942
14 CFR Ch. I (1–1–14 Edition)
Pt. 36, App. A
A36.9.3.2.1 The one-third octave band levels
SPL(i) comprising PNL (the PNL at the mo-
ment of PNLTM observed at K) must be ad-
justed to reference levels SPL(i)
r
as follows:
A36.9.3.2.1(a) For calculations using the
English System of Units:
SPL(
i)
r
=SPL(
i)+0.001[
a(i)¥a(i)
0
]QK
+0.001
a(i)
0
(QK¥Q
r
K
r
)
+20log(QK/Q
r
K
r
)
In this expression,
(1) The term 0.001[
a(i)¥a(i)
0
]QK is the ad-
justment for the effect of the change in
sound attenuation coefficient, and
a(i) and
a(i)
0
are the coefficients for the test and ref-
erence atmospheric conditions respectively,
determined under section A36.7 of this appen-
dix;
(2) The term 0.001
a(i)
0
(QK ¥ Q
r
K
r
) is the ad-
justment for the effect of the change in the
noise path length on the sound attenuation;
(3) The term 20 log(QK/Q
r
K
r
) is the adjust-
ment for the effect of the change in the noise
path length due to the ‘‘inverse square’’ law;
(4) QK and Q
r
K
r
are measured in feet and
a(i) and a(i)
0
are expressed in dB/1000 ft.
A36.9.3.2.1(b) For calculations using the
International System of Units:
SPL(i)
r
=SPL(i)+0.01[
a(i)¥a(i)
0
]QK
+0.01
a(i)
0
(QK ¥ Q
r
K
r
)
+20 log(QK/Q
r
K
r
)
In this expression,
VerDate Mar<15>2010
10:12 Mar 18, 2014
Jkt 232046
PO 00000
Frm 00952
Fmt 8010
Sfmt 8003
Y:\SGML\232046.XXX
232046
ER08JY02.017</MATH>
pmangrum on DSK3VPTVN1PROD with CFR