SAFETY
IN
RIGGING
AND
ERECTION OPERATIONS
Facts about material
handling
1. It does not add to the value of the product but
to the cost of the product.
2. It accounts for 36% of the total production cost.
3. Nearly 50 – 100 tones of material is handled or
re-handled for every tone of finished product.
4. A large part of the labour cost is accounted by
material handling department.
5. About 66.66% manufacturing cycle time is
spent in handling the material.
6. About 40 accidents out of 100 accidents take
place due to material handling.
Classification
lifting appliances
lifting machines lifting tackles
cranes D-shackles
hoists wire ropes
chain pulley blocks chains
jib crane clamps etc
Tips for good erection & rigging
•first find out the correct weight of the load to be
lifted
•slightly lift the load check for CG , imbalance etc
•while lifting ensure that the load is not
obstructing to any of the parts of structure
•while using spanners, riveting hammer at height
tie with a rope to a fixed structure.
•loose nuts & bolts must be kept in a box and not
on the structures.The box to be properly
anchored.
•Avoid sudden break or sudden release of
the load . Impact load may result in breaking
of the rope/chain
•persons with B.P or epilepsy shall not be
allowed to work at heights
•barricade the area of loads lifting/ sparks
falling
•safety belt is a must at heights more than
10 feet
Construction of 6/19 wire rope
6=no. of strands
19 =no. of wire ropes in each
strand
19( 1/6/12) I.e 12wires over 6
wires over one wire.
Core of the rope
Type of cores
1. Fiber core: sisal, polypropylene or nylon
2. Wire core : IWRC (Independent wire rope core),
SSC (steel strand core) or Armor core
Types arrangement of the wires in the strands
Ordinary: all wires in the strand are of same
diameter
scale: larger diameter wires out side and
smaller inside. This arrangement gives more
resistance to abrasion
Warrington: alternative large and small wires
are formulated to give great flexibility,
resistance to abrasion
Filler : small wires filled between large outer
and inner rows of large size wires
Safe working load
Point of
proportionality
Ultimate load
srtain Breaking load
Yield point
stress
SWL= max. breaking load
Factor of safety
SWL of natural ropes
Dia of Nylon Manila
the rope rope rope(Kgs)
in inch ( Kgs) FOS(6)
FOS(6)
¼ 170 Nil
½ 560 120
¾ 1290 245
1 2230 410
1¼ 3450 610
1 1/2 4990 840
LOAD CARRING CAPACITY THUMB RULE
FORMULA
W = 8d2
( W in Kgs. ; ‘d’ in mm )
Subject to zero included angles between the Ropes.
N.B : The same formula is valid for D-Shackles also.
Safe working load for ropes (kg)
Diameter Mild plow Improved Extra
of rope steel plow steel improved
inch FOS=6 FOS=6 plow
steel
FOS=6
¼ 313 414 456
½ 1230 1620 1780
¾ 2720 3600 3960
1 4780 6320 6950
1 1/4 7380 9765 10730
1 1/2 10750 14200 15460
Safe working load for chains (kg)
SWL (In Kgs)=6DxD, 8DxD OR 12DxD
where D is dia of the link in inches
Nominal size Dia(inches) Wrought High tensile Alloy steel
of the link iron or mild steel
(dia in mm) steel 8DxD 12DxD
6DxD
6 ¼ 360 450 680
8 5/16 640 800 1220
10 3/8 1000 1260 1900
12.5 ½ 1560 1960 2960
16 5/8 2560 3220 4860
19 ¾ 3680 4500 6840
20 - 4000 5030 7600
22 7/8 4840 6080 9310
25 1 6250 7860 11870
29 1 1/8 8410 10100 15400
32 1 1/4 10240 12500 18900
Permissible wear in chain link
Nominal size of Permissible wear at any
chain link point of link
inches mm inches mm
¼ 6 3/64 1.2
3/8 9 5/64 2.0
½ 13 7/64 2.8
5/8 16 9/64 3.6
¾ 19 5/32 4.0
7/8 22 11/64 4.4
1 25 3/16 4.8
1 1/8 29 7/32 5.6
1¼ 32 - 6.4
1 5/8 35 9/32 7.2
Safe working loads of D-shackles
Shackle Pin SWL(Kgs.)
Dia(IN) Dia(IN) FOS=5
½ 5/8 1283
5/8
¾
7/8
1 1/4
¾
7/8
1
1 1/8
2005
2884
3922
6059
LOAD CARRING CAPACITY THUMB RULE
FORMULA
W = 8d2
( W in Kgs. ; ‘d’ in mm )
Subject to zero included angles between the Ropes.
N.B : The same formula is valid for D-Shackles also.
1 3/8 1 3/8 7483
Five fingers
1½ 1½ 9052 formula
1 3/8 1 5/8 10, 766 is valid for
1¾ 2 14, 658 D-shackles
also
2 2¼ 19,138
Reduction in diameter of the rope due
to core failure , abrasion etc
should not be more than
•1.0 mm for the ropes up to---19mm dia
•1.5mm for ropes of------------22-28mm dia
•2.0mm for ropes of ------------32-38mm dia
SUCH ROPES TO BE REPLACED
Ropes with above defect should not be used.
Ropes with above defect should not be used.
Criteria to replace the wire rope
WIRE ROPE SAFETY:
1. Never over load.
2. Minimize shock loading to the extent possible.
3. Use higher capacity ropes when the exact load is not known. If
there is a possibility of shock loading and if there is a hazard to
personnel.
4. Prevent the rope from sharp corners with padding.
5. Avoid dragging the rope from under loads or over obstacles.
6. Avoid dropping the rope from heights.
7. If loop forms do not pull it out. Unfold it.
8. The rope must be replaced if the visible broken wires are 5% or
more of the total wires in a length of 10 rope diameter.
9. The rope must be replaced if this wear exceeds 1/3 of the
diameter of the wire.
10. An approximate elongation of 150 mm per 30 M of rope in a
six stranded rope and approximately 230 to 255 mm in eight
stranded rope can be expected when a new steel rope is put in
use, which is known as constructional stretch. Ropes having an
excessive stretch beyond this should be replaced.
Precautions in use of chains
•chains or chain slings should never be shortened
by tying knots in them
• do not use the chains if the links are locked,
stretched or without free movement.
•Do not hammer a link to straitened it or force it into
the position.
•Do not drop chains from heights
•use padding at sharp corners
•use slings such that the angle between slings is
more than 90 dig.
Type of hitches in material
handling
1. Bridle hitch
2. Basket Hitch
3.choker hitch
1. Bridle hitch
Two legged bridle hitch
Two legged bridle hitch
SWL= SWL of single vertical sling x H/L x 2
Assumption: only two
Three legged bridle hitch
legs are taking the load
SWL= SWL of single vertical sling the other one balance
x H/L x 2 the load.
Four legged bridle
hitch
SWL=
SWL of single vertical
sling x H/L x 2
Assumption: only
two legs are taking
the load the other
two balance the
load.
2. Basket Hitch
Single basket hitch:
vertical legs
SWL=
SWL of single vertical
hitch x 2
inclined legs
SWL=
SWL of single vertical
hitch x H/L x2
Double basket hitch:
inclined legs SWL=SWL of single vertical hitch x H/L x4
3.choker hitch
Single choker
hitch
SWL=
SWL of
single vertical
sling x A/B
When the
angle is less
than 45
degrees
Double choker hitch, SWL=SWL of single vertical hitch x
A/B X H/L x2 when the angle is less than 45 dig.
Note:If the angle is more than 45 dig. Take A/B=3/4
Capacity of a hook at different inclinations
As for as possible the angle between the two slings to be
ensured less than 90 dig , so that only limited excess weight
is coming on each sling
Minimum diameter of the drums or sheaves to avoid
excessive bending of the wire rope
Construction of rope min. dia of drum/ sheaves
6x19 23 Dia of rope
6x24 19 Dia of rope
6x37 17 Dia of rope
Minimum number of
clips
up to 19 mm----- 3
19-32mm--------- 4
6 dia
of rope 32-38mm--------- 5
38-44mm-------- 6
above 44mm---- 6
The bridge of the bull-dog grip to come load side and U-bolt on
shorter end of the rope,don't tight the grips too much tight or too
loose.The clips shall be kept 6 dia of the rope apart.
Specifications of welding glass
s. no Type of operation Shade
number of
filter
1 Torch brazing /soldering 3-4
2 Light gas cutting/gas 4-5
welding
3 Heavy gas welding &arc 6-8
welding up to 75 amps
4 Arc welding 75-200amps 10
5 Arc welding 200- 12
400amps
6 Arc welding more than 14
400 amps
CAUSE OF BACKFIRE PREVENTIVE MEASURES
1.Insufficient pressure for a)Reduce the nozzle size as per the
the nozzle requirement of plate thickness to
be cut.
b)Increase the pressure on the
gauge.
2.Metal particles adhering 2.Rub the nozzle on a leather or
to the nozzle wooden surface to free it of particles.
3.The nozzle touching the 3.Maintain gap between torch nozzle
plate to be cut. and plate to be out.
4.Overheating of the 4.Immerse in a can of water to cool
blowpipe the nozzle from time to time.
Oxygen should be allowed to pass
slowly through the nozzle when
immersed in water, to prevent water
from entering the inside of the
blowpipe.
5.In the event of backfire 5.Immediately shut off acetylene
valve and then the oxygen.
CUTTING TYPE & NOZZLE DATA
Plate
Cutting
Thicknes Regulator Pressure Gas Consumption
Speed
s
Acetele Heatin Cutting Acetyl Heatin Cutting
Nozzle ne g Oxygen ene g Oxygen
2 2 2
Kg/cm Oxyge Kg/cm m /hr Oxyge m2 /hr mm/mi
mm
n n m2 /hr n
Kg/cm
2
0-5 A - 8(A-1/32) 0.14 1.4 20 0.4 0.5 0.9 400
5-10 A-12(A-3/64) 0.14 1.4 2.1 0.4 0.5 1.9 350
10-20 A-16(A-1/16) 0.14 1.7 2.8 0.4 0.5 4.0 275
20-50 A-16(A-1/16) 0.14 2.1 3.2 0.5 0.6 4.3 200
50-75 A-16(A-1/16) 0.14 2.1 3.5 0.5 0.6 4.9 175
75-100 A-20(A-5/64) 0.14 2.8 3.9 0.6 0.7 7.2 150
100-150 A-20(A-5/64) 0.14 2.8 4.5 0.6 0.7 10.0 125
150-200 A-24(A-3/32) 0.14 2.8 4.9 0.6 0.7 14.7 125
200-250 A-28(A-7/64) 0.14 3.2 5.3 0.9 1.1 21.5 110
250-300 A-32(A-1/68) 0.14 3.2 5.3 1.3 1.6 25.5 105
Requirement of loads for over load test
s.no SWL(t) Load required for
over load test (t)
1 100 110
2 75 82.5
3 50 55
4 25 30
5 1 1.25
6 5 6.25
7 2 2.5
Allowable noise levels
Noise (dB) Hours
90 8
95 4
100 2
105 1
110 1/2 (half an hour)
115 1/4 (15 minutes)
120 7.5 minutes
Proper Method of Lifting a Load (Manually):
1. Place your feet firmly on ground about one foot apart .
2. Keep your one leg slight in front of the other and as close to
the load as possible.
3. Bend your knee and hip with the back straight (“Straight” does
not mean “VERTICAL”)
4. Keep the load close to the body
5. Grip the load firmly from opposite ends by ensuring contact
between the object and the palm.
6. Lift the load in such a way that your chin remains straight in
line with back (this will help you to keep your spine straight and
firm) and the vision is not disturbed / obstructed
7. Position body so its weight is centered over the feet and lift by
straightening the legs
8. Put down the load again by bending hip and knee by keeping
the back straight.
9. One corner should be put first to remove fingers from other
side.
Gas cylinders safety -10 commandments
•Don't store them near wet soil or exposed to sun or
heat source
•Do not use them as work supports or rollers (may be
the cylinder full or empty
• Do not lubricate the cylinder valve threads or other
fittings
•Cylinders must be maintained in an upright position and
secured against tipping, falling or rolling. Never drop
cylinders or permit them to strike each other violently.
• Protect surface of cylinder from any cuts or abrasions.
•Valve protection caps must be fully threaded in place
when cylinders are not connected to user system.
•Do not carry the cylinder on your shoulder.
•Never lift cylinders by the caps.
•Never open the acetylene more than 1/2
turn, sudden opening may lead to explosion
•never keep the cylinders in battery
charging room or never allow them to come
in to contact with live wires.
