies rather than sourcing a separate thickness. It also means that where a coloured or printed effect is needed at a particular total thickness, coloured and clear plies can be combined.
Thickness by application
| Thickness | Plies | Typical application | Notes |
|---|---|---|---|
| 0.38 mm | 1 | Decorative glass, interior partitions, picture framing | Minimum for a safety laminate in most standards; insufficient for structural work |
| 0.76 mm | 2 | Architectural facades, windows, automotive windscreens | The default specification for the large majority of laminated glass |
| 1.14 mm | 3 | Higher-load glazing, some balustrade specifications | Used where 0.76 is insufficient but 1.52 is over-specified |
| 1.52 mm | 4 | Balustrades, overhead glazing, walkable floors, stair treads | Standard where post-breakage load-carrying is required |
| 2.28 mm+ | 6+ | Security, blast and bullet-resistant glazing | Multi-ply build-ups, often combined with polycarbonate |
What thickness changes, and what it does not
Increasing interlayer thickness increases post-breakage strength — the capacity of the broken panel to keep carrying load and stay in its frame. This is why balustrades and overhead glazing step up: the governing case is not the intact panel but the broken one.
It also improves acoustic performance and impact resistance, and it accommodates greater glass surface irregularity, which matters when laminating toughened glass with roller wave.
What thickness does not meaningfully change is optical clarity in a quality interlayer, or the UV blocking, which is already above 99% at a single ply. Specifying thicker interlayer for UV reasons is wasted money.
How to select thickness
Work through these in order — the governing standard usually decides it before preference does.
- 01
Identify the governing standard
IS 2553 Part 1 in India, EN ISO 12543 and EN 14449 in Europe, ANSI Z97.1 or CPSC 16 CFR 1201 in North America, AS/NZS 2208 in Australia and New Zealand. The standard sets the minimum for the application class.
- 02
Establish the failure case
For overhead glazing, balustrades and floors, the design case is the broken panel, not the intact one. That normally pushes the specification to 1.52 mm regardless of intact-state calculations.
- 03
Check the structural calculation
Have the structural engineer confirm deflection and post-breakage load capacity for the proposed build-up. Interlayer stiffness is temperature and load-duration dependent, so the calculation must use the correct design conditions.
- 04
Account for the glass surface
Toughened glass carries roller wave and greater surface deviation than annealed. Thicker interlayer accommodates it and reduces optical distortion and bond defects at the edges.
- 05
Add acoustic or security requirements
If sound reduction governs, specify an acoustic grade rather than simply adding thickness. If security governs, expect multi-ply build-ups designed to the specific threat class.
Frequently asked questions
Can I use two 0.38 mm plies instead of one 0.76 mm sheet?
Yes, and this is common practice. The finished laminate performs equivalently, provided both plies are handled and stored correctly and the autoclave cycle accounts for the total interlayer thickness. Stacking plies is also how intermediate and mixed colour specifications are built.
What is the minimum PVB thickness for safety glass?
Most standards set 0.38 mm as the minimum for a laminate to be classified as safety glass, but the practical minimum for architectural work is 0.76 mm. Check the governing standard for the application class rather than working to the absolute minimum.
Does thicker interlayer improve sound insulation?
Somewhat, but far less than switching to an acoustic grade. Acoustic PVB uses a softer core layer specifically tuned to damp the coincidence dip, and outperforms a thicker standard interlayer at the frequencies that matter for traffic and aircraft noise.
Which thickness is used for car windscreens?
0.76 mm is the automotive standard, laminated between two thin glass plies. Acoustic and head-up display variants use specialised wedge or acoustic interlayers at the same nominal thickness.