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3.1.3 Supplemental Safeguarding
As described in
Calculating the Safety Distance (Minimum
Distance)
on page 11, the EZ-SCREEN Type 2 must be properly
positioned such that an individual cannot reach through the
defined area and access the hazard point before the machine has
stopped.
Additionally, the hazard cannot be accessible by reaching around,
under, or over the defined area. To accomplish this, supplemental
guarding (mechanical barriers, such as screens or bars), as
described by ANSI B11.19 safety requirements or other
appropriate standards, must be installed. Access will then be
possible only through the defined area of the EZ-SCREEN Type 2
System or through other safeguarding that prevents access to the
hazard (see
Figure 4
on page 15).
The mechanical barriers used for this purpose are typically called
"hard (fixed) guarding"; there must be no gaps between the hard
(fixed) guarding and the defined area. Any openings in the hard
(fixed) guarding must comply with the safe opening requirements
of ANSI B11.19 or other appropriate standard.
Figure 4
on page 15 shows an example of supplemental safeguarding inside a robotic work cell. The EZ-SCREEN Type 2, in conjunction
with the hard (fixed) guarding, is the primary safeguard. Supplemental safeguarding (such as a horizontal-mounted safety light screen as
an area guard) is required in areas that cannot be viewed from the reset switch (for example, behind the robot and the conveyor).
Additional supplemental safeguarding may be required to prevent clearance or trapping hazards (for example, a safety mat as an area
guard between the robot, the turntable, and the conveyor).
WARNING: The Hazard Must Be Accessible Only through the Defined Area
The installation of the EZ-SCREEN Type 2 must prevent any individual from reaching around, under, over or
through the defined area and into the hazard without being detected. Mechanical barriers (for example, hard
(fixed) guarding) or supplemental safeguarding may be required to comply with this requirement, and is described
by ANSI B11.19 safety requirements or other appropriate standards.
3.1.4 Other Considerations
Reset Switch Location
The reset switch must be mounted at a location that complies with the warning and guidelines below. If any hazardous areas are not
in view from the switch location, additional means of safeguarding must be provided. The switch should be protected from accidental or
unintended actuation (for example, through the use of rings or guards).
A key-actuated reset switch provides some operator or supervisory control, as the key can be removed from the switch and taken into
the guarded area. However, this does not prevent unauthorized or inadvertent resets due to spare keys in the possession of others, or
additional personnel entering the guarded area unnoticed. When considering where to locate the reset switch, follow the guidelines
below.
WARNING: Reset Switch Location
When considering where to locate the reset switch, you must follow the guidelines outlined in this section.
If any areas within the guarded area are not visible from the reset switch, additional safeguarding must be
provided, as described by the ANSI B11.19 series or other appropriate standards.
Failure to follow these instructions could result in serious injury or death.
All reset switches must be:
•
Outside the guarded area
•
Located to allow the switch operator a full, unobstructed, view of the entire guarded area while the reset is performed
•
Out of reach from within the guarded area
•
Protected against unauthorized or inadvertent operation (such as through the use of rings or guards).
www.bannerengineering.com - Tel: 763.544.3164
EZ-SCREEN
Figure 4. An example of supplemental safeguarding
®
Type 2 Light Screen
15
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