Your COHE Program
In Part 1, we pointed out that the use of only OSHA 1910.147 Subpart J to develop control of hazardous energy (COHE) via lockout/tagout (LOTO) can effectively protect workers from non-electrical energy but is highly unlikely to be effective or compliant when applied to electricity.
In this Part, we’ll use examples to help explain the reasons why.
Affected Employees vs. Authorized Employees
OSHA’s General Industry regulations under 29CFR1910.147 Subpart J – Control of Hazardous Energy governance identifies two main groups of workers who are directly involved with the LOTO process, consisting of the “Affected Employee” and “Authorized Employee.” Many get these two roles confused or consider them as the same. While similar, they have distinct but overlapping roles and responsibilities within the control of hazardous energy program.
Let’s start with the definition of the two roles from 1910.147(b).
OSHA defines the Affected Employee as “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.”
A few examples would be employees who run milling equipment, lathes, broaching equipment, and permanently fixed cutting machines. This includes computer numerical control (CNC) production machines, production conveyor lines and those who operate systems in large industrial plants are a few examples of affected employees.
Authorized employee is defined as “A person who locks out or tags out machines or equipment in order to perform servicing or maintenance on that machine or equipment.”
These individuals are the tool users who repair the machine or equipment after failure or during routine servicing maintenance. The authorized employees are the ones with the greatest risk of serious injury or death if the machine should unexpectantly start or if other forms of hazardous energy are released because they are in harm’s way while working on the equipment.
The affected employee is mainly limited to the one who operates the equipment while the authorized worker performs the servicing or repairs. However, OSHA is aware that many employers allow their employees to perform dual functions, meaning they operate and repair machines and equipment when needed as a routine job activity. For this reason, OSHA permits the affected employee to become an authorized employee when the employee’s duties transition from operating the equipment to servicing or repairing the equipment.
At the same time, Subpart J also speaks of one more group of workers referred to as “Other Employees,” which we will discuss shortly.
Training Requirements for Affected, Authorized and Other Employees
Mandatory training of the three groups of employees (Affected, Authorized and Other) of their specific roles and responsibilities within the parameters of the LOTO program and its limitations are clearly defined by 1910.147(c)(7). For obvious reasons, authorized employees, who are the ultimate stakeholders, have significantly greater training requirements than the affected or other employees.
While not defined, OSHA also identifies a group of workers called “all other employees” in context with COHE program pursuant to 1910.147(c)(7)(i)(C). These “other employees” do not fall into the classifications of either “affected employees” or “authorized employees.”
This third group of workers, while not directly involved with plant operations or maintenance, must also receive some basic level of instructional training in the company’s COHE procedure to understand what the lock and tags indicate, and to be prohibited from starting equipment that has been locked or tagged or from removing a LOTO device.
Custodians, janitors, administrative personnel, engineers, QA/QC inspectors and any other workers outside of those who operate (affected employee) or repair (authorized employee) the equipment would fall into this category.
There is no defined periodicity for retraining employees in the company’s LOTO program because OSHA requires retraining based on certain conditions or after audit findings when any of the following apply:
- Changes in job assignments or roles
- Changes in machines, equipment or processes
- Changes are made to the LOTO procedures
- The annual audit inspections of authorized employees indicate a lack of proficiency or knowledge of the procedure
Subsequent training intervals are required by other standards, which will be discussed later.
Why 1910.147 Subpart J Is Adequate to Control Non-Electrical Energy
The type of hazardous energy or unintentional startup that could injure an authorized worker depends on the scope of work they are allowed to perform according to their employer, job classification, qualifications and the actual hazards they will be exposed to.
Many jobs have indirect exposures from electricity, meaning the electrical energy has been converted to another form of kinetic or potential energy, such as rotating or moving parts, hydraulic and pneumatic pressure, or thermal energy with extremely hot or cold temperatures.
When a worker reaches into the rollers to clear a jammed conveyor belt, the primary hazard is not electrical shock but the mechanical kinetic energy of an unexpected start-up of the conveyor. Even though an electric motor provides the torque to drive the belt, the primary hazard is not electrical shock but having his arms crushed or entangled in the belt.
In such cases, a LOTO program that fully adheres to the provisions of 1910.147 Subpart J using the circuit breaker that powers the conveyor’s motor as the isolation point followed by an attempt to start the equipment should provide adequate protection.
This simplistic demonstration of COHE actions for a nonelectrical hazard is normally cut and dry for certain tasks, but sometimes the lines are blurred. As an example, let’s use tasks common to heating, ventilation, air conditioning and refrigeration (HVACR) equipment.
HVACR work is normally classified as a mechanical discipline with elements of an electrical trade. HVACR technicians often replace pumps, flange gaskets, valves, fan blades or drive belts of large industrial chillers or air conditioning units. Since the hazardous energy when repairing or replacing such components is primarily limited to mechanical forces from the rotating/moving parts, extreme temperature, and pressure, the LOTO instructions pursuant to 1910.147 Subpart J will provide sufficient protection for the workers using electrical isolation devices, such as a circuit breaker or disconnect switch.
This is because the electric motor (the prime mover of the chiller pump, fan blade or drive belts) or high temperatures from heating elements all present an indirect exposure to electricity. By indirect, I mean the electrical power from the circuit breaker or disconnect switch is converted to another form of energy such as kinetic, thermal or pressure.
To control these non-electrical forms of hazardous energy originating from electricity, the logical energy isolation points for the mechanical LOTO will be circuit breakers or disconnect switches which prevent the pump or drive shaft from unexpectedly rotating or resistive heater elements from becoming hot.
As a side note, additional LOTOs on the valves, vents and drains may also be warranted for the pressure or fluids in tubes, tanks and piping systems.
LOTO Procedure in Six Steps
To demonstrate how a LOTO procedure according to 1910.147(d) Subpart J is sufficient for the mechanical side of the HVACR equipment, we’ll use the following six steps to establish a LOTO of the electrical isolation point(s) before beginning the non-electrical work:
- Prior to turning off the pump, the authorized employee must understand the type and magnitude the hazardous energies and the methods to control them. In the case of swapping the pump or drive belts, the main energies will be mechanical and possibly fluids or gases from the pressure and/or temperature from the heating elements (indirect electrical exposure).
- The energy isolation devices will consist of circuit breakers and/or disconnect switches placed in the open (off) position to stop the motors from running and heaters from coming on. The valves for the fluids or gases must also be fully closed, with tanks drained and the pipes vented as needed.
- The authorized employees must affix their personal LOTO to each isolation device to secure them in their safe positions.
- Any stored or residual energy must be relieved, restrained or rendered safe.
- Prior to starting work, the authorized employees must verify that isolation of the pump and piping are established, and the heaters are not emitting thermal energy. This can be accomplished by pushing the start button for the motor and checking pressure and/or temperature gauges monitoring the piping or tank.
- If the motor doesn’t start or the heaters remain at ambient temperature, then the equipment is properly isolated. But special caution must be considered when dealing with HVACR and other temperature and pressure sensitive systems, because the worker must also ensure all the thermostatic, pressure and float switches and other permissive contacts within the control circuit are also in the closed condition to validate the power circuit is correctly isolated by the circuit breaker or disconnect switch. If one or more control circuit contacts are open, the power circuit will still be active but the motor starter will not pick up when the start button is pressed. Great care must be exercised when navigating complex control circuits to ensure complete and total isolation.
If all six of the previous steps are satisfactorily met, then the pump or drive belts or any other mechanical parts can be safely replaced with no further actions required by the HVACR technician working as an authorized employee. These six steps, especially step #5, is the basis for the phrase LOTOTO, meaning “Lockout, Tagout, Tryout”.
However, things change when the worker is directly exposed to electric shock and/or arc flash.
Transitioning from Indirect to Direct Electrical Exposure from the Same Equipment
Many other tasks on the same HVACR equipment can also bring the hazard of electricity directly into the mix without the employer or employee realizing it, especially where employees are expected to perform a variety of different but similar activities.
For example, sometimes the HVAC technicians are directed to also troubleshoot, then repair components within the electrical power or control circuits, such as changing out a bad motor, contactor, relay, or the heater elements themselves. This seemingly small change in the work scope significantly changes the hazards the workers will now face when working on the same HVACR equipment.
This is because this will now expose them directly to electrical energy in the form of shock and arc flash. While the previous six steps would be adequate for replacement of the non-electrical mechanical parts (pump, drive belts, etc.), they will not be for work on the electrical components.
The same LOTO devices that are placed on the same circuit breakers and disconnect switches followed by an attempt to start the equipment would not be sufficient nor would it be compliant with OSHA regulations when direct exposure to electricity is the threat. At this point, the company’s COHE program must make a shift from 1910.147 Subpart J to the applicable OSHA electrical safety standard by implementing additional LOTO practices pursuant to 1910.333 Subpart S in order to abate the direct electrical hazards.
Work Safely!
In Part 3, we’ll delve deeper into the additional mandatory actions for the HVACR technicians required by OSHA’s electrical LOTO provisions according to 1910.333 Subpart S.
This governance will also apply to any other electrical employees whenever they work on electric parts such as motors, contactors, resistive heaters or any other electrical equipment whenever there is direct exposure to electricity. Doing so will ensure compliance with safety regulations, but, more importantly, it will ensure workers are properly protected from shock and arc flash.
