40 CFR § 1065.644 - Vacuum-decay leak rate.

§ 1065.644 Vacuum-decay leak rate.

This section describes how to calculate the leak rate of a vacuum-decay leak verification, which is described in § 1065.345(e). Use the following equation to calculate the leak rate n

leak, and compare it to the criterion specified in § 1065.345(e):

n · leak = V vac R · ( p 2 T 2 p 1 T 1 ) ( t 2 t 1 ) Eq. 1065.644-1

Where:
Vvac = geometric volume of the vacuum-side of the sampling system.
R = molar gas constant.
p2 = vacuum-side absolute pressure at time t2.
T2 = vacuum-side absolute temperature at time t2.
p1 = vacuum-side absolute pressure at time t1.
T1 = vacuum-side absolute temperature at time t1.
t2 = time at completion of vacuum-decay leak verification test.
t1 = time at start of vacuum-decay leak verification test.
Example:
Vvac = 2.0000 L = 0.00200 m 3
R = 8.314472 J/(mol · K) = 8.314472 (m 2 · kg)/(s 2 · mol · K)
p2 = 50.600 kPa = 50600 Pa = 50600 kg/(m · s 2)
T2 = 293.15 K
p1 = 25.300 kPa = 25300 Pa = 25300 kg/(m · s 2)
T1 = 293.15 K
t2 = 10:57:35 a.m.
t1 = 10:56:25 a.m.

n · leak = 0.0002 8.314472 · ( 50600 293.15 25300 293.15 ) ( 10 : 57 : 35 10 : 56 : 25 )

n · leak = 0.00200 8.314472 · 86 . 304 70 n · leak = 0.00030 mol / s

[79 FR 23795, Apr. 28, 2014]

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