Standard Practices for Sampling for Particles in Aerospace Fluids and Components

Importancia y uso:

7.1 Although a cleaning action is imparted to the test component, it is not the intent of this practice to serve as a cleaning procedure. Components are normally cleaner after each consecutive test; thus repeated tests may be used to establish process limits for a given component (Fig. 4). A specific set of test parameters must be supplied by the agency specifying cleanliness limits. Fig. 1, Fig. 2, and Fig. 3 may be used as a guide to establish the desired parameters of test fluid, vibration, extraction, and analysis.

FIG. 4 Contamination per Test Run Versus Consecutive Test Run Number

7.2 The curve in Fig. 4 shows the typical behavior of a component when tested for cleanliness several consecutive times. Stabilization generally occurs before the fifth successive run. The stabilized region starts where a horizontal line through the maximum stabilized value intersects the curve.

7.3 The allowable cleanliness limit of a test component should be based on the cleanliness requirements of the system in which it will be used, and the assigned value should be greater than the maximum stabilized value. When defining the allowable cleanliness limits, an important consideration is that the accuracy of the results decreases as the allowable limit value approaches the stabilized value.

Subcomité:

E21.05

Referida por:

F0311-08R20, F0331-13R20, D4898-23, E1548-23, G0121-18, F0312-08R23

Volúmen:

15.03

Número ICS:

49.080 (Aerospace fluid systems and components)

Palabras clave:

aerospace applications; aerospace fluids/propellants; flowing fluid sampling; particulate contamination; rinse fluid sampling; sampling—aerospace fluids; sampling—electronic materials/applications; static fluid sampling; sampling aerospace fluids from components; practice;