ASTM E1135-12
Standard Test Method for Comparing the Brightness of Fluorescent Penetrants

Standard No.

ASTM E1135-12

Release Date

2012

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM E1135-19

Latest

ASTM E1135-19(2024)

Scope

The penetrant is one of the major components of the fluorescent penetrant process, and very influential in the degree of performance attained by a given system or group of materials. The penetrant must enter the discontinuity, be removed from the part surface but not from the discontinuity, be brought out of the discontinuity by the developer, and finally viewed and detected by the inspector. If all processing parameters are optimized for the parts being examined and the examination materials in use, the intrinsic brightness of the penetrant becomes the factor which governs the sensitivity of the system.

Because the eye responds logarithmically rather than linearly to changes of brightness, differences in brightness must be fairly large to be significant. Differences of 25 % are obvious, 12 % noticeable, and 6 % detectable by the eye. Experts may sometimes detect 3 % differences, but these are not usually significant to the average observer.

The significance of the results also depends on the deviation between readings on the same material sample. Different samples, even when prepared out of the same initial quantity of penetrant will not exactly reproduce readings. These differences occur because of paper differences and penetrant migration on the paper samples.

To determine the confidence limits for the test results, it is necessary to perform certain statistical calculations. The confidence limits are determined by the equation:

where:
CL	=	the limits within which we can be confident the value lies,
¯X	=	the average of all readings,
t	=	“student''s t” (values of which are given by statistical manuals),
n	=	the number of readings used,
s	=	the standard deviation determined by the equation:

where:
X	=	the individual readings.

In this use, the 95 % confidence level (the value will lie within the limits 95 % of the time) is sufficient. At this level, t for 4 samples is 3.182.

If the confidence limits of two material samples overlap, the materials must be considered equal even though the measured average values are different.

1.1 This test method describes the techniques for comparing the brightness of the penetrants used in the fluorescent dye penetrant process. This comparison is performed under controlled conditions which eliminate most of the variables present in actual penetrant examination. Thus, the brightness factor is isolated and is measured independently of the other factors which affect the performance of a penetrant system.

1.2 The brightness of a penetrant indication is dependent on the developer with which it is used. This test method howeve......

ASTM E1135-12 Referenced Document

• ASTM E1316 Standard Terminology for Nondestructive Examinations
• ASTM E691 Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

ASTM E1135-12 history

• 2024 ASTM E1135-19(2024) Standard Test Method for Comparing the Brightness of Fluorescent Penetrants
• 2019 ASTM E1135-19 Standard Test Method for Comparing the Brightness of Fluorescent Penetrants
• 2012 ASTM E1135-12 Standard Test Method for Comparing the Brightness of Fluorescent Penetrants
• 1997 ASTM E1135-97(2008)e1 Standard Test Method for Comparing the Brightness of Fluorescent Penetrants
• 1997 ASTM E1135-97(2003) Standard Test Method for Comparing the Brightness of Fluorescent Penetrants
• 1997 ASTM E1135-97 Standard Test Method for Comparing the Brightness of Fluorescent Penetrants