Knowledge base
Building facades
Trickle vent types and performance

Trickle vent types and performance

Trickle ventilators must satisfy two design objectives in noisy environments: Approved Document F airflow requirements and BS 8233 / WHO Community Noise Guidelines acoustic targets. Performance is measured by Dn,e (element-normalised level difference) and Dn,e,w + Ctr (the weighted single-figure rating with a low-frequency correction). The table below collates the published performance of vents commonly specified on UK residential schemes.

Name Manufacturer Type Dne Dnew+Ctr
125mm Acoustic High Rise Aircore AAH5HM Rytons Wall vent 39
AAC125HP Rytons Wall vent 43
Passivent Fresh 90dB Passivent Wall vent 45
Airvac AAB Greenwood Wall vent 46
Fresh 80 dB Passivent Wall vent 50
Airvac MA3051 Greenwood Wall vent 55
5000EA.AC1 Greenwood Trickle 39 37
5000EA.AC2 Greenwood Trickle 42 38
2500EA.AC1 Greenwood Trickle 42 40
EAR24 Greenwood Trickle 42 42
2500EA.AC2 Greenwood Trickle 45 42
D Vent Greenwood Trickle 34
L Vent Greenwood Trickle 37
TVALdB 450 Passivent Trickle 40
TVALdB 800 Passivent Trickle 42
Sonovent (Small) Airslot 25 mm Renson Bulkhead 37 34
Sonovent (Medium) Airslot 25 mm Renson Bulkhead 39 35
Sonovent (Large) Airslot 25 mm Renson Bulkhead 41 35
Sonovent (Small) Airslot 20 mm Renson Bulkhead 40 37
Sonovent (Large) Airslot 20 mm Renson Bulkhead 44 38
Sonovent (Medium) Airslot 15 mm Renson Bulkhead 45 39
Sonovent (Small) Airslot 15 mm Renson Bulkhead 41 39
Sonovent (X-large) Airslot 25 mm Renson Bulkhead 45 39
Sonovent (Medium) Airslot 20 mm Renson Bulkhead 43 40
Sonovent (X-large) Airslot 20 mm Renson Bulkhead 46 40
Sonovent (Small) Airslot 10 mm Renson Bulkhead 46 41
Sonovent (Medium) Airslot 10 mm Renson Bulkhead 48 42
Sonovent (Large) Airslot 15 mm Renson Bulkhead 49 42
Sonovent (Large) Airslot 10 mm Renson Bulkhead 50 44
Sonovent (X-large) Airslot 15 mm Renson Bulkhead 53 47
Sonovent (X-large) Airslot 10 mm Renson Bulkhead 56 50
CAICE Acoustic Ventilator (2000 mm width x 400 mm depth) CAICE Bulkhead 41
Sonovent (X-large) Airslot 10 mm Renson Bulk head 56

How we use this

These ratings feed directly into our noise impact assessments for residential schemes near roads, railways or industrial sources, where passive ventilation is required to meet Approved Document F airflow rates without compromising BS 8233 internal noise targets.

Grazing the trickle vent calculation for facades