The Alternative Universe of Lockout/Tagout

On the surface, at least, machine lockout/tagout (LOTO) appears simple: Identify and isolate energy sources, lock and tag, and perform the procedure that needs to get done.

Simple, right? Wrong.

When energy is required to complete machine diagnostics or set-up work, or when a minor maintenance job is going to throw production hours behind schedule, LOTO becomes something far more complex than a textbook explanation.

Once you understand its intricacies, it is understandable why LOTO, as outlined in OSHA standard 29 CFR 1910.147 ”The Control of Hazardous Energy (Lockout/Tagout), has become an everyday struggle for many safety personnel. And why LOTO ranks among OSHA’s top ten violations, year after year. It is also understandable why industry is fast embracing the concept of “Alternative Measures”.

OSHA 29 CFR 1910.147 requires employees to remove power sources to a machine that could otherwise result in personal injury if energy were unintentionally released during maintenance or service. It clearly states facilities are responsible for establishing a written program covering how required safety measures will be applied. This includes provisions for developing machine-specific energy control procedures, training authorized workers to protect themselves with lockout/tagout, and for periodic inspections of the adequacy of the written procedures, along with the performance of personnel applying them.

As comprehensive as LOTO may be, it can be very time-intensive, often requiring longer than is required to finish the actual maintenance task on the machine. Production comes to a halt, resulting in the day’s production numbers potentially being missed. This becomes even more frustrating when the maintenance task is one that must be implemented several times a day. Loss of time and profits create a strong incentive to bypass LOTO to carry out repetitive machine tasks. However, it still violates OSHA requirements and puts workers in serious danger.

Thankfully, OSHA 29 CFR 1910.147 also outlines “Alternative Protection Measure” (APM) procedures that can result in increased efficiency without compromising the safety of the operation. This exception is also referred to as the “minor servicing exception”. Designed for machine tasks that demand frequent repetitive access, i.e., clearing a jam on a conveyor or a minor tool change, Alternative Measures do not require that power sources be completely cut off. Examples of Alternative Methods technology may include key-controlled locks, control switches, interlocked guards, remote devices and disconnects. It can also mean locking out just a section of a piece of equipment, rather than the entire machine.

The newest ANSI standard, ANSI/ASSE Z244.1 (2016) The Control of Hazardous Energy – Lockout, Tagout and Alternative Methods, agrees with OSHA in that workers should be protected from injury due to unexpected equipment startup or release of potentially hazardous energy. However, the ANSI committee did not try to align fully with every historic OSHA compliance requirement. Instead, the new standard gives expanded guidance beyond OSHA’s regulatory limitation to tasks that are “routine, repetitive and integral to production operations”.

ANSI makes it very clear that LOTO shall be used unless the user can demonstrate that a well-established alternative method will provide effective protection. In situations where the task is not well understood or risk assessed, lockout shall be the default protective measure applied to control machinery or processes. Section 8.2.1 of ANSI/ASSE Z244.1 (2016) specifies that alternative methods shall only be used after hazards have been assessed and documented through the application of a Practicability (or Justification) Study to determine that the techniques used will result in a negligible risk or no risk for sudden start up. Following the Hierarchy of Control model, ANSI/ASSE Z244.1 (2016) provides detailed guidance on if, when, and how a range of alternative control methods can be applied to result in equal or improved protection for people performing specific tasks. In addition, alternative risk reduction methodology is covered in detail specific to a number of new technologies including the Packaging, Pharmaceutical, Plastics, Printing, and Steel Industries; Semiconductor and Robotic Applications and others challenged by the current regulatory limitations.

Since the two standards are somewhat conflicting it is best to review ANSI first to help identify discrepancies that may not meet federal minimum regulations.

At this point, it would be appropriate to underscore that LOTO provides the greatest level of protection and, whenever possible, it should be utilized to protect employees from hazardous energy. In other words, inconvenience alone is not an acceptable excuse to use alternative measures. In addition, CFR 1910.147 clearly states that an allowable alternative measure must provide the same or greater level of protection as LOTO. Otherwise, it is considered noncompliant and therefore insufficient to replace LOTO.

By using standard safety-rated devices, such as interlock gates and e-stop buttons, a plant manager can achieve safe, reliable machine access that replaces standard LOTO procedures without violating OSHA requirements. Implementing alternative procedures to ensure equivalent protection for specific tasks can enhance productivity without endangering employees. But those procedures — and their benefits — come with strings attached, requiring a thorough understanding of the latest OSHA and ANSI standards.

Press Brake Safeguarding Basics

Press Brakes are currently a hot topic in the “Machine Safeguarding” arena. OSHA regulations consider press brakes to be a 1910.212 machine, saying to the employer; “one or more methods of machine guarding shall be provided to protect the operator and other employees in the machine area from hazards such as those created by point of operation, in-going nip points, rotating parts, flying chips, and sparks” … 1910.212 requirements are good place to start, but they leave out the details of exactly how to go about safeguarding any particular machine. Therefore, a reference to an ANSI Standard like B11.3 on press brakes is often used to identify specific safeguarding alternatives. ANSI B11.3 may however need some help from ANSI B11.19 on safeguarding methods, to provide a complete picture of how to go about protecting people.

Older press brakes, like those manufactured in the mid-1980’s and before, were mechanical (flywheel-type) machines, some of which are still in use today. Because the stopping times on mechanical press brakes are long, equally long light curtain safety-distances result, making that safeguarding device impractical in many cases.

Press brakes manufactured after the mid-1980’s are much more likely to be hydraulic. Hydraulic press brakes allow for a wider variety of safeguarding options than mechanical press brakes do, and offer faster stopping-times, resulting in closer safety-distances where light curtains or two-hand controls are used.

A common method of safeguarding press brakes is with a vertically mounted infra-red light curtain. Hydraulic press brakes allow for short stopping times so that a light curtain can be mounted relatively close to the dies.

Two-hand controls on press brakes are often used in the sequence-mode of operation where the actuators bring the machine down and stop before the dies close, allowing just enough die-space to feed the part. The part is placed in the remaining die-opening, then a foot-switch is used to make the bend and return the machine to its full-open position.

Safety distance is required for both light curtains, and two-hand controls. That distance must be calculated with a stop-time measurement (STM) device on a quarterly basis. STM readings must be documented to show safety inspectors.

ANSI B11.3 which was updated in 2012, offers two completely new categories of protection for hydraulic press brakes: Active Optical Protective Devices (lasers) and Safe Speed Safeguarding. Active Optical Protective Devices (AOPDs) detect hands and fingers in a danger area. The biggest attraction for AOPDs are for jobs where the operator must hand hold small parts up close to the dies. A unique feature of AOPDs is that that they are designed to be mounted with zero safety distance, unlike light curtains that must be mounted at a calculated safety-distance, as outlined in ANSI B11.3. Safe Speed Safeguarding is based on a ram speed of 10mm per second or less, providing that speed is carefully monitored. Again, these two new methods of protection can only be applied to hydraulic press brakes (and potentially Servo-Drive Press Brakes).

The Lazersafe® Sentinel Plus is the most advanced guarding solution available designed specifically for hydraulic press brakes. The Lazersafe ties directly into the machine’s existing hydraulic and electric control circuits, providing a Category 4 solution. The Lazersafe is CE rated and allows machine operators to hold workpieces within 20mm of the point of operation. Encoder feedback ensures that the speed and position of the tooling is continuously monitored, and a 4.3” HMI provides machine operators immediate feedback of all vital functions. The Lazersafe Sentinel Plus is compatible with a wide variety of machines and tooling types, material thickness and easily allows for box shapes to be formed.

The backs of press brakes cannot be left wide open. Two hazards exist often exist here. The first is reaching the dies from the back. The second is the possibility of a multi-axis back gauge moving and creating pinch points. As to exactly what is required on the back of equipment often depends on local OSHA interpretation. The very least, an awareness barrier, like a railing, chain, or cable with a “Danger” or “Warning” sign, complete with Pictograms, not just verbiage. (see photo)

For local OSHA interpretations that won’t accept awareness barriers, a full perimeter guard may be the answer for the back of a press brake. That guard can either be bolted into position, or if it’s movable, an electrical interlock switch can be installed to make sure it stays closed.

As with any industrial machine, Lockout/Tagout on Press Brakes must strive for “Zero Energy State” to and within each piece of equipment using both locks and tags.

Also mentioned in the ANSI standard is die safety blocks; please see our related blog post on “Demystifying Die Safety Blocks”.

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