CHUNLAN -B - Recommended Criteria for Indoor Noise Control; Max. Air Delivery Speed at Orifice, Strip Seam and Spout (M;S); Air Suction Speed at Return Air Port (M;S); Maximum Air Delivery Speed of Diffuser (M;S)

Air duct design & noise reduction
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Table 3: Maximum air delivery speed of diffuser (m/s)
Net indoor height /m
Building
Permitted noise
/dB (A)
3 4 5 6 7
Broadcasting 32 3.9 4.2 4.3 4.4 4.5
Theatre, residence, operation room
33—39
4.4 4.6 4.8 5.0 5.2
Hotel, personal office
40—46
5.2 5.4 5.7 5.9 6.1
Shop, bank, restaurant, department store
47—53
6.2 6.6 7.0 7.2 7.4
Public building; office, department store
bottom floor
54—60
7.4 7.9 8.3 8.7 8.9
Table 4: Max. air delivery speed at orifice, strip seam and spout (m/s)
Air port
Max air delivery
speed
Remark
Orifice 3—5
Seam port 2—4
Spout 4—10
Upper limit is preferred for high even delivery requirement
or hot air, for high installed position of port, or higher ai
r
speed is allowed in area of personnel activities.
Table 5: Air suction speed at return air port (m/s)
Position of return air port Air suction speed
Room upper part 4—5
Room lower part Near points of stay of personnel 1.5—2
Table 6: Recommended criteria for indoor noise control (referencing “High building air
conditioning design” published by China Architectural Industry Publishing House).
Type of room Noise level
Guest room
Grade I
Grade II
Grade III
Grade IV
30
35
40
55
Restaurant
Banquet hall
Multifunction hall
Grade I
Grade II
Grade III
Grade IV
（35）
40
45
55