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pdfPreventing Injuries Among Workers
in the Wood Pallet Industry
by
Robert Malkin, Dr.PH
Thomas Lentz, Ph.D.
Jenifer Tomiller, M.S.
Stephen Huddock, Ph.D.
Charles Hayden, M.S.
DEPARTMENT OF HEALTH AND HUMAN SERVICES
Centers for Disease Control and Prevention
National Institute for Occupational Safety and Health
This document is in the public domain and may be freely copied
or reprinted.
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National Institute for Occupational Safety and Health (NIOSH). In addition,
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or visit the NIOSH Web site at www.cdc.gov/niosh
DHHS (NIOSH) Publication No. 2006–XXX
September 2006
Safer ∙ Healthier ∙ PeopleTM
ii
This manual was written by Robert Malkin, Dr.PH; Thomas Lentz, Ph.D.; Jennifer Topmiller, M.S.; Stephen Hudock, Ph.D.; and Charles Hayden, M.S.
We wish to thank Mr. Bruce Scholnick of the National Wood Pallet and Container Association for his input in developing and his assistance in reviewing
the documents and Dr. Richard Niemeier for the idea of the project and accompanying me on the original field visits. We would like to thank all members of our research field team, particularly Mark and Carol Stephenson. We
would also like to thank Joseph Cauley, Anne Stirnkorb, and Vanessa Becks for
their work in graphic design and layout of the manual and Anne Hamilton,
Susan Afanuh, and Jane Weber for providing editorial assistance.
iii
iv
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
Chapter 1. Understanding Hazards in the Workplace . . . . . . 1
Controlling Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Communicating Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Creating a Safe Workplace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Chapter 2. Developing a Safety and Health Program . . . . . . . 9
Occupational Illness and Injury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Developing a Safety and Health Program . . . . . . . . . . . . . . . . . . . . . .
Be a Leader . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Involve Workers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Identify and Assess Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Prevent and Control Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Provide Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Evaluate the Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
9
11
12
12
13
13
14
Chapter 3. Issues Related to Noise Exposure . . . . . . . . . . . . . . 17
Question 1: What is noise-induced hearing loss? . . . . . . . . . . . . . . . .
Question 2: What other health effects are related
to noise exposute? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Question 3: What type of noise is involved in pallet work? . . . . . . . .
Question 4: What are the current exposure limits for noise? . . . . . . .
Question 5: What noise levels are workers and others
commonly exposed to? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Question 6: How can I control my noise exposure? . . . . . . . . . . . . . .
Question 7: How can I reduce the noise from the compressor? . . . .
17
17
17
18
19
20
22
Chapter 4. Wood Dust: Issues Related to Ventilation . . . . . . . 27
Question 1: What operations generate wood dust? . . . . . . . . . . . . . . 27
Question 2: What are the exposure standards for wood dust? . . . . . 27
Question 3: What were the measurements of wood dust
in pallet manufacturing? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Question 4: What are the effects of wood dust? . . . . . . . . . . . . . . . . . 29
Question 5: How can I improve ventilation? . . . . . . . . . . . . . . . . . . . . 31
Chapter 5. Improving Saw and Nail Gun Safety . . . . . . . . . . . 35
Things the Company Should Do to Improve Saw Safety . . . . . . . . . .
Things a Worker Must Do to Improve Saw Safety . . . . . . . . . . . . . . .
Things an Employer Can Do to Improve Nail Gun Safety . . . . . . . . .
Things a Worker Can Do to Improve Nail Gun Safety . . . . . . . . . . . .
35
38
40
41
Chapter 6. Forklift Safety: Problems and Solutions . . . . . . . . 45
What Managers Can Do to Improve Forklift Safety . . . . . . . . . . . . . . 45
Preventive Recommendations for Employers . . . . . . . . . . . . . . . . . . . 45
Preventive Recommendations for Workers . . . . . . . . . . . . . . . . . . . . . 48
Chapter 7. Carbon Monoxide and Heat Treatment . . . . . . . . 53
Question 1: What is carbon monoxied? . . . . . . . . . . . . . . . . . . . . . . . .
Question 2: What are the health effects of carbon monoxide? . . . . .
Question 3: How does carbon monoxide work? . . . . . . . . . . . . . . . . .
Question 4: Is carbon monoxide exposure regulated? . . . . . . . . . . . .
Question 5: What machines produce carbon monoxide? . . . . . . . . .
Question 6: What types of forklifts make carbon monoxide? . . . . . .
Question 7: How much carbon monoxide was present in
wood pallet manufacturing industry? . . . . . . . . . . . . . . . . . . . . . . . .
Question 8: What steps can employers and workers
take to protect themselves? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
53
53
54
54
55
56
56
57
Chapter 8. Ergonomics for Wood Pallet Manufacturers . . . . 63
Ergonomic Considerations for the Wood Pallet . . . . . . . . . . . . . . . . .
Manufacturing Industry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Manual Material Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Use of Power Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Workstation Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
vi
63
63
63
67
69
Workers manufacturing wood pallets are exposed to a multitude of potentially
hazardous exposures and operations including noise, saws, nail guns, forklifts,
heat chambers, and poor ergonomics. The end result is that these workers have
greater workplace injury. Workers in NAICS code 32192, which includes wood
container and pallet manufacturing, have an injury rate that is 193% greater
than the rate for all private industry; amputations among pallet workers are
922% greater.
This educational manual discusses those hazards and offers potential solutions
to safety problems. This is not intended to be a training manual, nor is it a definitive safety manual. The manual does touch on all aspects of pallet manufacturing in a way that will be useful to employees and employers and may result
in lower injuries for workers in the wood pallet manufacturing industry.
vii
CHAPTER 1
Understanding Hazards
in the Workplace
Chapter 1 Understanding Hazards in the Workplace
■
Chapter 1
Understanding Hazards in the Workplace
Can your business survive an injury?
Occupational injuries may result in higher Workers’ Compensation
rates.
■
I n Ohio, injuries that cause a business to be dismissed from an insurance
group can result in workers’ compensation rates that are five times the
rates charged by insurance groups.
■
allet manufacturing is an industry
P
classification with a high workers’
compensation rate (see Figure 1).
■
The average cost to the Bureau
of Workers’ Compensation for a
lost-work-time claim is $38,000.
However, this amount includes
only what the insurance company
pays for the claim—the direct costs.
A business must also consider the
indirect costs for such a claim.
12
$10.14
10
8
$7.01
$5.48
6
$3.46
4
2
0
$0.41
Pallet
manufacturers
Pencil or
crayon
manufacturers
Electroplating
Tin foil
manufacturers
Clerical
Figure 1. Workers' compensation base rates per $100 payroll in different industries, 2001.
PALLETS
■
Understanding Hazards in the Workplace
Direct costs
■ Medical
■ Lost-time
■ Reserve*
*The
Indirect costs
■ Morale
■ New-worker training
■ New-worker supervision
■ Reputation of company
■ Damage to equipment
■ Decreased production (difficult to work
when your neighbor is severely injured)
amount an insurance company must put aside to pay for future claims.
Worker stretching over a large table, possibly resulting in ergonomic injury.
Chapter 1 Understanding Hazards in the Workplace
■
Estimates indicate that for every $1 spent on direct costs of a lost-work-time
claim, $4 is spent on indirect costs. Therefore, the real cost of a $38,000 claim is
$190,000—not including the increased insurance cost resulting from the injury.
Could your company survive that?
The easiest way to deal with an injury is to prevent it!
Example: A pallet business, that grosses $1 million and nets 5% will net $50,000
per year. Thus if the owner must pay for an injury costing $190,000, the business
will have nearly 4 years with NO PROFIT!
Controlling Hazards
No single control is effective for all workplace hazards. The three principles of
hazard control are listed below in order of their effectiveness. Removing hazards is
the most effective control. Apply the principles in sequence until you find a workable solution.
Remove hazards—Replace hazardous materials, equipment, and
processes with safer alternatives.
Reduce exposures—Develop
policies and procedures that minimize exposures to hazards; encourage safe work practices; train
workers to recognize and report
hazards.
Use Safeguards—Provide
protective equipment to workers
(hearing protection, safety glasses,
and goggles, for example).
PALLETS
■
Understanding Hazards in the Workplace
Communicating Hazards
As a business owner, you play a major role in creating a safe workplace. Promoting
safety will help you maintain a productive workforce and protect your company’s
interests.
■
Establish policies that demonstrate that you are concerned with your
workers’ safety and want them to remain free of injury.
■
Involve workers in identifying hazards and equipment that needs repair or
maintenance.
■
Provide training and education for workers:
rovide information about the potential health effects of their expo— P
sures at work.
rain workers to use safe work practices and good personal hygiene
— T
measures.
each workers how to use and maintain appropriate protective equip— T
ment and safety devices.
— Provide copies of material safety data sheets (MSDSs) for all hazardous
materials at the workplace.
Two workers nailing pallets on a horizontal table.Note earplugs.
Chapter 1 Understanding Hazards in the Workplace
■
Creating a Safe Workplace
To protect your workers and reduce costs, follow these steps:
Identify injuries—Determine which injuries are the most frequent and severe in
your industry.
Measure costs—Analyze your costs to determine which injuries cost the most in
workers’ compensation, health care, and absenteeism.
Control Hazards—Remove or minimize hazards.
Safety and Health Programs
Offer high return on
your investment
Help workers
return to work faster
Involve workers in
problem solving
Prevent disabling
injury and illness
Band saw used for recycling pallets.
Worker using a nail gun to assemble
a pallet.
PALLETS
■
Understanding Hazards in the Workplace
Physical
Poor Ventilation
■
Wood dust
■
Noise
■
Carbon monoxide
■
Vibration
■
Mold
Occupational Hazards
of the Wood
Pallet Industry
Ergonomic
Traumatic injury
■
Falls
■
Lifting
■
Forklift and other motor
vehicle crashes
■
Materials handling
■
Poor workstation design
■
Amputations
■
Improper use of power tools
■
Lacerations
■
■
Broken bones
Repetitive motion injuries
from hand tool use
■
Eye injuries
■
Puncture wounds
CHAPTER 2
Developing a Safety and
Health Program
Chapter 2 Developing a Safety and Health Program
■
Chapter 2
Developing a Safety and
Health Program
Occupational Illness and Injury
Each day in the United States on average
■
9,000 workers sustain disabling injuries on the job,
■
17 workers die from workplace injuries, and
■
137 workers die from work-related diseases.
The total cost of occupational illness and injury is $171 billion annually—greater
than the cost of AIDS, Alzheimer’s disease, or cardiovascular diseases. Safety and
health programs are clearly needed in workplaces throughout the country.
Developing a Safety and Health Program
Like any other aspect of your business, safety
must be managed. Following the law is important, but compliance alone is not enough to
ensure a safe workplace.
Prevention efforts are most effective when they
are part of an overall written safety and health
program. Such programs promote a culture of
cooperation, awareness, and shared responsibility for safety and health.
Many business owners have the same question
about developing a program: Where do we
begin? The following guidelines will help you
get started on the right track.
PALLETS
Understanding Hazards in the Workplace
■
The steps outlined in each of these guidelines are components that
constitute an effective safety and health program.
hip
s
r
de
Lea
Com
mu
ni
t
en
m
s
s
e
Ass
Pre
ven
tion
on
ati
c
u
d
/E
ng
i
n
i
Tra
Eva
luat
10
ion
cati
on
Chapter 2 Developing a Safety and Health Program
■
Be a Leader
■
Establish workers’ responsibilities with regard to safety and
health in the workplace. Put these responsibilities in writing
and make sure all workers understand them.
■
Provide workers with information they need to carry out
their safety and health responsibilities
■
Respond promptly to reports about safety and health conditions and take corrective action if needed.
■
Delegate authority over safety and health issues to qualified
workers.
Leadership
11
PALLETS
■
Understanding Hazards in the Workplace
Involve Workers
■
Encourage workers to participate in
all aspects of the program.
■
Solicit safety and health recommendations on a continual basis.
■
Maintain constructive dialogue
throughout the company.
■
Establish procedures for reporting hazards.
Communication
Identify and Assess Hazards
■
Inspect the workplace for hazards at least a year—and any
time a change in working conditions could lead to additional hazards.
■
Evaluate the safety of new equipment, materials, and processes before they are used in the workplace.
■
Assess the severity of hazards and set priorities for controlling them accordingly.
Assessment
12
Chapter 2 Developing a Safety and Health Program
■
Prevent and Control Hazards
Prevention
■
eplace hazardous equipment, materials, and processes with
R
safer alternatives.
■
Develop policies and procedures that minimize exposure to
hazards.
■
Provide workers with appropriate personal protective
equipment (such as safety glasses).
Provide Training
■
Train workers on the following topics:
— Recognizing hazards on the job
— Using hazard control measures in the workplace
Training—
Education
— Taking
steps to protect themselves from exposure to
hazards
■
Provide initial training to all new workers and periodic
refresher training thereafter. (Refresher training is necessary for all workers whenever a work process or exposure
changes.)
■
Distribute Material Safety Data Sheets (MSDSs) for all hazardous materials at the job site.
■
Ask experienced workers to
serve as instructors.
■
Maintain safety and health
communication through bulletin boards, signs, posters,
and announcements.
13
PALLETS
■
Understanding Hazards in the Workplace
Evaluate the Program
■
Evaluation
Regularly
evaluate the program's effectiveness using surveys, interviews, and
personal observations. Examples of
useful data to collect are listed below:
— Types
and frequency of unsafe
behavior
— Attendance at safety meetings
— Number of reported “near misses”
— Changes
in the use of safe work practices (such as lockout/tag-out)
— Level of employee involvement in the program
— Number of “safe days” without an incident
■
stablish a database to track safety and health
E
information such as injury and illness rates,
workers' compensation claims, absenteeism,
and incident reports.
SURVEY
For More Information
BWC [1999]. 10-step business plan. Columbus, OH: Ohio
Bureau of Workers’ Compensation.
OSHA [2001]. Safety and health programs [http://www.oshaslc.gov/SLTC/safetyhealth/index.html]. Washington, D.C.:
U.S. Department of Labor, Occupational Safety and Health
Administration. Date accessed: July 21, 2005.
14
FORM
CHAPTER 3
Issues Related to
Noise Exposure
Chapter 3 Issues Related to Noise Exposure
■
Pallet making is very noisy!
Loud noise will hurt your hearing.
Question 1: What is noise-induced hearing loss?
INNER
Answer: Noise induced hearing loss is a loss of hearing caused when the
nerves in your ears are damaged by loud sounds. Too much noise kills the tiny
hair cells inside your inner ear. As more cells die off, hearing gets worse. This
damage to your ears is permanent and cannot be cured or repaired.
MIDDLE
OUTER
Question 2: What other health effects are related
to noise exposure?
Answer: Noise may cause injuries and deaths when workers cannot hear
instructions or warnings from coworkers or cannot hear back-up signals from
heavy equipment such as forklifts. Noise can also cause psychological stress,
anxiety, increased heart rate, and increased blood pressure.
Question 3: What type of noise is involved in
pallet work?
Answer: Two types of noise are involved in pallet work: impulsive and nonimpulsive (continuous) noise. Impulsive noises are sounds like those made by
nail guns and hammering (Figure 1). They are characterized by a sharp rise in
the sound level followed by a rapid decrease. Continuous noise is fairly constant and is similar to the noise created by saws.
Both types of noise are dangerous at levels over 85 decibels (dB). Continuous and impulsive noises together are synergistic: that is, they interact to cause
more hearing damage than either one would cause alone.
17
PALLETS
■
Understanding Hazards in the Workplace
Figure 1. Worker wearing ear plugs to protect against impulsive noise while using a
nailgun to assemble a pallet.
Question 4: What are the current exposure
limits for noise?
Answer: Exposure limits for noise have been established by the National
Institute for Occupational Safety and Health (NIOSH) and the Occupational
Safety and Health Administration (OSHA). They are as follows:
18
■
NIOSH recommended exposure limit (REL): 85 decibels measured
on the A scale (dBA) as an 8-hour time-weighted average (TWA).
NIOSH Recommends that personal protective equipment (PPE) be
worn with exposure above this level.
■
OSHA permissible exposure limit (PEL): 90 dBA as an 8-hour TWA.
■
OSHA action level: 85 dBA as an 8-hour TWA: the level at which a
hearing conservation program must be provided. This program should
include monitoring the hearing hazards, engineering and administrative controls, audiometric evaluations, personal hearing protection devices, education and motivation sessions, record keeping, and program
evaluation. Further information can be found in the NIOSH publication, Preventing Occupational Hearing Loss—A Practical Guide.
Chapter 3 Issues Related to Noise Exposure
■
An estimated 41% of workers in the lumber and wood products industry are
exposed to noise levels at or above the NIOSH REL of 85 dBA.
Question 5: What noise levels are workers and others
commonly exposed to?
Answer: Workers and others are often exposed to impulsive noise levels as
high as 136 dBA. Exposure to noise above 85 dBA for 8 hours or more may
cause permanent hearing loss. Figure 2 lists common noise levels produced by
various items and activities.
Gun shot
136 (impulsive)
Nail gun
136 (impulsive)
110.5
Chain saw
104
Notchers
Stacking machines
99.1
Some assembly stations 98.8
Lawn mower
94.5
Normal speech
0
30
60
70
90
120
150
Approximate noise level (dBA)
Figure 2. Noise levels produced by common items or activities.
19
PALLETS
■
Understanding Hazards in the Workplace
Question 6: How can I control my noise exposure?
Answer: There are three ways to control noise.
■
Engineering Controls—buy quieter power tools and maintain equipment properly (keep blades sharp).
■
Administrative controls—keep number of people exposed to a minimum
■
Hearing protection—this is the LEAST preferred method of noise
control
You will need to wear personal protective equipment (PPE) when you are
exposed to loud noises that you cannot reduce to a safe level. More than 300
types of hearing protection devices are available, so everyone should be able
to find something comfortable. The main types of hearing protection devices
include:
■
ear plugs
■
ear muffs
■
canal caps.
Ear plugs: Ear plugs, particularly foam ear
plugs, are a simple, effective type of hearing
protection that you can wear when you are
exposed to loud noises. There are three main
types of ear plugs: formable, pre-molded, and
custom molded. They are often provided to
workers exposed to loud noise. Make sure the
plugs are comfortable and fit well. Wear them
consistently. Remember: Ear plugs must be
inserted properly, to be effective.
Method for inserting ear plugs: Ensure hands are clean. Roll up the plug so
that half of it will fit into the ear canal. Avoid creases—they will allow noise
to enter the ear canal. While holding the ear plug in the ear canal with one
hand, pull up and back on the ear lobe with the other hand to straighten the
ear canal. Then insert the rolled-up ear plug and hold it in position for 10–20
seconds to give the plug time to expand in the ear canal.
20
Chapter 3 Issues Related to Noise Exposure
■
Ear muffs: Ear muffs fit over the ear. One big advantage is that some ear
muffs have electronic circuitry that allow speech to pass through the muff
while rejecting all loud noises above a certain frequency. Thus workers can
be protected from loud noise and still be able to communicate with each
other.
Canal caps: Canal caps often resemble earplugs on a flexible plastic or metal
band similar to a headband. Many can be worn over the head, behind the
neck, or under the chin. The earplug tips of a canal cap may be a formable or
pre-molded material. The main advantage of canal caps is convenience.
21
PALLETS
■
Understanding Hazards in the Workplace
Question 7: How can I reduce the noise from the
compressor?
Answer:
1.
Move the compressor outside. You must cover the compressor to
protect it from the elements, but do not allow heat to build up from
lack of ventilation. You can enclose the compressor with a wood barrier, but be sure to leave a place at the top for heat to escape.
2.
Erect a barrier for the compressor while leaving the compressor
inside. If you can’t move the compressor outside, it may be possible
to erect a wood barrier inside. At one pallet company, use of a wood
barrier lowered noise levels from 93 to 84 dB.
Be careful not to overheat
the compressor!
22
Chapter 3 Issues Related to Noise Exposure
■
For additional information:
Criteria for a Recommended Standard: Occupational Noise Exposure. Revised
Criteria 1998. NIOSH. NIOSH Publication Number 98–126. June 1998.
Preventing Occupational Hearing Loss. NIOSH Publication 96–110. June 1996.
NIOSH Safety and Health Topic: Noise and Hearing Loss Prevention. http://
www.cdc.gov/niosh/topics/noise/. Accessed August 15, 2005.
23
CHAPTER 4
Wood Dust Issues
Related to Ventilation
■
Chapter 4 Wood Dust: Issues Related to Ventilation
■
Chapter 4
Wood Dust ■ Issues Related
to Ventilation
Question 1: What operations generate wood dust?
Answer:
Saws
Nail guns—the exhaust of a nail
gun may loosen dust on a board.
Question 2: What are the exposure standards for
wood dust?
Answer: OSHA has no permissible exposure limit (PEL) for wood dust
but regulates it as a particle not otherwise classified (PNOC). The PEL for
a PNOC is a time-weighted average (TWA) of 15 miligrams per cubic meter
(mg/m3) for total dust and a TWA of 5 mg/m3 for the respirable fraction of
that dust.
27
PALLETS
■
Understanding Hazards in the Workplace
1.
The American Conference of Governmental Industrial Hygienists
(ACGIH) changed their threshold limit value (TLV) (2005) for all
wood dust to a TWA of 1 mg/m3.
2.
NIOSH has a recommended exposure limit (REL) of 1 mg/m3 for all
woods and classifies wood as a potential occupational carcinogen.
Question 3: What were the measurements of wood
dust in pallet manufacturing facilities?
Answer: NIOSH researchers conducted spot measurements of hardwood
dust and found average levels of 1.67 mg/m3 around the notcher and
1.45 mg/m3 around the radial arm saw. These measurements were not for
8-hour periods and it is unlikely, although possible, that these readings
would be the same for 8 hours.
Table 1. DataRAM measurements of dust in a pallet plant
Concentration (mg/m3)
10
Average
8
Maximum
Minimum
6
4
2
0
28
Resaw
3 min
Cut off saw #1 Radial arm saw Cut off saw #2
Notcher
4 min, 30 sec 3 min, 20 sec 6 min, 50 sec 1 min, 10 sec
Measurement location
Chapter 4 Wood Dust: Issues Related to Ventilation
■
Question 4: What are the effects of wood dust?
Answer: Respiratory effects. The respiratory effects of wood dust exposure
include asthma, eye irritation, nasal dryness and obstruction, prolonged colds,
and frequent headaches.
Cancer. Wood dust is known to be a human carcinogen. Wood dust may be
deposited in the nose and the upper and lower airways. According to the National Toxicology Program, “Particles with a diameter larger than 5 micrometers (µm) (inspirable particles) are deposited almost completely in the nose,
while particles 0.5 to 5 µm in diameter (respirable particles) are deposited in
the lower airways.
Eye and skin irritation. Contact with the irritant compounds in wood sap can
cause dermatitis and other allergic reactions.
29
PALLETS
■
Understanding Hazards in the Workplace
Mold exposure. Fine sawdust may also make an excellent medium for mold
growth, and exposure to wood dust has long been associated with a variety of
adverse health effects from mold, including dermatitis, allergic respiratory effects, and mucosal and nonallergic respiratory effects.
Poor housekeeping in a wood pallet manufacturing facility includes excess
wood dust in the air or on walking surfaces. Piles of sawdust on the floor can
become trip and fire hazards.
30
Chapter 4 Wood Dust: Issues Related to Ventilation
■
Question 5: How can I improve ventilation?
Answer:
■
Add local exhaust to all machines that create dust
■
I nstall a central exhaust system (if possible). Make sure that the wood
dust that is collected is protected from rain, snow, and wind.
Outlet for a central exhaust system. The exhausted material is
piled too high and is not protected from rain and wind.
■
osition exhaust hoods as close to the point of dust generation as posP
sible.
■
Perform
regular maintenance on the ventilation system or individual
dust collectors.
■
Consider removing dust deposited on wood that is being cut by a resaw
by using a vacuum cleaner with an appropriate filter.
■
Make
sure there are no leaks in the ventilation system and minimize
the use of flexible ducts.
31
PALLETS
■
Understanding Hazards in the Workplace
Make
sure the ventilation system is strong enough to capture and
transport the dust that is being collected. A transport velocity of 4,000
to 4,500 feet per minute is required for heavy and wet sawdust.
■
Make sure exhaust system is turned on and functioning
➡
■
A gap in the ductwork of an exhaust system
For additional information
American Conference of Governmental Industrial Hygenists [2005]. 2005
TLVs and BEIs.
Dement J [2001]. Wood dust. In: Bingham E, Cohrnssen B, Powell C, eds.
Patty’s Toxicology.
National Toxicology Program [2005]. 11th Report on carcinogens. Department
of Health and Human Services, http://ntp.niehs.gov/ntp/roc/eleventh/profiles/
s189wood.pdf.
NIOSH. NIOSH Pocket guide to chemical hazards [Online]. http://www.cdc.
gov/niosh/npg/npgd0667.html
32
CHAPTER 5
Improving Saw and
Nail Gun Safety
Chapter 5 Improving Saw and Nail Gun Safety
■
Chapter 5
Improving Saw and Nail Gun Safety
Things the company should do to improve saw safety:
■
Make sure saws have adequate guards and proper ventilation. Always
turn on ventilation when using the saw.
A large chain saw with minimal guarding, no exhaust ventilation,
and no barriers to prevent other workers from walking into the saw.
35
PALLETS
■
■
Understanding Hazards in the Workplace
Ensure all workers are aware of the safety concerns regarding band
saws; placing guards for band saws used in recycling is difficult. This
photo shows a guard on top of the band saw. A guard of this type will
allow access to the blade but prevent a worker from putting his hand
on the blade.
Band saw for recycling pallets that has a guard on top.
Band saw for recycling pallets that has no guarding.
36
Chapter 5 Improving Saw and Nail Gun Safety
■
■
Ensure all electric saws used are double-insulated or have a 3-prong
plug in a grounded outlet with a ground-fault circuit interrupter.
Electric saw
Outlet with a ground-fault circuit interrupter
37
PALLETS
■
Understanding Hazards in the Workplace
Things a worker must do to improve saw safety:
■
Eye (safety glasses) and ear protection (at least ear plugs) are required
when saws are used.
■
Make sure all guards are in place before operation. Never remove
guards or reach in guarded areas while the saw is on.
Chop saw with a guard on top
38
Chapter 5 Improving Saw and Nail Gun Safety
■
■
Make sure that each saw either has an effective brake to stop rotation
immediately when the saw is turned off or a program requiring the saw
operator to stay with the saw until it stops rotating.
■
Blades can rotate even if the motor is “off.” Saw blades are sharp and
can cut you even if the machine is “off,” and the blade is not rotating.
■
Lock out the motor of the saw before cleaning loose pieces of sawdust.
OSHA's hazardous energy control, or “lockout/tagout” standard mandates that such machinery be shut down and its power source be physically locked out before workers clean, service, or perform maintenance.
The standard requires employers to, among other things, develop and
use machine-specific lockout procedures, train workers in the procedures, annually review its lockout program, and ensure that lockout
devices are in fact affixed to the power source before workers begin
work on the machine.
Example of Lockout/tagout used on electrical equipment
39
PALLETS
■
Understanding Hazards in the Workplace
■
Institute lockout/tagout procedures for saws requiring repair
or maintenance.
■
Make sure each saw blade is sharp and well maintained. Replace
broken or worn blades
Things an employer can do to improve nail gun safety:
A nail gun is potentially a very dangerous tool because it fires a projectile at
high velocity like a firearm. Despite the hazards involved, these tools can lead
to increased production resulting in lower productions costs. Using a nail gun
requires constant awareness for safe operation.
■
Make sure all operators review the owner’s manual and safety procedures prior to tool operation or maintenance.
■
Use only clean, dry compressed air at the manufacturer-recommended
pressure, and never use bottled gases or air.
■
Suspend the nail gun from the ceiling, or provide a shelf that can be
adjusted to the appropriate height for each worker to rest the nail gun
on when not in use.
■
Make sure that workers have adequate experience using the “bump”
trigger method that may increase the risk of traumatic injury but
decreases the potential risk of musculoskelatal disorders.
The worker’s free hand is very close to the firing end of the nail gun.
40
Chapter 5 Improving Saw and Nail Gun Safety
■
■
Perform any necessary maintenance on the gun and compressor prior
to use.
■
Limit the weight of fully loaded nail guns so that the worker’s arm does
not get overly fatigued.
■
Investigate the use of automatic nailing machines to manufacture the
pallet.
Things a worker can do to improve nail gun safety:
■
Never assume the tool is empty.
■
Do not carry the tool by the hose or with a finger on the trigger.
■
Never point the gun at anyone even if it is empty or disconnected from
the air supply.
■
Disconnect the air hose prior to clearing a jam. Next, when you are sure
the gun is not pointed at anyone else, depress the gun trigger to ensure
that all air is exhausted from the tool.
■
Do not fire the tool unless the nose is firmly pressed against a work
piece.
■
Move forward, not backward when nailing horizontal areas.
■
Keep your free hand safely out of the way of the tool.
■
Always use safety glasses and hearing protection.
For Additional Information
OR-OSHA [2003]. Use of Pneumatic nail guns. http://www.cbs.state.or.us/external/osha/hazards/nailgun.htm.
Pneumatic nailer injuries: A report on Washington State 1990–1998. http://
www.cdc.gov/elcosh/docs/d0400/d000436/d000436.html.
U.S. Department of Labor, Occupational Safety and Health Administration.
Machine guarding standards. http://www.osha.gov/sltc/machineguarding/
standards.html.
U.S. Department of Labor, Occupational Safety and Health Administration.
Machine guarding etool. http://www.cdc.gov/elcosh/d0400/d000436/d000436.
html.
41
CHAPTER 6
Forklift Safety
Problems and Solutions
Chapter 6 Forklift Safety: Problems and Solutions
■
Chapter 6
Forklift Safety
Problems and Solutions
What Managers Can Do to Improve Forklift Safety
In order to prevent injuries and fatalities from forklifts, NIOSH recommends
that employers develop, implement, and enforce a comprehensive written
safety program that includes worker training and operator licensing.
Case Study
A 58 year-old male textile plant foreman was killed when a second
forklift falling off a loading dock struck his forklift truck. The incident
occurred as the victim and co-workers were transferring pipes from a
forklift located at ground level to a second forklift on the edge of the
loading dock. The workers had completed loading the second forklift
and were raising the load when the lift's front wheels slipped off the
edge of the dock. The forklift fell off the dock, striking the first forklift
at ground level and turning it over. The victim, who was operating the
first lift, was crushed under the roll cage as it turned over.
Preventive Recommendations for Employers
■
ake sure that workers do not operate a forklift unless they have been
M
trained and licensed.
■
nsure that operators always use seatbelts; if the forklift does not have
E
seatbelts, contact the manufacturer as many offer restraint systems
that can be retrofitted to older forklifts. Many fatalities resulting from
forklift overturn might have been prevented if the operator had been
restrained. The overhead guard of the forklift is generally the part that
crushes the operator's head or torso after he or she falls or jumps outside of the operator's compartment.
45
PALLETS
46
■
Understanding Hazards in the Workplace
■
In the event of a lateral or longitudinal tip-over, operators of sit-down
type forklifts should be trained to stay with the truck rather than trying to jump free. The operator should hold on firmly and lean away
from the point of impact.
■
The employer should develop, implement, and enforce a comprehensive written safety program for forklifts that includes worker training,
operator licensure, and a timetable for reviewing and revising the program in compliance with the Code of Federal Regulations [129 CFR
1910.178(1)]. This standard addresses specific training requirments
for truck operation, loading, seat belts, overhead protective structures,
alarms, and maintenance of industrial trucks. Refresher training is
required if the operator is observed operating the truck in an unsafe
manner, is involved in an accident or near miss, or is assigned to a different type of truck.
■
Employees should be told not use a forklift to elevate workers unless
an approved lifting cage is used and always make sure that the platform
is secured to the lifting carriage or forks.
■
Separate forklift traffic and other workers where possible; limit some
aisles to workers on foot only or forklifts only.
■
Restrict the use of forklifts near time clocks, break rooms, cafeterias,
and main exits, particularly when the flow of workers on foot is at a
peak (such as at the end of a shift or during breaks).
■
Install physical barriers where practical to ensure that workstations are
isolated from aisles traveled by forklifts.
Chapter 6 Forklift Safety: Problems and Solutions
■
■
Evaluate intersections and other blind corners to determine whether
overhead dome mirrors could improve the visibility of forklift operators or workers on foot.
■
Install workstations, control panels, and equipment away from the
aisle when possible. Do not store bins, racks, or other materials at corners, intersections, or other locations that obstruct the view of forklift
operators or workers at workstations.
■
Make sure forklift operators
make every effort to alert workers when a forklift is nearby. Use
horns, audible backup alarms,
and flashing lights to warn workers and other forklift operators
in the area. Flashing lights are especially important in areas with
high ambient noise levels.
■
Ensure that workplace safety inspections are routinely conducted by a
person who can identify hazardous conditions such as obstructions in
the aisle, blind corners and intersections, and forklifts that come too
close to workers on foot or at their workstation.
■
Enforce safe driving practices for forklift operators such as obeying
speed limits, stopping at stop signs, and slowing down and sounding
the horn at intersections.
■
Repair and maintain cracks, crumbling edges, and other defects on
loading docks, aisles, and other operating surfaces.
■
Check carbon monoxide (CO) emissions at
every tune-up.
47
PALLETS
■
Understanding Hazards in the Workplace
Case Study
A 19 year-old male warehouse order picker was fatally injured after falling from a pallet that was raised on the forks of a forklift truck. The incident occurred when the victim and a co-worker were getting an order
of paper products that had been stored on the top tier of a warehouse
storage rack. The victim was raised on the forklift and had retrieved a
box of paper when he stepped off the edge of the pallet, falling 12 feet to
the concrete floor. The victim died 4 hours after the incident.
Preventive Recommendations for Workers
48
■
levate a worker on a platform only when the vehicle is directly below
E
the work area; workers on the platform should use a restraining means
such as rails, chains, or a body belt with a lanyard or deceleration device.
■
Do not drive to another location with the work platform elevated.
■
When a forklift is to be left unattended, the forks are to be lowered,
power shut off, brakes set, and key removed.
■
Do not enter areas with a forklift that do not have adequate ventilation.
■
Do not operate a forklift unless you have been trained and licensed.
■
Always wear eye and ear protection.
■
The forklift should be thoroughly inspected and findings recorded
before each shift. Any problems found with the forklift during the shift
should be reported to the supervisor.
■
Always use seatbelts if they are available.
■
Report to your supervisor any damage or problems that occur to a
forklift during your shift.
Chapter 6 Forklift Safety: Problems and Solutions
■
Case Studies
Fall from Forklift Platform—A 36-year-old furniture warehouse
worker was killed after falling from a platform mounted on the forks
of an order-picker forklift truck. The incident occurred when the
victim and a co-worker were moving boxes of furniture onto a newly
installed racking system. The workers had loaded the boxes onto the
forklift platform and were raising the lift to place the boxes on the new
racks. The victim was standing on the forklift platform with the boxes
and fell off when the lift shook as it was being raised. He fell 8 feet 8
inches to the floor, striking his head on a section of steel angle iron lying on the cement. The victim, who only had a few inches of platform
to stand on, apparently lost his balance and fell, pulling down a wardrobe he was holding. The forklift operator heard the wardrobe fall and
looked down to see the victim on the floor with the box on top of him.
Forklift Overturn—A 43 year-old male company president/coowner died as a result of injuries he sustained after a forklift he was
operating overturned. The victim and the director of field operations
(the witness) were in the process of unloading materials from a tractor
trailer when the incident occurred. The victim had completed unloading material from one side of the trailer and drove down and alongside
the trailer and while turning the corner to go behind the trailer, the
forklift began to tip over and trapped the the victim.
Forklift Crushes Driver—A 16 year-old male part-time cleaner
was fatally injured when the forklift he was operating at a seafood
processing/retail facility overturned, pinning him and crushing his
chest. The victim was moving a wooden pallet loaded with trash. The
load was raised approximately 4½ feet when, during a right-hand turn,
the forklift overturned. The victim was either thrown or attempted to
jump from the forklift as the falling object protective structure (FOPS)
attched to the forklift landed on his chest. He died the next morning.
Fall from Forklift—A 21 year-old warehouseman died after being
crushed between a forklift and the edge of the floor of a railroad boxcar. The victim was attempting to close the boxcar door using a chain.
The victim had parked the forklift on the loading dock without setting
49
PALLETS
■
Understanding Hazards in the Workplace
the parking brake or chocking the wheels. The forklift rolled backward
falling partially off of the dock, crushing the victim against the edge of
the boxcar floor. The victim was not trained or certified to operate a
forklift.
For additional information
NIOSH [2001]. NIOSH alert: preventing injuries and deaths of workers who
operate or work near forklifts. http://www.cdc.gov/niosh/2001–109.html.
NIOSH [2005]. Fatality and Control Evaluation (FACE) Program. http://www.
cdc.gov/niosh/face/
OSHA safety and health topics: powered industrial trucks. http://www.osha.
gov/sltc/poweredindustrialtrucks/index.html.
50
CHAPTER 7
Carbon Monoxide and
Heat Treatment
Chapter 7 Carbon Monoxide and Heat Treatment
■
Chapter 7
Carbon Monoxide and Heat Treatment
Question 1: What is carbon monoxide?
Answer: Carbon monoxide is a lethal gas that is produced when fossil fuels
such as gasoline or propane are burned. It is one of many chemicals found in
engine exhaust and can rapidly accumulate even in areas that might appear to
be well ventilated.
Question 2: What are the health effects of carbon
monoxide?
Answer: Because carbon monoxide is colorless, tasteless, oderless, and
nonirritating, it can overcome the exposed person without warning. At low
concentrations, carbon monoxide can cause fatigue in healthy people and
chest pain in people with heart disease. At higher concentrations, it can cause
impaired vision and coordination, headaches, dizziness, confusion, and nausea. High exposures can result in death.
Avoid carbon monoxide exposure by making sure the
work area is well ventilated
when operating a forklift
indoors.
53
PALLETS
■
Understanding Hazards in the Workplace
Case Study
Two carpenters were overcome by carbon monoxide when they entered a basement area where a gas-powered engine was running. There
was no electricity at the site and the gas engine powered an electric
generator. It appears that the first worker may have gone into the
basement via a ladder to check the generator and was overcome. The
second worker may have gone into the basement to assist the downed
worker and was also overcome. Both victims were found at the bottom
of an opening in the basement wall. One of them had tried to punch
out one of the basement windows to provide ventilation. The workers
were deceased when they were found.
Question 3: How does carbon monoxide work?
Answer: Carbon monoxide poisons primarily by competing with oxygen
for binding sites on hemoglobin. The affinity of carbon monoxide for hemolglobin (forming carboxyhemoglobin) is more than 200 times greater than
hemoglobin’s affinity for oxygen. Carbon monoxide thus replaces oxygen, and
reduces the oxygen-carrying capacity of the blood. Carbon monoxide may also
poison by binding to tissues and cells of the human body and interfering with
their normal function.
Question 4: Is carbon monoxide exposure regulated?
Answer: Carbon monoxide is regulated by OSHA and the current OSHA
PEL for carbon monoxide is 50 parts per million (ppm) as an 8-hour timeweighted average (TWA) The NIOSH recommended exposure limit (REL)
for carbon monoxide is 35 ppm as an 8-hour TWA with a ceiling limit (CL)
54
Chapter 7 Carbon Monoxide and Heat Treatment
■
of 200 ppm that should not be exceeded at any time. NIOSH recognizes the
immediately dangerous to life and health (IDLH) concentration for carbon
monoxide as 1,200 ppm. The IDLH is the concentration that could result in
death or irreversible health effects, or prevent escape from the contaminated
environment within 30 minutes. The American Conference of Governmental
Industrial Hygienists (ACGIH) has adopted a threshold limit value (TLV) for
carbon monoxide of 25 ppm as an 8-hour TWA.
Question 5: What machines produce carbon
monoxide?
Answer: In the wood pallet manufacturing industry carbon monoxide was
predominantly produced by fork lifts (both gasoline and liquid propane gas
[LPG]) operating inside but also by unvented propane powered space heaters.
Case Study
A 15-year-old male camp counselor died of carbon monoxide poisoning when the furnace malfunctioned in the cabin where he was sleeping. The victim had worked as a counselor at the camp for 9 weeks.
On the night of the incident, he was the only person assigned to sleep
in the building that housed Health Services. The wood frame building had a furnace room that housed a liquid propane (LP) gas-fueled
furnace. The furnace was used infrequently and for brief time periods. There were no records to indicate when the furnace had last been
inspected or repaired. There were no carbon monoxide detectors in
the building. The victim went into the building about 8:30 p.m. and
turned on the furnace before he went to bed. He kept the windows and
doors closed. When the victim did not show up for breakfast the next
morning, a supervisor went to the building and found him motionless
in bed. Emergency services were summoned.
55
PALLETS
■
Understanding Hazards in the Workplace
Question 6: What types of forklifts make carbon
monoxide?
Answer: All forklifts except for those that are electrically powered produce
carbon monoxide. Gasoline powered forklifts usually produce the highest
amounts of carbon monoxide. Propane powered forklifts may also emit substantial amounts of carbon monoxide, particularly if a forklift was not properly maintained. If a propane powered lift was not properly maintained, some
propane engines may generate more carbon monoxide than a gasoline engine.
A carbon monoxide emissions test is needed to properly tune up all forklifts.
Question 7: How much carbon monoxide was present
in the wood pallet manufacturing
industry?
Answer: Carbon monoxide levels were measured for part of the work day at
four plants that used either LP or gasoline forklifts. The plant managers that
had diesel forklifts did not use them inside their facilities for any extended
period of time, and their carbon monoxide measurements were not substantially elevated. Forklifts, however, were
used to load pallets on a trailer. High
concentrations of carbon monoxide
were generated (138 ppm) for a short
period of time while a forklift was in a
trailer that did not have ventilation.
The results from three of the four
plants indicated that both worker
and area measurements of carbon
monoxide were approximately 10 ppm.
Plant number 4 had carbon monoxide concentrations that potentially
exceeded both NIOSH and OSHA
criteria (109 ppm). That plant used
an older LP forklift. The OSHA standard is 50 ppm (8-hour TWA).
56
A forklift in a trailer.
Chapter 7 Carbon Monoxide and Heat Treatment
■
Question 8: What steps can employers and workers
take to protect themselves?
Answer:
Employers
1.
ducate workers about the sources and conditions that may result in
E
carbon monoxide poisoning as well as the symptoms and control of
carbon monoxide exposure.
2.
Develop a program of preventive maintenance that includes a tune up
based on exhaust gas measurements.
3.
onitor workers" carbon monoxide exposure to determine the extent
M
of the hazard.
4.
I mprove ventilation in the plant, particularly in the winter. Carbon
monoxide levels in the summer were usually within the standard, and
most plants had open doors and windows. In the winter the doors
and windows of the plant were closed, and few plants had mechanical
ventilation systems. Owners were concerned that heating and adding
outside air in the winter would greatly increase heating costs; however,
the alternative may be unsafe carbon monoxide levels.
5.
I nstall carbon monoxide monitors. If the carbon monoxide level is too
high, it may be necessary to turn off.
6.
o not require workers to enter a trailer for an extended period of
D
time. Our measurements showed carbon monoxide levels rising up to
138 ppm in the trailer when a worker entered on a forklift.
7.
I t may be necessary to purchase a new forklift if the forklift you have
is not reparable. The plant owner with the carbon monoxide of 109
ppm purchased a modern LPG forklift, and carbon monoxide measurements for both the worker and the plant floor declined to approximately 4 ppm in the summer. Besides improving working conditions,
the new forklift used less fuel (approximately one tank of propane a
week for the new machine as compared to a tank every day for the old)
and was more reliable.
57
PALLETS
■
Understanding Hazards in the Workplace
Workers
1.
Turn off the forklift when it is not in use. Do not leave it idling indoors.
2.
Do not remain in unvented areas for an extended period of time. Carbon monoxide levels rise rapidly if there is no fresh air supply.
A new propane powered forklift.
Heat Treatment of Pallets
As of March 31, 2002, heat treatment was required of all nonmanufactured
(solid sawn) softwoods and hardwoods used in packaging that are to be exported. This is to prevent the introduction of the pinewood nematode that has
caused extensive disease in pines in Japan and China. Heat treatment requires
that the pallet be heated to a minimum core temperature of 56˚C (132.8˚F) for
a minimum of 30 minutes.
Heat treatment is usually done in a heat chamber. Suggestions for safe operation of a heat chamber include the following:
■
To avoid burn injuries
— Do not open the door to the heat chamber until the heat chamber
is off. There is no reason for someone to go into a heat chamber or
be inside the heat chamber during operation.
— Let the heat chamber cool off before entering.
58
Chapter 7 Carbon Monoxide and Heat Treatment
■
■
To avoid explosion injuries
— Do not smoke around the heat source for the heat chamber. This is
particularly true if the heat chamber uses propane gas to generate
heat.
■
To avoid toxic vapor exposure
— Minimize the amount of time you are in the heat chamber with a
forlift, even if the heat chamber is off. Carbon monoxide may build
up rapidly when the forklift is operated in the heat chamber.
— Do not use direct fire systems because of the possibility of exhaust
buildup and of starting a fire. Move the flame out of the heat
chamber; make sure that there is sufficient ventilation or use an
indirect system. If you have a boiler on the property, consider using
steam.
■
To avoid running into other workers with a forklift
— Only trained operators should run the forklift.
— Make sure loads are stable, with the forks as low as possible.
Home-made heat treatment chamber with pallets loaded, and ready
to start heat treatment cycle.
59
PALLETS
■
Understanding Hazards in the Workplace
Commercially manufactured heat treatment chamber.
For additional information
OSHA [1997]. Carbon monoxide standard. http://www.osha.gov/pls/
owadisp.show_document?p_table=STANDARDS&p_id=10366&p_text_
version=FALSE.
OSHA Fact sheet: carbon monoxide. http://www.osha.gov/OshDoc/data_
General_Facts/carbonmonoxide-factsheet.pdf.
OSHA Health guidelines for carbon monoxide. http://www.osha.gov/SLTC/
healthguidelines/carbonmonoxide/
60
CHAPTER 8
Ergonomics for
Wood Pallet Manufacturers
Chapter 8 Ergonomics for Wood Pallet Manufacturers
■
Chapter 8
Ergonomics for
Wood Pallet Manufacturers
Ergonomic Considerations for the Wood Pallet
Manufacturing Industry
Within the wood pallet manufacturing industry, three issues should be addressed by the application of ergonomic principles:
■
Manual material handling of raw material and finished product
■
Use of power tools and exposure to impulse and cyclical vibrations
■
Workstation design issues related to awkward positions
Manual Material Handling
The NIOSH recommended weight limit for manual material handling tasks
is a maximum of 51 pounds under ideal conditions. (Applications Manual for
the Revised NIOSH Lifting Equation). The size and weight of the raw material
(timber and/or cants) would often exceed this limit, requiring the use of mechanical lifting aids or team lifting to move the material. This requirment helps
to minimize low back or upper arm injury, particularly when moving material
from storage areas to work areas where saws, nailers, etc. are present. Gravity
feed or roller table systems may also be implemented to move heavy objects.
63
PALLETS
■
Understanding Hazards in the Workplace
Worker manually positioning wood into saw.
Worker lifting wood from supply pile below knee height.
64
Chapter 8 Ergonomics for Wood Pallet Manufacturers
■
If possible, keep the supply of raw material, or finished product between the
shoulders and the knees. Do not stack above shoulder height or below knee
height. Performing such tasks may result in neck, shoulder, and lower back injuries over time. Automatic height adjusting carts (e.g., those which use springs
to raise or lower the work surface) adjust the shelf height based on the weight of
the material on the cart. Hydraulic-powered elevating carts are also an option.
Worker moving heavy timber into saw.
Worker moving pallet through saw.
65
PALLETS
■
Understanding Hazards in the Workplace
Keeping load close to body while moving pallet component.
When manually transferring raw material or product to a different location,
keep the load as close to the worker’s torso as possible. In the case of pallets,
carry vertically close to the body as opposed to horizontally in front of the
body, if vision is not obstructed by the load. For example, carrying a 50 pound
pallet with hands 20 inches in front of the spine results in 1,000 inch-pounds
of force. By carrying the 50-lbs pallet 8 inches in front of the spine results in
only 400 inch-pounds of force.
Minimize the distance walked when manually carrying loads. Carrying heavy
loads over more than a few feet extracts a physiologic toll from the worker.
Prolonged energy expenditure can lead to fatigue, which in turn may result in
injuries or accidents.
66
Chapter 8 Ergonomics for Wood Pallet Manufacturers
■
Use of Power Tools
Exposure to hand-arm or segmental vibration would primarily be from the
use of handheld power tools. This exposure can be minimized through proper
tool selection, preventive tool maintenance, and the use of anti-vibration
gloves where appropriate. Gloves should meet or exceed the requirements of
the International Organization for Standardization (ISO) [ISO-10819 Mechanical vibration and shock. Hand-arm vibration. Method for the measurement
and evaluation of the vibration transmissibility of gloves at the palm of the
hand 1997.]
Impact tools, such as pneumatic nailers, should be designed to minimize kickback. The tools may be counterbalanced to alleviate some of the stresses to the
worker’s wrist and forearm. Pneumatic nailers often weigh over nine pounds
when loaded with fasteners. In a dedicated pallet assembly area or workstation
the tool can be easily suspended overhead, above the work area. Suspending
the tool would eliminate some of the weight of the tool the worker must hold
as well as provide a permanent location for the tool for general housekeeping
issues.
Worker in awkward posture to use saw.
67
PALLETS
■
Understanding Hazards in the Workplace
Worker in stressful awkward posture with twisted torso.
Worktable too high, forcing awkward arm posture.
68
Chapter 8 Ergonomics for Wood Pallet Manufacturers
■
Worker reaching with tool rather than bringing work closer to body.
Powered handtools that require the use of a single-finger trigger place undue
stress on the soft tissues (e.g., tendons) of that finger; usually the index finger,
due to the many repetitions over the course of the day. Tools with multiplefinger or strip triggers allow the user to alternate which finger activates the
tool while still maintaining control of the tool in the hand. Pressure-activated
tools eliminate the need for triggers by starting upon steady pressure on the
end of the tool.
Workstation Design
Keeping the worker’s arms as close to the body as possible while using a tool
is less stressful than using the tool with the arm fully extended. Extreme reach
with a tool places additional stress on the arm, shoulder, neck, and spine. Additional stresses occur to the legs as well as shown in the photo on the next page.
Place the raw materials in a jig on a rotating surface so that the pallet (and surface) can be spun in front of the worker to minimize reach with the pneumatic
nailer. Turntable tops are relatively inexpensive and can be mounted to many
existing work surfaces.
69
PALLETS
■
Understanding Hazards in the Workplace
Worker stretching to nail far side of pallet.
Worker in awkward posture due to table height with work on the far side of pallet.
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Chapter 8 Ergonomics for Wood Pallet Manufacturers
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Use jigs, fixtures, and vises versus hands to hold material in place. Simple
clamps and fixtures can be used to secure the raw material in place during pallet construction.
One common principle to improve productivity in the workplace is to have a
predetermined location for each tool or item needed and to always return that
item to that location after each use.
Many facilities are indoors with relatively poor area lighting and little to no
task lighting. The elimination of poor lighting is especially important in areas
where saws or other power equipment is being used.
Minimize bending, stooping, squatting, lifting and lowering of loads. A variety
of lift tables, scissors lifts, pallet tables, etc. can be used that would help minimize worker fatigue over the course of the work shift.
Where possible use workstations with easily adjustable heights that readily
accommodate most workers. Pneumatic, hydraulic, or manually adjustable systems are available. Where possible allow both standing and seated workstations
which lessens muscle fatigue among the workers.
For More Information
Applied Occupational Ergonomics [1998]. Fernandez JE, Marley RJ.
Cumulative trauma disorders: a manual for musculoskeletal diseases of the upper limbs [1988]. Putz-Anderson V, ed.
Elements of Ergonomics Programs [1997]. NIOSH Publication No. 97–117.
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| File Modified | 2007-12-14 |
| File Created | 2006-09-25 |