T.O. 33B-1-1
2-10
a. Type of penetrant (fluorescent or visible dye).
b. Method of removing excess surface penetrant.
c. Sensitivity Level of a penetrant system.
d. Form of developer.
e. Class of solvent remover.
NOTE
Form designations reflect ASM 2644, which has superseded MIL-25135. ASTM E
1417-95a did not reflect this change at the time of publication. The Specific
Application categories in Table 2-1 for nonaqueous developers and solvent
removers allow a manufacturer the opportunity to optimize the formulation of these
products for one of their own specific penetrant systems or for a specific user need.
Table 2-1. Classification of Penetrant Materials Contained in ASM 2644.
Type
Type I
Fluorescent Dye
Type II
Visible Dye
Type III
Dual Mode (Visible and Fluorescent Dye)
Method
Method A
Water Washable
Method B
Postemulsifiable, Lipophilic
Method C
Solvent Removable
Method D
Postemulsifiable, Hydrophilic
Sensitivity Level
Level ½
Very Low
Level 1
Low
Level 2
Medium
Level 3
High
Level 4
Ultra High
Developer
Form a
Dry Powder
Form b
Water Soluble
Form c
Water Suspendible
* Form d
Nonaqueous (Wet; for Type I)
* Form e
Nonaqueous (Wet; for Type II)
* Form f
Specific Application
Solvent Remover
Class 1
Halogenated
Class 2
Nonhalogenated
Class 3
Specific Application
2.2.5.2
Classifications in Other Documents.
The ASM 2644 classifications are referenced in process standard ASTM E 1417 (latest version), the American Society
for Testing and Materials (ASTM) Practice for Liquid Penetrant Examination. The Type and Method classifications
