Film-to-Glass Primary Stress Score Reference Chart
This chart lets you calculate a film-to-glass thermal stress score by hand, using the same primary stress data behind our online Film to Glass Compatibility Calculator. If you'd rather have the calculator do the math for you, use that tool directly — this page is for anyone who wants to work through the numbers manually or double-check a result.
How to Use This Chart
- Find your film below and look up its primary stress score for your glass type and thickness.
- Add your site condition points from the table below to get your Additional Stress total.
- Add the two together for your Total Stress Score.
- Compare the total against the thresholds table to find your minimum required glass specification.
Step 1: Additional Stress Points
| Factor | Condition | Points |
|---|
| Summer Temperature | Below 109°F | 0 |
| 109°F – 115°F | +1 |
| Over 115°F | +2 |
| Glass Condition | No scratches or chips | 0 |
| Badly scratched | +2 |
| Chipped edges | Automatic NR |
| Pane Size | Under 50 sq ft | 0 |
| 50 – 100 sq ft | +1 |
| Over 100 sq ft | Automatic NR |
| Gasket Condition | Healthy rubber gasket | 0 |
| Deteriorated rubber gasket | +1 |
| No rubber gasket | +2 |
| Frame Material | Steel or concrete frame | +1 |
| Wood frame* | 0 |
| Plastic / PVC frame | 0 |
| Aluminum frame | 0 |
| Shadow Type | No shadows | 0 |
| Straight shadow | +1 |
| "L" shaped shadow | +2 |
| "T" or "V" shaped shadow | +3 |
| Altitude | Below 2,000 ft | 0 |
| 2,000 – 7,000 ft | +1 |
| 7,000 – 10,000 ft | +2 |
| Over 10,000 ft | +3 |
| Window Treatment | Less than 4 inches from glass | +1 |
| No treatment, or more than 4 inches away | 0 |
*Wood frames require inspection before installing film — check for exposed fasteners near the glass edge, paint buildup, warping, and deteriorated glazing compound. When in doubt, consult a glazier.
Step 2: Score Thresholds
| Total Score | Requirement |
|---|
| 10 or under | Any glass — standard annealed is fine |
| 11–14 | Requires heat strengthened glass |
| 15–18 | Requires fully tempered glass |
| 19 or higher, or automatic NR | Not Recommended, regardless of glass type |
Step 3: Primary Stress Scores by Film
Find your film below, then look up your exact glass type and thickness. Add this number to your Additional Stress total from Step 1 to get your Total Stress Score. "NR" in a cell means that film-and-glass combination is not recommended regardless of site conditions.
Dualflex
Dualflex 5%
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 5 | 5 | 6 |
| Clear Dual Pane | 7 | 7 | 8 |
| Clear Triple Pane | 8 | 8 | 10 |
| Tinted Single Pane | 7 | 7 | 8 |
| Tinted Dual Pane | 7 | 7 | 8 |
| Low-E Dual Pane | 9 | 9 | 10 |
| HP Low-E Dual Pane | 4 | 4 | 5 |
| Clear Single Pane - Laminated | 5 | 5 | 6 |
| Clear Dual Pane - Laminated | 7 | 7 | 8 |
| Tinted Single Pane - Laminated | 7 | 7 | 8 |
| Tinted Dual Pane - Laminated | 7 | 7 | 8 |
Dualflex 15%
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 6 | 6 | 7 |
| Clear Dual Pane | 9 | 9 | 10 |
| Clear Triple Pane | 11 | 11 | 13 |
| Tinted Single Pane | 7 | 7 | 8 |
| Tinted Dual Pane | 8 | 8 | 9 |
| Low-E Dual Pane | 9 | 9 | 10 |
| HP Low-E Dual Pane | 4 | 4 | 5 |
| Clear Single Pane - Laminated | 6 | 6 | 7 |
| Clear Dual Pane - Laminated | 9 | 9 | 10 |
| Tinted Single Pane - Laminated | 7 | 7 | 8 |
| Tinted Dual Pane - Laminated | 8 | 8 | 9 |
Dualflex 25%
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 6 | 6 | 7 |
| Clear Dual Pane | 10 | 10 | 11 |
| Clear Triple Pane | 12 | 12 | 14 |
| Tinted Single Pane | 8 | 8 | 9 |
| Tinted Dual Pane | 5 | 5 | 6 |
| Low-E Dual Pane | 10 | 10 | 11 |
| HP Low-E Dual Pane | 4 | 4 | 5 |
| Clear Single Pane - Laminated | 6 | 6 | 7 |
| Clear Dual Pane - Laminated | 10 | 10 | 11 |
| Tinted Single Pane - Laminated | 8 | 8 | 9 |
| Tinted Dual Pane - Laminated | 5 | 5 | 6 |
Dualflex 35%
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 6 | 6 | 7 |
| Clear Dual Pane | 8 | 8 | 9 |
| Clear Triple Pane | 9 | 9 | 12 |
| Tinted Single Pane | 6 | 6 | 7 |
| Tinted Dual Pane | 5 | 5 | 6 |
| Low-E Dual Pane | 8 | 8 | 9 |
| HP Low-E Dual Pane | 4 | 4 | 5 |
| Clear Single Pane - Laminated | 6 | 6 | 7 |
| Clear Dual Pane - Laminated | 8 | 8 | 9 |
| Tinted Single Pane - Laminated | 6 | 6 | 7 |
| Tinted Dual Pane - Laminated | 5 | 5 | 6 |
Chromoflex
Chromoflex 15%
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 5 | 5 | 6 |
| Clear Dual Pane | 6 | 6 | 7 |
| Clear Triple Pane | 7 | 7 | 9 |
| Tinted Single Pane | 8 | 8 | 9 |
| Tinted Dual Pane | 9 | 9 | 10 |
| Low-E Dual Pane | 9 | 9 | 10 |
| HP Low-E Dual Pane | 4 | 4 | 5 |
| Clear Single Pane - Laminated | 5 | 5 | 6 |
| Clear Dual Pane - Laminated | 6 | 6 | 7 |
| Tinted Single Pane - Laminated | 8 | 8 | 9 |
| Tinted Dual Pane - Laminated | 9 | 9 | 10 |
Chromoflex 35%
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 4 | 4 | 5 |
| Clear Dual Pane | 5 | 5 | 6 |
| Clear Triple Pane | 6 | 6 | 8 |
| Tinted Single Pane | 7 | 7 | 8 |
| Tinted Dual Pane | 7 | 7 | 8 |
| Low-E Dual Pane | 7 | 7 | 8 |
| HP Low-E Dual Pane | 4 | 4 | 5 |
| Clear Single Pane - Laminated | 4 | 4 | 5 |
| Clear Dual Pane - Laminated | 5 | 5 | 6 |
| Tinted Single Pane - Laminated | 7 | 7 | 8 |
| Tinted Dual Pane - Laminated | 7 | 7 | 8 |
Sputterflex
Sputterflex Neutral 20%
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 7 | 7 | 8 |
| Clear Dual Pane | 11 | 11 | 12 |
| Clear Triple Pane | 12 | 12 | 14 |
| Tinted Single Pane | 8 | 8 | 9 |
| Tinted Dual Pane | 11 | 11 | 12 |
| Low-E Dual Pane | 11 | 11 | 12 |
| HP Low-E Dual Pane | 4 | 4 | 5 |
| Clear Single Pane - Laminated | 7 | 7 | 8 |
| Clear Dual Pane - Laminated | 11 | 11 | 12 |
| Tinted Single Pane - Laminated | 8 | 8 | 9 |
| Tinted Dual Pane - Laminated | 11 | 11 | 12 |
Sputterflex Neutral 35%
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 6 | 6 | 7 |
| Clear Dual Pane | 9 | 9 | 10 |
| Clear Triple Pane | 11 | 11 | 12 |
| Tinted Single Pane | 7 | 7 | 8 |
| Tinted Dual Pane | 8 | 8 | 9 |
| Low-E Dual Pane | 9 | 9 | 10 |
| HP Low-E Dual Pane | 4 | 4 | 5 |
| Clear Single Pane - Laminated | 6 | 6 | 7 |
| Clear Dual Pane - Laminated | 9 | 9 | 10 |
| Tinted Single Pane - Laminated | 7 | 7 | 8 |
| Tinted Dual Pane - Laminated | 8 | 8 | 9 |
Sputterflex Bronze 20%
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 5 | 5 | 6 |
| Clear Dual Pane | 7 | 7 | 8 |
| Clear Triple Pane | 9 | 9 | 11 |
| Tinted Single Pane | 7 | 7 | 8 |
| Tinted Dual Pane | 7 | 7 | 8 |
| Low-E Dual Pane | 9 | 9 | 10 |
| HP Low-E Dual Pane | 4 | 4 | 5 |
| Clear Single Pane - Laminated | 5 | 5 | 6 |
| Clear Dual Pane - Laminated | 7 | 7 | 8 |
| Tinted Single Pane - Laminated | 7 | 7 | 8 |
| Tinted Dual Pane - Laminated | 7 | 7 | 8 |
Sputterflex Bronze 35%
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 5 | 5 | 6 |
| Clear Dual Pane | 6 | 6 | 7 |
| Clear Triple Pane | 8 | 8 | 10 |
| Tinted Single Pane | 6 | 6 | 7 |
| Tinted Dual Pane | 7 | 7 | 8 |
| Low-E Dual Pane | 7 | 7 | 8 |
| HP Low-E Dual Pane | 4 | 4 | 5 |
| Clear Single Pane - Laminated | 5 | 5 | 6 |
| Clear Dual Pane - Laminated | 6 | 6 | 7 |
| Tinted Single Pane - Laminated | 6 | 6 | 7 |
| Tinted Dual Pane - Laminated | 7 | 7 | 8 |
Panashield
Panashield 40%
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 7 | 7 | 8 |
| Clear Dual Pane | 12 | 12 | 13 |
| Clear Triple Pane | NR | NR | NR |
| Tinted Single Pane | 10 | 10 | 11 |
| Tinted Dual Pane | 10 | 10 | 11 |
| Low-E Dual Pane | 12 | 12 | 14 |
| HP Low-E Dual Pane | 6 | 6 | 7 |
| Clear Single Pane - Laminated | 8 | 8 | 9 |
| Clear Dual Pane - Laminated | 12 | 12 | 13 |
| Tinted Single Pane - Laminated | 10 | 10 | 11 |
| Tinted Dual Pane - Laminated | 10 | 10 | 11 |
Panashield 50%
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 6 | 6 | 7 |
| Clear Dual Pane | 6 | 6 | 7 |
| Clear Triple Pane | 14 | 14 | NR |
| Tinted Single Pane | 7 | 7 | 8 |
| Tinted Dual Pane | 6 | 6 | 7 |
| Low-E Dual Pane | 8 | 8 | 9 |
| HP Low-E Dual Pane | 4 | 4 | 5 |
| Clear Single Pane - Laminated | 6 | 6 | 7 |
| Clear Dual Pane - Laminated | 6 | 6 | 7 |
| Tinted Single Pane - Laminated | 7 | 7 | 8 |
| Tinted Dual Pane - Laminated | 6 | 6 | 7 |
Panashield 70%
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 5 | 5 | 6 |
| Clear Dual Pane | 5 | 5 | 6 |
| Clear Triple Pane | 10 | 10 | 13 |
| Tinted Single Pane | 6 | 6 | 7 |
| Tinted Dual Pane | 5 | 5 | 6 |
| Low-E Dual Pane | 7 | 7 | 8 |
| HP Low-E Dual Pane | 3 | 3 | 4 |
| Clear Single Pane - Laminated | 5 | 5 | 6 |
| Clear Dual Pane - Laminated | 5 | 5 | 6 |
| Tinted Single Pane - Laminated | 6 | 6 | 7 |
| Tinted Dual Pane - Laminated | 5 | 5 | 6 |
Decorative
White Frost
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 5 | 5 | 5 |
| Clear Dual Pane | 7 | 7 | 7 |
| Clear Triple Pane | 8 | 8 | 8 |
| Tinted Single Pane | 7 | 7 | 7 |
| Tinted Dual Pane | 7 | 7 | 7 |
| Low-E Dual Pane | 8 | 8 | 8 |
| HP Low-E Dual Pane | 6 | 6 | 7 |
| Clear Single Pane - Laminated | 5 | 5 | 5 |
| Clear Dual Pane - Laminated | 7 | 7 | 7 |
| Tinted Single Pane - Laminated | 7 | 7 | 7 |
| Tinted Dual Pane - Laminated | 7 | 7 | 7 |
White Out
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 6 | 6 | 7 |
| Clear Dual Pane | 9 | 9 | 10 |
| Clear Triple Pane | 11 | 11 | 13 |
| Tinted Single Pane | 7 | 7 | 8 |
| Tinted Dual Pane | 8 | 8 | 9 |
| Low-E Dual Pane | 9 | 9 | 10 |
| HP Low-E Dual Pane | 4 | 4 | 5 |
| Clear Single Pane - Laminated | 6 | 6 | 7 |
| Clear Dual Pane - Laminated | 9 | 9 | 10 |
| Tinted Single Pane - Laminated | 7 | 7 | 8 |
| Tinted Dual Pane - Laminated | 8 | 8 | 9 |
Black Out
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 16 | 16 | 16 |
| Clear Dual Pane | NR | NR | NR |
| Clear Triple Pane | NR | NR | NR |
| Tinted Single Pane | 16 | 16 | 16 |
| Tinted Dual Pane | NR | NR | NR |
| Low-E Dual Pane | NR | NR | NR |
| HP Low-E Dual Pane | NR | NR | NR |
| Clear Single Pane - Laminated | 16 | 16 | 16 |
| Clear Dual Pane - Laminated | NR | NR | NR |
| Tinted Single Pane - Laminated | 16 | 16 | 16 |
| Tinted Dual Pane - Laminated | NR | NR | NR |
Safetyflex
Safetyflex 4 mil
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 1 | 1 | 2 |
| Clear Dual Pane | 2 | 2 | 3 |
| Clear Triple Pane | 4 | 4 | 5 |
| Tinted Single Pane | 3 | 3 | 4 |
| Tinted Dual Pane | 4 | 4 | 5 |
| Low-E Dual Pane | 2 | 2 | 3 |
| HP Low-E Dual Pane | 3 | 3 | 4 |
| Clear Single Pane - Laminated | 1 | 1 | 2 |
| Clear Dual Pane - Laminated | 2 | 2 | 3 |
| Tinted Single Pane - Laminated | 3 | 3 | 4 |
| Tinted Dual Pane - Laminated | 4 | 4 | 5 |
Safetyflex 7 mil
| Glass Type | 1/8" (3mm) | 1/4" (6mm) | 3/8" (10mm) |
|---|
| Clear Single Pane | 1 | 1 | 2 |
| Clear Dual Pane | 2 | 2 | 3 |
| Clear Triple Pane | 4 | 4 | 5 |
| Tinted Single Pane | 3 | 3 | 4 |
| Tinted Dual Pane | 4 | 4 | 5 |
| Low-E Dual Pane | 2 | 2 | 3 |
| HP Low-E Dual Pane | 3 | 3 | 4 |
| Clear Single Pane - Laminated | 1 | 1 | 2 |
| Clear Dual Pane - Laminated | 2 | 2 | 3 |
| Tinted Single Pane - Laminated | 3 | 3 | 4 |
| Tinted Dual Pane - Laminated | 4 | 4 | 5 |
A Note on Accuracy
This chart is a guide based on manufacturer film-to-glass stress data. Results are informational only. Flexfilm is not liable for glass breakage and/or seal failure. When in doubt, have your glass verified by a licensed glazier before installation.
Helpful Links
