Frequency of Process Control Checks.
Table 1-3 establishes MAXIMUM process control intervals allowed. Laborato-
ries shall use the guidelines listed below to establish their process control
requirements and intervals.
One of the factors inf luencing the degradation of a penetrant process (materials, equipment and procedures)
is the volume of parts being processed. The opportunities for materials contamination, drag-out, equipment
malfunction, and procedure deviation are directly proportional to the number of parts being inspected. Since
there is no uniformity in workload between activities, a single calendar schedule cannot be established. Each
activity SHALL set inspection intervals based on their workloads. The inspection intervals SHALL be
documented as shown in Chapter 1, page 1-15, paragraph 1.4.5. Guidance on inspection intervals is provided
in the following paragraphs.
A high volume workload is considered to be a penetrant system that is in continuous use or is utilized
for more than 4 hours every workday. A suggested inspection interval for materials verification of
high volume penetrant systems is a daily check.
A medium volume workload is considered to be a penetrant system that is used daily for less than 4
hours. A weekly inspection interval is suggested for materials verification of penetrant systems
processing a medium volume workload.
A low volume workload is considered to be a penetrant system that is used to process parts less than 3
days a week. An inspection interval of once every two weeks is suggested for materials verification of
low volume workload penetrant systems.
In a penetrant system used occasionally with a one-week interval between uses, the minimum
monthly verification requirement must apply.
Equipment and process control inspection intervals vary depending upon the specific item to be checked.
Many items will degrade on a time rather than a use basis. Equipment and process SHALL be inspected at
weekly, monthly, quarterly or semiannual intervals as specified in ASTM 1417 or other applicable process
Process Control Requirements.
The capability and reliability of penetrant inspections depend upon the materials, equipment, and proce-
dures. Degradation in any of the three areas will reduce the effectiveness of the process. The following
paragraphs highlight some process steps requiring audit. At minimum these steps should be audited, and
additional applicable steps should be added to cover specific equipment or processes as necessary.