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Dipping And Coating Operations

Dipping And Coating Operations. Summary. Rule developed to accomplish Rewrite former standards in plain language Consolidate former requirements Increase compliance options. Coverage and Definitions -1910.123 . Does This Rule Apply to Me?. When a dip tank contains a liquid other than water

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Dipping And Coating Operations

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  1. Dipping And Coating Operations

  2. Summary • Rule developed to accomplish • Rewrite former standards in plain language • Consolidate former requirements • Increase compliance options

  3. Coverage and Definitions -1910.123

  4. Does This Rule Apply to Me? • When a dip tank contains a liquid other than water • When you use a liquid or vapors to: • Clean or coat • Alter the surface • Change the characteristic • Draining or drying an object,dipped or coated

  5. What Operations Are Covered? • Paint dipping • Electroplating • Pickling • Quenching • Tanning • Degreasing

  6. Operations Covered (Continued) • Stripping • Cleaning • Roll coating • Flow coating • Curtain coating

  7. What Operations Are Not Covered? • An operation that only uses a molten material • Alloy • Salt

  8. How Are Terms Defined? • Adjacent area • Any area within 20 feet of a vapor area that is not separated by tight partitions • Approved • Designated equipment - listed/approved by a nationally recognized testing laboratory • Autoignition temperature • The minimum temperature required to cause self-sustained combustion, independent of any other source of heat

  9. Terms Defined (Continued) • Combustible liquid • A liquid with a flash point of 100 deg.F or > • Dip tank • A container holding a liquid other than water and used for dipping or coating • An object may be immersed (or partially immersed) or it may be suspended in a vapor area • Flammable liquid • A liquid with a flashpoint < 100 deg.F

  10. Terms Defined (Continued) • Flashpoint • The minimum temperature where a liquid gives off a vapor in sufficient concentration to ignite • Lower flammable limit (LFL) • The lowest concentration of a material that will propagate a flame • Expressed as a % by volume of the material in air (or other oxidant)

  11. Terms Defined (Continued) • Vapor area • Any tank, including drain boards, drying or conveying equipment, and any surrounding area where the vapor concentration > 25% of the LFL • You • The employer, as defined by the occupational safety and health act of 1970

  12. General Requirements -1910.124

  13. What Construction Requirements Apply to Dip Tanks? • Any container that must be strong enough to withstand any expected load

  14. What Ventilation Requirements Apply to Vapor Areas? • Keep airborne concentration < 25% of its LFL • Meet levels specified Subpart Z • Use of tank covers or floating materials

  15. When You Use Mechanical Ventilation? • Must conform with standards incorporated by reference: • ANSI • NFPA • ACGIH • Draw the flow of air into a hood or exhaust duct

  16. Mechanical Ventilation (Continued) • Tanks must have an independent exhaust system unless the combination of substances being removed will not cause a: • Fire • Explosion • Chemical reaction

  17. What Requirements Must I Follow to Recirculate Exhaust Air? • Can not recirculate exhaust air when substance poses a health hazard to employees • > 25% the LFL

  18. Recirculate Exhaust Air (Continued) • Exhausted air recirculated using flammable or combustible liquids is: • Free of any solid particulate • Monitored by approved equipment • Sounds an alarm, automatically shuts down when the vapor concentration > 25% the LFL

  19. What Must I Do When I Use an Exhaust Hood? • Provide area with a volume of outside air that is at least 90 % of the volume of the exhaust air • Outside air supply does not damage exhaust hoods

  20. What Requirements Must I Follow When an Employee Enters a Dip Tank? • Meet the entry requirements for permit-required confined spaces

  21. What First-aid Procedures Must My Employees Know? • The first-aid procedures that are appropriate for the operation

  22. What Hygiene Facilities Must I Provide? • Lockers or other storage space to prevent contamination of employee's street clothes • Emergency shower and eye-wash station close to the operation • Can use water hose at least 4’ and at least 3/4” thick, a quick-opening valve, and a pressure of 25 lbs. psi or < • At least one basin with a hot-water faucet for every 10 employees

  23. What Treatment and First Aid Must I Provide? • A physician's approval before an employee with a sore, burn, or other skin lesion that requires medical treatment works in a vapor area • Treatment by a properly designated person of any small skin abrasion, cut, rash, or open sore • Appropriate first-aid supplies located near the operation • Employees who work with chromic acid, periodic examinations of exposed body parts, especially their nostrils

  24. What Must I Do Before an Employee Cleans a Dip Tank? • Drain the tank, open the cleanout doors • Ventilate and clear any pockets where hazardous vapors may have accumulated

  25. What Must I Do to Inspect and Maintain My Dipping or Coating Operation? • Inspect hoods and ductwork of ventilation system for corrosion or damage: • At least quarterly during operation • Prior to operation after a prolonged shutdown • Ensure that the airflow is adequate: • At least quarterly during operation • Prior to operation after a prolonged shutdown

  26. Inspect and Maintain (Continued) • Periodically inspect all equipment • Covers • Drains • Overflow piping • Electrical • Fire-extinguishing systems • Promptly correct any deficiencies

  27. Inspect and Maintain (Continued) • Provide mechanical ventilation or respirators to protect employees from exposure to toxic substances during • Welding • Burning • Open-flame work • Clean solvents and vapors before permitting welding, burning, or open-flames

  28. Additional Requirements for Flammable or Combustible Liquids - 1910.125

  29. Flammable or Combustible Liquids • Must comply 1910.123, 124, 125, and126 • Must comply if: • Flashpoint of flammable or combustible liquid is 200 deg. F or > • Liquid is heated as part of the operation • Heated object is placed in the liquid

  30. What Type of Construction Material Must Be Used in Making My Dip Tank? • Noncombustible material

  31. When Must I Provide Overflow Piping? • Properly trapped overflow piping that discharges to a safe location for: • A capacity > 150 gallons • A liquid surface area > 10 feet

  32. Overflow Piping (Continued) • Overflow piping is at least 3” in diameter and has sufficient capacity to prevent the tank from overflowing • Piping connections on drains and overflow pipes allow ready access to the interior of the pipe for inspection and cleaning • Bottom of the overflow connection is at least 6” below the top of the tank

  33. When Must I Provide a Bottom Drain? • For tanks that contain > 500 gallons of liquid, unless: • The tank is equipped with an automatic closing cover • The viscosity of the liquid at normal atmospheric temperature does not allow the liquid to flow or be pumped easily

  34. Bottom Drain (Continued) • Must ensure that the bottom drain: • Will empty the dip tank during a fire • Has pipes that permit the contents to be removed in 5 minutes • Is properly trapped • Discharges to a safe location

  35. Bottom Drain (Continued • Must be capable of manual and automatic operation • Manual operations must be from a safe and accessible location • Must ensure that automatic pumps are used when gravity flow from the bottom drain is impractical

  36. When Must My Conveyor System Shut Down Automatically? • If a conveyor system is used, the system must shut down automatically: • If there is a fire • If the ventilation rate drops below requirements

  37. What Ignition and Fuel Sources Must Be Controlled? • In each vapor area and any adjacent area: • All electrical wiring and equipment conform requirements of Subpart S • Except as permitted in 1910.126 • There are no flames, spark-producing devices, or other surfaces that are hot enough to ignite vapors

  38. Ignition and Fuel Sources (Continued) • Portable container used to add liquid to the tank is electrically bonded and grounded • Heating systems used in a drying operation that could cause ignition: • Is installed in accordance with NFPA • Has adequate mechanical ventilation that operates before and during drying operation

  39. Ignition and Fuel Sources (Continued) • Shuts down automatically if any ventilating fan fails to maintain adequate ventilation • All vapor areas are free of combustible debris • Rags and other contaminated material placed in approved waste cans immediately after use • Waste can contents are properly disposed of at the end of each shift • Post "no smoking" sign near each tank

  40. What Fire Protection Must I Provide? • Required for: • Any tank with a capacity of at least 150 gallons or a liquid surface area of at least 4’ • Any hardening or tempering tank with a capacity of at least 500 gallons or a liquid surface area of at least 25’

  41. Fire Protection (Continued) • For vapor areas, you must provide: • Manual fire extinguishers for flammable and combustible liquid fires • Automatic fire-extinguishing system, Subpart L

  42. Fire Protection (Continued) • May substitute a cover that is closed by an approved automatic device for the automatic fire-extinguishing system if the cover: • Can also be activated manually • Is noncombustible or tin-clad, with the enclosing metal applied with locked joints • Is kept closed when the tank is not in use

  43. To What Temperature May I Heat a Liquid in a Dip Tank? • Must maintain the temperature of the liquid: • Below the liquid's boiling point • At least 100 deg. F below the liquid's autoignition temperature

  44. Additional Requirements for Special Dipping and Coating Operations - 1910.126 • In addition to the requirements in 1910.123 -125, must comply with any requirement that applies to your operation

  45. What Additional Requirements Apply to Hardening or Tempering Tanks? • Must ensure that hardening or tempering tanks: • Are located as far as practicable from furnaces • Are on noncombustible flooring • Have noncombustible hoods and vents for venting to the outside • Vent ducts must be treated as flues and kept away from combustible materials, particularly roofs

  46. Hardening or Tempering (Continued) • Must equip each tank with an alarm that will sound if the temperature of the liquid comes within 50 deg. F of its flashpoint (the alarm set point) • When practicable, provide each tank with a limit switch to shut down the conveyor supplying work to the tank

  47. Hardening or Tempering (Continued) • If the temperature of the liquid can exceed the alarm set point, equip the tank with a circulating cooling system • If the tank has a bottom drain, it may be combined with the oil-circulating system • Must not use air under pressure when filling the tank or agitate liquid

  48. What Additional Requirements Apply to Flow Coating? • Must use a direct low-pressure pumping system or a 10-gallon or < gravity tank to supply the paint for flow coating • In case of fire, an approved heat-actuated device must shut down the pumping system • Must ensure that the piping is substantial and rigidly supported

  49. What Additional Requirements Apply to Roll Coating, Roll Spreading, or Impregnating? • When using a flammable or combustible liquid with a flashpoint < 140 deg. F, prevent static electricity by: • Bonding and grounding all metallic parts (including rotating parts) • Installing static collectors • Maintaining a conductive atmosphere (for example, one with a high relative humidity)

  50. What Additional Requirements Apply to Vapor Degreasing Tanks? • Must ensure that the condenser or vapor-level thermostat keeps the vapor level at least 36” or 1/2-half the tank width, whichever is less, below the top of the tank

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