Hemp Ceiling Raft

Name: Hemp Ceiling Raft
Brand: Natural Acoustic

Natural Acoustic Hemp Ceiling Raft

NRC 0.90

CeilingFree-hanging

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Manufacturer

Natural Acoustic

Natural Acoustic is a Tyrolean manufacturer of sound absorbers made from natural fibres, based in Mutters near Innsbruck. The main materials are sheep's wool, hemp, flax and wood fibre. The company provides reverberation measurement, planning and installation from a single source. The range includes acoustic panels, ceiling rafts and baffles made from hemp, hemp absorbers with flax fleece, sheep's wool and wood fibre absorbers, and the FRAMY frame absorbers for use as wall absorbers, room dividers or partitions. It also covers bass traps, wool room dividers, acoustic pictures and meeting pods. Areas of use are offices, hotels, restaurants and public buildings.

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Documents

Certificate (SHI)Product datasheet

Description

Ceiling raft made of Austrian industrial hemp and flax for offices, open-plan offices and meeting rooms.

Technical data

Material: Hemp and flax with 13 % bicomponent fibre, 1 % ammonium phosphate as basic fire protection

Surface: Natural hemp, white glazed or coated in any RAL colour with a matt, water-based interior emulsion paint

Fire class (EN 13501-1): E (EN 13501-1)

Certifications: SHI product passport 15341-10-1000 of the hemp acoustic panel, tested for pollutants, with assessments for QNG and DGNB

Measurement data

Sound absorption

Reverberation chamber (ASTM C423 / ISO 354)· 3 variants

NRC

0.90

Frequency values

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		Value
0 in (direct mounting)	plane absorber	NRC0.90
39 in suspended	ceiling raft 74 × 48 in	Sabins/unit39
20 in suspended	ceiling raft 74 × 47 in	Sabins/unit37

NRC: 0.90 (derived from ISO 354 lab data)

Measured values as a table (3 measurements)

Hemp Ceiling Raft: sound absorption coefficient αs per ISO 354 by frequency and test build-up
Build-up	NRC	100 Hz	125 Hz	160 Hz	200 Hz	250 Hz	315 Hz	400 Hz	500 Hz	630 Hz	800 Hz	1000 Hz	1250 Hz	1600 Hz	2000 Hz	2500 Hz	3150 Hz	4000 Hz	5000 Hz
1.8 in · 0 in (direct mounting) · plane absorber	0.90	0.16	0.21	0.25	0.34	0.41	0.60	0.79	0.92	1.02	1.10	1.16	1.11	1.11	1.05	1.05	1.05	1.04	1.02
1.8 in · 20 in suspended · ceiling raft 74 × 47 in (sabins/unit)	–	9.7	14	18	20	23	24	23	28	31	33	38	40	42	44	44	45	46	47
1.8 in · 39 in suspended · ceiling raft 74 × 48 in (sabins/unit)	–	11	14	15	15	19	25	26	30	33	37	39	42	45	47	47	48	48	51

Measured values as a table (3 measurements)

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Last updated: 11/08/2026

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