Lockout/Tagout, Part 1
Since the inception of its enforcement program, OSHA has relied on the General Duty Clause (Section 5(a)(1) of the OSH Act) to ensure that employers safeguarded their maintenance and service employees from the hazards involving the unintentional release of hazardous energy through the use of lockout/tagout (also called LOTO) devices. Lockout/tagout violations reached a level so significant that the development and promulgation of a lockout/tagout standard was required.
OSHA's "Control of Hazardous Energy" (29 CFR 1910.147), which was promulgated on September 1, 1989, and made effective on January 2, 1990, specifically addresses practices and procedures necessary to disable machinery or equipment and to prevent the release of potentially hazardous energy while maintenance and servicing activities are being performed. The standard, as specified in 29 CFR 1910.147(b), applies to any source of mechanical, hydraulic, pneumatic, chemical, thermal or other energy. Depending on the manufacturing processes occurring in your plant, lockout/tagout may be required in several areas. In this series, I will discuss those specific to heat-processing manufacturing operations and equipment.
Facilities that use thermal processes must take precautions to follow lockout/tagout procedures. "In my 12 years as a safety manager in the chemical process industry, I have always required that heat, regardless of severity, be considered a 'hazardous energy source,'" says Bryan Haywood, manager of industrial safety services at PSARA Technologies, Cincinnati, and webmaster of www.safteng.net, a free safety site.
Heated ExamplesHaywood describes a case at a chemical processing plant where workers were just minutes into a confined space entry into a double-jacketed vessel when the monitor alarm sounded for a high lower explosive limit (LEL) percentage. Investigation into the alarm found that the hot oil coils were not isolated per standard operating procedure (SOP) and that an operator-in-training turned on the wrong hot oil system. This sent 900oF (482oC) heat transfer oil into the coils of the entry vessel, which is 50' high with about a 40' radius.
The workers were in the very center working on the agitator and had no idea that the upper heat system had been turned on. Unfortunately, they entered from the top manway, which forced them to travel through the vapors for quite some time, exposing them to both chemical and flammable/explosive hazards. "They could have been severely injured," Haywood says.
Investigation showed the root cause as being failure to isolate all recognizable energy sources that could potentially be hazardous to the entrants. While the standard operating procedure called for the coils to be isolated per the lockout/tagout standard, the existing devices did not lock out all potential hazardous sources.
When dealing with lockout of coils to vessels, Haywood says, "My belief is that everything to and from that space must be isolated to zero energy, including the coils on the other side of the jacket wall."
Another case Haywood remembers further supports his position. In this case, the workers were testing coils for leaks and decided to pressure test them with nitrogen rather than using plain water. When the nitrogen was forced into a still-leaking tube during testing, it passed into the vessel, thereby exposing the workers. "You name it, it can happen," Haywood says. "Had LOTO [lockout/tagout] been followed, this incident would not have occurred."
These examples underline the very reason the standards and rules are in place: to protect your company and its employees. In the second part of this series, I will outline OSHA's lockout/tagout inspection guidelines as well as what questions your employees should anticipate regarding your company's lockout/tagout training program should an OSHA compliance officer ask. I also will discuss lockout vs. tagout and the types of devices that can be used to control hazardous energy sources.