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COMMERCIAL SAFETY PRODUCTS |
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Hydraulic Systems Modifications.
- INFORMATION DATE : 19910711
- RECORD TYPE : Hazard Information Bulletin
- SUBJECT : Hydraulic Systems Modifications.
U.S. Department of Labor Occupational Safety and Health Administration
Washington, D.C. 20210
Reply to the attention of:
JUL 11 1991
MEMORANDUM FOR: REGIONAL ADMINISTRATORS
THRU: LEO CAREY
Director
Office of Field Programs
FROM: THOMAS J. SHEPICH
Director
Directorate of Technical Support
SUBJECT: Hazard Information Bulletin - Hydraulic
Systems Modifications
The Dallas Regional Office has brought to our attention a hazard
associated with the improper modification of hydraulic systems.
According to information received from the Lubbock Area Office,
an auxiliary pump was installed on a hydraulic cotton baler to
increase the working pressure from 3000 to 5000 p.s.i. The
hydraulic flexible fluid hoses, designed for 3000 p.s.i. maximum,
were not replaced by ones appropriate for 5000 p.s.i. When the
pump was placed in operation, the hydraulic hose coupling failed.
The failed coupling caused hydraulic fluid to be discharged
creating a short in a 440 V electrical power line resulting in a
fatal fire ball. An employee was killed and others were injured
as a result of the flash fire.
It is our understanding that many cotton gins in the United
States are modifying presses in order to reduce bale pressing
time. Modifications to a higher pressure should always be
approved by a competent engineer or the manufacturer of the
equipment. An appropriate system safety analysis should be
applied to assure that the subsystem modification will not
adversely affect the safe performance of the operation.
Petroleum based hydraulic fluids are widely used. Hydraulic oil
becomes hot during operations. A heated petroleum based
hydraulic fluid presents a considerable fire hazard, particularly
in those processes where ignition sources are usually present. A
typical petroleum based hydraulic fluid has flash point that
range from 300 to 600 degrees fahrenheit and an auto ignition
temperature of 500 to 750 degrees fahrenheit. However, when
hydraulic fluid is accidentally discharged under high pressure an
easily ignited fine oil mist is sprayed over the surrounding
area. When the mist reaches an ignition source the result can be
a torch-like ball of fire.1 If the oil mist is confined, a
violent explosion can occur.
All hydraulic hoses, tube lines and fittings should be
periodically inspected. Any deterioration must be carefully
examined to determine whether further use of the component would
constitute a hazard. Conditions such as the following should be
sufficient for consideration of replacement:
a. Any evidence of hydraulic oil leakage at the surface of
a flexible hose or its junction with the metal and
couplings;
b. Any blistering or abnormal deformation to the outer
covering of a hydraulic hose;
c. Hydraulic oil leakage at any threaded or clamped joint
that cannot be eliminated by normal tightening or
recommended procedures; and/or
d. Evidence of excessive abrasion or scrubbing on the
outer surface of a hose, rigid tube, or hydraulic
fitting. Modification must be made to eliminate the
interference of the elements in contact, or otherwise
protect the components.2
Please distribute this bulletin to all Area Offices, State Plan
States and Consultation Project Officers.
_____________________________
The Directorate of Technical Support issues Hazard Information Bulletins
(HIBs) 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. Information is compiled based
on a thorough evaluation of available facts, literature and in coordination
with appropriate parties. HIBs do not necessarily reflect OSHA policy.
REFERENCES
1) Ryan, Kenneth E., Fire hazards of hydraulic fluids,
Professional Safety, June, 1984, pages 34 to 36.
2) OSHA Requirement Guide Corporation, Equipment Guide
Book, 1977, pages 12 and 13.
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