At the Emerson Exchange America’s Virtual Series, Emerson’s Jeff Welker discussed products and solutions for machine safety. Here is his presentation abstract:
Machine Safety is demanded by international machine directives, guidelines and human sense. Emerson provides a full range of products and solutions to fulfill the individual application needs. Furthermore, our technical experts are supporting customers to find the best solution in functional safety. In this presentation, you will get a Short introduction to Machine Safety, you will see some examples of basic pneumatic circuits, learn the Components as safety-related parts of control and what Safety components meet the machinery directive.
Jeff opened making a distinction between process safety and machine safety. A safety demand in a process may be once per year where a safety demand for machine safety may be once per month. Availability is critical in continuous processes, where machines often run on schedules and have periods of scheduled downtime.
The goal in machine safety is safe pneumatic motion. This motion must be considered and mitigated to a safe level. Some of the directives and standards include Machinery Directive 2006/42/EC, Standard EN/IEC 62061 (machine-based SIL) and Standard EN/ISO 13849-1: Safety of Machinery-Safety-related parts of control systems. ISO 13849 is the predominant standard globally.
He showed an architecture of safety-related parts.
Category 3 and 4 are key ones where machine automation technology plays an important role.
ISO 13849 is a performance-based standard and requires the support of a category, which defines the architecture of the system. A performance level (PL)-based standard provides ways to eliminate or mitigate the hazardous motion.
Pneumatic machine safety products include point-of-use solutions, discrete component solutions and fieldbus valve system solutions.
Point of use devices are used in lockout tagout (LOTO) to release energy from the machine. They dump air and are used at the front end of a machine, used in lower demand applications, and are typically lower in cost.
Discrete components are used in the stopping of motion. They provide complete stopping of pneumatic motion and pneumatic energy is trapped. These are typically used in higher demand applications with a single actuator implementation.
Manifold systems such as fieldbus valve systems are used to release energy. The are used in multi-actuator implementation and combine safety rated and non-safety rated valves. They are typically used in higher demand applications and are most cost effective as the number of actuators increase.
Jeff shared an example of a zoned safety manifold solution to provide a safe release of energy. This application included a manifold housing both safety-related valves and valves for normal machine operations.
He closed by noting the U.S. National Safety Council (NSC) estimate that the direct costs of a life-threatening injury to be approximately a million dollars or more. Indirect costs such as workplace disruptions, loss of productivity, worker replacement, training, and increased insurance costs and legal fees may run 2 to 17 times more.
Visit the Machine Safety section on Emerson.com for more on these and other products to help drive safer machine operations.