[Code of Federal Regulations]
[Title 29, Volume 8]
[Revised as of July 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 29CFR1926.307]
[Page 232-237]
TITLE 29--LABOR
CHAPTER XVII--OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT
OF LABOR
PART 1926_SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION--Table of Contents
Subpart I_Tools_Hand and Power
Sec. 1926.307 Mechanical power-transmission apparatus.
(a) General requirements. (1) This section covers all types and
shapes of power-transmission belts, except the following when operating
at two hundred and fifty (250) feet per minute or less: (i) Flat belts 1
inch (2.54 cm) or less in width, (ii) flat belts 2 inches (5.08 cm) or
less in width which are free from metal lacings or fasteners, (iii)
round belts \1/2\ inch (1.27 cm) or less in diameter; and (iv) single
strand V-belts, the width of which is thirteen thirty-seconds (\13/32\)
inch or less.
(2) Vertical and inclined belts (paragraphs (e) (3) and (4) of this
section) if not more than 2\1/2\ inches (6.35 cm) wide and running at a
speed of less than one thousand (1,000) feet per minute, and if free
from metal lacings or fastenings may be guarded with a nip-point belt
and pulley guard.
(3) For the Textile Industry, because of the presence of excessive
deposits of lint, which constitute a serious fire hazard, the sides and
face sections only of nip-point belt and pulley guards are required,
provided the guard shall extend at least 6 inches (15.24 cm) beyond the
rim of the pulley on the in-running and off-running sides of the belt
and at least 2 inches (5.08 cm) away from the rim and face of the pulley
in all other directions.
(4) This section covers the principal features with which power
transmission safeguards shall comply.
(b) Prime-mover guards--(1) Flywheels. Flywheels located so that any
part is 7 feet (2.128 m) or less above floor or platform shall be
guarded in accordance with the requirements of this subparagraph:
(i) With an enclosure of sheet, perforated, or expanded metal, or
woven wire;
(ii) With guard rails placed not less than 15 inches (38.1 cm) nor
more than 20 inches (50.8 cm) from rim. When flywheel extends into pit
or is within 12 inches (30.48 cm) of floor, a standard toeboard shall
also be provided;
(iii) When the upper rim of flywheel protrudes through a working
floor, it shall be entirely enclosed or surrounded by a guardrail and
toeboard.
(iv) For flywheels with smooth rims 5 feet (1.52 m) or less in
diameter, where the preceding methods cannot be applied, the following
may be used: A disk attached to the flywheel in such manner as to cover
the spokes of the wheel on the exposed side and present a smooth surface
and edge, at the same time providing means for periodic inspection. An
open space, not exceeding 4 inches (10.16 cm) in width, may be left
between the outside edge of the disk and the rim of the wheel if
desired, to facilitate turning the wheel over. Where a disk is used, the
keys or other dangerous projections not covered by disk shall be cut off
or covered. This subdivision does not apply to flywheels with solid web
centers.
(v) Adjustable guard to be used for starting engine or for running
adjustment may be provided at the flywheel of gas or oil engines. A slot
opening for jack bar will be permitted.
(vi) Wherever flywheels are above working areas, guards shall be
installed having sufficient strength to hold the weight of the flywheel
in the
[[Page 233]]
event of a shaft or wheel mounting failure.
(2) Cranks and connecting rods. Cranks and connecting rods, when
exposed to contact, shall be guarded in accordance with paragraphs (m)
and (n) of this section, or by a guardrail as described in paragraph
(o)(5) of this section.
(3) Tail rods or extension piston rods. Tail rods or extension
piston rods shall be guarded in accordance with paragraphs (m) and (o)
of this section, or by a guardrail on sides and end, with a clearance of
not less than 15 (38.1 cm) nor more than 20 inches (50.8 cm) when rod is
fully extended.
(c) Shafting--(1) Installation. (i) Each continuous line of shafting
shall be secured in position against excessive endwise movement.
(ii) Inclined and vertical shafts, particularly inclined idler
shafts, shall be securely held in position against endwise thrust.
(2) Guarding horizontal shafting. (i) All exposed parts of
horizontal shafting 7 feet (2.128 m) or less from floor or working
platform, excepting runways used exclusively for oiling, or running
adjustments, shall be protected by a stationary casing enclosing
shafting completely or by a trough enclosing sides and top or sides and
bottom of shafting as location requires.
(ii) Shafting under bench machines shall be enclosed by a stationary
casing, or by a trough at sides and top or sides and bottom, as location
requires. The sides of the trough shall come within at least 6 inches
(15.24 cm) of the underside of table, or if shafting is located near
floor within 6 inches (15.24 cm) of floor. In every case the sides of
trough shall extend at least 2 inches (5.08 cm) beyond the shafting or
protuberance.
(3) Guarding vertical and inclined shafting. Vertical and inclined
shafting 7 feet (2.128 m) or less from floor or working platform,
excepting maintenance runways, shall be enclosed with a stationary
casing in accordance with requirements of paragraphs (m) and (o) of this
section.
(4) Projecting shaft ends. (i) Projecting shaft ends shall present a
smooth edge and end and shall not project more than one-half the
diameter of the shaft unless guarded by nonrotating caps or safety
sleeves.
(ii) Unused keyways shall be filled up or covered.
(5) Power-transmission apparatus located in basements. All
mechanical power transmission apparatus located in basements, towers,
and rooms used exclusively for power transmission equipment shall be
guarded in accordance with this section, except that the requirements
for safeguarding belts, pulleys, and shafting need not be complied with
when the following requirements are met:
(i) The basement, tower, or room occupied by transmission equipment
is locked against unauthorized entrance.
(ii) The vertical clearance in passageways between the floor and
power transmission beams, ceiling, or any other objects, is not less
than 5 ft. 6 in. (1.672 m).
(iii) The intensity of illumination conforms to the requirements of
ANSI A11.1-1965 (R-1970).
(iv) [Reserved]
(v) The route followed by the oiler is protected in such manner as
to prevent accident.
(d) Pulleys--(1) Guarding. Pulleys, any parts of which are 7 feet
(2.128 m) or less from the floor or working platform, shall be guarded
in accordance with the standards specified in paragraphs (m) and (o) of
this section. Pulleys serving as balance wheels (e.g., punch presses) on
which the point of contact between belt and pulley is more than 6 ft. 6
in. (1.976 m) from the floor or platform may be guarded with a disk
covering the spokes.
(2) Location of pulleys. (i) Unless the distance to the nearest
fixed pulley, clutch, or hanger exceeds the width of the belt used, a
guide shall be provided to prevent the belt from leaving the pulley on
the side where insufficient clearance exists.
(ii) [Reserved]
(3) Broken pulleys. Pulleys with cracks, or pieces broken out of
rims, shall not be used.
(4) Pulley speeds. Pulleys intended to operate at rim speed in
excess of manufacturers normal recommendations shall be specially
designed and carefully balanced for the speed at which they are to
operate.
[[Page 234]]
(e) Belt, rope, and chain drives--(1) Horizontal belts and ropes.
(i) Where both runs of horizontal belts are 7 feet (2.128 m) or less
from the floor level, the guard shall extend to at least 15 inches (38.1
cm) above the belt or to a standard height except that where both runs
of a horizontal belt are 42 inches (106.68 cm) or less from the floor,
the belt shall be fully enclosed.
(ii) In powerplants or power-development rooms, a guardrail may be
used in lieu of the guard required by paragraph (e)(1)(i) of this
section.
(2) Overhead horizontal belts. (i) Overhead horizontal belts, with
lower parts 7 feet (2.128 m) or less from the floor or platform, shall
be guarded on sides and bottom in accordance with paragraph (o)(3) of
this section.
(ii) Horizontal overhead belts more than 7 feet (2.128 m) above
floor or platform shall be guarded for their entire length under the
following conditions:
(a) If located over passageways or work places and traveling 1,800
feet or more per minute.
(b) If center to center distance between pulleys is 10 feet (3.04 m)
or more.
(c) If belt is 8 inches (20.32 cm) or more in width.
(iii) Where the upper and lower runs of horizontal belts are so
located that passage of persons between them would be possible, the
passage shall be either:
(a) Completely barred by a guardrail or other barrier in accordance
with paragraphs (m) and (o) of this section; or
(b) Where passage is regarded as necessary, there shall be a
platform over the lower run guarded on either side by a railing
completely filled in with wire mesh or other filler, or by a solid
barrier. The upper run shall be so guarded as to prevent contact
therewith either by the worker or by objects carried by him. In
powerplants only the lower run of the belt need be guarded.
(iv) Overhead chain and link belt drives are governed by the same
rules as overhead horizontal belts and shall be guarded in the same
manner as belts.
(3) Vertical and inclined belts. (i) Vertical and inclined belts
shall be enclosed by a guard conforming to standards in paragraphs (m)
and (o) of this section.
(ii) All guards for inclined belts shall be arranged in such a
manner that a minimum clearance of 7 feet (2.128 m) is maintained
between belt and floor at any point outside of guard.
(4) Vertical belts. Vertical belts running over a lower pulley more
than 7 feet (2.128 m) above floor or platform shall be guarded at the
bottom in the same manner as horizontal overhead belts, if conditions
are as stated in paragraphs (e)(2)(ii) (a) and (c) of this section.
(5) Cone-pulley belts. (i) The cone belt and pulley shall be
equipped with a belt shifter so constructed as to adequately guard the
nip point of the belt and pulley. If the frame of the belt shifter does
not adequately guard the nip point of the belt and pulley, the nip point
shall be further protected by means of a vertical guard placed in front
of the pulley and extending at least to the top of the largest step of
the cone.
(ii) If the belt is of the endless type or laced with rawhide laces,
and a belt shifter is not desired, the belt will be considered guarded
if the nip point of the belt and pulley is protected by a nip point
guard located in front of the cone extending at least to the top of the
largest step of the cone, and formed to show the contour of the cone in
order to give the nip point of the belt and pulley the maximum
protection.
(iii) If the cone is located less than 3 feet (0.912 m) from the
floor or working platform, the cone pulley and belt shall be guarded to
a height of 3 feet (0.912 m) regardless of whether the belt is endless
or laced with rawhide.
(6) Belt tighteners. (i) Suspended counterbalanced tighteners and
all parts thereof shall be of substantial construction and securely
fastened; the bearings shall be securely capped. Means must be provided
to prevent tightener from falling, in case the belt breaks.
(ii) Where suspended counterweights are used and not guarded by
location, they shall be so encased as to prevent accident.
(f) Gears, sprockets, and chains--(1) Gears. Gears shall be guarded
in accordance with one of the following methods:
[[Page 235]]
(i) By a complete enclosure; or
(ii) By a standard guard as described in paragraph (o) of this
section, at least 7 feet (2.128 m) high extending 6 inches (15.24 cm)
above the mesh point of the gears; or
(iii) By a band guard covering the face of gear and having flanges
extended inward beyond the root of the teeth on the exposed side or
sides. Where any portion of the train of gears guarded by a band guard
is less than 6 feet (1.824 m) from the floor a disk guard or a complete
enclosure to the height of 6 feet (1.824 m) shall be required.
(2) Hand-operated gears. Paragraph (f)(1) of this section does not
apply to hand-operated gears used only to adjust machine parts and which
do not continue to move after hand power is removed. However, the
guarding of these gears is highly recommended.
(3) Sprockets and chains. All sprocket wheels and chains shall be
enclosed unless they are more than 7 feet (2.128 m) above the floor or
platform. Where the drive extends over other machine or working areas,
protection against falling shall be provided. This subparagraph does not
apply to manually operated sprockets.
(4) Openings for oiling. When frequent oiling must be done, openings
with hinged or sliding self-closing covers shall be provided. All points
not readily accessible shall have oil feed tubes if lubricant is to be
added while machinery is in motion.
(g) Guarding friction drives. The driving point of all friction
drives when exposed to contact shall be guarded, all arm or spoke
friction drives and all web friction drives with holes in the web shall
be entirely enclosed, and all projecting belts on friction drives where
exposed to contact shall be guarded.
(h) Keys, setscrews, and other projections. (1) All projecting keys,
setscrews, and other projections in revolving parts shall be removed or
made flush or guarded by metal cover. This subparagraph does not apply
to keys or setscrews within gear or sprocket casings or other
enclosures, nor to keys, setscrews, or oilcups in hubs of pulleys less
than 20 inches (50.8 cm) in diameter where they are within the plane of
the rim of the pulley.
(2) It is recommended, however, that no projecting setscrews or
oilcups be used in any revolving pulley or part of machinery.
(i) Collars and couplings--(1) Collars. All revolving collars,
including split collars, shall be cylindrical, and screws or bolts used
in collars shall not project beyond the largest periphery of the collar.
(2) Couplings. Shaft couplings shall be so constructed as to present
no hazard from bolts, nuts, setscrews, or revolving surfaces. Bolts,
nuts, and setscrews will, however, be permitted where they are covered
with safety sleeves or where they are used parallel with the shafting
and are countersunk or else do not extend beyond the flange of the
coupling.
(j) Bearings and facilities for oiling. All drip cups and pans shall
be securely fastened.
(k) Guarding of clutches, cutoff couplings, and clutch pulleys--(1)
Guards. Clutches, cutoff couplings, or clutch pulleys having projecting
parts, where such clutches are located 7 feet (2.128 m) or less above
the floor or working platform, shall be enclosed by a stationary guard
constructed in accordance with this section. A ``U'' type guard is
permissible.
(2) Engine rooms. In engine rooms a guardrail, preferably with
toeboard, may be used instead of the guard required by paragraph (k)(1)
of this section, provided such a room is occupied only by engine room
attendants.
(l) Belt shifters, clutches, shippers, poles, perches, and
fasteners--(1) Belt shifters. (i) Tight and loose pulleys on all new
installations made on or after August 31, 1971, shall be equipped with a
permanent belt shifter provided with mechanical means to prevent belt
from creeping from loose to tight pulley. It is recommended that old
installations be changed to conform to this rule.
(ii) Belt shifter and clutch handles shall be rounded and be located
as far as possible from danger of accidental contact, but within easy
reach of the operator. Where belt shifters are not directly located over
a machine or bench, the handles shall be cut off 6 ft. 6 in. (1.976 m)
above floor level.
[[Page 236]]
(2) Belt shippers and shipper poles. The use of belt poles as
substitutes for mechanical shifters is not recommended.
(3) Belt perches. Where loose pulleys or idlers are not practicable,
belt perches in form of brackets, rollers, etc., shall be used to keep
idle belts away from the shafts.
(4) Belt fasteners. Belts which of necessity must be shifted by hand
and belts within 7 feet (2.128 m) of the floor or working platform which
are not guarded in accordance with this section shall not be fastened
with metal in any case, nor with any other fastening which by
construction or wear will constitute an accident hazard.
(m) Standard guards--general requirements--(1) Materials. (i)
Standard conditions shall be secured by the use of the following
materials. Expanded metal, perforated or solid sheet metal, wire mesh on
a frame of angle iron, or iron pipe securely fastened to floor or to
frame of machine.
(ii) All metal should be free from burrs and sharp edges.
(2) Methods of manufacture. (i) Expanded metal, sheet or perforated
metal, and wire mesh shall be securely fastened to frame.
(n) [Reserved]
(o) Approved materials--(1) Minimum requirements. The materials and
dimensions specified in this paragraph shall apply to all guards, except
horizontal overhead belts, rope, cable, or chain guards more than 7 feet
(2.128 m) above floor, or platform.
(i) [Reserved]
(a) All guards shall be rigidly braced every 3 feet (0.912 m) or
fractional part of their height to some fixed part of machinery or
building structure. Where guard is exposed to contact with moving
equipment additional strength may be necessary.
(2) Wood guards. (i) Wood guards may be used in the woodworking and
chemical industries, in industries where the presence of fumes or where
manufacturing conditions would cause the rapid deterioration of metal
guards; also in construction work and in locations outdoors where
extreme cold or extreme heat make metal guards and railings undesirable.
In all other industries, wood guards shall not be used.
(3) Guards for horizontal overhead belts. (i) Guards for horizontal
overhead belts shall run the entire length of the belt and follow the
line of the pulley to the ceiling or be carried to the nearest wall,
thus enclosing the belt effectively. Where belts are so located as to
make it impracticable to carry the guard to wall or ceiling,
construction of guard shall be such as to enclose completely the top and
bottom runs of belt and the face of pulleys.
(ii) [Reserved]
(iii) Suitable reinforcement shall be provided for the ceiling
rafters or overhead floor beams, where such is necessary, to sustain
safely the weight and stress likely to be imposed by the guard. The
interior surface of all guards, by which is meant the surface of the
guard with which a belt will come in contact, shall be smooth and free
from all projections of any character, except where construction demands
it; protruding shallow roundhead rivets may be used. Overhead belt
guards shall be at least one-quarter wider than belt which they protect,
except that this clearance need not in any case exceed 6 inches (15.24
cm) on each side. Overhead rope drive and block and roller-chain-drive
guards shall be not less than 6 inches (15.24 cm) wider than the drive
on each side. In overhead silent chain-drive guards where the chain is
held from lateral displacement on the sprockets, the side clearances
required on drives of 20 inch (50.8 cm) centers or under shall be not
less than \1/4\ inch (0.635 cm) from the nearest moving chain part, and
on drives of over 20 inch (50.8 cm) centers a minimum of \1/2\ inch
(1.27 cm) from the nearest moving chain part.
(4) Guards for horizontal overhead rope and chain drives. Overhead-
rope and chain-drive guard construction shall conform to the rules for
overhead-belt guard.
(5) Guardrails and toeboards. (i) Guardrail shall be 42 inches
(106.68 cm) in height, with midrail between top rail and floor.
(ii) Posts shall be not more than 8 feet (2.432 m) apart; they are
to be permanent and substantial, smooth, and free from protruding nails,
bolts, and splinters. If made of pipe, the post shall be 1\1/4\ inches
(3.175 cm) inside diameter,
[[Page 237]]
or larger. If made of metal shapes or bars, their section shall be equal
in strength to that of 1\1/2\ (3.81 cm) by 1\1/2\ (3.81 cm) by \3/16\
inch angle iron. If made of wood, the posts shall be two by four (2 x 4)
inches or larger. The upper rail shall be two by four (2 x 4) inches, or
two one by four (1 x 4) strips, one at the top and one at the side of
posts. The midrail may be one by four (1 x 4) inches or more. Where
panels are fitted with expanded metal or wire mesh the middle rails may
be omitted. Where guard is exposed to contact with moving equipment,
additional strength may be necessary.
(iii) Toeboards shall be 4 inches (10.16 cm) or more in height, of
wood, metal, or of metal grill not exceeding 1 inch (2.54 cm) mesh.
(p) Care of equipment--(1) General. All power-transmission equipment
shall be inspected at intervals not exceeding 60 days and be kept in
good working condition at all times.
(2) Shafting. (i) Shafting shall be kept in alignment, free from
rust and excess oil or grease.
(ii) Where explosives, explosive dusts, flammable vapors or
flammable liquids exist, the hazard of static sparks from shafting shall
be carefully considered.
(3) Bearings. Bearings shall be kept in alignment and properly
adjusted.
(4) Hangers. Hangers shall be inspected to make certain that all
supporting bolts and screws are tight and that supports of hanger boxes
are adjusted properly.
(5) Pulleys. (i) Pulleys shall be kept in proper alignment to
prevent belts from running off.
(6) Care of belts.
(i) [Reserved]
(ii) Inspection shall be made of belts, lacings, and fasteners and
such equipment kept in good repair.
(7) Lubrication. The regular oilers shall wear tight-fitting
clothing. Machinery shall be oiled when not in motion, wherever
possible.
[58 FR 35176, June 30, 1993, as amended at 69 FR 31882, June 8, 2004]
