Hazelwood Power Station

Forced Draft Fans

Hazelwood Power Station near Morwell in Victoria had noise levels up to 105 dB(A), in the vicinity of the station's double inlet centrifugal FD fans.

The challenge laid down in the specification, issued by the State Electricity Commission of Victoria was:

1) To reduce the noise levels to 85db(A) at 1m from the unit, whilst still allowing operators full access to the fans, motor bearings, couplings and inlet vane actuators.
2) To build equipment which could also withstand the aerodynamic buffeting created by the fan inlet flow conditions and the wind tunnel effects occurring through the Power Station equipment gallery.

NAP Silentflo won the competitive tender and set about the task through the combined application of four comprehensive noise suppression techniques:

1) Acoustic cladding, applied to the fan case and discharge ductwork.
2) Acoustic screens or shielding around the 870kw CACW electric motors.
3) Industrial construction NAP 'D' series absorptive silencers, installed to each of the fan air inlets (2 per enclosure).
4) A plenum, consisting of NAP'S demountable Sound Snap acoustic panels, designed to attenuate break out noise and with a performance comparable to the inlet silencer.

The Result?
Strict testing by the client's engineers has proven the noise reduction required has indeed been comfortably achieved whilst still maintaining access and reliability.

As a result of NAP'S achievements on the first units the Commission took up options to treat four more FD units at the station, each with two acoustic enclosures. Shown above are examples of work carried out on Units 2 and Unit 3 at Hazelwood. NAP'S success in this field of noise control also includes power station projects in Queensland, New South Wales, Western Australia and the Northern Territory, Australia.