Nailor 37S Manual page 51
Low profile fan powered terminal unit with epic ecm or psc motor
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Also See for 37S:
- Installation and operation manual (10 pages) ,
- Installation and operation manual (10 pages)
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FAN POWERED TERMINAL UNITS
Performance Data Explanation
Sound Power Levels vs. NC Levels
The Nailor Model Series: 35S, 35SST, 37S, 37SST, 35N and
37N fan powered terminal unit performance data is presented in
two forms.
The laboratory obtained discharge and radiated sound power
levels in octave bands 2 through 7 (125 through 4000 Hz) center
frequency for each unit size at various flow rates and inlet static
pressures is presented. This data is derived in accordance with
ANSI/ASHRAE Standard 130 and AHRI Standard 880. This data is
raw with no attenuation deductions and includes AHRI Certification
standard rating points.
Nailor also provides an "NC Level" table as an application aid
in terminal selection, which include attenuation allowances as
explained below. The suggested attenuation allowances are typical
and are not representative of specific job site conditions.
recommended that the sound power level data be used and a
C
detailed NC calculation be performed using the procedures outlined
in AHRI Standard 885, Appendix E for accurate space sound levels.
Explanation of NC Levels
Tabulated NC levels are based on attenuation values as outlined
in AHRI Standard 885 Procedure for Estimating Occupied Space
Sound Levels in the Application of Air Terminals and Air Outlets".
AHRI Standard 885, Appendix E provides typical sound attenuation
values for air terminal discharge sound and air terminal radiated
sound.
As stated in AHRI Standard 885, Appendix E, These values can
be used as a quick method of estimating space sound levels when
a detailed evaluation is not available. The attenuation values are
required for use by manufacturers to catalog application sound
levels. In product catalogs, the end user environments are not
known and the following factors are provided as typical attenuation
values. Use of these values will allow better comparison between
manufacturers and give the end user a value which will be expected
to be applicable for many types of space.
Radiated Sound
Table E1 of Appendix E provides typical radiated sound attenuation
values for three types of ceiling: Type 1 – Glass Fiber; Type 2 –
Mineral Fiber; Type 3 – Solid Gypsum Board.
Since Mineral Fiber tile ceilings are the most common construction
used in commercial buildings, these values have been used to
tabulate Radiated NC levels.
The following table provides the calculation method for the radiated
sound total attenuation values based on AHRI Standard 885.
Environmental Effect
Ceiling/Space Effect
Total Attenuation Deduction
The ceiling/space effect assumes the following conditions:
1. 5/8" (16) tile, 20 lb/ft
2. The plenum is at least 3 feet (914) deep.
3. The plenum space is either wide [over 30 feet (9 m)] or lined with
insulation.
C132
Octave Band
2
3
4
5
2
1
0
0
16
18
20
26
18
19
20
26
3
(320 kg/m
3
) density.
Discharge Sound
Table E1 of Appendix E provides typical discharge sound attenuation
values for three sizes of terminal unit.
1. Small box;
2. Medium box;
3. Large box;
These attenuation values have been used to tabulate Discharge NC
levels applied against the terminal airflow volume and not terminal
unit size.
The following tables provide the calculation method for the discharge
sound total attenuation values based on AHRI Standard 885.
Small Box
It is
<300 cfm
Environmental Effect
5 ft. (1.5 m) 1" (25) Duct Lining
Branch Power Division (1 outlet)
5 ft. (1.5 m), 8 in. dia. (203) Flex Duct 5
End Reflection
Space Effect
Total Attenuation Deduction
Medium Box
300 – 700 cfm
Environmental Effect
5 ft. (1.5 m) 1" (25) Duct Lining
Branch Power Division (2 outlets)
5 ft. (1.5 m), 8 in. dia. (203) Flex Duct 5
End Reflection
Space Effect
Total Attenuation Deduction
Large Box
>700 cfm
Environmental Effect
5 ft. (1.5 m) 1" (25) Duct Lining
Branch Power Division (3 outlets)
5 ft. (1.5 m), 8 in. dia. (203) Flex Duct 5
End Reflection
Space Effect
Total Attenuation Deduction
1. Flexible duct is non-metallic with 1" (25) insulation.
6
7
2. Space effect (room size and receiver location) 2500 ft.
0
0
(69 m
3
) and 5 ft. (1.5 m) distance from source.
31
36
31
36
For a complete explanation of the attenuation factors and the
procedures for calculating room NC levels, please refer to the
acoustical engineering guidelines at the back of this catalog and
AHRI Standard 885.
Less than 300 cfm (142 l/s)
[Discharge Duct 8" x 8" (203 x 203)].
300 – 700 cfm (142 - 330 l/s)
[Discharge Duct 12" x 12" (305 x 305)].
Greater than 700 cfm (330 l/s)
[Discharge Duct 15" x 15" (381 x 381)].
Octave Band
2
3
4
2
1
0
2
6
12
0
0
0
10
18
10
5
2
5
6
7
24
28
39
Octave Band
2
3
4
2
1
0
2
4
10
3
3
3
10
18
10
5
2
5
6
7
27
29
40
Octave Band
2
3
4
2
1
0
2
3
9
5
5
5
10
18
10
5
2
5
6
7
29
30
41
5
6
7
0
0
0
25
29
18
0
0
0
19
21
12
1
0
0
8
9
10
53
59
40
5
6
7
0
0
0
20
20
14
3
3
3
19
21
12
1
0
0
8
9
10
51
53
39
5
6
7
0
0
0
18
17
12
5
5
5
19
21
12
1
0
0
8
9
10
51
52
39
3
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