BLD2022-0986_Other_7.25.2022_9.51.58_AM_3008970Carrier 24ABB330ABN3 2-1/2 Ton A/C Unit @ 72dBa. @ 1 V = 53.8 dBa (55.0 dBa Maximum per code)
ARI STANDARD 275-97
4.2 Procedure for Estimating Sound Pressure Levels -
Single Unit Installation. The basic procedure for
estimating A -Weighted sound pressure levels at a given
point of evaluation consists of combining the sum of the
application and evaluation factors with the Sound Rating
Level for the equipment: 11 f t
Sound Rating Level from ARI 270 72.0
+ Equipment Location Factor
— Barrier Shielding Factor
None Installed
— Sound Path Factor
Not used for property lines
18.2
— Distance Factor
Estimated A -Weighted Sound 53.8
Pressure Level I dB*
+/- 2 dBa Tolerance Allowed for Testing
Code Target is 55 Dba Max for A/C
4.1.2 Barrier Shielding Factor. This factor
accounts for the sound reduction benefit of any solid
structure that obstructs the line of sight (or sound)
from the equipment location to the point of
evaluation. Such a barrier may be the corner of a
building, the edge of a roof, or a heavy wall of
masonry, etc., built for the specific purpose of
shielding noise from a unit to an area of concern.
See Item 2, Table 1, for sketches and the normal
barrier factors.
74.11.�oundPath Factor. This factor adjusts for the
th of soun he unit to the point of evaluation,
which may be to the ou only, to a room through
open windows, to a room throng windows, or
through a wall. See Item 3, Table 1.
4.1.4 Distance Factor. The direct distance, D, from
the equipment location to the point of evaluation is a
very significant application factor in determining the
estimated A -Weighted sound pressure levels resulting
from the operation of outdoor equipment in any
installation. The distance factor is obtained from
Table 2.
Table 2. Distance Factor
Factor Value
ft.
[in]
(M)
4
1.2
9.5
5
1.5
11.5
6
1.8
13.0
7
2.1
14.5
8
2.4
15.5
9
2.7
16.5
10 11
3.0
18.2 17.5
4.6
15
21.0
20
6.1
23.5
25
7.6
25.5
30
9.1
27.0
40
12.2
29.5
50
15.2
31.0
60
18.3
33.0
70
21.3
34.5
80
24.4
35.5
90
27.4
36.5
100
30.5
37.5
125
38.1
39.5
150
45.7
41.0
175
53.3
42.5
200
61.0
43.5
400
122.0
49.5
5