Air-tightness Classes
Relevant Norms:
DIN EN 24194-2 (old)
EUROVENT 2/2
DIN EN 1507 (old)
DIN EN 13779 (old)
DIN EN 12237 (old)
DIN EN 16798-3 (ATC, current)
| Allowed leakage | 16798 | 13779/12237 | 24194-2 | SMACNA | |
| (0,027 × p 0,65) l/s/m2 | ATC 5 | A | II | 27 | |
| (0,009 × p 0,65) l/s/m2 | ATC 4 | B | III | 9 | |
| (0,003 × p 0,65) l/s/m2 | ATC 3 | C | IV | 3 | |
| (0,001 × p 0,65) l/s/m2 | ATC 2 | D | - | 1 | |
| (0,00033 × p 0,65) l/s/m2 | ATC 1 | - | - | - | |
Studies have demonstrated that total energy consumption related to ventilation can be reduced by over 30% by achieving an air-tight air-ducts (Soenens, 2011).
The METU-SYSTEM round duct connections automatically achieve the air-tightness class ATC 3, and the ATC 4 if additional measures are taken (application of sealant).
The METU-FORM ducts, fittings and connections automatically achieve the air-tightness ATC 1 without having to take any additional measures. This system of ducts is even liquid and oil-tight.
The Energy Performance of Building Directive (EPBD) norm EN 13779 indicates the necessity of conducting leakage tests in order to save energy and confirm the suitability of the entire ventilation system. This norm replaces the DIN 1946-2.
| Pa | ATC 5 | ATC 4 | ATC 3 | ATC 2 | ATC 1 |
| 100 Pa | 0,54 | 0,18 | 0,06 | 0,02 | 0,01 |
| 200 Pa | 0,85 | 0,28 | 0,09 | 0,03 | 0,01 |
| 300 Pa | 1,10 | 0,37 | 0,12 | 0,04 | 0,01 |
| 400 Pa | 1,33 | 0,44 | 0,15 | 0,05 | 0,02 |
| 500 Pa | 1,53 | 0,51 | 0,17 | 0,06 | 0,02 |
| 600 Pa | 1,73 | 0,58 | 0,19 | 0,06 | 0,02 |
| 700 Pa | 1,91 | 0,64 | 0,21 | 0,07 | 0,02 |
| 800 Pa | 2,08 | 0,69 | 0,23 | 0,08 | 0,03 |
| 900 Pa | 2,25 | 0,75 | 0,25 | 0,08 | 0,03 |
| 1000 Pa | 2,41 | 0,80 | 0,27 | 0,09 | 0,03 |
| 1100 Pa | 2,56 | 0,85 | 0,28 | 0,09 | 0,03 |
| 1200 Pa | 2,71 | 0,90 | 0,30 | 0,10 | 0,03 |
| 1300 Pa | 2,85 | 0,95 | 0,32 | 0,11 | 0,03 |
| 1400 Pa | 2,99 | 1,00 | 0,33 | 0,11 | 0,04 |
| 1500 Pa | 3,13 | 1,04 | 0,35 | 0,12 | 0,04 |
| 1600 Pa | 3,27 | 1,09 | 0,36 | 0,12 | 0,04 |
| 1700 Pa | 3,40 | 1,13 | 0,38 | 0,13 | 0,04 |
| 1800 Pa | 3,53 | 1,18 | 0,39 | 0,13 | 0,04 |
| 1900 Pa | 3,65 | 1,22 | 0,41 | 0,14 | 0,04 |
| 2000 Pa | 3,78 | 1,26 | 0,42 | 0,14 | 0,05 |
| 2100 Pa | 3,90 | 1,30 | 0,43 | 0,14 | 0,05 |
| 2200 Pa | 4,02 | 1,34 | 0,45 | 0,15 | 0,05 |
| 2300 Pa | 4,14 | 1,38 | 0,46 | 0,15 | 0,05 |
| 2400 Pa | 4,25 | 1,42 | 0,47 | 0,16 | 0,05 |
| 2500 Pa | 4,37 | 1,46 | 0,49 | 0,16 | 0,05 |
