Concrete Mixers

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Concrete Mixers
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What is a Concrete Mixer

• By definition a concrete mixer is a device that
  combines cement, aggregate such as sand or
  gravel, and water to form concrete. A typical
  concrete mixer uses a revolving drum to mix the
  components. For smaller volume works portable
  concrete mixers are often used so that the
  concrete can be made at the construction site,
  giving the workers ample time to use the concrete
  before it hardens.

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Why Is Safety a Concern

• Safety is a major concern when it comes to
  concrete mixers
• Why?- Solely because injuries can and
  unfortunately happen on construction jobs.
• Injuries not only cause health problems, lost
  time limbs and things of the like but inevitably
  lost time and money for all parties involved.

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Injury Statistics

• More than 250,000 people work in concrete
  manufacturing.
• Over 10 percent of those workers - 28,000 -
  experienced a job-related injury or illness and
  42 died in just one year.

• Potential hazards for workers in concrete
  manufacturing
• Eye, skin and respiratory tract irritation from
  exposure to cement dust
• Inadequate safety guards on equipment
• Inadequate lockout/tagout systems on machinery
• Overexertion and awkward postures
• Slips, trips and falls and
• Chemical burns from wet concrete

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Safety Procedure Examples

• Many Injuries occur in relation with cement
  mixers. Some examples and how to curb the
  occurrence of such injures are as follows
• Cement Dust
• Hazard Exposure to cement dust can irritate
  eyes, nose, throat and the upper respiratory
  system. Skin contact may result in moderate
  irritation to thickening/cracking of skin to
  severe skin damage from chemical burns. Silica
  exposure can lead to lung injuries including
  silicosis and lung cancer.Solutions Rinse eyes
  with water if they come into contact with cement
  dust and consult a physician.Use soap and water
  to wash off dust to avoid skin damage.
• Wear a P-, N- or R-95 respirator to minimize
  inhalation of cement dust
• Eat and drink only in dust-free areas to avoid
  ingesting cement dust.

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Safety Procedure Examples

• Wet Concrete
• Hazard Exposure to wet concrete can result in
  skin irritation or even first-, second- or
  third-degree chemical burns. Compounds such as
  hexavalent chromium may also be
  harmful.Solutions Wear alkali-resistant gloves,
  coveralls with long sleeves and full-length
  pants, waterproof boots and eye protection.Wash
  contaminated skin areas with cold, running water
  as soon as possible.Rinse eyes splashed with wet
  concrete with water for at least 15 minutes and
  then go to the hospital for further treatment.

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Safety Procedure Examples

• Machine Guarding
• Hazard Unguarded machinery used in the
  manufacturing process can lead to worker
  injuries.
• Solutions Maintain conveyor belt systems to
  avoid jamming and use care in clearing jams.
• Ensure that guards are in place to protect
  workers using mixers, block makers, cubers and
  metalworking machinery such as rebar benders,
  cutters and cage rollers.
• Establish and follow effective lockout/tagout
  procedures when servicing equipment.
• Be sure appropriate guards are in place on power
  tools before using them.

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Safety Procedure Examples

• Poor Ergonomics
• Hazard Improper lifting, awkward postures and
  repetitive motions can lead to sprains, strains
  and other musculoskeletal disorders.
• Solutions
• Use hand trucks or forklifts when possible.
• Lift properly and get a coworker to help if a
  product is too heavy.
• Avoid twisting while carrying a load. Shift your
  feet and take small steps in the direction you
  want to turn.
• Keep floors clear to avoid slipping and tripping
  hazards.
• Avoid working in awkward postures.

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Safety Procedure Examples

• Confined Spaces
• Hazard Mixers and ready-mix trucks have confined
  spaces that pose safety risks for workers.
• Solutions Follow established procedures for
  confined space entry and work to assure safety.
• Guard against heat stress when cleaning truck
  mixer drums.
• Wear appropriate protective equipment to avoid
  silica exposure when removing concrete residues
  from inside truck mixer drums.

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Safety Procedure Examples

• Vehicles
• Hazard Poorly maintained or improperly handled
  vehicles can lead to crushing injuries at the
  plant site or other injuries for truck drivers.
• Solutions Make sure back-up alarms on all
  vehicles are functioning.
• Avoid overloading cranes and hoists.
• Use care with the load out chute on concrete
  mixers to avoid injuries to hands and fingers.
• Beware of hot surfaces on equipment and truck
  components.
• Guard eyes against splashes of aggregate
  materials during loading and unloading.
• Use hearing protection if needed to guard against
  excessive noise exposure during cement
  loading/unloading and while using pneumatic
  chippers inside truck mixer drums.

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Safety is Key

• Laborer Fatally Injured While Cleaning Concrete
  Mixer - Tennessee
• On May 15, 1995, a 25-year-old male laborer (the
  victim) at a concrete-pipe-manufacturing facility
  died from injuries he received while cleaning a
  ribbon-type concrete mixer. The mixer is cleaned
  out each day at the end of the shift, by the
  laborer and the mixer operator. The procedure for
  cleaning the mixer is to shut off the power at
  the breaker box (approximately 35 feet from the
  mixer), push the toggle switch (adjacent to the
  mixer) for the mixer to determine if the power is
  off, and then enter the mixer to scrape down the
  inside and shovel the concrete debris out the
  front discharge chute. The event was
  un-witnessed however, it is assumed that the
  mixer operator shut off the main breaker, and,
  instead of the normal procedure for checking the
  mixer before entry, decided to make a telephone
  call. The victim, a Mexican immigrant who spoke
  or read very little English, not knowing the
  mixer had been de-energized at the main breaker,
  turned the mixer back on, thinking he had shut it
  off. The victim then entered the mixer without
  first pushing the toggle switch to verify that
  the power was off and started cleaning. The mixer
  operator returned from making his telephone call,
  and pushed the toggle switch to check the mixer,
  and heard the victim scream. He proceeded
  immediately to the main breaker and shut off the
  mixer. The emergency medical services was called,
  arrived at the site in 30 minutes, and
  transported the victim to a local hospital, where
  he was then transferred to a local trauma center.
  He died at the trauma center approximately 4
  hours later.

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What does OSHA Have to Say

• The 10 OSHA standards most frequently included in
  the agency's citations were
• Hazard communication
• Lockout/tag out
• Confined spaces
• Respiratory protection
• Guarding floor wall openings and holes
• Electrical wiring methods
• Noise exposure
• Forklifts
• Electrical systems design
• Machine guarding

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OSHA Regulations

• 1926.726(b)
• Concrete mixers. Concrete mixers with one cubic
  yard (-8 m(3)) or larger loading skips shall be
  equipped with the following
• 1926.702(b)(1)
• A mechanical device to clear the skip of
  materials and
• 1926.702(b)(2)
• Guardrails installed on each side of the skip.

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For More Information

• All information was compiled from internet and
  can be found at
• www.osha.gov
• www.wikepedia.com
• www.cdc.gov

• For more information concerning concrete mixers
  these sites can and will provide more insight on
  the topic.