4
©SAFETY STANDARDS®
The following rules and regulations have been adopted by the Industrial Board, of the
Pennsylvania Department of Labor and Industry, subject to the provisions of the law, [Act
267, section 15, P. L. 1913) which provides that persons affected may petition the Board for
changes in the regulations. Upon the receipt of such petition, it will be reviewed by the
Board and if considered necessary a public hearing will be called in regard thereto.
POWER TRANSMISSION
The word (SHOULD) where used is;
to be understood as advisory and
as mandatory.
Note: Unless otherwise provided for
by regulations approved by the In
Uustrial Boar 1, the following safety
regulations for transmission of power
shall apply also to all power driven
machinery having exposed collars, set
screws, shafts, couplings, clutches, keys,
pulleys, gearing and belts.
Emergency Stops—A station or sta
tions siust be provided in each room,
section or department to stop immedi
ately all power transmission therein.
Buch station or stations shall be prop
erly marked and easily accessible. The
prompt stoppage of machinery is an
emergency is hastened by allowing the
full load to remain on all machines.
Set Collars shall be cylindrical, and
the screws used to fasten the same to >
tie shaft shall not project beyond the
largest periphery of the collar.
Split Collars." after assembly, shall
conform to the above specifications for
solid collars.
All projecting set screws in moving
parts of machinery shall be removed
and replaced by tlush set screws.
Horizontal Shafts less than six feet
from the tloor or working platform lev
el including dead ends of same, shall;
be guarded, or protected by standard
railing, as provided for horizontal belts,
Shafts less than twenty feet in j
heights over driveways above floor or ;
ground level shall be guarded.
Vertical Shafts shall be encased or
guarded to a height of six feet from
tloor or working platform, or be guard-,
ed by a Standard Railing with not less
than 15 inches clearance.
Revolving Shaft Couplings shall be
cylindrical, and bolts used shall not
project beyond the largest periphery of
Coupling or its projecting daiiges.
Clamp Couplings —Heads and nuts
of all bolts in clamp couplings shall
not project beyoud the largest per
iphery. It is recommended that the use
of this style of Coupling be discour
aged unless guarded by a cylindrical
sleeve, the full length of the Coupling.
New installations of such Couplings
must be guarded by a cylindrical sleeve
the full length of Coupling.
Jaw Clutch Couplings shall be pro
vided with a cylindrical sleeve to cov
er the jaws.
Universal and Flexible Couplings
ehall be guarded in a manner to re
move all hazard.
Friction Clutch Couplings shall have
their operating mechanism completely
guarded where exposed.
All projecting Keys in revolv ag
shafts, where ex[>o«e 1 to contact, shall
be made flush oi shall be guarded.
Pulleys—When the bearings are not
self-oiling and the clearance between
the pulley and bearing on line shafting
is 3(5 inches or less, pulley shall be
compieteiv guarded on side nearest
hearing and all key ways in shaft be
tween such pulley and bearing shail be
substantially encased or properly filled.
All parts of Pulleys within seven,
feet of floor or working platform level
shall be guarded underneath, or pro
tected by a Railing as provided for
horizontal belts. Where the space ice
tween two Pulleys or between a Pulley
and a bearing is less than the width of
the widest belt used, such space shall
be guarded so that the belt cannot get
between the Pulleys or between the
Pulley and bearing. A flanee on site of
pulley-nearest bearing, or adjacent pul
ley, Will he considered a guard.
On Counter Shafts, the space be
tween pulleys and the nearest bear
ing shall uot be less than the width
of the belt used unless such space is
properK* guarded. A flange on side o r
pulley nearest bearing, or adjacent pul
iey, will be consi iered a guard.
Gears—All toothed, chain driven anil
t-procket gearing used in the transmis
sion of power or on machinery snail be
completely enclosed wherever practic-J
able, otherwise, a: teast to base of
teeth.
It is strongly re ommended that pul-1
leys, gears, sprockets, sheaves, etc.,
having spake arm- should be guarded
bv discs, as nearly as possible tlush
with rims of wheeU. All friction drives
ttaall oe completely guarded.
Belts—Vertical and inclined belts
extending to within -,x feet of floor or'
working platform level shall be sub- j
stantially guarded as follows:
If guard is placed less than six
inches from belt, w;ta an enclosure on 1
all sides, not over 1-2 inch between |
members to a height of six feet above
floor or working platform. If guard is
placed between 6 inches and Id inches
in clearance from belt, with an enclos-;
ure on all sides, not over 2 inches be
tween members to a height of 6 feet
above floor or working platform.
A standard railing may be used if i
placed to allow 15 inches clearance;
from the belt.
Where belts pass through floor, a j
standard toe board shall protest floor j
opening.
If upper part of horizontal belt is
less than 6 feet from floor level or
working platform it shall be guarded on
top and sides or provided with a stand
ard railing at least 15 inches horizon
tally from the edge of the belt.
Overhead belts with lower part 7
feet or less from floor or working plat-,
form level, shall be guarded on sides:
and bottom.
Passageways between upper and low
er parts of belts are prohibited unless
special permit is granted by the De
partment of Labor and Industry, Space
traversed by such belt shall be com-:
pletely barred again*t passage. Over- !
head belts 10 inches or more in width ]
and more than 7 feet from floor or I
working platform shall be guarded un-1
I derneath in such a manner as to insure:
the safety of persons below.
Hereafter no change belts shall be
. • laced with metal.
Shifters shall be provided for all
tight and loose pulleys and clutches.
Shifting and disengaging levers,
when suspended overhead shall be ar
ranged to haag vertically when belt is
on loose pulley, or clutch is disengaged.
Belt shifters shall be automatically
held so that the belt will not creep
from loose to tight pulley.
All controls for stopping machines
shall be within convenient reach of the ;
operator from any operating positiou.
Mechanical shifters for change belts
are strongly recommended.
Lubrication—Loose pulleys shall
have oiling devices so arranged as to
permit oiling, in any position of loose
pulley when machinery is shut down.
An efficient system of self-oiling is
recommended for all bearings. Shafting
shall not be oiled by hand while in mo
tion.
Drip cups and pans shall be securely '
fastened.
Oiling shall be done only by author- j
ized and experienced persons, properly
clothed and in accordance with approv
( ed and safe practice.
Starting Signals—Ample notice
should be given before transmission
machinery is started by means of an
! efficient alarm or signal.
Inspection—All power transmission
equipment should be given careful and
thorough inspection at frequent and
regular intervals, and records kept of
such inspection.
Caution. It is unlawful to remove
guards from machinery, except when t
| shut down, and in that case the guards
must be repla ed before starting.
STANDARD RAILINGS
Standard Railings shall be not less
than three and one-half feet high, and
be provided with an additional rail
midway between the top rail and the
floor, and shall be constructed in a
permanent and substantial manner.
If constructed of pipe, shall be not
!es< than 1 1-4 inches inside diameter.
If constrained of structural metal or
bars, their section shall be at least
equal to that of 1 1-2 xl 1-2x3-16
angles.
If constructed of wood, the posts.
shall be not less than 2x4 inches or its
equivalent section, having rails not less
than 7-Bx6 inches or its equivalent sec
tion.
Posts and uprights shall be spaced
not more than 8 feet apart.
Tne rails when of metal shapes, met
al bars or wood should be placed on the
side of the posts that will afford the
greatest support and protection.
One or more sides may be hinged,
preferably with self-closing gates.
. Railings already installed, if of sub-1
stautial construction and proper posi-1
tion and approved by the Department !
of Labor and Industry, will be accept- j
ed. although not permitted in new in- !
i stallations.
Where panels are filled with substan- j
tial expanded metal or wire mesh, the
middle rails may be omitted.
Toe Boards—ln addition to standard
railings a toe board or toe piece, 6
inches high of wood or metal, shall be
provided at working platforms, bal-1
conies and galleries if 6 feet or more !
I above floor level.
Floor openings and hoistways.
Fly wheel and pulley pits.
All other openings in floors and plat-,
forms where the safety of persons be-1
low is involved.
STATIONARY STEAM ENGINES
By stationary steam engines it meant
an engine normally in one place and
1 used regularly for furnishing motive
power, farm and saw mill portable en
gines. portable hoisting engines, pumps;
i used by contractors aTe not classed as j
stationary engines.
Xote —Xn ese standards are to be con-1
sidered as also applicable to gas en-;
gines, pump engines and air compres-1
i sors. if their construction is such as jp j
bring them within the scope of these |
1 requirements.
I AmrJe notice should be given before
machinery is started by the use of an !
efficient alarm or signal,
i All steam, gas and hot air pumping!
! engines and air compressors, shail have
all exposed collars, set screws, shafts, |
couplings, clutches, keys, pulleys, gears,)
fly wheels and belts guarded as speci- j
iied in Vol. 1, No. 1, for the transmis- j
sion of power by the industrial board.
| unless other regulations have been ap
| proved for special cases.
Automatic Stops—lt is recommend
j ed that an approved type of automatic
engine stop, with speed limit device, be
I put on all stationary engines of more
| than 500 h. p.
Xo live steam connections should be
made to the receiver of a compound I
engine without a reducing valve, set
so that the pressure will be well with- j
in the safe working pressure of the re-;
i ceiver and of the low pressure cylinder.
Such receiver shall be equipped with '
one or more safety relief valve of !
ample capacity, adjusted to a pressure
well within the safe working pressure
j of the receiver and of the low pressure,
cylinder. These valves shall be provid-,
ed with facilities for testing, such as!
a hand lever.
Jet condensers shall be provided with !
vacuum breakers to prevent water from ;
entering the engine cylinders. Steam
I traps used to discharge waiter from
steam Separators shall be so installed
that their operation will be evident.
HARRISBURQ STAR-INDEPENDENT, THURSDAY EVENING, DECEMBER 31. 1914.
Each engine shall be equipped with
an efficient governor which will at all
times automatically control the speed
of the engine uuder varied loads, ex
cept where the load itself acts as an
efficient governor. AH belts or rope
driven governors shall be equipped with
a device for stopping the engine in case
the belt or rope should break.
Vale gear she'll be so arranged, or,
other provisions shall be made, that in
the event of the load being removed,
the engine will stop if the governor
would fall to act. (A broken belt stop
will be considered sufficient for slide or
four-valve engines).
Positive uu-aiis shall be provided for
blocking vertical and large orizontal
engines, compressors, and pumps. dur
ing adjustments and repairs.
A safe method should be provided for
turning over engines by hand.
Stationary stairs or iron ladders
shall be provided for access to su.-h
emergency valves as cannot be operat
ed from the floor or other accessible
place.
Platforms and walks on engines shall
have standard railings and toe guards.
This applies also to the engine bed
along side of the connecting rod or
crosshead, when it is used as a foot
walk.
Provisions should be made where
practicable for oiling all engine bear
ings, journals, eccentrics, crank pins,
etc.. from outside the guard railings.
All power transmission equipment
should be given careful and thorough
inspection at frequent and regular in
tervals. and complete records kept of
such inspections. __
MACHINE TOOLS
Note—Unless otherwise provided for
by regulation* approved by the indus
trial board, all lathes, planers, milling
machines, boring mills, metal saws,
key sea ting machines, shapers, slotters.
gear cutter, drill presses, and all other
machine tools shall have all gears,
sprockets, chains, bands, belts, pulleys,
clutches, wheels, shafting, spindles,
couplings, clutches, counterweights, re
volving and reciprocating parts and all
as specified in Volume 1. No. 2. Rules
and Regulations for the Transmission of
Power.
The use of safety dogs is strongly
recommended. Set screws aud bolt heids
shall be made flush or shall be guarded.
All new installations of face plates,
chucks and collets, shall be cylindrical
with no projecting parts, on rim or'
periphery-
Face plates, chucks and collets now 1
in use having projecting parts on rim
or periphery -hall be encased, guarded
with hinged or other effective guard.
The use of drills on dead centers un
less securely fastened there, should not
be permitted.
Cams and other automatic parts shall j
be carefullv guarded.
On hollow spindle lathes bar stocks
should be guarded full length.
Chip guard* should be provided on
lathes and ether machines for the pro
tection of nearby persons as well as the
operator, "where there is an eye hazard
by reason of flying chips or cuttings.
Goggles will be considered adequate
protection for operator.
Eye protection, in all lathe, machine
and grinding work shall be carefully
considered.
All openings in bed frames shall be j
covered with sheet metal, expanded
metal or wire mesh aprons, securely j
fastened in place. Openings in housings;
shall be filled or guarded.
Not less than 24 inches clearance
shall be provided at both ends and sides i
of planers for planer bed. the work be
ing machined and its chucking.
If clearance is less than 24 inches, 1
clearance space shall be guarded with
standard railings.
Floor openings and pits shall be
guarded with standard railings and toe
boards.
Attention is called to hazard attend- j
ing the practice of reversing planing,
table by hand, except when absolutely j
necessary in setting up work.
Counterweights shall be .placed in.
wells or securely guarded for their en
tire travel.
FORGING AND STAMPING MA
CHINERY
Note—l'nless otherwise provided for ;
by regulations approved by the Indus-!
trial Board, all fonging, pressing, form
ing and stamping machines, shall have
all exposed collars, set screws, shafts,
couplings, clutches, keys, pulleys, gears
and belts guarded as provide,! for tin
Volume 1, No. 1, Rules and Regulations
for the Transmission of Power.
A locking device shall be provided
for presses and shears to prevent the
machine coming into action premature
ly or while the tools are being set.
Where tight and loose pulleys are used,
the locking device may be applied to
the same instead of to the machine.
Where direct motor-drive is used the
switch shall be secured in an open
position.
On all cold work a positive guard,
which is controlled bv the moving ram
is recommended for blanking, drawing
and forming presses operating on cold
material. The guard should be arrang
ed to throw the operator's hands away
from the danger zone.
Sheet material presses for stamping,
blanking, forming, trimming, sharing
and punching should, where the nature
of the work permits, have an inclined
bed or have an automatic or roll feed.
If neither false fingers, sliding dies,
double trips, soft metal plyers, or
work holders using compressed air or
suction for handling of the material
operated on, are us«l, then guards of
' metal strips, metal netting or plate
glass to protect the operator are recom
' mended: the same being either fixed or
automatic.
A positive disengaging device for
clutches is recommended.
All hammers oj»erated by steam, air,
gravity or stationary, shall be provid
ed with positive locking devices so that
when the ram is at the top or the bot
tom of its stroke, it cannot be acci
dentally moved.
Every steam and air hammer-shall
be provided with a stop valve in the
admission pipe line, which must be
closed, preparatory to, ami during the
! repair of the hammer or while changing
dies.
Extreme care shall be talcen in mak
ing and using hammer die keys on all
power hammers to see that they are
not only of suitable material, but that
they are driven into place with due re
gard to the safety of the operator and
of the neighboring workmen.
It is suggested that hammer die keys
be made of open hearth material (Mn.
.40 to .50 per ceot.; C .50 to .60 per
cent.); that they be machined accu
rately to tit notches; and. that the ends
be tempered to prevent spreading, up
setting or breaking. The ends of keys
shail be redressed when necessary.
POIiISHING AND GRINDING MA
CHINERY
Note—Ail polishing and grinding
machines shall have all exposed collars,
. set screws, shafts, couplings, clutches,
keys, pulleys, gears, fly wheels and
belts gears as specified in Volume 1,
Xo. 1. for the Transmission of Power by
the Industrial Board.
Grinding wheels are to !>e under
stood as wheels composed of a prac
tically uniform mixture of an abrasive
material and a bonding cement, formed
or molded into a single piece. This does
not include grinding wheels of natural
stone.
Polishing wheels are to be under
stood as wheels composed of -material
other than abrasive, to all or a portion
of whose surface an abrasive material
is applied.
Disc grinders haviug discs of steel,
iron or equally strong material are
classed as polishing wheels with respect
to safety of operation.
Grinding Wheels—The use of defec
tive grinding wheels is prohibited.
Grinding wheels shall fit freely on
their spindles. Thev should never be
forced on, nor should they be too loose.
A clearance of .005 inch is recommend
ed.
The soft metal bushings shall not
extend beyond the sides of the wheels
at their centres. Wheels shall be kept
•is true as practicable and work rests
f-hall be kept adjusted close to wheels.
Wherever )>ossiible, a compressible
medium, such as blotting paper, rubber,
lead, etc.. at least as large as the dia
meter of the flanges, shail be fitted be
tween a wheel and each of its flanges.
Flanges For Grinding Wheels—Each
flange whether straight or tapered must
be relieved or recessed at the centre at
least 1-16 inch on the side next to the
wheel for a distance as provided in
Table B.
The maximum and minimum dimen
sions of flanges and the minimum dia
meter of flat spot at centre of wheel,
as given in Tables A and B must be
observed.
Tapered Flanges for Emery Wheels
A—Maximum flat spot at centre of
flange.
B Minimum flat spot at centre of
wheel.
C—Minimum diameter of flanges.
D—Minimum thickness of flange at
bore tor wheels 1 inch or less in
thi-kne^.
K—Simc a» D but for wheels over
1 inch m thickness.
TABLE A
Tapered Flanges and Tapered Wheels
ABC D E
soi>: ii I s \ |
f • • 1 3 in
.5 • • ' ■' iu
,o ' 4 ® in.
® .... in
is 1 ••••
18 4 5 12 % !°-
|2 J 5 \\ 3&
•U A - 2 ••••
1 ? I s •••• % in.
oo t - r'® ■ * in.
30 5 24 • ••
° • • • • '£ in.
TABLE B
Straight flanges and Straight Wheels
—' Jz r' ' r. ' Koi
£ 'Z a, £ : S
5 11 '& : %z
® jo , £ "
t ? c ' !- > S £
- £ ! s £
1 :§| : = Ii;
2 a ~ | 5 |2 °
6 2 in. 1 in. %
8 3 in. 2 in. %
10 3 M in. 2 in. %
12 4 in. in.
14 4 in. 3 in. 14
16 5 % in. 3Vi in. V 4
18 6 in. \ ' 4 in. %
20 7 in. 4 Vg in. %
22 7 in. 5 in. %
24 8 in. 5 in. %
2ti 8 Vi in. 6 in. %
28 10 in. 7 in. %
30 10 in. 7 in. *4
Flanges shall be made of steel or
other equally strong material.
Both flanges in contact with a wheel
' shall be of the same diameter.
New installations of tapered flanges
1 shall have a taper of not losb than 3-8
i inch (preferably 3-4 inch) to the foot
on each flange and where a flat spot is
used it shall conform to dimensions set
forth in above table. But one taper
should' be used iu any one establish
ment.
If but one tapered flange is used,
the taper shall be 1 1-2 inchos to the
foot.
Wherever possible only 2 inches of
1 the wheel should project beyond the
flanges where the wheel is over 10
inches in diameter.
All grinding wheels shall conform to
the dimensions for flanges as set forth
i in above table.
The surface of wheels in coutaet
. with straight or tapered flanges, the
| surface of flanges in contact with
! wheels and the compressible material
between flanges and wheels shall be
1 clean, smooth and free from foreign
! material.
jj *
Q or £
I
TafiereJ Fianjes far Emery iVAee/*
Protection For Grinding Wheels—
Either substantial tapered
flanges, or both, sufficiently strong to
retain the pieces of a wheel in case of
breakage and so designed as to leave
exposed the least portion of the wheel
compatible with the work in hand shall
be fitted to all grinding machines.
Precision Grinding Machines—Pre
cision and tool grinding machines shall
be thoroughly guarded where possible.
Proper champing devices and hoods
shall be applied to precision grinding
machines where the diameter of the
hole in the wheel will not permit the
application of the specifications for
guards elsewhere set forth in these
regulations.
Cup and Cylinder Grinding Wheels—
Cup ami cylinder grinding wheels shall
be surrounded, as much as operating
conditions will allow, cither by a sub
stantial hood or be retained by a chuck
which surrounds the periphery at lean
3-4 the height of the rim of the wheel.
All specially shaped wheels shall be
substantially guarded.
Arbors, Fixed Collars and Machines
—The protruding end of the arbor and
its nut shall be guarded.
Arbor bearings shall be of ample
size and shail be kept carefully adjust
ed and lubricated.
Arbors of floor, bench and swing
frame grinding machines for wheels' 12
inches or more in diameter, shall have
flsed collars not less than 1-3 the di
ameter of the wheel being used.
Floor and bench grinding machines
shall be rigidly constructed and se
curely fastened to a suitable founda
tion.
Grinding wheel manufacturers shall
furnish information regarding speeds
at which wheels are recommended to
operate safely.
Wheels must not be operated at a
speed in excess of that which is recom
mended by the manufacturer.
Eye Protection—Approved eye pro
tection shall be provided for operators
on grinding wheels if the operation in
volves the possibility of eye injury.
BLOWERS AND EXHAUSTERS FOB
GRINDING AND POLISHING
MACHINERY
Not#—All blowers and exhausters
shall have all exposed collars, sert. screws,
shafts, couplings, clutches, keys, pulleys,
gears, fly wheels and belts guarded as
specified in Volume 1, No. 1, for the
transmission of jower by the industrial
board.
Suction Test—Sufficient suction head
shall be maintained in each branch
pipe within 15 inches of the 'hoods to
displace a minimum of two inches of
water column in a U-shaped ttfbe. Pres
sure to b« taken bv pressing tube at
tachment over small opening through
jwpe, commonly called static method.
Tests to be made with all branches
open and unobstructed.
Piping—'Round pipe shall be used for
all main ducts and brancib connections
unless some other form is specifically
approved by the Commissioner' of 1/a
i>or and Industry. All branch pipes
must enter the main trunk pipe at an
angle of 45 degrees or less. All bends,
turns, or elbows in such pipes must be
made with easy, smooth surfaces having
a radius in the throat of not less than
two diameters of the pipe on which they
are connected. No branch pipe shall
extend into the main duct and all laps
shall be made in the direction of air
flow.
Emery wheel and buffing wtheel ex
haust systems shall be kept separate
owing to danger of sparks from the
former setting fire to the lint dust from
the latter, if both are drawn into the
same suction main.
The inlet of the exhauster shall be
at least 20 per cent, greater in area
than the 'combined areas of the sev
eral connections to the hoods, and this
increase in the main 'pipe shall be car
ried proportionately throughout the
entire trunk line. The piping on the
outlet of the fan is also to be at
20 per cent, greater than the combined
areas of the several connections to the
hoods.
The area of the main duet at any
point should 'be equal as near as pos
sible to the combined areas of all
| branch pipes to that point, plus the
| necessary 2o per cent, excess area. In
general not more than two branches
should be connected to a section of
; uniform diameter in the main duct.
The use of Screens across tJhe mouth
of branch pipes is prohibited.
'Phe withdrawal of air from a room
I by an exhaust system tends to create a
vacuum and for this reason sufficient
I inlets for air shall be left open.
The main trunk lines shall be provid
ed with suitable clean-cuts not over
ten feet apart and the end of the main
trunk line shall be blanked off with a
removal cwp placed on the end.
The sizes of the branch pipes leading
to the hoods for polishing and grinding
wheels shall be as follows:
Diameter of
Diameter of Wheels Branch Pipe
From 6 in. up to and including
16 in 4 in.
More than 16 in. up to and in
cluding 24 in 5 in.
More than 24 in. up to and in
cluding 30 in., 6 in.
For rag wheels the following di
mensions shall be used:
Diameter of
Diameter of Wheels Branch Pipe
Up to and including 6 in 3 in.
More than 6 in. up to and in
eluding 12 in., 4 in.
More than 12 in. up to and in
cluding 16 in., 4 % in.
More than 16 in. up to and in
cluding 24 in 5 in.
More than 24 in. up to and in
cluding 30 in 6 in.
Plans
Pluns for all blower installations
should be submitted to this department
in duplicate for approval before work
is commenced aud it should be clearly
specified that the ijystem is to be in
stalled iu strict accordance with the
above rules and regulations.
These plans should show the diameter
of all wheels, dimensions of all piping,
and should also show the general con
struction of hoods to be used. These
rules ami regulations as set forth above
should be complied with before the
system will be acceptable to the Depart
ment of Labor and Industry.
Note—The above rules and regula
tions ahal) not apply to Grinding Ma
chines upon which water is used at the
point of the grinding contact, nor shall
they- apply to any factory or workshop
where men are not employed continu
ously at such wheels or belts more than
three hours in twenty-four.
AIR COMPRESSORS
Note—All air compression machin
ery shall have all exposed collars, set
screws, shafts, couplings, clutches, kevs,
pulleys, gears, fly wheels and belts
guarded as specified in Volume I, No.
1, for the transmission of power and
air compressors shall have fly wheels,
tail rods, i ranks and other dangerous
moving parts guarded as specified in
Volume 1, Xo. 2, for the use of stand
ard railings and toe boards by the In
dustrial Board.
Pneumatic Hammers—New in starva
tions of pneumatic hammers shall be
totted witli a device to prevent the pis
ton from leaving the cylinder.
Portable Pneumatic Drills—l n new
installations every portable pneumatic
drill and pneumatic wood-boring ma
chine shall be provided with an auto
matic device to stop the machine and
prevent accidental starting when the
operator's hand i 3 removed from the
controlling valve.
Pipe Connections for Compressed Air
A straightway valve shall be fitted in
new installations where a valve is re
quired in a pipe line between a com
pressor and its air tank.
Where a stop valve is placed in dis
charge line between a compressor and
an air tank a spring pop safety valve
shall be placed between the compressor
and such stop valve.
Air Tanks-—The design and con
struction of air tanks shall conform »to
specifications approved by this depart
ment. A drain cock shall be fitted at
the lowest part of each air tank and
the accumulated oil and water shall
'be frequently withdrawn.
BLOWERS AND EXHAUSTERS
Note— All blowers and exhausters
shall have all exposed collars, set
screws, shafts, couplings, clutches, keys,
■pulleys, gears and belts guarded as pro
vided for by the regulation for tho
transmission of power, unless other reg
ulations have been approved toy tho
Industrial Board for special cases.
Suction Test—Sufficient suction head
shall be maintained in each branch
pjpe within 15 inches of the hoods to
displace a minimum of two inches of
water column in a U-shaped tube.
Pressure to be taken bv pressing tube
attachment over small opening through
pipe, commonly called static method.
Tests to be made with all branches open
and unobstructed.
Piping—Bound pipe shall be used
for all main ducts ajul branch connec
tions, unless some other form is spe
cifically approved by the Commissioner
of Labor and Industry. All branch
pipes must enter the main trunk pipe
at an angle of 45 degrees or less. All
bends, turns or elibows in such pipes
must be made with easy, smooth sur
faces having a radius in the throat of
not less than two diameters of the pipe
on which they are connected. Xo
'branch pipe shall extend into the main
duct and all laps shall be made in the
direction of air flow.
Emery wheel and buffing wheel ex
haust systems shall be kept separate
owing to danger of sparks from the
former setting fire to the lint dust
from the latter, if both are drawn into
the same suction main.
The inlet of the exhauster shall be at
least 20 per cent, greater in area than
the combined areas of the several con
nections to the hoods, and this in
crease in the main pipe shall be car
ried throughout the en
tire trunk line. The piping on the out
let of the fan is also to be at least.
20 per cent, greater than the combined
areas of the several connections to tho
hoods.
The area of the main duet at any
point should be equal as near as pos
sible to the combined areas of all
branch pipes to that point, plus the nec
essary 20 per cent, excess area. In
general not more ♦han two branches
should be connected to a section of uni
form diameter in thu main duct.
The use of screens across the mouth
of branch pipes is prohibited.
The withdrawal of air from a room
'by an exhaust system creates a vacuum
and for this reason sufficient inlets for
air shall be left open.
The main trunk lines shall be pro
vided with suitable cle-anouts not over
10 feet apart and the end of the main
trunk line shall be blanked off with a
removal cap placed on the end.
The sizes of the branch pipes lead
ing to the hoods for polishing and
grinding wheels shall be as follows:
Diameter of
Diameter of Wheels Branch Pipe
From 6 in. up to and including
16 in • 4-ia-
More thiin 16 in. up to and in
cluding 24 in., _. . a in.
More than 24 in. up to and in
cluding 30 in., 6 in.
For rag wheels the following di
mensions shall be used:
Diameter of
Diameter of Wheels Branch Pipe
T'p to and including 6 in 3 in.
More than 6 in. up to and in
cluding 12 in., 4 in.
More than 12 in. ur> to and in
cluding 16 in 4 M in.
More than 16 in. up to and in
cluding 24 in., 5 in.
More than 24 in. up to and in
cluding 30 in 6 in.
PLANB for all blower installation
should be submitted to this department
in duplicate for approval before work
is commenced and it should be clearly
specified that the system is to be in
stalled in strict accordance with the
above rules and regulations.
These plans should show the diameter
of all wheels, dimensions of all piping,
and should also show the general con
struction of hoods to be used. These
rules and regulations as set forth above
should be complied with before the sys
tem will be acceptable to the Depart
ment of Labor and Industry.
Note —The above rules and regula
tions shall not apply to Grinding Ma
chines upon which water Is used at the
point of the grinding contact, nor shall
they apply to any factory or workshop
where men are not employed continu
ously at such wheels or belts more than
three hours in twenty-four.