PET Acoustic Board — 4 Finish-Quality Checks Absorption Data Misses

Questions that keep coming back after handover

Complaints that absorption is insufficient fall outside this discussion; they arise because the absorption prediction was wrong at the design stage. The rest are almost always about what can be seen and touched. The four below are the ones that come back from site most often.

① “The wall colour differs from the sample. One face looks off.”

This is a two-tone board. The front and back faces are different colours, and the installer fixed the back face outwards. Where both faces match, an installer can turn a board over without it showing.

② “It feels rough to lean on, and something rubs off onto clothing.”

This is pilling. Fine surface fibres lift, then come away when clothing or skin brushes past. On walls and partitions at leaning height, complaints tend to arrive in the first months of occupancy.

③ “Parts of it look like a different colour.”

This is yarn clumping. Where the fibre is not blended evenly, differently coloured yarn gathers in patches, and from a distance the whole face reads as another colour.

④ “It feels cheaper than expected. It gives way when pressed.”

This is softness. At the same thickness a softer board marks quickly where hands reach it, and the drop in finish quality shows most at edges and cut faces.

What the documents cover — the items absent from an absorption report

The absorption rating of PET acoustic board is largely settled by thickness and material. Values therefore do not diverge much between manufacturers, and most products on the market hold a test report. A product that cannot produce a report would have been dropped from the shortlist at the outset, but an absorption or thermal report does not by itself show whether the board is a good finish material.

When reviewing an absorption report, check the installation condition used in the test before the absorption figures themselves. For the same product, the depth of the air cavity behind the board in the test chamber changes the absorption curve, and a deeper cavity raises the low-mid range and moves the peak down in frequency. Applying a figure measured with a 100mm cavity to a site where the board is fixed directly to the wall means a designer counts on performance that their own space will not produce.

Viewed as a matter of finish quality, the domestic standards a designer can refer to are still thin.

기준	흡음 · 단열 규격	마감 품질 기준
Absorption performance	Yes	—
Thermal conductivity	Yes	—
① Two-tone faces	None	None
② Pilling	None	None
③ Yarn clumping	None	None
④ Softness	None	None

The reason those standards are still thin is simple. PET has been used as an interior finish for only a short time, and criteria for judging a product emerge only once a market has taken shape. For that reason, specifying correctly is hard, and carrying a specification through to installation is equally hard. When the documents look alike on both sides and no shared basis exists for comparing finish quality, designers and clients end up comparing price alone. When another supplier says “the same thing, cheaper”, the claim is not untrue on paper, which leaves a designer little to argue with.

The items below come from distributing and fabricating products from several manufacturers. They are not standards, but they are set out so a designer can review them in advance with a sample and a specification.

Checking the sample

The three checks below can be made on the sample you have requested.

PET acoustic board samples usually arrive in A4 size. ②③④ can be judged at that size. Because a supplier may send only boards in good condition, ① cannot be checked from a sample. Two-tone faces are handled in the specification.

Rub the surface gently with the palm

Check for unpleasant roughness, or the sense of fine fibres pricking the palm. For a material going where people lean or reach, this has a meaningful effect on the end-user experience. → ②

Look for yarn gathering that reads as off-colour

Held up close, an A4 sample shows how far the yarn has gathered. Where it is pronounced, consider dropping the product from the shortlist. → ③

Press the samples with a thumb and compare how far they give

The less it gives, the better it serves as a finish and the more refined it looks. Press samples of the same thickness with the same force. → ④

Specification and delivery check

Recording what has been checked, so that the board delivered matches what was expected.

Requests to change the specification usually arrive just before installation. Saying at that point that “the sample looked different” gives a designer little to stand on. Writing the checked items into the specification lets designer and contractor compare against the same document.

Sharing the reviewed sample with the site also allows the delivered goods to be compared against it on the spot. The three items below belong in the specification and are checked again at delivery.

Two-tone facesNo colour difference between the front and back faces is best; where that is not the case, ask the manufacturer to apply front/back marking stickers.

Yarn clumpingShare the sample with the site and check at delivery whether there is a difference.

Softness (areal density)Share the sample with the site and press it at delivery. Where the difference is pronounced, the board may have been supplied at a lower density of the same thickness — a cheaper product. Weigh it, or confirm with the supplier. 2000gsm at 9mm thickness means a weight of 2kg/㎡.

Absorption test reportSubmission is mandatory, and the air cavity used in the test is to be stated. Where it differs from the installation condition on this site, a value tested at that condition is to be submitted separately.

Fabrication

Confirm the fabrication envelope in advance so it can be carried into the drawing. Even where finish quality has been confirmed, the final fabrication quality varies with the equipment and capability of the fabricator. Confirming beforehand what level of work a fabricator can carry out, and reflecting that in the drawing, reduces rework and raises the final result. Where the requested quantity is large, run a sample production before going to volume.

In closing

“The same thing, cheaper” carries weight because on paper the claim holds. When absorption grades are close and both sides hold a test report, a designer struggles to find an item in the comparison table that measures finish quality.

These issues can be identified at the specification stage. To select PET acoustic board of the quality expected, check the three points named above on the sample already to hand, confirm two-tone faces with the supplier in advance, and leave a line each in the specification for what was reviewed.

← All Journal Next — Choosing commercial vinyl tile, site by site →