WHAT IS HAZARDOUS ENERGY
Hazardous energy is any energy source either in primary form or residual form that has the potential to cause injury or death to workers while undertaking servicing or maintenance activities on machines or equipment due to unexpected energization or accidental release of stored energy.
The different types of hazardous energies are
1. Electrical Energy
2. Chemical Energy
3. Radiation Energy
4. Thermal Energy
5. Kinetic Energy
6. Potential Energy
ELECTRICAL ENERGY: Electrical energy is the commonest energy hazard encountered in industries, it is dangerous because it can cause shock, burns, secondary injuries, arc blast exposures. Source of energy is either live through conductors or stored as capacitors, either in the form of low voltage or high voltage. These electrical hazards can be hazardous or injurious to health
CHEMICAL ENERGY: Energy associated with hazardous chemical reactions. Explosions, fires and heat of reaction caused by hazardous chemical reactions result in the release of large amounts of energy in the form of heat and pressure. All types of chemicals whether they are flammable, combustible or corrosive release hazardous chemical energies. All chemicals stored near a potential ignition source can cause explosions are fires.
RADIATION ENERGY: Electromagnetic sources like X rays, UV rays, IR rays have radiation energy, Exposure to alpha, beta and gamma rays are harmful to human health and can cause burns and radiation sickness
THERMAL ENERGY: This energy is also encountered frequently in industries during servicing or maintenance operations, Thermal energy which involves both cold and hot systems is about the motion of particles at the particulate level. Instances of fire and release of gases during welding, torch work, cryogenic systems, working near boiler which involves steam to dissipate hazardous thermal energy in the form of heat. The most common injuries are burns, frostbite and dehydration. Service personnel working on steam pipes can encounter these situations
KINETIC ENERGY: This is the energy of machinery, equipment or material in motion. Moving, spinning or rotating equipment parts continuing their motion even after power is switched off are the examples of kinetic energy
POTENTIAL ENERGY:
o Energy stored in coiled materials like springs which get released when expands suspended or elevated objects or materials
o Energy stored within pressurized liquids used to lift objects or equipment
CONTROL OF HAZARDOUS ENERGY THROUGH
LOTO (LOCKOUT / TAGOUT)
Since hazardous energy can cause injuries or fatalities if not properly disconnected or isolated from the required workplace, there should be a system that should be in place for controlling the hazardous energy during servicing or maintenance operations, one such procedural system is LOTO procedure. LOTO is LOCKOUT / TAGOUT, it is a safety procedure that assists in the protection of employees who are working near equipment and machinery for servicing/maintenance by locking out/tagging out to ensure that all possible and potential sources of hazardous energies have been isolated. Normal production operations do not require isolation as this work is a repetitive, routine and integral to the normal use of equipment or machinery
The following steps are to be followed for every de-energization and lockout process.
1. IDENTIFICATION AND NOTIFICATION: The Machinery or equipment to be identified for LOCKOUT on which service or maintenance is planned. All employees who work near the machine or who operate any part of the machine or any part of the equipment should be notified that LOTO will be performed on their equipment. This LOTO will be an integral part of the WORK PERMIT SYSTEM if work permit system is taken.
2. SHUTDOWN OF MACHINE: The identified machinery to be Shut off completely by ensuring that all the moving or rotating parts come to a complete halt. The machine or equipment must be shut down in a STEP-BY-STEP procedure to avoid the generation of new hazard(s) to employees or damage to the machine or equipment as a result of the de-energization.
3. ISOLATION OF MACHINE OR EQUIPMENT: Identifying and de-energizing all primary and residual hazardous energy sources so that the machine or equipment comes to a complete zero energy state. Isolating devices are needed to control the energy to the machine or equipment. These energy isolating devices must be located and operated in such a manner as to isolate the machine or equipment from all the energy source(s). that are needed to control the energy to the machine or equipment.
4. APPLICATION OF LOCKS: Across each identified hazardous energy sources, there should be a personal lock applied at all energy isolating devices along with the tag. Employees who are performing the lockout / Tagout must attach a lockout/ Tagout device to each energy-isolating device and ensure that they will hold the energy isolating devices in a safe or off position.
5. VERIFICATION OF DE-ENERGIZATION: Before carrying out the service/maintenance work, the de-energization and lockout process to be verified for its effectiveness by testing after each energy-isolating device is locked out or after a group of nearby devices is locked out. For example, checking the valve position, checking with the help of instruments to see if any supply still exits like pressure gauges, to check the electrical points and circuit elements for any induced voltages and all the keys to open the locks are kept in LOTO BOX which is also LOCKED and kept with the person who undertakes the service/maintenance work.
6. RELEASE FROM LOCKOUT / TAGOUT AFTER THE WORK IS COMPLETED: Once the work has been completed and the unit is to be placed in service the following steps to be performed for release from Lockout / Tagout
· Work area to be inspected and ensured that all tools and employees have been removed and machine or equipment components are operationally ready. All affected employees to be notified that Lockout / Tagout devices are being removed.
· Lockout / Tagout Devices to be removed by the authorized personnel in their respective departments along after getting a confirmation by the service/maintenance personnel and physically inspecting the work area. All energy isolating devices are kept back to the normal positions
· After Lockout / Tagout devices have been removed all affected employees to be notified that the machine or equipment can be taken up for and before a machine or equipment is started, affected employees shall be notified that the Lockout / Tagout device(s) have been removed.
HSE Notes by PJ Mohan
Sr.Faculty, NIFS
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