1910.216
Mills and calenders in the rubber and plastics
industries
a. General requirements.
(1) [Reserved]
(2) [Reserved]
(3) Auxiliary equipment. Mechanical and
electrical equipment and auxiliaries shall be installed in
accordance with this section and Subpart S of this
part.
(4) Mill roll heights. All new mill
installations shall be installed so that the top of the
operating rolls is not less than 50 inches above the level on
which the operator stands, irrespective of the size of the
mill. This distance shall apply to the actual working level,
whether it be at the general floor level, in a pit, or on a
platform.
(b) Mill safety controls -
(1) Safety trip control. A safety trip
control shall be provided in front and in back of each mill. It
shall be accessible and shall operate readily on contact. The
safety trip control shall be one of the following types or a
combination thereof:
(i) Pressure-sensitive body bars. Installed
at front and back of each mill having a 46-inch roll height or
over. These bars shall operate readily by pressure of the mill
operator's body.
(ii) Safety triprod. Installed in
the front and in the back of each mill and located within 2
inches of a vertical plane tangent to the front and rear rolls.
The top rods shall be not more than 72 inches above the level
on which the operator stands. The triprods shall be accessible
and shall operate readily whether the rods are pushed or
pulled.
(iii) Safety tripwire cable or
wire center cord. Installed in the front and in the back of
each mill and located within 2 inches of a vertical plane
tangent to the front and rear rolls. The cables shall not be
more than 72 inches above the level on which the operator
stands. The tripwire cable or wire center cord shall operate
readily whether cable or cord is pushed or
pulled.
(2) [Reserved]
(3) Auxiliary equipment. All auxiliary
equipment such as mill divider, support bars, spray pipes, feed
conveyors, strip knives, etc., shall be located in such a
manner as to avoid interference with access to and operation of
safety devices.
(c) Calender safety controls
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(1) Safety trip, face. A safety triprod,
cable, or wire center cord shall be provided across each pair
of in-running rolls extending the length of the face of the
rolls. It shall be readily accessible and operate whether
pushed or pulled. The safety tripping devices shall be located
within reach of the operator and the bite.
(2) Safety trip, side. On both sides of the
calender and near each end of the face of the roll, there shall
be a cable or wire center cord connected to the safety trip.
They shall operate readily when pushed or
pulled.
(d) Protection by location
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(1) Mills. Where a mill is so installed that
persons cannot normally reach through, over, under, or around
to come in contact with the roll bite or be caught between a
roll and an adjacent object, then, provided such elements are
made a fixed part of a mill, safety control devices listed in
paragraph (b) of this section shall not
apply.
(2) Calenders. Where a calender is so
installed that persons cannot normally reach through, over,
under, or around to come in contact with the roll bite or be
caught between a roll and an adjacent object, then, provided
such elements are made a fixed part of a calender, safety
control devices listed in paragraph (c) of this section shall
not apply.
(e) Trip and emergency switches. All trip and
emergency switches shall not be of the automatically resetting
type, but shall require manual resetting.
(f) Stopping limits -
(1) Determination of distance of travel. All
measurements on mills and calenders shall be taken with the
rolls running empty at maximum operating speed. Stopping
distances shall be expressed in inches of surface travel of the
roll from the instant the emergency stopping device is
actuated.
(2) Stopping limits for mills. All mills
irrespective of the size of the rolls or their arrangement
(individually or group-driven) shall be stopped within a
distance, as measured in inches of surface travel, not greater
than 1 1/2 percent of the peripheral no-load surface speeds of
the respective rolls as determined in feet per
minute.
(3) Stopping limits for
calenders.
(i) All calenders, irrespective of size of
the rolls or their configuration, shall be stopped within a
distance, as measured in inches of surface travel, not greater
than 1 3/4 percent of the peripheral no-load surface speeds of
the respective calender rolls as determined in feet per
minute.
(ii) Where speeds above 250 feet per minute
as measured on the surface of the drive roll are used, stopping
distances of more than 1 3/4 percent are permissible. Such
stopping distances shall be subject to engineering
determination.
[39 FR 23502, June 27, 1974, as amended at 49
FR 5323, Feb. 10, 1984; 61 FR 9227, March 7,
1996]
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