**Process Specification for Radiographic Inspection**

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| **Engineering Directorate**                                           |
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| **Structural Engineering Division**                                   |
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| **February 2007**                                                     |
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| ![](media/image1.png)                                                 |
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| National Aeronautics and                                              |
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| Space Administration                                                  |
|                                                                       |
| **Lyndon B. Johnson Space Center**                                    |
|                                                                       |
| Houston, Texas                                                        |
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**Process Specification for Radiographic Inspection**

  --------------------- ------------------------------ ------ ------------
  **Prepared by:**                                            

                        Ajay M. Koshti, ES4                   Date

                                                              

                        Norman P. Ruffino, ESCG-ES4           Date
  --------------------- ------------------------------ ------ ------------

+--------------------+-----------------------------+-----+-----------+
| **Approved by:**   |                             |     |           |
+--------------------+-----------------------------+-----+-----------+
|                    | Bradley S. Files            |     | Date      |
|                    |                             |     |           |
|                    | Chief, Materials and        |     |           |
|                    | Processes Branch/ES4        |     |           |
+--------------------+-----------------------------+-----+-----------+

  ----------- --------------------------------------------- ---------------
  REVISIONS                                                 

  VERSION     CHANGES                                       DATE

  Baseline    Original version                              7/26/99

  A           Reviewed document per QMS requirements.       12/19/02
              Updated division name, organization codes,    
              and document numbers.                         

  B           Deleted SNT-TC-1A and MSFC-STD-1249. Added    2/14/07
              NASA-STD-5009 and NASA-STD-5019. Added        
              definition of discontinuity and indication.   

                                                            

                                                            
  ----------- --------------------------------------------- ---------------

**1.0 [SCOPE]{.underline}**

This process specification establishes the minimum requirements for
radiographic inspection of metallic and nonmetallic materials,
components, and assemblies.

# **2.0 APPLICABILITY**

This specification is applicable to in-process, final, and in-service
radiographic inspections to detect cracks, porosity, voids, inclusions,
improper assembly, density variations, corrosion, and other
discontinuities.

**3.0 [USAGE]{.underline}**

This specification shall be invoked by including an inspection note on
the applicable engineering drawing or by reference in a Process
Specification, Task Performance Sheet, Discrepancy Report/Material
Review Record, or other appropriate document. The engineering drawing or
referencing document shall specify the criteria by which components are
judged acceptable. An example of acceptance criteria for welded
components are contained in NAS 1514. When there are different
acceptance criteria for different areas on a component, the drawing
shall be zoned with the acceptance criteria identified for each zone. If
the number of components to be inspected and the amount of coverage of
each component are not specified, all components shall be examined and
shall receive 100 percent radiographic coverage.

A typical radiographic inspection note for welded flight hardware is
given in Figure 1.

Figure 1.

**3.1 INSPECTION SEQUENCE**

The stage in the manufacturing process where radiographic inspection is
performed should be specified on the engineering drawing or in the
referencing document. Factors to be considered when specifying the
inspection sequence are: the accessibility of both sides of the
component; the complexity of the assembly as it relates to optimal
alignment of the radiation beam; loading of the component or assembly
(compressive loads reduce cracks detectability); and the need for
subsequent manufacturing processes that could generate discontinuities.
Radiographic inspection may be performed before heat treatment, provided
liquid penetrant or magnetic particle inspections are performed after
heat treatment.

**3.2 SPECIAL NDE OF FRACTURE CRITICAL COMPONENTS**

When implementation of fracture control requirements necessitates
Special Nondestructive Evaluation (NDE) of a fracture critical
component, the requirement for Special NDE shall appear in the
inspection note as shown in Figure 2. When Special NDE is required, the
specific inspection procedure and inspector shall be qualified in
accordance with Section 7.0.

Figure 2.

**4.0 [REFERENCES]{.underline}**

The following specifications, standards, and handbooks form a part of
this document to the extent specified herein. All documents listed are
assumed to be the current revision unless a specific revision is listed.
In the case of conflict between this specification and the technical
requirements cited in other referenced documents, the requirements of
this document take precedence.

ASTM E 1742 *Standard Practice for Radiographic Examination*

NASA-STD-5009 Nondestructive Evaluation Requirements for Fracture
Critical Metallic Components

NAS 410 *NAS Certification & Qualification of Nondestructive*

*Test Personnel*

NAS 1514 *Radiographic Standard for Classification of Fusion Weld
Discontinuities*

NASA-STD-5003 *Fracture Control Requirements for Payloads Using the
Space Shuttle*

# NASA-STD-5019 *fracture Control Requirements for Spaceflight Hardware*

SSP 30558 *Fracture Control Requirements for Space Station*

The following references were used to develop this process
specification:

SOP-007.1 *Preparation and Revision of Process Specifications (PRC's)*

JSC 8500 *Engineering Drawing System Requirements*

**5.0 [MATERIAL REQUIREMENTS]{.underline}**

Film, non-film recording media, and film processing solutions shall be
in accordance with ASTM E 1742.

**6.0 [PROCESS REQUIREMENTS]{.underline}**

**6.1 GENERAL**

Radiographic inspections shall be performed in accordance with ASTM E
1742 except as modified by this specification.

**6.2 WRITTEN PROCEDURES**

A detailed written procedure shall be prepared for each part to be
inspected. The procedure shall meet the requirements of this
specification and shall ensure the consistency and reproducibility of
the inspection at the required radiographic quality level. General
procedures covering a variety of different parts may be used provided
they meet the requirements of this procedure and clearly apply to the
parts to be inspected. When general procedures are used, a written part
specific technique shall be prepared. At a minimum, the part specific
procedure or the general procedure and part specific technique shall
cover all of the information required by ASTM E 1742.

For work performed at JSC facilities, written procedures should consist
of Detailed Process Instructions (DPIs) selected for use from the
DPI-6503-XX series of work instructions.

**6.3 FILM DENSITY**

Film density in the area of interest shall be in the range from 2.0 to
4.0 (inclusive). Film densities greater than 4.0 are permitted when
approved by the JSC Materials and Processes Branch (ES4). Densities less
than 2.0 are permitted only when items not requiring an image quality
indicator (IQI) are inspected.

**6.4 APPLICABLE AREA**

For components requiring an IQI, only the area of the film that falls
within a 10 degree cone of radiation (10 degree total solid angle, apex
at the radiation source, central axis of the cone equal to the central
axis of the radiation beam) shall be considered valid for
interpretation.

**6.5 SOURCE-TO-FILM DISTANCE**

The minimum allowable source-to-film distance for flight hardware shall
be calculated using a maximum geometric unsharpness (Ug) of 0.003 inch.

**6.6 FRACTURE CRITICAL COMPONENTS**

Radiographic inspections of fracture critical components shall be
performed in accordance with the process requirements in NASA-STD-5009.
The requirements in NASA-STD-5009 not otherwise covered in this
specification are included in the following:

a\. The Radiographic Quality Level shall be at least Level 1 (2 - 1T);

b\. Film density in the area of interest shall be in the range from 3.0
to 4.0 (inclusive);

c\. Only the area of the film that falls within a 5 degree cone of
radiation (5 degree total solid angle, apex at the radiation source,
central axis of the cone equal to the central axis of the radiation
beam) shall be considered valid for interpretation;

d\. Potential crack-like flaws shall be oriented in the plane of
radiation;

e\. Components shall be of consistent thickness; and

f\. Film shall be placed in close contact with the component.

When Special NDE is specified by the engineering drawing or referencing
document, the inspection procedure and inspector shall be qualified in
accordance with Section 7.0.

**7.0 [SPECIAL NDE QUALIFICATION]{.underline}**

Use of Special NDE in accordance with NASA-STD-5019, NASA-STD-5003 or
SSP 30558 requires formal demonstration of the capability to detect
flaws at least as small as the critical initial crack size for the
specific component to a 90/95 detection level. Each procedure, procedure
application, and operator must demonstrate the required capability.
Requests for Special NDE qualification shall be directed to the JSC
Materials and Processes Branch (ES4).

## **8.0 [DEVIATIONS AND WAIVERS]{.underline}**

Any deviations or waivers regarding the use of this process
specification shall be requested in writing. This request shall be
directed to the JSC Materials and Processes Branch (ES4) with the
appropriate justification and rationale. A written response will be
provided upon such a request.

**9.0 [TRAINING AND CERTIFICATION OF PERSONNEL]{.underline}**

Personnel performing radiographic inspections shall be qualified and
certified in accordance with NAS 410. Personnel making accept/reject
decisions shall be certified to at least Level II. Personnel performing
inspections on fracture critical components shall, at a minimum, be
certified to Level II.

For work performed at JSC facilities, these requirements may be
satisfied by the training and certification of personnel per the
TI-6503-XX series of Training Instructions (TIs).

**10.0 [DEFINITIONS]{.underline}**

90/95 The point where the 95% lower confidence bound on the

Probability of Detection (POD) vs. flaw size curve crosses 90% POD or
90% POD with 95% lower confidence bound.

Final Inspection The final inspection performed for the acceptance of
the component.

Fracture Critical Classification which assumes that fracture or failure
of the

Component component resulting from the occurrence of a crack will result
in a catastrophic hazard. Fracture critical components will be
identified as such on the engineering drawing.

In-Process Inspections that occur during manufacturing before a
component is in final form.

In-Service Inspections performed on components that are in use or
storage.

Special NDE A fracture control term denoting nondestructive inspection
personnel, procedures, and equipment with a demonstrated capability to
reliably (90/95) detect flaws smaller than those normally detected by
Standard NDE procedures.

Discontinuity An intentional or unintentional interruption in the
physical structure or configuration of a material or component that may
be detectable by nondestructive testing; a flaw. Discontinuities are not
necessarily rejectable.

Indication Evidence of a discontinuity that requires interpretation to
determine its significance.