Are LOTO, Machine Guarding and OSHA Compliance Interconnected?

Understanding the high level approaches to removing hazardous energy from machinery is vitally important to employee safety and OSHA compliance. This article provides brief introduction into the Lock Out Tag Out approach and Machine Guarding.

Is physically opening the main disconnect switch and locking it in the open position, i.e. LOTO (LockOut/TagOut), the only option when servicing machinery? The answer, it would appear, is no. There are codes and standards in the US and overseas that permit other options. In this article we will discuss the general approach in the US for addressing the hazards associated with operating and servicing machinery, as well as update the community regarding a new standard under development, UL6420, which provides requirements for isolation devices.

Lock Out/Tag Out

OSHA regulation 29 CFR1910.147 directly addresses the need to remove hazardous energy from machinery for the protection of service and maintenance personnel. There are some exceptions of scope such as oil rigs and construction machinery and the standard also allows for minor servicing.

The purpose for requiring LOTO is easy to understand;  remove the energy, be it electrical, mechanical, hydraulic or any other means of energy, and therefore, remove the hazard associated with that energy. Despite this requirement a Bureau of Labor Statistics survey on injuries related to servicing equipment, 80 percent of workers surveyed failed to turn off the equipment before performing the service work. An effective program for LOTO should ensure (but by no means be limited to) the following:

• Management support — Substantial and genuine commitment from management — as in all safety related issues – is the number one factor.  Management commitment sets the tone and communicates to all employees that the safety program, including Lock Out/Tag Out should be taken seriously.
• Equipment inspection — A trained individual thoroughly familiar with the equipment and the hazards should perform and inspect.
• ID and Label – Devices that are under lockout should be identified and labeled.
• Procedures — A standard written operating procedure that all employees are trained on and follow.  The Procedure should include generic procedures or specific procedures applicable to each machine if necessary. The important point is that all machinery may not have the same procedure.
• Ongoing review — Periodic review of the program should be conducted. Is the program effective? Is it being used, is it being used effectively?

Lock Out/Tag Out, Isolation and UL6420

In some cases it may be necessary to allow use of isolated parts of the equipment while servicing other parts. NFPA 79, the Electrical Standard for Industrial Machinery, Clause 5.5.4 and Article 430.109(A)(7) of NFPA 70, the National Electric Code, provide guidance guidance on wiring a machine to allow personnel to lock out part of the equipment but not the entire equipment if applicable.  These standards all specify the use of traditional motor circuit switches, molded case switches and circuit breakers. However at the request of, and in collaboration with industry, UL is preparing to send out to ballot a standard, UL6420, titled Equipment Used for System Isolation and Rated as a Single Unit.

This means that this standard, if approved,  will provide a means for evaluating and certifying equipment to serve as isolation equipment required per 29 CFR 1910.147 and referenced in NFPA 70 and 79 as noted above. It also means that the equipment may include a remote operation that opens the operating contactor and provides for monitoring of the isolation. Although the standard is only open for initial ballot, if accepted by the voting members of the standard technical panel this will provide an industry consensus standard that allows for remote lockout switches with monitoring.

Machine Guarding and Safeguarding

Although the Lock Out /Tag Out requirements quite easily lend themselves to definite requirements as we have included in this article, by its nature machine guarding is more specific to the design, hazards and operation of the machine. Therefore, OSHA doesn’t give you the step-by-step instructions but outlines the goals. The OSHA web site provides the requirements and also provides excellent guidance on the concepts and techniques for safeguarding mechanical motion. Ultimately the OSHA approach is that industry recognized evaluation and reduction methods are used when feasible. One of the more notable standards with regards to guards and safeguards is ANSI B11.19 Performance criteria for Safeguarding.

Some important points from B11.19 are included below.

The point-of-operation of an industrial machine is defined as that part of the machine where the work is performed on the material being processed. Typically the point of operation, i.e where the work is being performed, is the area of greatest concern from a safety standpoint. Therefore the point-of-operation safeguarding is important.

Point-of-operation safeguarding is usually designed with two primary objectives:

1. Prevent human access during hazardous machine motion

2. Prevent hazardous machine motion during human access

ANSI B11.19 identifies five primary choices for point-of-operation safeguarding, as well as several secondary methods that can be used to complement the primary methods. The five primary methods of protection are: guards, devices, distance, location, and opening.

A guard is defined as an enclosure that provides a physical barrier to prevent an operator from reaching into the point-of-operation hazard. This includes both inadvertent access and intentional entry.

Safeguarding devices are controls or attachments that are intended to prevent inadvertent access by employees to hazardous machine areas. Examples include light curtains, two hand actuators, gates, safety mats, emergency stop devices and other devices.

In order to properly address the hazards and subsequently institute the guarding that will mitigate the risks, it’s important to do a thorough risk assessment. A risk assessment will help identify, quantify, prioritize and ultimately reduce the risks to allow for proper operation and maintenance of the machine.

Conclusion

 The proper use of the combination of Lock Out /Tag Out and machine guarding and safeguarding provides an effective approach to avoid serious accidents in operating and servicing equipment.  Although this information is only an overview it is our intention that it help industry in understanding the requirements and begin reducing the incident rate.

For further information on Lock Out /Tag Out, Machine Guarding and Safeguarding, UL6240 or Risk Assessments please contact Kevin Connelly at UL: call 631-546-2691 or e-mail kevin.connelly@ul.com

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