I was on a site walk in Jakarta last month when the contractor pulled me aside.
"We bought STC 55 panels," he said. "Lab certified. But when we close the wall, we can hear the ballroom AV test through it. The consultant is rejecting the milestone."
I didn't need to see the panels. I knew exactly what happened.
He had a lab report. What he didn't have was the right lab report, interpreted honestly, with a system designed for reality.
This happens every week. Here's how to make sure it doesn't happen on your project.
Red Flag 1: They Quote STC Without Showing the Frequency Curve
STC is a single number. It weights 16 frequencies into one figure. That weighting assumes human hearing sensitivity-which means low-frequency noise gets under-weighted.
Why does this matter? Because the sounds that kill operable wall performance in hotels and convention centers are all low frequency:
HVAC rumble: 63–125Hz
Ballroom bass and subwoofers: 40–80Hz
Footfall and vibration: 31–63Hz
A panel that tests beautifully at 1000Hz can be nearly transparent at 125Hz. If your supplier won't show you the 100–5000Hz transmission loss curve, they're hiding something.
What to ask for: The full one-third octave band data. 125Hz, 250Hz, 500Hz, 1000Hz, 2000Hz, 4000Hz.
What Egood provides:
| Frequency | Lab TL (dB) | Field Estimate (dB) |
|---|---|---|
| 125Hz | 37.4 | 30–32 |
| 250Hz | 44.0 | 38–40 |
| 500Hz | 52.1 | 47–49 |
| 1000Hz | 60.4 | 56–58 |
| 2000Hz | 63.7 | 60–62 |
| 4000Hz | 65.2 | 63–65 |
Source: Shanghai Jianke Technical Assessment, Report GS228-190169*, GB/T 19889.3-2005. Test specimen: EGDX-100#, 3500mm × 1000mm × 100mm.
The 125Hz gap is your problem. We publish it because we want you to specify correctly.
Red Flag 2: They Only Have Lab Data, No Field Test Method
ASTM E90 (lab) and ASTM E336 (field) exist for a reason. The gap between them is real.
Lab conditions:
Perfectly level floor
Zero ceiling gaps
No flanking paths through ducts or plenums
Controlled temperature and humidity
Your site has none of these. Typical field degradation: 5–10dB.
If a supplier claims "STC 55" without qualifying it as lab-only, they're either naive or misleading you.
What to ask: "What's your typical field STC relative to lab?" If they say "the same," walk away.
What Egood provides:
| Model | Lab Rw | Typical Field Estimate | Test Standard |
|---|---|---|---|
| EG100 | 56 dB | 48–51 dB | GB/T 19889.3-2005 |
| EG85 | 52 dB | 44–47 dB | GB/T 19889.3-2005 |
| EG65 | 45 STC | 38–40 STC | ASTM E413 |
We tell you the lab number and the realistic field range. Because a specifier who gets surprised on site is a specifier who never specifies us again.
Red Flag 3: Track Load Claims Without Durability Testing
Static load ratings are meaningless. A track that holds 2000kg in a single test tells you nothing about whether it will still hold that load after 5,000 operations, or 10,000, or 20,000.
For walls over 7 meters, this is critical. Aluminum tracks deflect. Steel tracks don't-but you need to verify the bearings, the safety systems, and the long-term wear.
What to ask: "Show me the cyclic durability test. 20,000 cycles minimum. What standard?"
What Egood provides:
| Track Model | Material | SGS Tested Load | Cycles | Standard | Result |
|---|---|---|---|---|---|
| G2000 | Steel, 8mm | 1860 kg / 2 casters | 20,000 | BS 4875-7:2006 / ISO 7170:2005 | PASS |
| L1000 | 6061-T6 Aluminum | 1000 kg / 2 casters | 20,000 | BS 4875-7:2006 / ISO 7170:2005 | PASS |
Test location: Egood factory, Foshan. SGS engineer on-site. Report numbers: SDHL2009026433FT (G2000), SDHL2009026435FT (L1000).
The G2000 is the only operable wall track system we know of with SGS-verified 18-meter capacity and 20,000-cycle durability. We used it at Hainan International Convention Center-14.38m finished height, 390kg/m panel weight, 9× safety factor. Four years in, still operating smoothly.
Red Flag 4: Fire Rating Is a Material Certificate, Not an Assembly Test
A piece of paper saying "Class A surface" or "2-hour fire rated material" is not a fire-rated wall system.
Fire travels through:
Panel-to-panel gaps
Panel-to-wall junctions
Ceiling and floor perimeter gaps
Hardware penetrations
If the supplier hasn't tested the complete installed assembly-multiple panels, seals, junction details, the actual track interface-you don't have a fire rating. You have a material certificate.
What to ask: "Is the fire test for the complete assembly, including perimeter seals? How many panels were tested? What standard?"
What Egood provides:
SGS fire test, Report SDFS2105003260FR_CN:
Standard: GB/T 9978.1-2008 (general requirements) + GB/T 9978.8-2008 (non-loadbearing vertical separating elements)
Assembly: 3 panels, 3000mm × 1000mm each, joined and installed in masonry frame with glass fiber wool gap fill
Result: 180 minutes integrity + 180 minutes insulation
Termination: Client request at 180 minutes-not material failure
Back-face temperature rise: Average 63.5°C, maximum 72.6°C (limits: 140°C / 180°C)
We tested three panels joined together. Because that's what a real wall looks like. Not one panel in isolation.
Red Flag 5: No Installation Tolerance Protocol
The best panel in the world fails if the bottom seal can't engage because the floor is 3mm higher on the left than the right.
Finished floors are never flat. Ceilings are never perfectly level. Structural openings have tolerances.
If your supplier's answer to installation variation is "the installer will figure it out," you have an acoustic failure waiting to happen.
What to ask: "What's your adjustment range for floor levelness? Ceiling height variation? How do you verify seal engagement?"
What Egood provides:
| Seal Location | Type | Compensation Range | Verification |
|---|---|---|---|
| Top | Retractable seal | ±30mm height variation | Visual + pressure check |
| Bottom | Retractable seal | ±50mm height variation | Uniform pressure across full width |
| Vertical edges | Magnetic seal, 450GS | 40N/m contact force | Gap gauge |
| Panel-to-wall | Soft rubber contact | Field-trimmable | Physical inspection |
The 1-meter level line rule: We measure from the civil engineer's datum, not the finished floor. Because finished floors lie.
The Bottom Line
Lab data is a starting point. Field performance is the only score that matters.
If your supplier can't answer these five questions with specific numbers, report references, and test standards, you're buying a commodity, not a system.
| Question | Egood Answer |
|---|---|
| Frequency curve? | 100–5000Hz, published above |
| Field vs lab gap? | 5–10dB, disclosed upfront |
| Track durability? | 20,000 cycles, SGS-verified |
| Fire assembly test? | 3-panel assembly, 180 min, SGS |
| Installation tolerance? | ±50mm bottom, ±30mm top, magnetic vertical |
About Egood Partition
Since 1998, manufacturing advanced operable wall systems from Foshan, China. Strategic technology partnership with German AE.
Reference projects:
Hainan International Convention Center: 14.38m height, G2000 steel track, EG100 panels
Kaohsiung Marriott: 11m height, EG100 system
Typical delivery lead time: 25–31 days.
[Download the complete test report package with full SGS and Shanghai Jianke documentation ]