Pharmaceutical and Medical Packaging News Magazine
PMPN Article Index

Originally Published December 1998

REGULATORY FOCUS

Robot Safety Standards to Improve

ANSI proposal includes more-precise information about safeguards and risk reduction.

Robotics are being used more widely in the healthcare industry, especially in operations at sites that range from warehouses and drug and device production plants to the processing areas of automated pharmacies. Therefore, industry should be aware of the revisions being proposed to the American National Standards Institute (ANSI) robot safety requirements standard (R15.06), which was introduced in 1986 and was last revised in 1992. The comment period was scheduled to end November 10. Roberta Nelson, chairperson of the R15.06 subcommittee on safety, and Jeff Fryman, standards manager of the Robotics Industry Association (RIA), explained the proposed revisions at RIA's 10th Annual Robot Safety Conference, held October 5—8 in Novi, MI.

Comments from those in the robotics industry identified several major weaknesses with the standard. These include the use of open-ended language that is widely interpreted (such as application and risk assessment), a lack of specific safeguarding requirements, and a risk assessment requirement that is difficult to complete. The revision process, now involving more than 40 people, began in February 1995.

The goals are to make the guidelines easier to understand, to gather information on accidents and near accidents, to outline the proper use of robots, to forge doable requirements, and, of course, to improve safety and safeguards. Several issues are being addressed. To ensure robot reliability and safety, operators need to make sure that no failure in any area leads to the machine. The current standard requires a certain electrical configuration—two separate channels of circuitry with a monitor—to meet that goal. The new standard would require such a configuration for the overall system, but not for each individual component so long as a risk assessment has been done properly. Safety circuit performance levels will be established, as will categories of safeguard types. There will also be a requirement for two separate stopping circuits, one an emergency stop and one a safety stop.

The committee has tried to make the standard appropriate for both large and small companies. And it has attempted to harmonize it with European standards where possible.

The standard has been modified to cover all industrial robots, including gantry robots, tabletop robots, and parallel-link manipulators using cables or screw drives.

Instead of relying on attended continuous operation for supervising robots, operators would need to perform attended program verification. The current method allows robots to operate continuously in an automatic mode. The new method would only let them operate for one cycle before being restarted, decreasing the risk of human injury.

The revision also describes axis requirements more clearly and in greater detail. The first (main motion) axis must have a mechanical stop, unless the axis is rotary and maximum operating space is full circle (360°). The next two axes with the most motion or energy must have axis-limiting devices, preferably adjustable mechanical ones.

Robot manufacturers will now be responsible for the following safeguards: barriers, interlocked barriers, interlocking devices used with barriers, safety light curtains, safety mats, safety area scanners, safety hand beams, and two separate hand controls. Information about the design and manufacture of these safeguards must be provided to users. The use of operational safeguards that protect operators during many maintenance tasks is encouraged.

Use of the safeguards, however, is the responsibility of the operator. Requirements for installing and using safeguards are now detailed, and users must either follow the safeguarding requirements described in R15.06 or do a comprehensive risk assessment. If a risk assessment is not done, operators need to follow the minimum safeguards listed as "Category R2" in the ANSI standard and minimum circuit performance listed as "Control Reliable/Dual Channel with Monitoring."

Risk assessment is more clearly defined in the revision, which includes a matrix for setting minimum safeguards and programming, teaching, and operating capability based on risk and hazard. It identifies the category of risk reducing safeguards to be used as well as the circuit performance required.

The committee will respond to the public feedback on the proposal, revise it if necessary, and then submit it to ANSI to become the current standard. If all goes well, the committee's work will be complete at the end of 1998 and the standard will take effect in 1999.

To obtain a copy of the draft standard, contact RIA at 734/994-6088.