Pumpsets
(A) Noise Problems
Air-borne Noise
• The major noise source of a pump is usually the bearing noise as a result of bearing worn-out. However, the noise contributed by the pump itself is small relative to that generated from its associated motor. The major noise source of a motor is usually the air movement induced by the cooling fan, which may cause noise disturbance to nearby residents (see Figure 25).
Structure-borne Noise
• Vibration from an operating pumpset may be transmitted to the interior of the building through building structure when the pumpset is directly mounted on a supporting structure without proper isolation (see Figure 26). The vibration transmitted may activate the building structure to generate noise which causes noise disturbance to residents inside the building.
(B) Practical Remedies
Air-borne Noise
• Replace worn-out bearing so as to reduce the noise.
• Erect a barrier between the pumpset and nearby residential buildings (see Figure 27) so as to block the noise propagation path.
• Fabricate a partial enclosure to contain and absorb the noise energy radiated by the source.
(Noise Reduction Up to 10 dB(A))
• Fabricate a complete enclosure with silencers at inlet and outlet of the enclosure (see Figure 28) so as to contain and absorb the noise energy radiated by the source.
(Noise Reduction Up to 30 dB(A))
• Locate the pumpset inside a plantroom (see Figure 29) with silencers at air inlet and outlet, and a soundproof door.
(Noise Reduction Up to 30 dB(A))
Structure-borne Noise
• Provide an inertia block to support the pumpset (see Figure 30) so as to add rigidity and stability to the pumping system, and provide vibration isolators (see Figure 30) to support the inertia block, thereby isolating it from the building structure.
• Provide flexible connectors between the pump and associated pipework, thereby preventing the vibration of the pumpset being transmitted to the pipework (see Figure 30).
(Noise Reduction Up to 20 dB(A))
