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SOUND POWER and SOUND PRESSURE LEVELS
556 SERIES WM (L) (E)
SOUND POWER LEVELS
SOUND PRESSURE LEVELSFrequency Hz
MODEL SPEED 125 250 500 1K 2K 4K dBA dBA NC
60
MIN 36.8 37 39.1 38.8 34.4 31.7 43 25 19
MED 41.0 43.4 45.8 45.1 39.6 35.4 49 31 25
MAX 46.7 48.6 50.6 50.4 46.6 39.0 54 37 31
80
MIN 39.1 44.3 47.2 46.8 41.6 40.8 51 33 27
MED 43.8 49.1 51.3 51.3 46.7 39.5 55 37 32
MAX 45.5 50.5 53.7 52.9 48.7 40.8 57 39 34
100
MIN 34.1 38.0 44.0 42.3 41.0 38.0 48 30 24
MED 42.7 45.8 48.9 49.1 44.2 38.1 53 35 30
MAX 46.4 51.6 54.2 54.2 49.9 42.9 57 40 35
Sound Power Levels obtained in conformance with BS 4196: Part 5: 1981. Values are shown in dB with a standard
reference of 1 pW.
Sound Pressure Levels are dB relative to 2 x 10-5N/m2and are calculated from results measured in anechoic conditions.
Values relate to a position 3m away from the centre line of the unit, 1m down.
550/551 SERIES MCU, MCU+ MHPUL MHPUE
MAXIMUM SPEED SOUND POWER LEVELS SOUND PRESSURE LEVELS
Frequency Hz
MCU(+) MHPUL(E) 125 250 500 1K 2K 4K dBA dBA NC
50 50 73.6 68.2 67.1 65.5 61.1 53.4 70 49 44
60 - 72.9 67.7 67.8 66.4 61.9 54.1 70 50 45
80 - 70.9 68.6 68.1 65.3 59.5 53.8 70 49 43
- 80 75.4 72.9 69.1 68.8 62.6 56.6 72 52 47
90 90 81.8 71.8 69.2 68.6 63.1 57.4 73 52 47
100 - 79.4 73.7 71.5 68.5 63.8 58.1 73 53 47
MINIMUM SPEED SOUND POWER LEVELS SOUND PRESSURE LEVELS
Frequency Hz
MCU(+) MHPUL(E) 125 250 500 1K 2K 4K dBA dBA NC
50 50 67.4 64.1 66.0 63.6 58.7 51.8 68 47 42
60 - 67.4 64.3 67.1 66.8 60.7 51.7 70 49 45
80 - 69.4 66.5 66.9 62.1 56.1 51.6 68 47 41
- 80 67.5 63.4 64.4 64.2 57.4 51.0 67 47 43
90 90 79.0 65.4 64.9 61.5 58.5 53.7 68 47 40
100 - 75.3 69.4 70.9 63.7 59.7 53.6 70 50 46
Sound Power Levels obtained in conformance with ISO 3741: 1988. Values are dB with a standard reference of 1 pW.
Sound Pressure Levels are dB relative to 2 x 10-5N/m2and are calculated from results measured in anechoic conditions.
Values relate to a position 3m away from the centre of the unit (in cooling mode); (add 3dBA or 3NC for units at an
intersection of a wall, add 1dBA or 1NC for high level wall mounted units).
SOUND PRESSURE LEVELS - DUCTED CONDENSING UNITS
Measurement Point Unit Fan Speed dBA NC
3m from unit in void DCUE 50, 60, 80
DHPUE 50
Max 54 48
Min 44 31
Adjacent office area DCUE 50, 60, 80
DHPUE 50
Max 42 28
Min 32 17
3m from discharge grille DCUE 50, 60, 80
DHPUE 50
Max 52 44
Min 40 28
All readings taken from a typical application of a unit suspended in a ceiling void complete with 5m of insulated
ducting, conditioning an office directly below. Sound Pressure Levels are dB relative to 2x10-5N/m2.
