Appendix
B:
Nonmandatory guidelines for
certification/validation of safety systems for presence sensing
device initiation of mechanical power
presses
Objectives
This Appendix
provides employers, manufacturers, and their
representatives, with nonmandatory guidelines for use
in developing certification documents. Employers and
manufacturers are encouraged to recommend other
approaches if there is a potential for improving
safety and reducing cost. The guidelines apply to
certification/validation activity from design
evaluation through the completion of the installation
test and the annual recertification/revalidation
tests.
General
Guidelines
A. The
certification/validation process should confirm that
hazards identified by hazard analysis, (HA), failure
mode effect analysis (FMEA), and other system
analyses have been eliminated by design or reduced to
an acceptable level through the use of appropriate
design features, safety devices, warning devices, or
special procedures. The certification/validation
process should also confirm that residual hazards
identified by operational analysis are addressed by
warning, labeling safety instructions or other
appropriate means.
B. The objective of the certification/validation program is
to demonstrate and document that the system satisfies
specification and operational requirements for safe
operations.
Quality
Control
The safety
attributes of a certified/validated PSDI safety
system are more likely to be maintained if the
quality of the system and its parts, components and
subsystem is consistently controlled. Each
manufacturer supplying parts, components, subsystems,
and assemblies needs to maintain the quality of the
product, and each employer needs to maintain the
system in a non-degraded condition.
Analysis
Guidelines
A.
Certification/validation of hardware design below the
system level should be accomplished by test and/or
analysis.
B. Analytical methods may be used in lieu of, in
combination with, or in support of tests to satisfy
specification requirements.
C. Analyses may be used for certification/validation when
existing data are available or when test is not
feasible.
D. Similarity analysis may be used in lieu of tests where
it can be shown that the article is similar in design,
manufacturing process, and quality control to another
article that was previously certified/validated in
accordance with equivalent or more stringent criteria. If
previous design, history and application are considered to
be similar, but not equal to or more exacting than earlier
experiences, the additional or partial
certification/validation tests should concentrate on the
areas of changed or increased requirements.
Analysis
Reports
The analysis
reports should identify: (1) The basis for the
analysis; (2) the hardware or software items
analyzed; (3) conclusions; (4) safety factors; and
(5) limit of the analysis. The assumptions made
during the analysis should be clearly stated and a
description of the effects of these assumptions on
the conclusions and limits should be included.
Certification/validation by similarity analysis reports
should identify, in addition to the above, application of
the part, component or subsystem for which
certification/validation is being sought as well as data
from previous usage establishing adequacy of the item.
Similarity analysis should not be accepted when the
internal and external stresses on the item being
certified/validated are not defined.
Usage experience should also include failure data
supporting adequacy of the design.
[53 FR 8360, Mar. 14, 1988]
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