For classrooms DIN 18041 requires a volume-dependent target value (A3), and a shorter one for inclusive teaching (A4). The calculator starts with 202 m³ (Classroom, seminar room), target value 0.57 s (0.45 to 0.68), checks every octave band and suggests the missing area from 2,004 products with measured data.
Target values by standard
Target values for classrooms in three room sizes. The target value applies as the average of 500 and 1,000 Hz; at 125 Hz the tolerance is wider.
| Standard | Use | 150 m³ | 200 m³ | 300 m³ |
|---|---|---|---|---|
| DIN 18041, group ADIN 18041:2016-03 | Classroom, seminar room (A3) | 0.53 s (0.42 to 0.63) | 0.57 s (0.45 to 0.68) | 0.62 s (0.50 to 0.75) |
| OIB guideline 5OIB-Richtlinie 5:2023-05 | Classroom, meeting room, media room (Kommunikation) | 0.53 s (0.42 to 0.63) | 0.57 s (0.45 to 0.68) | 0.62 s (0.50 to 0.75) |
| UNI 11532-2, schools (Italy)UNI 11532-2:2020 | Classroom (A3) | 0.53 s (0.42 to 0.63) | 0.57 s (0.45 to 0.68) | 0.62 s (0.50 to 0.75) |
| Arrêté du 25 avril 2003, educationArrêté du 25 avril 2003 | Teaching, music, study or practical-work room | 0.60 s (0.40 to 0.80) | 0.60 s (0.40 to 0.80) | 0.90 s (0.60 to 1.20) |
| BB93, schoolsBuilding Bulletin 93 (2015) | Secondary classroom, seminar room, language lab | at most 0.80 s | at most 0.80 s | at most 0.80 s |
| SS 25268, schools (Sweden)SS 25268:2023 | Classroom, group room, focus room (by volume) | at most 0.50 s | at most 0.50 s | at most 0.60 s |
| BR18, schools, day care, offices (Denmark)BR18 (2018) mit Vejledning om lydforhold | Classroom, specialist teaching room | at most 0.60 s | at most 0.60 s | at most 0.60 s |
| SFS 5907, classes A1 and A2 (Finland)SFS 5907:2022 | Teaching room (A2) | 0.60 s (0.50 to 0.70) | 0.60 s (0.50 to 0.70) | 0.60 s (0.50 to 0.70) |
| Frisse Scholen, classrooms (Netherlands)PvE Frisse Scholen 2021 | Classroom (Klasse B) | at most 0.60 s | at most 0.60 s | at most 0.60 s |
| NBN S 01-400-2, schools (Belgium)NBN S 01-400-2:2012 | Classroom, seminar room, language lab (normal) | at most 0.80 s | at most 0.84 s | at most 0.90 s |
| CTE DB-HR (Spain)CTE DB-HR (2019) | Classroom or conference room without seating (< 350 m³) | at most 0.70 s | at most 0.70 s | at most 0.70 s |
| PN-B-02151-4, reverberation and speech intelligibility (Poland)PN-B-02151-4:2015-06 | Classroom, lecture room (by volume, up to 2,000 m³) | at most 0.60 s | at most 0.60 s | at most 0.80 s |
| ČSN 73 0527, 2005 values (Czechia)ČSN 73 0527 (2005) | Classroom, lecture room | at most 0.70 s | at most 0.70 s | at most 0.70 s |
| ANSI/ASA S12.60, classroomsANSI/ASA S12.60-2010/Part 1 (R2020) | Classroom, core learning space (by volume) | at most 0.60 s | at most 0.60 s | at most 0.70 s |
Typical measures
- Class A acoustic ceiling, with a reflective strip above the board zone.
- Wall absorbers on the rear wall, mounted above head height.
- For inclusive teaching, cover one side wall in addition.
- Pin boards and shelves help little; low frequencies need mounting depth.
Acoustic ceilings and wall absorbers with measured data
All products in the search
Frequently asked questions
What reverberation time does DIN 18041 require for a classroom?
For teaching (A3) Ttarget = 0.32 · lg(V) − 0.17 s, so 0.60 s at 250 m³. For inclusive teaching (A4) Ttarget = 0.26 · lg(V) − 0.14 s, around 0.48 s.
What changes for inclusive teaching?
The target value drops by around 20 percent, because pupils with hearing loss or a second language need more speech intelligibility. In practice: ceiling plus rear wall plus one side wall.
How much absorber area does a classroom need?
A room of 200 m³ is often above 1.5 s when empty. For around 0.6 s it needs about 50 m² of equivalent absorption area, so a class A acoustic ceiling over the whole area.
Other room types
Formulas, DIN 18041 and worked example on the calculator page