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COMMERCIAL SAFETY PRODUCTS |
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Defective Imported Lap Joint Stub Ends.
- INFORMATION DATE : 19940824
- RECORD TYPE : Hazard Information Bulletin
- SUBJECT : Defective Imported Lap Joint Stub Ends.
August 24, 1994
MEMORANDUM FOR: REGIONAL ADMINISTRATORS
THROUGH: JIMMY ROBERTS
Acting Director
Office of Field Programs
FROM: CHARLES E. ADKINS, CIH
Acting Director
Directorate of Technical Support
SUBJECT: Hazard Information Bulletin(1) - Defective
Imported Lap Joint Stub Ends:
________
FOOTNOTE(1) The Directorate of Technical Support issues Hazard
Information Bulletins (HIB) in accordance with OSHA Instruction CPL 2.65
to provide relevant information regarding unrecognized or misunderstood
health hazards, inadequacies of materials, devices, techniques, and safety
engineering controls. HIBs are initiated based on information provided by
the field staff, studies, reports and concerns expressed by safety and
health professionals, employers, and the public. Bulletins are developed
based on a thorough evaluation of available facts and in coordination with
appropriate parties.
The Federal Trade Commission (FTC) has brought to our attention a
potentially serious safety hazard that exists in lap joint stub ends
installed in piping systems used in any facility (see attached figure).
The defective stub ends were discovered by two corporations as a result of
tests performed prior to start-up of their piping systems.
Two types of stub ends were tested: Stub ends manufactured by Ta Chen of
single piece construction containing no welds, and ones manufactured by
Tru-Flow and Tung Teng of welded construction using materials of different
chemistry for the tube and flange sections. The stub ends range in size
from 1/2 to 6 inches (1.27 - 15.24 cm) in diameter and are marked with the
ASTM A403 specification. The stub ends are free from any visual defects.
The following is a list of organizations that performed tests on the stub
ends:
* Lehigh Testing Laboratories performed an evaluation and
testing for the FTC of stub ends from three Taiwanese
manufacturers: Ta Chen, Tung Teng and Tru Flow. The stub
ends manufactured by Ta Chen were acceptable. Lehigh,
however, found the stub ends from Tung Teng and Tru Flow to
be unacceptable because they had an incomplete penetration
of the weld. The American Society of Mechanical Engineers
(ASME) standard, Section VIII requires the welded connectors
between the pipe and flange be a full penetration of the
weld.
* Lehigh Testing Laboratories also conducted testing for the
Occidental Chemical Corporation. Occidental Chemical
Corporation submitted test reports indicating that Tru Flow
stub ends were defective.
* The Henkel Corporation, a major manufacturer of chemicals,
suspected that the stub ends that it was installing in a new
facility were defective. The company radiographed eighteen
units and found five to be defective due to lack of fusion
or penetration. All were manufactured by Tru Flow and sold
as Merit stub ends.
A review of test reports submitted by the above organization revealed the
following common findings of the Tung Teng and Tru Flow stub ends:
* Radiographs taken of the welds indicated either lack of
fusion or incomplete penetration. All the tested welded
stub ends failed the American Society for Testing Materials
(ASTM) A403 radiographic requirements. These results were
confirmed later when the stub ends were sectioned for
metallographic examination.
* The manufacturers' certification (stub ends stamped with
ASTM A403) was not reliable. Follow-up quality control must
be provided by intermediate suppliers or end users
(employers.)
* The stub ends did not meet the fatigue testing required by
ASTM A403. The partial penetration welds failed much
earlier than those with full penetration. The fatigue life
of a stub end with a full penetration weld was 10 to 100
times that of the weld with a lack of penetration.
A midwestern manufacturer contracted outside consultants to conduct tests
to determine the life expectancy of the defective fittings. The results
are confidential. The manufacturer received fittings from numerous
suppliers, some of which may have provided the defective stub ends. These
suppliers are: Wilkins Pipe, Robert-James, Central Stainless, Service
Pipe, Mutual Manufacturing, Mid-Valley, CTI, RJ Gallagher,
Indiana-Michigan Supply, and Industrial Supply.
The in-service failure of these stub ends under cyclic loading would most
likely result in a crack leading to a leak. It is not possible to predict
if or when a failure will occur because the in-service loads on the stub
ends are not known. In applications, such as pump circuits, it is
possible that a cyclic loading can occur that may lead to cracks and
result in a leak.
These stub ends may be installed in petrochemical and chemical facilities
that are covered under the Process Safety Management Standard, 29 CFR
1910.119. 29 CFR 1910.119(j) covers piping systems and requires that the
employer establish and implement written procedures to maintain the
ongoing integrity of process equipment.
Visual inspection of stub ends will not reveal defects such as lack of
penetration or fusion, magnetic particle test can not be used to examine
stainless steel stub ends, and periodic dye penetrant inspection of
suspected joints detects only surface cracks and near surface defects.
Therefore, radiographic examination or other nondestructive testings are
recommended.
Please distribute this bulletin to all Area Offices, State Plan States,
Consultation Project Officers, and appropriate local and industry groups.
(For Figure , Click Here)
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