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Acoustic ceilings: systems, values and sizing

An acoustic ceiling is a full-area sound-absorbing ceiling finish, usually suspended: mineral wool lay-in tiles in a grid, perforated metal cassettes with an acoustic fleece, perforated gypsum board or profiled wood acoustic elements. Because the ceiling is the largest free surface of a room, it delivers the absorption that furniture and walls cannot. Capable systems reach weighted absorption coefficients up to αw 1.0; how much of the ceiling must be covered follows from DIN 18041.

This page compares the four system families, explains the DIN 18041 requirements for offices, canteens and similar rooms, and the interactive ceiling check shows the coverage that follows from room use and ceiling height.

Last updated: 9 July 2026

open-plan office per DIN 18041 (h ≤ 2.5 m)
A/V ≥ 0.25 m⁻¹
mineral wool systems, class A
αw up to 1.00
usual suspension depth (plenum)
200–400 mm
ISO 354 ceiling mounting (e.g. E-200)
Type E

Interactive

How much ceiling does your room need? The DIN 18041 check

Pick a use and a ceiling height. The check shows the standard's A/V requirement and the ceiling coverage that follows.

Room use (group B)

Clear ceiling height

3.0 m

A/V requirement
0.23m⁻¹ (absorption area per m³)
Absorption per m² of floor
0.69m²/m²
Ceiling coverage at class A (αw 0.9)
76%

Simplified sizing per DIN 18041, room group B. Furnishing and people add absorption; ceiling built-ins reduce the area. Rooms for teaching, lectures or music (group A) are designed via reverberation time.

Ceiling solutions in the catalogueOpen the reverberation calculator

Ceiling products with measurement data

Published ceiling solutions with high absorption (αw from 0.6), sorted by absorption coefficient.

View all in search
  • Acospray DC1αw 1.00

    Acosorb

    Acospray DC1

  • Acospray DC3αw 1.00

    Acosorb

    Acospray DC3

  • alpha AKUSTIK NANOLITEαw 1.00

    alpha AKUSTIK

    alpha AKUSTIK NANOLITE

  • aPerf® padαw 1.00

    BK Raumakustik

    aPerf® pad

  • aPerf® panelαw 1.00

    BK Raumakustik

    aPerf® panel

  • aPerf® panel colourαw 1.00

    BK Raumakustik

    aPerf® panel colour

  • aPerf® woolαw 1.00

    BK Raumakustik

    aPerf® wool

  • B11 Archisonic Feltαw 1.00EPD

    B11

    B11 Archisonic Felt

  • FURAL Metal Cassette Ceilingαw 1.00EPD

    Fural Systeme in Metall GmbH

    FURAL Metal Cassette Ceiling

  • Green Lineαw 1.00

    Acosorb

    Green Line

  • LinePerf®αw 1.00

    BK Raumakustik

    LinePerf®

  • Schallsauger ALU LINE SKY HORIZONTALαw 1.00

    SCHALLSAUGER (KASPER GmbH)

    Schallsauger ALU LINE SKY HORIZONTAL

The four acoustic ceiling system families compared

The four acoustic ceiling system families compared
Typical αwFire behaviourStrengthsTypical use
Mineral wool grid ceiling0.90 to 1.00 (class A is common)Usually A2 (non-combustible)Highest absorption, accessible, economical per m²Offices, administration, schools, clinics
Perforated metal cassette + fleece0.60 to 0.90, per open area and fleeceA1/A2 (metal)Robust, durable, wipeable, precise lookRepresentative areas, transport buildings, corridors
Perforated gypsum board0.40 to 0.70, per perforation and cavityA2 (board)Seamless look, freely formable, integrableDesign ceilings, foyers, high-end residential
Wood acoustics (perforated/slotted + fleece)0.50 to 0.90, per slot ratio and build-upUsually B-s1/s2 (flame-retardant)Warm look, visible wood, good mid-band absorptionConference rooms, halls, restaurants, premium fit-out

Why the ceiling is the most effective surface

In a furnished room, floor and walls are largely taken: shelves, windows, doors, screens. The ceiling is the only large surface fully available for absorption, and it faces every sound source in the room. A full-area acoustic ceiling therefore delivers the most even baseline absorption a room can get.

DIN 18041 builds on exactly this for group B rooms: offices, canteens, counter halls and similar rooms are not designed to a target reverberation time but to a minimum ratio of equivalent absorption area to room volume (A/V). With a capable ceiling this ratio is almost always achievable without touching a wall.

DIN 18041 for ceilings: the A/V requirement

For ceiling heights up to 2.5 m the standard sets fixed minimums: A/V ≥ 0.15 m⁻¹ for rooms with several people (B2, e.g. counter areas), 0.20 for rooms where people talk to each other (B3, e.g. private and shared offices), 0.25 for open-plan offices (B4) and 0.30 for canteens and teaching pools (B5). For greater heights, height-dependent formulas of the form A/V ≥ [c + 4.69 · lg(h/1 m)]⁻¹ apply.

Coverage follows from the requirement: at 3 m height, an open-plan office needs around 0.7 m² of absorption area per square metre of floor, which with a class A ceiling (αw around 0.9 to 1.0) means covering most of the ceiling. The ceiling check above computes this live for use and height; group A rooms (teaching, lectures, music) are designed via reverberation time instead, for which the reverberation calculator is the right tool.

Suspension depth and the low end

Suspended acoustic ceilings have a cavity (plenum) between the structural slab and the finish, typically around 200 to 400 mm. This air space acts like the air gap behind a wall absorber: it clearly improves absorption towards low frequencies, because the material then sits where the air particles move fast.

That is why the mounting condition is part of the measured value: ISO 354 ceiling measurements are made in a defined mounting (type E), labelled with the cavity depth in millimetres, e.g. E-200 or E-400. An αw from an E-400 test does not automatically apply to a directly mounted ceiling. Acoustic Index stores the mounting type with every measurement.

Full area or rafts: which solution when

The closed acoustic ceiling is the default in new builds and wherever the ceiling area is free. It is ruled out when the slab has to work: with concrete-core activation a closed finish would decouple the thermal mass, and with visible services or exposed-concrete architecture it is unwanted. Free-hanging ceiling rafts and baffles then recover part of the ceiling effect selectively.

The question is practical in refurbishment too: a grid ceiling can often be upgraded with absorbing lay-in tiles without changing the substructure. Where no suspension is possible at all, directly mounted ceiling absorbers or the raft solution remain.

Built-ins eat absorption area

Luminaires, ventilation outlets, sprinklers, loudspeakers and access panels reduce the absorbing area, sometimes considerably. Anyone sizing a ceiling to A/V should calculate with the net absorption area, not the gross ceiling area. On heavily occupied ceilings it is worth comparing a higher-grade system (more αw per m²) against additional area on walls or as rafts.

For specification this means: state αw or the per-band values per build-up and mounting type, name the planned share of built-ins, and base the proof on the measurement data of the actual products.

Frequently asked questions

What is an acoustic ceiling?+

A full-area sound-absorbing ceiling finish, usually suspended: mineral wool tiles in a grid, perforated metal cassettes, perforated gypsum board or wood acoustic elements. It reduces reverberation because the ceiling is the largest freely available surface in the room.

What absorption coefficient does an acoustic ceiling reach?+

Depending on the system: mineral wool lay-in tiles typically reach αw 0.90 to 1.00 (class A), perforated metal cassettes with acoustic fleece around 0.60 to 0.90, perforated gypsum 0.40 to 0.70, wood acoustics 0.50 to 0.90 depending on the slot ratio. What counts is the ISO 354 measurement of the actual build-up including its mounting.

How much of the ceiling must be covered?+

Per DIN 18041 via the A/V ratio: at 3 m ceiling height an open-plan office needs around 0.7 m² of absorption area per m² of floor, i.e. most of the ceiling with a class A system. A private office needs considerably less. The ceiling check on this page computes use and height live.

What does E-200 or E-400 mean in a test report?+

The mounting of the ISO 354 ceiling measurement (type E) with the cavity depth in millimetres: E-200 means 200 mm to the structural slab. The cavity improves low-frequency absorption, so an E-400 value does not automatically apply to a directly mounted ceiling. Test mounting and project build-up must match.

Does an acoustic ceiling work with concrete-core activation?+

A closed acoustic ceiling decouples the thermally active slab and is therefore usually ruled out. The common solution are free-hanging ceiling rafts or baffles with limited coverage, which deliver absorption while leaving the slab largely free thermally.

Suspended or directly mounted: which is better?+

Acoustically the suspension wins: the cavity clearly improves low-frequency absorption. Direct mounting is the answer at low ceiling heights. In both cases the measured value only applies to the tested mounting, so the mounting condition belongs in every product decision.

Is an acoustic ceiling alone enough for good room acoustics?+

In group B rooms (offices, canteens) usually yes, if the coverage is right. In communication-heavy rooms, flutter echoes between parallel hard walls remain an issue; wall absorbers at ear height complement the ceiling there. Rooms for teaching, lectures or music (group A) are designed via reverberation time per frequency band.

Which fire requirements apply to acoustic ceilings?+

Escape routes and many public buildings require non-combustible finishes (A1/A2); mineral wool and metal systems usually comply. Wood acoustics mostly reaches flame-retardant (B-s1/s2). The class is on the datasheet, and the search can filter by minimum fire class.

Further reading

  • Ceiling absorbers: panels for the ceilingThe ceiling is the most effective surface against reverberation: closed acoustic ceilings, suspended systems and rafts with measurement data.
  • Acoustic ceiling rafts and bafflesFree-hanging sound absorbers for rooms without a closed acoustic ceiling, absorbing on both faces and rated by equivalent absorption area A.
  • Reverberation Time Calculator: RT60 with Sabine & EyringCalculate reverberation time (RT60) with the Sabine formula, check DIN 18041 target values and size the required absorber area including panel count. With a worked office example.

Compare ceiling solutions with measurement data

Compare acoustic ceilings and ceiling absorbers in the catalogue by αw, material, fire class and mounting type.

Ceiling solutions in search
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