# Body Tinted Glass — Heat Absorbing Float

> Body tinted glass is float glass with metal oxide colourants added to the melt, so the colour runs through the full thickness and cannot scratch or peel. It reduces glare by absorbing solar energy rather than reflecting it, which makes it weak as a solar control strategy on its own and, when annealed, prone to thermal stress cracking on sunny or partly shaded elevations.

## What it is

Float glass with **metal oxide colourants added to the melt**, giving bronze,
grey, green, blue or black through the full thickness of the pane.

Because the colour is in the body, it cannot scratch, peel or wear.

## Specification at a glance

| Property | Typical specification |
| --- | --- |
| Standard | IS 14900 for float glass |
| Colours | Bronze, grey, green, blue, black |
| Thickness | 5mm — 12mm common |
| Mechanism | Absorbs solar energy; does not reflect it |
| Heat treatment | Heat-strengthened advisable on sunny elevations |
| Combination | Frequently used as substrate for a coating |

## How tint behaves, honestly

Absorbed energy has to go somewhere. Roughly, a tinted pane re-radiates part of
the absorbed heat inward and part outward, so the net solar reduction is far
smaller than the drop in visible light suggests. A building can end up darker
inside without being much cooler — which then increases artificial lighting
load and works against the ECBC lighting power density target.

That trade-off is the reason tint alone is rarely the right answer in Indian
conditions, and why spectrally selective coatings on a lightly tinted or clear
substrate have largely replaced heavy tints on commercial work.

## Where it still makes sense

Glare control on elevations where a view must be retained · architectural
colour where a specific elevation tone is wanted · as a **substrate** beneath a
solar control coating · secondary and back-of-house glazing where coated glass
is not justified.

## Where projects go wrong

- **Dark tint in annealed glass** on a sunny elevation — thermal stress cracks.
- **Partial shading from a reveal or louvre** across a tinted pane, which
  concentrates the stress at the shadow line.
- **Relying on tint for an SHGC target.**
- **Mixing float batches**, since tint colour varies subtly between runs and
  shows across a continuous elevation.

## Standards referenced

Float glass specification under **IS 14900**. Fenestration SHGC under
**ECBC 2017**. Architectural safety glass to **IS 2553 (Part 1)**.

## Frequently asked questions

### Does tinted glass keep a building cooler?

Partly, and less than people expect. Tint absorbs solar energy rather than reflecting it, so the glass itself heats up and then re-radiates a share of that heat inward. It reduces glare and visible light effectively, but as a solar control strategy on its own it is weak. Meeting an ECBC SHGC target usually needs a coating, with tint as a supporting choice rather than the main mechanism.

### Why does tinted glass break more often?

Because it absorbs heat, the centre of a pane in sun runs much hotter than the shaded edge held in the frame. That temperature difference creates thermal stress, and annealed tinted glass can crack from an edge under it. Dark tints on sunny elevations, or panes partly shaded by a reveal or a louvre, should be heat-strengthened as a matter of course.

### Is tint the same as a reflective coating?

No. Tint is a colourant mixed into the molten glass, so it runs through the full thickness and cannot be damaged or scratched off. A coating is a layer applied to a surface. Tint changes colour and absorption; coatings change reflection and emissivity. They are frequently combined — a tinted substrate with a solar control coating on surface 2.

## Sources

- [IS 14900](https://standards.bis.gov.in/website/published-standards/department-wise) — Transparent float glass — specification
- [ECBC 2017](https://beeindia.gov.in/) — Building envelope — fenestration SHGC
- [IS 2553 (Part 1)](https://standards.bis.gov.in/website/published-standards/department-wise) — Safety glass — architectural

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Source: https://hagerstone.com/materials/body-tinted-glass