KARIKA / The material

The material

What polyester acoustic felt actually is.

Crafted from discarded drinking bottles. Free of formaldehyde and other chemical binders. Low embodied energy, healthier indoor air. Scroll to see how the material is made, how it absorbs sound, how it burns, and how it ages.

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Composition100% PET

Recycled75%

Density2000 / 2400 / 4000 GSM

BindersZero

Material journey

From discarded bottle to acoustic surface.

Every KARIKA panel begins as discarded drinking bottles. Ten precise steps turn post-consumer PET into 100% polyester fibre. Heat-bonded, zero binders, low embodied energy, fully recyclable. Scroll to follow the journey.

Stage

PET Bottle

Post-consumer plastic drinks bottles, sourced from waste streams. The chain of custody from bottle to baled fibre is documented under the Global Recycled Standard 4.0, audited annually by Intertek.
Sort & Colour-Sort

PET separated from other plastics, then divided by colour using optical scanners and air jets. Clear bottles are kept for the highest-grade fibre stream.
Crush

Bottles broken into small fragments called flakes. Each flake is roughly the size of a fingernail.
Wash

Flakes cleaned to remove labels, residue, and heavier plastics. Float-sink separation drives out PVC, polypropylene and aluminium fragments.
Air-Dry

Flakes dried with air jets, separating any remaining contaminants. Moisture is driven below 50 ppm before pelletising.
Refine & Collect

Clear white flakes separated from coloured ones, then gathered for the next stage. The clear stream produces the highest tensile fibre.
Pelletise

Heated, extruded into spaghetti strands, cooled, and cut into pellets. The pellets become the feedstock for the spinning line.
Spin Fibre

Granules pushed through fine spinnerets to form a continuous filament. The filament is then crimped, cut to staple length, and baled.
Polyester Fibre

100% recycled polyester fibre. Soft, lightweight, ready to bond. Three-quarters of the fibre that enters a KARIKA panel arrives in this form; the remaining quarter is virgin PET binder fibre with a lower melting point. Both are pure PET.
KARIKA Panel

Layers of fibre are needled into a felt and passed through a heated press. The binder fibre softens and locks the structure. Mechanical and thermal bond only. No resin, no glue, no chemical binder. Cut to specification.

Product characteristics

Engineered to specify with confidence.

Twelve qualities that make KARIKA a reliable specification. Acoustically performant, materially honest, and quietly designed for the spaces architects build.

Twelve qualities, four themes

Performance

What it does to sound, vibration and heat.
- Acoustical
  NRC up to 1.00 with cavity. Absorbs reverberation across the speech range.
- Buffered
  Layered fibre dampens impact and structure-borne sound.
- Insulation
  Thermal insulator. Contributes to building energy performance.
Composition

Materially honest. Recycled, fire-safe, zero off-gassing.
- Recycled
  75% post-consumer recycled PET. Fully recyclable at end of life.
- Fire-Rated
  Naturally fire-resistant. No chemical retardants required.
- No VOC
  Zero volatile organic compounds. Heat-bonded, no chemical binders.
Surface

94 colours, accepts print, is tackable.
- Decorative
  94 colours. Grooves, CNC patterns, 3D embossed and printed finishes.
- Printable
  Surface accepts direct digital print and custom graphic application.
- Tackable
  Holds pins. Doubles as a wall and a pinboard.
Practicality

What a contractor needs to handle on site.
- Light Weight
  2000 / 2400 / 4000 GSM at 9 / 12 / 24 mm. Easy to handle and suspend overhead.
- Easy Install
  Direct-fix, suspended or framed. Cuts cleanly with a router or a sharp blade.
- Ventilate
  Open fibre lets air move through. Resists moisture and bacteria.

9 mm sheet2000 GSM

12 mm sheet2400 GSM

24 mm sheet4000 GSM

Stock size2440 × 1220 mm

Tolerance±1 mm thickness

Made to specCustom size & thickness on request

How it sounds

KARIKA acoustic controls reverberation.

PET felt has a porous fibre matrix. Air moves through the fibres and loses energy as friction. The room hears less noise, less echo, less reverberation. Headline NRC depends as much on the air gap behind the panel as on the panel itself. Used in offices, classrooms, hospitals and auditoriums.

ASTM C423-23 · the headline figure

A single number summarising absorption from 250 to 2000 Hz. The current Intertek test report (March 2025) covers three panel thicknesses across three mounting conditions. From a panel laid flat on the slab (Type A) to a panel suspended above a 200 mm or 400 mm cavity.

Why cavity matters

Polyester felt absorbs by friction. The bigger the air gap behind the panel, the more bass and mid-bass it can pull down. Which is why a 12 mm panel on a slab rates NRC 0.60, but the same panel suspended over 150 mm of air rates 0.92. Cavity is the unsung half of acoustic specification.

Reverberation-room sound-absorption tests, ASTM C423-23 and equivalent ISO 354:2003. Per-frequency curves on the chart below.
Mounting	9 mm	12 mm	24 mm
Direct mount (no cavity)	NRC 0.45	NRC 0.60	NRC 0.75
50 mm cavity	NRC 0.70	NRC 0.80	NRC 0.90
100 mm cavity	NRC 0.80	NRC 0.90	NRC 0.95
150 mm cavity	NRC 0.85	NRC 0.92	NRC 1.00
200 mm cavity	NRC 0.80	NRC 0.85	NRC 0.90
400 mm cavity	NRC 0.80	NRC 0.85	NRC 0.90

A useful rule of thumb: the panel begins to absorb meaningfully at frequencies whose wavelength is roughly four times the cavity depth. A 200 mm cavity therefore handles mid-range conversation well; a 400 mm cavity reaches into the bass that makes a concrete slab ring.

Full octave-band data

9 mm panel under three mounting conditions.

The full sound-absorption curve from 100 Hz to 5000 Hz, across the three mounting conditions Intertek tested in March 2025. Use the pills below the chart to isolate one curve at a time. Hover for individual coefficients; scroll the table for the raw octave-band values.

Higher values absorb more sound. A coefficient of 1.00 means almost all incident energy at that frequency is absorbed. ASTM C423-23 reverberation-room test, Intertek Shanghai, March 2025.

Sound absorption coefficient (α) per octave band · 9 mm panel, 2000 GSM
Mounting	100	125	160	200	250	315	400	500	630	800	1k	1.25k	1.6k	2k	2.5k	3.15k	4k	5k	NRC
No cavity	0.03	0.02	0.03	0.02	0.05	0.09	0.13	0.17	0.30	0.44	0.58	0.70	0.81	1.00	1.10	1.10	1.10	1.10	0.45
50 mm	0.09	0.09	0.16	0.23	0.29	0.39	0.54	0.68	0.78	0.86	0.95	0.97	1.00	0.95	0.89	0.81	0.91	0.62	0.70
100 mm	0.21	0.26	0.39	0.49	0.55	0.72	0.88	0.91	0.97	0.98	0.98	0.89	0.75	0.76	0.88	0.87	0.92	0.73	0.80
150 mm	0.27	0.42	0.59	0.67	0.74	0.88	0.97	0.96	0.99	0.93	0.79	0.72	0.86	0.83	0.85	0.89	0.94	0.78	0.85
200 mm	0.25	0.37	0.39	0.64	0.76	0.82	0.84	0.96	0.89	0.79	0.67	0.76	0.80	0.80	0.83	0.88	0.87	0.83	0.80
400 mm	0.35	0.59	0.54	0.66	0.80	0.75	0.74	0.67	0.76	0.80	0.79	0.82	0.84	0.84	0.85	0.92	0.96	0.99	0.80

Sound absorption coefficient (α) per octave band · 12 mm panel, 2400 GSM
Mounting	100	125	160	200	250	315	400	500	630	800	1k	1.25k	1.6k	2k	2.5k	3.15k	4k	5k	NRC
No cavity	0.03	0.02	0.02	0.06	0.10	0.13	0.21	0.30	0.50	0.67	0.86	0.99	1.10	1.10	1.10	1.10	1.10	1.10	0.60
50 mm	0.10	0.10	0.19	0.26	0.34	0.45	0.63	0.79	0.90	1.00	1.04	1.04	1.04	1.04	1.04	0.94	1.04	0.72	0.80
100 mm	0.24	0.29	0.44	0.55	0.62	0.81	0.99	1.02	1.09	1.10	1.10	1.00	0.84	0.86	0.99	0.98	1.04	0.82	0.90
150 mm	0.30	0.47	0.65	0.74	0.82	0.98	1.07	1.06	1.10	1.03	0.88	0.80	0.95	0.92	0.94	0.99	1.04	0.86	0.92
200 mm	0.29	0.39	0.45	0.61	0.74	0.81	0.88	0.95	0.86	0.78	0.72	0.81	0.87	0.89	0.89	0.92	0.98	0.94	0.85
400 mm	0.42	0.58	0.57	0.75	0.74	0.76	0.78	0.75	0.78	0.85	0.93	0.91	0.93	0.90	0.96	0.92	0.98	0.97	0.85

Sound absorption coefficient (α) per octave band · 24 mm panel, 4000 GSM
Mounting	100	125	160	200	250	315	400	500	630	800	1k	1.25k	1.6k	2k	2.5k	3.15k	4k	5k	NRC
No cavity	0.05	0.02	0.07	0.12	0.18	0.31	0.45	0.62	0.82	0.94	1.07	1.10	1.10	1.10	1.10	1.10	1.10	1.10	0.75
50 mm	0.12	0.12	0.21	0.32	0.40	0.53	0.75	0.94	1.07	1.10	1.10	1.10	1.10	1.10	1.10	1.10	1.10	0.85	0.90
100 mm	0.25	0.31	0.46	0.58	0.66	0.85	1.04	1.08	1.10	1.10	1.10	1.06	0.89	0.90	1.04	1.03	1.09	0.86	0.95
150 mm	0.33	0.50	0.70	0.81	0.89	1.06	1.10	1.10	1.10	1.10	0.95	0.86	1.03	1.00	1.02	1.07	1.10	0.94	1.00
200 mm	0.35	0.38	0.41	0.62	0.80	0.84	0.86	0.99	0.96	0.86	0.81	0.91	0.91	0.91	0.93	0.97	0.99	0.96	0.90
400 mm	0.38	0.64	0.61	0.67	0.83	0.87	0.80	0.87	0.87	0.90	0.90	0.96	0.94	0.93	0.94	1.02	1.02	1.08	0.90

How it burns

Class B-s1, d0, by composition.

EN ISO 11925-2 + EN 13823

Polyester does not catch fire easily; it melts and self-extinguishes. The panel is rated B-s1, d0 under EN ISO 11925-2:2020 (ignitability) and EN 13823:2020+A1:2022 (single burning item). The European reaction-to-fire classification for construction products.

Translated: limited contribution to fire (B), very low smoke emission (s1), no flaming droplets (d0).

Achieved without flame retardants. No phosphorus-based or halogenated chemistry is added at any stage of manufacture. The rating is intrinsic to the polymer.

For Indian and US-coded specifications, the panel is supplied to either Class A or Class B ratings on request.
The choice is made at order, not at install.

How it ages

An acoustic panel stays an acoustic panel.

PET acoustic is dimensionally stable and chemically inert. Colour is dyed into the fibre before it is spun, not surface-printed. It does not lift, mark from contact, or fade under normal interior light.

Cleaning: Vacuum with a soft-brush head. Spot-clean with a damp cloth and pH-neutral detergent. Steam-clean deep stains. No solvents.
Moisture: PET acoustic does not absorb water unless submerged. Wipe dry. Our acoustic panels do not warp, mould or harbour bacteria.
UV: Direct sunlight fades any dyed material over time. KARIKA acoustic panel is rated for interior use only.
Allergens: None known. Hypoallergenic and low-VOC. Used in hospitals, schools and clinics.
Warranty: Two years against workmanship and manufacturing defects.
End of life: Fully recyclable. The panel returns to the PET fibre stream and is re-spun. Off-cuts from fabrication are recovered the same way.

In the spirit of full disclosure

Marks of a hand-made material.

KARIKA panels are pressed and finished by people, not robots. Five things to expect in every shipment. Written here so they don't come as a surprise on site.

01
Colour varies up to ±5% across batches

The fibre is dyed before spinning, and small variations in dye-lot saturation carry through the panel. Specify the full wall from a single production run and the wall reads as one surface. Order a sample chip from the same batch as your delivery if a colour-critical install is planned.
02
Surface texture is never identical twice

Fibre composition and surface texture fluctuate within tolerance. That variation is what makes felt read as felt rather than as plastic. The grain and the slight nap are the material's signature, not its flaw.
03
Thickness sits within ±1 mm of nominal

The press settles each panel to its specified thickness, and minor substrate unevenness is normal. Specify shadow gaps, reveal details, or trim profiles that tolerate a millimetre rather than fight it.
04
Every panel has a grain direction

Like a textile or a timber veneer, KARIKA panels have an inherent grain. For ease of correct orientation during installation, panels without the KARIKA^® logo are marked in the corner. Hang them all the same way for an unbroken read.
05
Inspect before you install

Panels should be inspected at delivery and before fitting. Once a panel has been cut, drilled, glued or hung, claims relating to surface, colour or dimension cannot be entertained. The moment of installation is the moment of acceptance.

The paperwork

Nine active certifications & tests.

Issuing body, scope, certificate number and credit pathway for each one.
In the language a green-building consultant will recognise on the first read.

GRS

GRS 4.0

Global Recycled Standard 4.0, Intertek-issued. Verifies 75% post-consumer recycled PET content and the chain of custody from fibre through to finished panel.

Cert # ITS-TE-00031312-GRS-02768200 · License TE-00035112

$OEKO-TEX$ OEKO100

OEKO-TEX® STANDARD 100

TESTEX AG-issued, Class I (baby articles). The strictest tier. Verifies the panel is free of harmful substances at the level required for items in skin contact with infants.

Cert SH001 252785 · valid 15.01.2026

GRA

GreenRate Level A

Global GreenTag GreenRate Level A. The highest tier. The pathway by which LEED, WELL and Green Star recognise Sustainable Products credits.

LEED · WELL · Green Star · valid 8 April 2026

PHD

PHD Platinum HEALTH

Product Health Declaration at Platinum tier. Full ingredient disclosure and risk assessment under GGT International v4.1.

Cert KKS:SZ01:2025:PH · valid 8 April 2026

INTERTEK2025

Intertek sound absorption

Reverberation-room sound-absorption testing at Intertek under ASTM C423-23. Three panel thicknesses (9, 12, 24 mm) across multiple mounting conditions. Per-frequency absorption curves above; full reports available on request.

ASTM C423-23 · reverberation room

ARAI

ARAI sound absorption

Earlier reverberation-room test by the Automotive Research Association of India under ASTM C423-22 (August 2025). Available on request alongside the current Intertek 2025 reports.

Report ULR-TC55652550006032F · NVH/3100/02543

LEEDv4

LEED v4.0 / v4.1

Material Ingredients credit. Option 1 (Material Ingredient Reporting) and Option 2 (International ACP. REACH). Contributes via GreenRate and the PHD.

MR Credit · Material Ingredients

WELLv2

WELL v1 / v2

v1.0: Features 04, 11, 25, 26, 97. v2.0: X07 Materials Transparency, X08 Materials Optimisation, plus X01, X05, X06.

Materials Transparency & Optimisation

GREENSTAR

Green Star (GBCA)

Sustainable Products credit and Procurement and Purchasing credit, contributed via the GreenRate Level A pathway.

Sustainable Products · Procurement

Colour library

Ninety-four colours, one library.

The full standard range, codes KA-7901 to KA-7995. Click any tile for a larger view. Physical swatches are posted by the studio at no cost within India.

Neutrals 31

KA-7904

KA-7944

KA-7974

KA-7905

KA-7979

KA-7967

KA-7910

KA-7985

KA-7973

KA-7936

KA-7907

KA-7911

KA-7929

KA-7959

KA-7938

KA-7912

KA-7987

KA-7939

KA-7945

KA-7957

KA-7978

KA-7995

KA-7980

KA-7925

KA-7984

KA-7970

KA-7982

KA-7983

KA-7926

KA-7928

KA-7927

Earth 10

KA-7966

KA-7962

KA-7906

KA-7930

KA-7986

KA-7951

KA-7908

KA-7964

KA-7991

KA-7989

Warms 18

KA-7901

KA-7943

KA-7902

KA-7950

KA-7946

KA-7949

KA-7903

KA-7958

KA-7975

KA-7977

KA-7932

KA-7917

KA-7952

KA-7948

KA-7956

KA-7960

KA-7918

KA-7969

Greens 9

KA-7931

KA-7955

KA-7913

KA-7972

KA-7914

KA-7981

KA-7953

KA-7988

KA-7971

Cools 26

KA-7909

KA-7963

KA-7941

KA-7965

KA-7937

KA-7942

KA-7935

KA-7954

KA-7940

KA-7920

KA-7921

KA-7933

KA-7968

KA-7924

KA-7994

KA-7915

KA-7916

KA-7976

KA-7934

KA-7990

KA-7923

KA-7992

KA-7961

KA-7947

KA-7993

KA-7919

From the journal

Next steps

What polyester acoustic felt actually is.

From discarded bottle to acoustic surface.

PET Bottle

Sort & Colour-Sort

Crush

Wash

Air-Dry

Refine & Collect

Pelletise

Spin Fibre

Polyester Fibre

KARIKA Panel

Engineered to specify with confidence.

Performance

Acoustical

Buffered

Insulation

Composition

Recycled

Fire-Rated

No VOC

Surface

Decorative

Printable

Tackable

Practicality

Light Weight

Easy Install

Ventilate

KARIKA acoustic controls reverberation.

Class B-s1, d0, by composition.

An acoustic panel stays an acoustic panel.

Marks of a hand-made material.

Colour varies up to ±5% across batches

Surface texture is never identical twice

Thickness sits within ±1 mm of nominal

Every panel has a grain direction

Inspect before you install

Nine active certifications & tests.

GRS 4.0

OEKO-TEX® STANDARD 100

GreenRate Level A

PHD Platinum HEALTH

Intertek sound absorption

ARAI sound absorption

LEED v4.0 / v4.1

WELL v1 / v2

Green Star (GBCA)

Ninety-four colours, one library.

Neutrals 31

Earth 10

Warms 18

Greens 9

Cools 26

Three reads on specifying acoustic panels.

What is NRC?

Why cavity depth changes the number

Open office acoustic treatment

Three next steps.

Browse the catalogue

Request a sample set

Speak to the studio