Machine Safety
Chapter 296-806, WAC |
Effective
Date: 01/01/05 |
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Safeguarding Methods
Guards
WAC 296-806-20042
Make sure guards meet these requirements
You must
- Make sure guards do not
create additional hazards such as sharp edges or pinch points
between the guard and moving machine parts.
- Make sure guards are:
- – Made of durable materials
- – Strong enough to withstand the
forces to which they are exposed
- – Securely fastened to the machine,
if possible, or to the building structure if they cannot
be attached to the machine
- Make sure guards protect employees by doing
both of the following:
- – Preventing hands or other body
parts from reaching through, over, under, or around the
guard into the hazard area
and
- – Preventing objects or debris from
falling onto or being thrown towards an employee.
- Make sure barrier guards:
- – Are properly installed, adjusted,
and maintained
- – Have no
opening at any point larger than shown in Table
200-1, Largest Allowable Guard Opening
| 
|
Reference:
Metal cutting shears are allowed
to be guarded with properly applied awareness barrier
safeguarding as described in ANSI B11.4-1993,
Sections 6.3.3. |
Table
200-1
Largest Allowable Guard Opening (inches) |
| If the distance (A) from hazard to the guard
is |
Then the opening (B) in the guard or between
the table and the guard can not be greater than |
| ½ to 1 ½ |
¼ |
| 1 ½ to 2 ½ |
3/8 |
| 2 ½ to 3 ½ |
½ |
| 3 ½ to 5 ½ |
5/8 |
| 5 ½ to 6 ½ |
¾ |
| 6 ½ to 7 ½ |
7/8 |
| 7 ½ to 12 ½ |
1 ¼ |
| 12 ½ to 15 ½ |
1 ½ |
| 15 ½ to 17 ½ |
1 7/8 |
| 17 ½ to 31 ½ |
2 1/8 |
| Over 31 ½ |
6 |
This diagram illustrates the information
found in Table 200-1. The size of the opening
in the guard, or between the bottom edge of the guard and the
feed table is small enough to prevent any part of the operator’s
body from reaching the hazardous area.
Illustration
200-1
DISTANCE FROM HAZARD TO GUARD (A)

WAC
296-806-20044
Make sure devices meet these
requirements
You must
- Make sure devices used to safeguard employees
do either of the following:
- – Stop the motion of a moving part
before an employee comes in contact with it and has to be
manually reset before machines can be restarted
or
- – Be designed and constructed to
prevent the operator from having any part of their body
in the danger zone during the hazardous part of the operating
cycle.
| 
|
Reference:
For more information on installation
of safety devices, see Performance Criteria for
Safeguarding, ANSI B11.19-2003. |
WAC 296-806-20046
Make sure light curtains meet
these requirements
IMPORTANT:
All devices must meet the general
requirements for devices found in Make sure devices meet these
requirements, WAC 296-806-20044.
You must
- Make sure light curtains, when used:
- – Respond to the presence of an
operator’s hand, other body part, or a work piece
- – Have indicators that are easily
seen by the operator showing when the device is functioning
or has been bypassed.
| 
|
Note:
Even if a shiny reflective object
or work piece is used with a light curtain or other
electro-optical device, it should still respond to the
operator’s hand or other body part |
You must
- Make sure only authorized persons can make
the following adjustments to light curtains:
- – Variations in operating conditions
- – Fixed or channel blanking
- – Floating blanking (sometimes referred
to as floating channel or floating window features)
- Safeguard access to the point of operation
that is not protected by light curtains.
| 
|
Reference:
For more information on light curtains
and their requirements, see Performance Criteria for
Safeguarding, ANSI B11.19-2003. |
WAC
296-806-20048
Make sure pressure-sensitive
mats meet these requirements
IMPORTANT:
All devices must meet the general
requirements for devices found in Make sure devices meet these
requirements, WAC 296-806-20044.
You must
- Make sure pressure-sensitive mats:
- – Detect the presence or absence
of the operator or others
- – Send the stop command and prevent
successive machine cycles if any single component fails
- – Are connected with the machine
control system so the device’s stop signal immediately
stops action of the machine tool and requires use of the
start control before the machine can begin another cycle
- – Are located so that the operator
can not reach the recognized hazard before
hazardous motion has stopped
- – Have an indicator easily seen
by the operator that shows the mat is operating.
WAC
296-806-20050
Make sure restraint or pullback
devices meet these requirements
IMPORTANT:
All devices must meet the general
requirements for devices found in Make sure devices meet these
requirements, WAC 296-806-20044.
You must
- Make sure restraint or pullback devices:
- – Prevent the operator from reaching
into the point of operation or withdraw the operator’s
hands from the point of operation before motion of the machine
creates a hazard
- – Have fasteners, pins, and other
items used to secure and maintain the setting of the device
applied in a way that minimizes loosening, slipping, or
failure during use
- – Are worn inside gloves, if used,
so if a glove becomes trapped inside a machine or tool,
the device can still remove the operator’s hand from
the hazard area.
WAC
296-806-20052
Make sure two-hand devices
meet these requirements
IMPORTANT:
All devices must meet the general
requirements for devices found in Make sure devices meet these
requirements, WAC 296-806-20044.
You must
- Make sure two-hand devices:
- – Protect each hand device against
accidental operation
- – Require simultaneous operation
of both hand devices to begin the cycle, including the first
cycle (automatic mode)
- – Are provided with an anti-repeat
feature when used in single cycle mode
- – Have a set of devices for each
operator if more than one needs to be safeguarded
- – Are located far enough from the
nearest hazard so the operator can not
reach the hazard before hazardous motion stops.
| 
|
Reference:
For more information on proper
installation of safety devices, see Performance
Criteria for Safeguarding, ANSI B11.19-2003. |
WAC
296-806-20054
Make sure devices used with
barrier guards meet these requirements
IMPORTANT:
All devices must meet the general
requirements for devices found in Make sure devices meet these
requirements, WAC 296-806-20044.
You must
- Make sure movable barrier devices:
- – Return to the open position if
they encounter an obstruction while enclosing the hazardous
area
- – Are designed so the operator or
others cannot reach the hazard by reaching over, under,
around or through the device when it is in the closed position.
- Make sure interlocks used with barrier guards
do all of the following:
- – Stop hazardous motion of machines
when interlocks are open
- – Are not easily
bypassed
- – Are designed and installed so
that closing the interlocks won't cause a hazard to employees.
WAC
296-806-20056
Make sure safeguarding by distance
meets these requirements
You must
- Make sure means used to safeguard by distance
do both of the following:
- – Prevent parts or material from
falling on employees below
and
- – Separate employees on fixed ladders,
stairs, floors, or other walking or working surfaces from
the hazard by:
- More than 7 feet vertically
or
- A horizontal distance that prevents
employees from contacting or being injured by the
hazard according to the distances in Table
200-2.
Table 200-2
helps you identify either the required horizontal distance from
the hazard to the barricade (B), or the required height of the
barricade (C), as long as you know A and either variable, B or
C.
Table
200-2
Safe Distances for
Fixed Barricades (B)
Height of the Barricade
(C)
| |
96 |
86 |
78 |
71 |
63 |
55 |
48 |
40 |
| 96 |
0 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
| 86 |
|
10 |
14 |
16 |
20 |
20 |
24 |
24 |
| 78 |
|
|
14 |
20 |
24 |
28 |
36 |
43 |
| 71 |
|
|
|
24 |
36 |
36 |
40 |
43 |
| 63 |
|
|
|
20 |
36 |
36 |
40 |
51 |
| 55 |
|
|
|
4 |
32 |
36 |
40 |
55 |
| 48 |
|
|
|
|
20 |
36 |
40 |
55 |
| 40 |
|
|
|
|
12 |
36 |
40 |
55 |
| 32 |
|
|
|
|
|
24 |
36 |
51 |
| 24 |
|
|
|
|
|
|
20 |
48 |
| 16 |
|
|
|
|
|
|
12 |
48 |
| 8 |
|
|
|
|
|
|
8 |
43 |
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Note:
- The height and distance requirements
of Table 200-2 are designed to
safeguard workers from a fixed hazard. If a hazard involves
flying chips, fluids, parts or materials, the barrier
height, distance, and construction may need to be adjusted
to provide adequate protection.
|
Illustration
200-2
HOW TO MEASURE VARIABLES FOR TABLE 200-2

Examples:
- If the height of the hazard (A) is
78 inches, and the horizontal distance from the hazard to the
barricade (B) is 14 inches, the required height of the barricade
(C) is 78 inches.
- If the height of the hazard (A) is 86 inches,
and the height of the barricade (C) is 55 inches, then the required
horizontal distance from the hazard to the barricade (B) is
20 inches.
WAC
296-806-20058
Make sure guardrails used for
safeguarding meet these requirements
| 
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Note:
- Guardrails may be used to safeguard:
- – Flywheels
- – Cranks and connecting rods
- – Tail rods and extension
piston rods
- – Horizontal belts in a power
generating room
- – Clutches, cutoff couplings,
or clutch pulleys in an engine room occupied only
by an attendant
- – Power transmission parts
on a runway used only for oiling, maintenance, running
adjustment, or repair work.
|
You must
- Make sure top rails are:
- – Smooth-surfaced
- – Strong enough to withstand a force
of at least 200 pounds
- – Between 39 and 45 inches above
the floor, platform, runway, or ramp
- Make sure guardrails have an intermediate
rail (midrail) installed approximately halfway between the top
rail and the floor, platform, runway, or ramp
- Make sure rails don't extend beyond the end
posts of the guardrail and create a projection hazard
- Make sure toe boards, if required by this
chapter to safeguard a machinery hazard, are:
- – At least 4 inches high
- – Securely fastened in place with
no more than ¼ inch between the bottom of the toe
board and the floor, platform, runway, or ramp
- – Made of substantial material that's
either solid or that has openings in the material no larger
than one inch.
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