Transcript
EXPERTS Lockout/Tagout Machine Guarding
Michael D. Klein, PE, CHMM, CFEI
Objectives • Establish the requirements of Lockout/Tagout (LOTO) Program • Establish the individual roles within a LOTO Program
• Types of hazardous energy • When should LOTO be applied
• Energy isolation devices • How Do Injuries Occur During Machine Servicing?
What is LOTO? Specific practices and procedures to safeguard employees from the unexpected ENERGY being released during the SERVICING of machinery and equipment, or the release of hazardous energy during service or MAINTAININACE activities.
How Injuries Occur During the Servicing of Equipment Your facility may have a machine that needs to be serviced. To the untrained worker, the machine is turned off from the power source and service work may begin. In the meantime, another employee arrives and reactivates the machine while unaware that the worker is still working inside the machine. The maintenance worker is then injured or killed by moving parts in the reactivated machine. Failure to lockout, blockout and tagout machinery, as required by OSHA regulations, can cause devastating injuries and/or death to workers. These injuries can be prevented by having effective hazardous energy control procedures
How Injuries Occur During the Servicing of Equipment The Bureau of Labor Statistics (BLS) study on injuries while servicing equipment revealed: • 80% failed to turn off equipment • 10% equipment activated by someone else • 5% failed to control potential energy
• Most of remaining 5% disconnected power but failed to verify effectiveness
Types of Hazardous Energy What types of hazardous energy are subject to LOTO? Any source of: • electrical • mechanical • hydraulic • pneumatic • chemical • thermal • or other energy Some energy sources can be turned on/off • Others can only be dissipated or controlled
Potential Energy vs. Kinetic Energy Potential energy can be converted to kinetic! Goal of LOTO is to achieve “Zero Energy State” When does LOTO need to be applied? “…during the SERVICING of equipment”. When is LOTO applied? • Adjusting • Inspecting • Modifying • Replacing parts
• Clearing jams • Lubricating • Cleaning • Tool changes
Exceptions to LOTO Normal production operations • Routine, repetitive, & integral to production • Guards/safety devices not bypassed • Body part not placed in the point of operation or other dangerous area during machine cycle • Need to use alternative measures for protection Cord & plug connected equipment • Plug is only source of energy • Plug is under continuous control of one person
Energy Isolation Devices Accomplished by placing locks on ENERGY ISOLATION DEVICES…” A mechanical device that physically prevents the transmission or release of energy, including but not limited to the following: • Manually operated electrical circuit breaker • Disconnect switch • Manually operated switch by which the conductors of a circuit can be disconnected from all ungrounded supply conductors •and, in addition, no pole can be operated independently
• Line valve • A block to prevent the unexpected movement of machinery/ working parts or other sources of energy within a machine • Any similar device used to block or isolate energy
Energy Isolation Devices Examples: • Electrical disconnect switch
• Electrical breaker switch • Hydraulic valve • Pneumatic valve • Line valve
Energy Isolation Devices Push buttons, selector switches and other control circuit type devices are NOT energy isolating devices. • There is a difference between turning off a machine and actually disengaging or de-energizing a piece of equipment. • When an employee simply turns off a control switch, there are no positive means in place to prevent other employees from reactivating the machine while the worker is performing maintenance work inside the machine.
Energy Isolation Devices
Interlocks are NOT a substitute for lockout • Electrical interlocks are safety devices which are used to help prevent a machine from harming its operator or damaging itself by stopping the machine when tripped. • It is not to be used as a substitute for lockout because it is prone to failures.
The LOTO Definition “LOTO” is a technique used to prevent energy from being released during the servicing of equipment. This is accomplished by placing locks on energy isolation ensuring that the energy isolating device and the equipment being controlled cannot be operated until the lockout device is removed.
LOTO Employee Roles All employees fit into one of the following LOTO roles: “Authorized employee”
• A person who locks out or tags out machines or equipment in order to perform servicing or maintenance on that machine or equipment. An affected employee becomes an authorized employee when that employee's duties include performing servicing or maintenance covered under this section.
LOTO Employee Roles All employees fit into one of the following LOTO roles: “Affected Employee”
•An employee whose job requires him/her to operate or use a machine or equipment on which servicing or maintenance is being performed under lockout or tagout, or whose job requires him/her to work in an area in which such servicing or maintenance is being performed.
LOTO Employee Roles All employees fit into one of the following LOTO roles: “Other employee”
•Works in an area where LOTO being used.
LOTO Basics
• Preferred means of controlling hazardous energy is LOCKOUT IN CONJUNCTION WITH TAGOUT.
• Each isolation point must have both a lock and a tag attached to it. • Locks must be standardized & used only for LOTO. • Tags must indicate lock holder & date of application.
General LOTO Procedure OSHA 1910-147 App A, “Typical Minimum Lockout Procedures” 1. Notify all affected employees that servicing or maintenance is required on a machine or equipment and that the machine or equipment must be shut down and locked out to perform the servicing or maintenance. 2. The authorized employee shall refer to the company procedure to a) identify the type and magnitude of the energy that the machine or equipment utilizes b) understand the hazards of the energy, and c) know the methods to control the energy 3. If the machine or equipment is operating, shut it down by the normal stopping procedure (depress the stop button, open switch, close valve, etc.).
General LOTO Procedure OSHA 1910-147 App A, “Typical Minimum Lockout Procedures” 4. De-activate the energy isolating device(s) so that the machine or equipment is isolated from the energy source(s). 5. Lock out the energy isolating device(s) with assigned individual lock(s). 6. Attach accident prevention tags which state the reason for placing the tag, date and time the tag was placed, name of the person placing the tag, how he/she may be contacted. No one removes the lock without proper authority. 7. Stored or residual energy (such as that in capacitors, springs, elevated machine members, rotating flywheels, hydraulic systems, and air, gas, steam, or water pressure, etc.) must be dissipated or restrained by methods such as grounding, repositioning, blocking, bleeding down, etc.
General LOTO Procedure OSHA 1910-147 App A, “Typical Minimum Lockout Procedures” 8. Ensure that the equipment is disconnected from the energy source(s) by a) first checking that no personnel are exposed, then b) verify the isolation of the equipment by operating the push button or other normal operating control(s) or by testing to make certain the equipment will not operate. c) the machine or equipment is now locked out. 9. Complete required service work. a) Avoid doing anything that could potentially reactivate the equipment. b) OK to interrupt LOTO, but must be reapplied if servicing is to continue.
General LOTO Procedure OSHA 1910-147 App A, “Typical Minimum Lockout Procedures” 1. When the servicing or maintenance is completed and the machine or equipment is ready to return to normal operating condition, take the following minimum steps to return the equipment to service. 2. Check the machine or equipment and the immediate area around the machine to ensure that nonessential items have been removed and that the machine or equipment components are operationally intact. a) Replace all machine guards. 3. Check the work area to ensure that all employees have been safely positioned or removed from the area.
General LOTO Procedure OSHA 1910-147 App A, “Typical Minimum Lockout Procedures” 3. Verify that the controls are in neutral. 4. Remove the lockout devices and reenergize the machine or equipment. 5. Notify affected employees that the servicing or maintenance is completed and the machine or equipment is ready for use.
Special Situations Group LOTO • Each employee applies own locks/tags to each isolation point. • EHS must OK alternative procedures. Shift changes • Oncoming employee attaches locks/tags prior to outgoing employee removing theirs. • Environmental Health and Safety must review and approves of alternative procedures. Lock removal procedure • Supervisor must be notified if lock owner not present.
LOTO Summary • All hazardous energy sources must be controlled (kinetic & potential). • Control via energy isolation device (do not rely on control circuit).
• Only use designated lock for LOTO. • Tags must accompany all locks. • Fourteen -step general procedure – remember to VERIFY ISOLATION. • Protection must be ensured during special situations.
Tire Shredding Machine Incident • A worker from a tire recycling facility climbed on top of a tire shredder to clear a jam. His foot was caught by the in-feed shredding wheels. The lower part of his body was shredded by the cutters. Cause: failure to block out potential energy sources (tire shredding wheel).
Cotton Gin Incident • A cotton gin operator climbed into a jammed cotton cleaner/separator to clear a jam. The toggle switch controlling the operation of the gin was turned off but not locked out. For reasons unknown, a fellow worker turned the machine back on; not realizing the operator was inside the gin. The operator's left leg was pulled through the feed rollers. • Cause: failure to disconnect the power source and lockout the machine.
Asphalt Pug Mill Mixer Incident • Three men were performing maintenance inside an asphalt pug mill mixer. One employee was still inside the mixer when the power was turned back on, thereby starting the mixer. • He was killed instantly. Cause: failure to disconnect power source and lock out the pug mill mixer.
Air Operated Valve Incident • A warehouse worker was repairing an air operated valve which he had turned off but was not disconnected and locked out. During the repair operation he slipped and inadvertently turned on the switch which let air into the valve. His hand was caught and crushed in the valve.
Cause: failure to disconnect power source and lockout the valve.
Exhaust Fan Incident • A maintenance employee was changing V- belts on an exhaust fan. He deenergized the fan before the start of the regular work shift but did not secure the blades of the fan from moving. The suction in the duct work turned the fan blades and belt drive, and his hand was caught in the V- belt drive. Cause: failure to secure fan blades from moving.
Questions
EXPERTS Lockout/Tagout Machine Guarding
Michael D. Klein, PE, CHMM, CFEI
