Kitchen Extract Fan Noise


We have been appointed acoustic consultants to a client proposing to convert a shop to a food takeaway with associated kitchen extract fan & silencer exterior to the building, supplied by yourselves.

The proposed specification is for a 450mm S&P fan (I think this may translate to either a model TCBBx2/4-450 or TCBTx2/4-450) together with a 450mm unpodded silencer (suspect : CDA 450 x 1D). The broadband sound pressure level at 3m is thought to be 67 or 68dBA for the fan and the silencer is believed to reduce noise by c.7-10dBA.

In order that I can provide proof to the local authority that noise levels will be acceptable, I need a breakdown by octave band of (preferably) the sound power levels of the fan (or sound pressure levels in octave bands at a given distance), together with an octave band breakdown of the silencer.

Can you email me this information please?

Many thanks,



  • Hello again,

    I think I may have posted on a different forum to the one I was expecting - apologies.
    Nonetheless, does anyone the information I'm looking for?



  • Matt
    Please find info below as requested. If you advise the Fan design Duty we can forward a more accurate spectrum, but this shouldn't be far off. The silencer insertion loss is based on a 450mm dia x 1D Straight through.
    Hope of some help
    Its difficult to format it correctly but if you copy and [paste it into word and line up the columns you should be OK
    If you send an email I can forward it to you as a PDF

    Sound Performance Hz 63 125 250 500 1k 2k 4k 8k Overall
    F Drawing Inlet (LwA) 47 73 84 81 83 79 71 64 88
    Inlet LpA @ 3m 27 52 63 60 62 58 50 43 68
    Outlet (LwA) 53 73 85 84 87 81 74 67 91
    Outlet LpA @ 3m 33 52 64 63 66 61 53 46 70
    Silencer insertion loss 2 3 6 12 13 11 10 6

  • Many thanks admin, I'm impressed.
    Not sure about the design duty - do you data on the various options?
    Don't suppose you also have casing breakout noise data too...?

    I would appreciate the .pdf.
    Can't immediately find your email address so mine is :

    Thanks again.

Sign In or Register to comment.