Brochure

SS Spiral Diffuser (Page 39)

Diffuser Length (Feet) Multiplication Factor Diffuser Length (Feet) NC Correction

1 0.50 1 -2

2 0.85 2 -2

3 0.95 3 -1

4 1.00 4 0

Notes:

1. Tests conducted in accordance with ANSI/ASHRAE 70-1991 at isothermal conditions.

2. Engineering Units: Airflow Rate = CFM/linear foot

Static Pressure = in. w.c.

Throw = ft. at 50, 100, and 150 FPM terminal velocity

3. Noice Criteria is based on 10 dB room absorption (Re: 10

watts) evaluated at 125 through 4000 Hz

octave bands.

4. Throw data are based on a a horizontal discharge in one direction only. For two-way discharge pattern,

the throw is determined from the published engineering data based on the number of slots and

CFM/linear feet discharging in each direction.

5. Throw data are for 4-foot active diffuser lengths.

For other active lengths, throw may be determined

by applying the following multiplication factors.

6. Sound data are for 4-foot active diffuser lengths.

For other lengths, add or deduct the following

values to or from the reported NC level.

Recommended Noise Criteria and Face Velocity Ranges are on page 75

Engineering Data