Increasing efficiency through safety standards

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 & ANSI/PMMI B155.1-2006 2 standards are two examples of how standards promote safe work environment as well as make 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 energised, 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) 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 while minimising machine downtime occasioned 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 such as a ROSS DM2 series double valve, for example. 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 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.

Time = money

One company using Ross’ DM2 series valve was able to reduce lockout time by more than four minutes on a particular machine that averaged eight jams per shift! That is 32-minute more of uptime per shift, or an hour and thirty-six minutes per day. Amazingly, this adds up to a full 8-hour shift of additional production time over a five-day period. The ANSI/PMMI B155.1-2006 safety requirements for packaging machinery and packaging-related converting machinery standard address safety requirements for packaging machinery and packaging-related converting machinery. The standard now requires that safety shut-off and exhaust valves, which shut off and release pressure from the various systems during times of maintenance, need to be:

• lockable only in the off position
• easy to operate
• equipped with an exhaust port having exhaust capacity equal to or greater than the capacity of the supply port, and
• equipped with a visible pressure indicator

In some situations, there can be a false perception that the air has been quickly and totally dissipated when a shut-off and exhaust valve gets shut off, even when the valve only has a small bleed vent for an exhaust port as is the case with most ball valves used in most common packaging applications. The requirement of having a full exhaust port helps avoid this situation. For example, when exhausting one cubic foot of 100 psig compressed air, a fully ported one-inch valve will dump the air in 1.2 seconds as opposed to a one-inch ball valve with a vented exhaust, which will exhaust over a period of four minutes. An operator might not realise that it could take so long to exhaust the system and might begin the task at hand before the air is fully exhausted. Having a valve with a full-size exhaust port will help avoid this situation. In addition to the increased level of safety, the time-equals-money equation begs the question: What is the value to minimising downtime for a particular task (by 99.5 per cent in this example)? The ROSS L-O-X valve complies with all the requirements of ANSI/PMMI B155.1-2006 including the full-size exhaust port, while the majority of vented ball valves do not. Standards promote safety and uptime. Safety + uptime in production = money, an equation that meets with ANSI/ASSE Z244.1-2003 (R2008) and ANSI/PMMI B155.1-2006 standards.