Safety standards being written today not only provide guidance to help reduce the risk of injury or equipment damage, but also improve productivity in the workplace. The ANSI/ASSE Z244.1-2003 (R2008)1 and ANSI/PMMI B155.1-20062 standards are two examples of how standards promote safe work environments as well as making it possible for companies to increase productivity.
The ANSI/ASSE Z244.1- 2003 (R2008) Control of Hazardous Energy Lockout/Tagout and Alternative Methods standard addresses the need of manufacturers to reduce the time involved in performing safety procedures, while increasing the degree of safety provided. In the past, a routine task of clearing a simple jam could require a worker to spend considerable time commuting to different locations on a machine to perform lockout on multiple energy sources.
In the time-equals-money equation, this results in operators taking short cuts. These short cuts could include missing some lockout points and not locking out all the energy sources connected to the machine. Since lockout points are there to help prevent the equipment from being energized, neglecting one or more of the lockout tasks could very likely increase the risk of worker injury or equipment damage. The present ANSI/ASSE Z244.1-2003 (R2008) standard addresses this issue by allowing (in certain situations) for reducing the number of required lockout locations to one, which can be located near the operator.
When properly implemented, such a single-point lockout can provide an excellent safety solution and while minimizing machine downtime occassioned by a lockout event. To accomplish these dual goals, the system must use a dedicated control system with a dual-channel, low-voltage lockable switch, dual control-reliable relays and control-reliable components.
The term used for reducing the number of lockout locations to one is called Single-Point Lockout (SPLO). This alternative method may only be used for tasks that are part of the normal production and operation of the machine, and a risk assessment must be done for a given task to determine if the task qualifies for SPLO.
Why is SPLO so popular? It reduces the chance that an operator may miss or skip locking out an energy source when he/she is rushed to lockout the machine. Providing better assurance that lockouts will be properly used increases the safety for the operator and equipment. In addition, SPLO reduces the time required to put the machine into a safe mode.