T.O. 33B-1-1
6-108
acceptability are prepared as a guide to the radiographer. There are two general types of standards prepared the
specific standard applicable to only one particular part and the general standard.
6.8.20.2
A specific standard for a part is prepared by x-raying the part, then destructively testing the part by applying force of
the same type and direction as would be expected in actual service. If the yielding force is greater than the design load,
the X-ray film of the part may be used as a standard. These types of standards are normally used by foundries and
copies of these standards are limited in supply since the part is destroyed by testing and additional retakes cannot be
made.
6.8.20.3
General standards are prepared by an engineering society, company, or government agency as a guide in determining if
the casting and weldments are sound. These standards are based on experience and engineering judgment to provide a
casting and weldment that is generally acceptable for normal use. Radiographic standards prepared by the American
Society for Testing and Materials, 1916 Race Street, Philadelphia 3, Pennsylvania, are approved for use. ASTM
standards dealing with radioscopic and radiographic inspection of castings and weldments are cited in Reference 16.
6.8.20.4
Paints, sealants and adhesives used in fabricating structures often build up to thicknesses that are readily observed on
radiographs. Radiographic indications of these materials can result in obliterating the area of concern and/or cause
misinterpretation of the radiograph. The method of application and the built up thickness causes a very rough surface
of widely varying thicknesses. The radiographic indication often appears similar to a radiograph of a weld bead. The
materials in the liquid or gel state can entrap foreign particles such as metal chips or gas bubbles. These cause
radiographic indications similar to inclusions or porosity. During curing, drying, or service, the organic material can
form crack patterns. Radiographic indications of the cracks can appear as dry mud cracks, dendrites (tree branches), or
one or two very wide cracks. It is difficult and requires experience to interpret these indications. Cracks in coating
materials are normally recognized by the crack pattern and the fact the crack will exceed normal or usual metal crack
width. The best method of confirming the indications is to remove the paint, sealant, or adhesive and to re-X-ray.
Unfortunately, limited access does not always permit coating removal. Triangulation can be used to define the location
of the indication as being on top of the structure.
SECTION IX
RADIATION PROTECTION
6.9
SCOPE AND PURPOSE.
a. This section is intended to serve as a guide toward the safe use of X-ray and sealed gamma-ray sources
for industrial radiographic purposes. It provides guidance to persons who use these sources and to
others who may have a responsibility for their use. It recommends operational procedures, personnel
controls and radiation protection practices to eliminate needless exposure of personnel to ionizing
radiation. In addition, it provides criteria for the guidance of qualified personnel for the design or
modification of industrial radiographic X-ray and sealed gamma-ray installations.
b. The word “shall” identifies requirements that are necessary to meet the standards of protection of this
section. The word “should” indicates advisory recommendations that are to be applied when
practicable.
c. The provisions of this section incorporate provisions of Title 10, Code of Federal Regulations, Parts 19-
21, and 34, for the Air Force, AFI 48-125 and miscellaneous policy statements, and for the Army, AR
40-5, AR 40-14, and AR 385-11. Although the provisions incorporated herein are correct at the time of
issuance, users should review these federal, Air Force and Army regulations periodically to assure
