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

Eq. 1065.644-1

Where:

V_vac = geometric volume of the vacuum-side of the sampling system.

R = molar gas constant.

p₂ = vacuum-side absolute pressure at time t _2.

T₂ = vacuum-side absolute temperature at time t _2.

p₁ = vacuum-side absolute pressure at time t _1.

T₁ = vacuum-side absolute temperature at time t _1.

t₂ = time at completion of vacuum-decay leak verification test.

t₁ = time at start of vacuum-decay leak verification test.

Example:

V_vac = 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.

[79 FR 23795, Apr. 28, 2014; 89 FR 29808, Apr. 22, 2024]