Fans by Fantech Electronic Catalogue

H-3

NOISE CONTROL PRODUCTS

2016

ATTENUATOR SELECTION PROCEDURE

2. Attenuator Pressure Loss

A sound attenuator restricts the passage of air flow through it.

The restriction of the attenuator is defined in Pa of static

pressure loss. The pressure loss of the attenuators in this

catalogue is charted in two different ways:

a) Pressure loss at a given air flow

For the C, C.P, CC series circular attenuators

and POW series attenuators, the static pressure

loss is charted for each model at different airflows.

For example, if we select an attenuator model

C2P-071 with an air flow of 4m

/s, the pressure

loss is 50Pa.

b) Variable Face Area (Width or Height)

Some attenuator types are expected to be built to varying

widths and heights to suit the duct or wall sizing. With acoustic

louvres for example, pressure losses for a given model are

graphed against face velocity:

Face velocity, m/s

100

0.5

0.75

1.0

2.0

1.5

SBL1 (500H)

Pressure loss, Pa

For rectangular attenuators, the velocities are

provided for a given model at 20Pa or 50Pa at

different lengths as per below: (See Page H-7)

Face Velocity of 50Pa

Pressure Drop