Acoustic Glass Testing
How Acoustic Glass Is Tested & How to Read a Test Report
**Key Specs Badge:** ASTM E90 ｜ EN ISO 10140 ｜ TL Curve ｜ STC / Rw Calculation ｜ Lab vs Field ｜ JUMBO Glass Group
01 – What This Page Covers
This page explains **how acoustic glass is tested**, what the test results mean, and **how to read a test report** without being misled by incomplete or inflated claims. It is written for procurement managers, specifiers, and acoustic consultants who need to verify supplier data before specifying glass for office pods, meeting rooms, recording booths, and acoustic partitions.
Acoustic testing is not a single measurement — it is a **standardized procedure** that produces a Transmission Loss (TL) curve, from which rating systems like STC and Rw are derived. Understanding the procedure, the standards, and the limitations is essential for making informed procurement decisions.
02 – The Testing Standards – ASTM vs EN/ISO
Acoustic glass testing is governed by two major standard families:
| Standard | Region | What It Covers |
|----------|--------|---------------|
| **ASTM E90** | North America | Laboratory measurement of airborne sound transmission loss |
| **ASTM E413** | North America | Calculation of STC from TL data |
| **EN ISO 10140-1/2** | Europe / International | Laboratory measurement of sound insulation of building elements |
| **ISO 717-1** | Europe / International | Calculation of Rw from TL data |
| **ASTM E336** | North America | Field measurement of sound isolation in buildings |
| **ISO 16283** | Europe / International | Field measurement of sound insulation in buildings |
> **Key point:** JUMBO Glass Group tests are conducted per **ASTM E90** and **EN ISO 10140**, with calculation of STC (ASTM E413) and Rw (ISO 717-1) from the same TL dataset.
03 – How a TL Test Is Conducted – Step by Step
The Laboratory Setup
1. A glass sample is mounted in a **test aperture** between two reverberant rooms (source room and receiving room)
2. A **broadband noise source** (typically pink noise) is played in the source room
3. Sound pressure levels (SPL) are measured in **1/3-octave bands** from 100 Hz to 5000 Hz in both rooms
4. The **Transmission Loss (TL)** at each frequency is calculated: `TL = L_source - L_receive + 10·log₁₀(S/A)`
Where:
- `L_source` = average SPL in source room
- `L_receive` = average SPL in receiving room
- `S` = area of test sample
- `A` = absorption in receiving room
### The Result
A **TL curve** — 18 to 20 data points (one per 1/3-octave band) showing how many decibels the glass blocks at each frequency.
> **Critical:** STC is **not measured directly**. It is calculated by fitting a reference contour to the TL curve. **No TL curve, no STC.**
04 – From TL Curve to STC / Rw
### STC Calculation (ASTM E413)
1. Plot the TL curve (1/3-octave, 125–4000 Hz)
2. Overlay the **STC reference contour** (a fixed shape defined by ASTM)
3. Shift the contour vertically until the **total deficiency** (sum of deviations where TL < contour) ≤ 32 dB
4. The STC rating = the contour value at 500 Hz
### Rw Calculation (ISO 717-1)
1. Plot the TL curve (1/3-octave, 100–3150 Hz)
2. Overlay the **ISO reference contour**
3. Apply the same deficiency rule (≤ 32 dB)
4. Rw = contour value at 500 Hz
5. Optional adaptation terms: **C** (pink noise) and **Ctr** (traffic noise)
> **Key insight:** STC and Rw are **curve-fitting exercises**, not direct physical measurements. Two glasses with identical STC can have very different TL curves — one may leak speech while the other is private.
05 – What a Complete Test Report Must Contain
A credible acoustic test report should include:
| Item | Requirement |
|------|-------------|
| Laboratory name | Accredited third-party (NVLAP, UKAS, DAkkS, etc.) |
| Standard cited | ASTM E90 / ISO 10140 (not just "tested to STC") |
| Glass build-up | Exact thickness, PVB type, cavity width, gas fill |
| Sample dimensions | Must represent production capability |
| Mounting condition | Lab only (no frame/seal data) |
| Frequency range | Minimum 100–4000 Hz (1/3-octave) |
| TL data table | All 1/3-octave bands |
| STC / Rw value | With contour fit verification |
| Date of test | Within 3 years |
| Disclaimer | "Glass-only rating; system performance depends on installation" |
06 – Lab vs Field – Three Generations of Data
| Generation | Rating | Standard | What It Measures |
|------------|--------|----------|------------------|
| **Lab (Glass-only)** | STC / Rw | ASTM E90 / ISO 10140 | Single glass component in test chamber |
| **Field (Installed)** | FSTC / NIC | ASTM E336 / ISO 16283 | Installed glass + frame + seals |
| **System (Complete)** | ASTC | ISO 23351 | Entire pod/cabin enclosure |
### Critical Distinctions
- **Lab STC** is a **glass-only** value. It does not include frame, seals, or flanking paths.
- **Field STC (FSTC)** is measured on the installed wall/pod. Typically **3–6 dB lower** than lab STC.
- **ASTC (ISO 23351)** is a **complete booth/cabin system standard, not a glass certificate**. It measures the entire enclosure including door, ceiling, and ventilation.
> **Warning:** A glass with lab STC 47 does **not** produce a pod with ASTC 47. The complete system loses 3–6 dB through frame, seals, ceiling plenum, and door gaps. Glass STC is a component value; ASTC is the system value.
07 – Common Testing Pitfalls – What to Watch For
| Pitfall | Why It Matters | How to Verify |
|---------|---------------|---------------|
| **STC without TL curve** | Single number hides coincidence dips | Request full 1/3-octave TL data |
| **Lab STC claimed as system STC** | Misleads buyer about real performance | Check if report specifies "glass-only" |
| **Old test data (>5 years)** | Standards evolve; PVB formulations change | Confirm date within 3 years |
| **Small sample size** | May not represent jumbo production | Verify sample ≥ 1.2 × 1.2 m |
| **No lab accreditation** | Results may not be credible | Check for NVLAP/UKAS/DAkkS |
| **ASTC claimed for glass** | ISO 23351 is a **cabin standard**, not glass | Reject; request ASTM E90 / ISO 10140 |
08 – How to Read a Test Report – 9-Point Checklist
When your supplier provides an acoustic test report, verify:
1. **Laboratory name** – Accredited third-party (e.g., SGS, Intertek, NVLAP)
2. **Standard cited** – ASTM E90 / ISO 10140 (not just "tested to STC")
3. **Glass build-up** – Exact thickness, PVB type, cavity width, gas fill
4. **TL curve** – Full 1/3-octave data, not just a single number
5. **Frequency range** – Minimum 100–4000 Hz
6. **Sample size** – Must represent production capability (≥ 1.2 × 1.2 m)
7. **Date of test** – Within 3 years
8. **Mounting condition** – Lab only (no frame/seal data)
9. **Disclaimer** – "Glass-only rating; system performance depends on installation"
09 – JUMBO Glass Group Testing Capability
- **In-house acoustic line** – dedicated PVB laminating room, humidity-controlled IGU chamber
- **Third-party testing** – SGS / Intertek on request per ASTM E90 / ISO 10140
- **Jumbo sample capability** – up to 3300 × 13000 mm (IGU), 3300 × 18000 mm (laminated)
- **CNC machining** – hinge/lock cut-outs, ±0.5 mm tolerance
- **QC per batch** – 100% spark test, dimensional laser scan, flatness ≤ 0.3%
- **Certifications** – EN 14449, EN 12150, EN 14179, ANSI Z97.1, AS/NZS 2208, ISO 9001:2015
- **Export crating** – fumigated wood, EVA edge guard, vertical dividers, shock label
- **Lead time** – samples 10–14 days; bulk 25–35 days FOB
10 – When to Request Testing
| Situation | Recommended Action |
|-----------|-------------------|
| Specifying glass for a new pod model | Request TL curve for your exact build-up |
| Comparing suppliers | Compare TL curves, not just STC numbers |
| Troubleshooting a field complaint | Request field measurement (NIC / FSTC) |
| Regulatory compliance | Confirm test standard matches local code |
| Marketing claims | Ensure ASTC (ISO 23351) is measured on complete pod, not glass |
11 – Children / Grandchildren Pages – Testing Sub-Topics
For deeper dives, the following sub-topics may be explored (not part of the core AcouSpace three-level hierarchy):
- **ASTM E90 Explained** – Detailed walkthrough of the North American test method
- **EN ISO 10140 Explained** – Detailed walkthrough of the European test method
- **How to Read a TL Curve** – Visual guide to interpreting transmission loss data
- **Lab vs Field Testing** – Why field performance is always lower
- **ISO 23351 for Office Pods** – Complete cabin system standard
> **Note:** These are educational resources. The core AcouSpace architecture remains Products / Applications / Technology at three levels.
12 – FAQ
**1. What is the difference between ASTM E90 and EN ISO 10140?**
Both measure airborne sound transmission loss in the lab. ASTM E90 is the North American standard; EN ISO 10140 is the European/international standard. Results are comparable but not identical due to different room geometries and procedures.
**2. Can I compare STC from ASTM E90 with Rw from ISO 10140?**
Roughly, but not exactly. STC and Rw use different contours and frequency ranges. "STC 40 ≠ Rw 40."
**3. Why is a TL curve more important than STC?**
STC is a single-number summary. Two glasses with identical STC can have very different TL curves — one may leak speech while the other is private.
**4. What is the difference between lab STC and field STC?**
Lab STC is measured on bare glass in a test chamber. Field STC is measured on the installed system. Field is typically 3–6 dB lower due to flanking paths.
**5. Is ISO 23351 a glass test?**
No. ISO 23351 measures acoustic attenuation of a **complete booth/cabin system**. It is not a glass certificate.
**6. How often should glass be re-tested?**
Acoustic properties of glass do not change over time. However, test reports should be within 3 years to reflect current production methods and standards.
**7. Can JUMBO provide a test report for my specific build?**
Yes. Send your glass specification (thickness, PVB, cavity, gas). We arrange third-party testing per ASTM E90 / ISO 10140. Lead time: samples 10–14 days + testing 2–3 weeks.
**8. What is the cost of acoustic testing?**
Third-party lab testing typically costs $2,000–$5,000 per build, depending on sample size and lab location. Contact us for a quote.
**9. Do you provide free test reports?**
We provide indicative TL curves for standard builds at no charge. Custom builds require new testing at cost.
**10. How do I request a quote?**
Send your glass build-up, target STC/Rw, dimensions, and project details to sales@jumbotemperedglass.com.
13 – Final CTA
### Need a Test Report for Your Acoustic Glass Specification?
Send us your drawing or specification. Our engineering team will arrange third-party testing per ASTM E90 / ISO 10140 and provide a full TL curve with STC / Rw calculation.
[Request a Quote] [Download Test Report Template] [Send Your Drawing]
📩 Email: tomron1688@gmail.com
- [Request a Quote] [Download Datasheet]
🔗 Internal Link Cluster
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