WDX USER INSTRUCTIONS ENGLISH 71576322 06-05
Page 9 of 46
®
1.9 Noise le vel
When pump noise level exceeds 85dBA attention must
be given to prevailing Health and Safety Legislation, to
limit the exposure of plant operating personnel to the
noise. The usual approach is to control exposure time
to the noise or to enclose the machine to reduce
emitted sound. You may have already specified a
limiting noise level when the equipment was ordered,
however if no noise requirements were defined then
machines above a certain power level will exceed 85
dB(A). In such situations consideration must be given
to the fitting of an acoustic enclosure to meet local
regulations.
Pump noise level is dependent on a number of factors
- the type of motor fitted, the operating capacity,
pipework design and acoustic characteristics of the
building. Typical sound pressure levels measured in
dB and A-weighted are shown in the table below.
The figures are indicative only, they are subject to a +3
dB tolerance, and cannot be guaranteed.
The values are based on the noisiest ungeared electric
motors which are likely to be encountered. They are
L
pA
sound pressure levels at 1m (3.3ft) from the
directly driven pump, for "free field over a reflecting
plane". For estimating L
wA
sound power level (re 1 pW)
add 14 dB(A) to the sound pressure value.
If a pump only has been purchased, for fitting with your
own driver, then the "pump only" noise levels from the
table should be combined with the level for the driver
obtained from the supplier. If the motor is driven by an
inverter, it may show an increase in noise level at
some speeds. Consult a Noise Specialist for this
calculation
For units driven by equipment other than
electric motors or units contained within enclosures,
see the accompanying information sheets and
manuals.
Typical sound pressure level, dBA, L
pA
at 1 m reference 20
μ
Pa
(L
wA
sound power1 pW where L
pA
>85 dBA)
3550 r/min
2900 r/min
1750 r/min
1450 r/min
Motor size
and speed
kW (hp)
Pump and
motor
dBA
Pump
onl y
dBA
Pump and
motor
dBA
Pump
onl y
dBA
Pump and
motor
dBA
Pump
onl y
dBA
Pump and
motor
dBA
Pump
onl y
dBA
5.5 (7.5)
90 (
99
)
77
83
73
76
73
72
71
7.5 (10)
90 (
99
)
78
83
74
77
74
73
72
11 (15)
91 (
100
)
80
84
76
78
76
74
73
15 (20)
92 (
101
)
83
85 (
94
)
79
80
79
76
75
18.5 (25)
92 (
101
)
83
85 (
94
)
79
80
79
76
75
22 (30)
92 (
101
)
83
85 (
94
)
79
81
79
77
75
30 (40)
100 (
109
)
85 (
94
)
93 (
102
)
81
84
80
80
76
37 (50)
100 (
109
)
86 (
95
)
93 (
102
)
82
84
80
80
76
45 (60)
100 (
109
)
87 (
96
)
93 (
102
)
83
84
80
80
76
55 (75)
100 (
109
)
88 (
97
)
95 (
104
)
84
86 (
95
)
81
82
77
75 (100)
100 (
109
)
90 (
99
)
95 (
104
)
86 (
95
)
88 (
97
)
81
83
78
90 (120)
100 (
109
)
90 (
99
)
95 (
104
)
86 (
95
)
90 (
99
)
81
85 (
94
)
78
110 (150)
100 (
109
)
91 (
100
)
95 (
104
)
87 (
96
)
91 (
100
)
83
86 (
95
)
79
150 (200)
101 (
110
)
92 (
101
)
96 (
105
)
88 (
97
)
91 (
100
)
83
86 (
95
)
79
200 (270)
*
*
*
*
*
83
*
80
300 (400)
-
-
-
-
*
84
*
81
500 (670)
-
-
-
-
*
85 (
94
)
*
83
*
Motors in this range are generall y job s pecific and nois e levels should be c alculated based on ac tual equipment installed.
For 960 rpm reduce 1450 r pm values by 5 dBA.
