Text from
the OSHA Logging PreambleSection V: Summary and
Explanation of the Final Standard
Paragraph (h) Tree Harvesting
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Chipping
At paragraph (h)(4) of the final rule, OSHA has specified various work practices
regarding chipping that is performed at in-woods locations. Paragraph (h)(4)(i) of the
final rule requires that access covers or doors not be opened until the drum and disc is
at a complete stop. The access covers and doors are the means by which employees are
safeguarded from the risk of contacting these parts while they are moving. This provision
is adopted from the proposed rule. The 1978 ANSI logging standard also contains a similar
provision. OSHA did not receive any comment opposing this provision.
OSHA believes that this requirement is necessary to keep employees away from the
dangerous moving drums, discs, knives and blower blades of a chipper. OSHA's FCI reported
indicated that two employees have been killed while operating a chipper or trying to free
jammed logs (Ex. 4-61). The moving chipper mechanism presents significant hazards, and
employees need protection from contact with those mechanisms when they are moving.
Paragraph (h)(4)(ii) of the final rule requires that infeed and discharge ports be
guarded to prevent contact with the disc, knives, or blower blades. This provision has
been adopted from the proposed rule. There were no comments opposing this provision.
Paragraph (h)(4)(iii) of the final rule requires that the chipper be shut down and
locked out in accordance with 29 CFR 1910.147 when an employee performs any servicing of
maintenance on the chipper. The proposed rule required that the chipper be shut down and
locked out before an employee works in the infeed.
OSHA did not receive any comments opposing lockout of the chipper while working on the
infeed. OSHA received one comment stating that lockout should be expanded to apply when an
employee is working on the drive mechanism or chipping disc (Ex. 5-28). The lockout/tagout
standard, 29 CFR 1910.147, applies to servicing and maintenance of all machines and
equipment in which the unexpected energization or start up of the machine or equipment, or
release of stored energy could cause injury to employees. This includes machines and
equipment used in logging operations.
The lockout-tagout standard permits employers to either place a lock or tag on any
machine before beginning servicing. However, OSHA believes that the environmental
conditions involved in logging operations necessitates the use of locks rather than tags
when servicing chippers. As OSHA stated in the preamble of the lockout/ tagout standard,
it is intended to interact with any new or revised standard to address the use of specific
control measures on an individual basis (54 FR 36644, 36665, Sept. 1, 1989). Selection of
the specific method of control, at that time, will reflect a thorough evaluation of the
extent of exposure to the hazard, the risk of injury involving the particular machine or
industry, and the feasibility of applying a particular method of control. OSHA also
pointed in the preamble of the lockout/tagout standard that damage to or loss of tagout
devices is a serious drawback to the use of tagout. Logging operations are carried out in
all kinds of weather, including rain, snow, ice and wind, and there is a significant
possibility that tags could be damaged or lost. In such circumstances, OSHA believes only
locking machinery will provide adequate protection for employees who are servicing it.
Therefore, OSHA is requiring chippers to be shut down and lockout out before an employee
performs any servicing or maintenance activities.
Paragraph (h)(4)(iv) of the final rule requires that detached chippers be chocked
during usage on any slope when movement of the chipper is reasonably foreseeable. As with
other mobile equipment that is intended to be operated from a stationary position, the
unexpected movement of the equipment can endanger employees who are either operating the
equipment or in the path of the equipment when it moves. The vibration caused by the
operation of the equipment can enhance the potential for unintended equipment movement.
Chocking of mobile equipment to prevent movement is recognized throughout industry as a
necessary and appropriate means to prevent unintended movement. For example, OSHA requires
in 29 CFR 1910.178(k)(1) that trailers be chocked before being boarded by powered
industrial trucks.
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