good slinging practice - Site Safe

CRANEAGE: SLINGING - INTRODUCTION 1 

TRAINING MODULE 

SLINGING 

Modules 1 to 3 

NOTE: This is Part 1 of a 4-part 

module set covering Slinging. 

Part 2 covers Sections 4 to 7. 

Part 3 covers Sections 8 and 9. 

Part 4 covers Sections 10 to 12. 

Weights and C of G 

Tackle 

Included Angles

CRANEAGE: SLINGING - INTRODUCTION 1 

SLINGING 

Modules 1 to 3 

This Training Module comes to you courtesy of: 

Site Safe would like to acknowledge Fletcher Construction’s on-going support

CRANEAGE - SLINGING: BASICS PAGE 1 

CRANEAGE - SLINGING BASICS 

SECTION 1: 

WEIGHTS AND CENTRE OF GRAVITY 

1.1 Know the Load Weight 

1.2 Estimating Weights 

1.3 Weights of Common Materials 

1.4 Centre of Gravity 1 

1.5 Centre of Gravity 2 

1.6 Centre of Gravity 3


GOOD SLINGING PRACTICE 

BASIC RULES ... 1 

1.1 KNOW THE LOAD WEIGHT. 

Lifting any load with gear which is inadequate for the job is just not an 

option. Commonsense tells you this is dangerous. 

Before carrying out a lift, there are TWO factors which MUST be known: 

a) The weight of the object or material being lifted 

b) The lifting capacity of the tackle 

On the following sheets, are some simple formulas which will allow you to 

estimate the weights of most common materials on a construction site. 

Details of the lifting capacities of common slinging systems are shown in 

a separate section (Section 2).

CRANEAGE - SLINGING: ESTIMATING WEIGHTS 

PAGE 3 




L 

W 

RECTANGLE 

This applies for cubes and rectangles of any size. 

H 

L x W x H x wt./cu.m 

L 

SOLID CYLINDER 

(3.14 ÷ 4) x D x D x L x Wt./Cu.M. 

D 

D 

HEAVY WALL PIPE 

(3.14 ÷ 4) x D x D x L x Wt./Cu.M = Solid weight, 

MINUS 

(3.14 ÷ 4) x d x d x l x Wt./Cu.M = Hole weigh. 

Take the "hole" from the "solid" = Pipe weight! 

d 

C 

D 

THIN WALL PIPE 

Working this out is imagining that you have split the pipe 

lengthways, and have rolled it out into a flat sheet. 

3.14 x D x L x t x wt./cu.m. 

OR 

C x L x t x wt./cu.m 

t 

STEEL SECTIONS 

Any steel section can be divided into convenient 

sections, and the weight of each worked out. Add 

all the totals together, and you have the overall 

weight of the complete section. 

(This trick can also be used for 

any irregular-shaped object.) 

1 

e.g; an RSJ 

is three 

rectangles! 

2 

Wt. of 1 + Wt. of 2 + Wt. of 3 = Total weight. 

3


PAGE 4 




A GUIDE TO WEIGHTS. 

STEEL BARS 

& RODS 

Dia. 

(mm) 

Approx. kg 

per metre 

WEIGHTS OF 

COMMON MATERIALS 

Material: 

Approx. kg. per 

cubic metre 

5 

0.15 

Aluminium 

2,645 

6 

0.22 

Asphalt 

1,410 

8 

0.40 

Blocks - conc. 

1,134 

10 

0.62 

Brick - common 

2,005 

12 

0.90 

Cement - loose 

1,506 

13 

1.05 

Concrete - plug 

2,305 

14 

1.20 

Concrete - reinf. 

2,405 

16 

1.60 

Copper 

8,950 

17 

1.80 

Earth - dry 

1,280 

18 

2.25 

Earth - wet 

1,600 

20 

2.45 

Glass sheet 

2,565 

22 

3.00 

Granite 

2,725 

24 

3.55 

Gravel - dry 

1,760 

25 

3.85 

Gravel - wet 

1,920 

28 

4.80 

Marble 

2,720 

30 

5.55 

Oils 

930 

32 

6.30 

Timber - dry 

810 

35 

7.55 

Timber - wet 

960 

40 

9.85 

Sand - dry 

1,730 

50 

12.50 

Sand - wet 

1,890 

100 

61.65 

Steel 

7,800 

150 

138.75 

Water 

1,000


PAGE 5 



1.4. KNOW HOW TO FIND THE CENTRE OF GRAVITY ... 1. 

Every load has a "centre of gravity". 

The "Centre of Gravity" of a load is a point which, if the load could be suspended from it, the 

load would be in perfect balance. 

In a simple rectanglar or square shape, the C of G is easily found, as the exact centre of the 

load. It gets a little more complicated with odd-shaped loads, but the following illustrations 

may make it a little easier. 

In a simple rectangle, the C of G is in the dead centre of the load, at a point where 

all the diagonals (from corner to corner) would intersect. A quick way is to divide 

the sides in half - the mid-point is the line of the C of G. 

Make sure the hook is over the centre of the load and it will be quite stable. 

Half the width will 

locate the C of G 

horizontally. 

= 

= 

= 

= 

Half the depth will 

locate the C of G 

vertically. 

= 

= 

The C of G for a cylinder or pipe is readily 

found, by halving the length. The C of G is 

on this line, on the centreline of the cylinder 

or pipe. 

The problems can arise where an irrgular-shaped load has to be 

lifted, which may require slings of different length, or the load on 

each sling may be markedly different. 

How to find the centres of gravity with these loads is covered on 

the following sheets.

PAGE 6 




The "Centre of Gravity" of a load is a point which, if the load could be suspended from it, 

the load would be in perfect balance. 

The crane hook needs to be directly over the centre of gravity, for the load to be stable. 

This load is not stable. 

The hook is over the 

centre of gravity, but 

the C of G is above the 

crane hook. 

This load is top-heavy, 

and could overturn 

while being craned. 

This load is 

stable. The 

hook is right 

over the 

load's centre 

of gravity. 

WHAT WILL HAPPEN....? 

UNSTABLE 

Hook is not over 

centre of gravity. 

The load will shift until the 

centre of gravity is under the 

hook. 

This will make landing the 

load very difficult, and could 

cause major problems in 

craneage.


PAGE 7 




A load that is not centred will swing as soon as it is lifted. 

This puts a greater stress on one sling, and can be dangerous. 

It becomes important to set the slings so the hook is right 

over the centre of gravity of the load, and this requires 

a bit of calculation. 

METHOD 1. 

In this case, the load is formed of two 

rectangles. The centre of gravity for each 

rectangle can easily be found, and the weight 

of the section estimated. 

Section 1 = 800kg; C of G = CG1. 

Section 2 = 1,200kg; C of G = CG2. 

Combined weight = 2,000kg. 

The larger section is (1200/2000), or 60% of 

the total load. 

Draw a line from CG1 to CG2, and measure it. 

Say it is 2.400 metres. 

60% of 2.400 m is 1.584 metres. 

The combined centre of gravity is then 

1.584 m from CG1. This is shown as CG3. 

The hook needs to be located over this point. 

800kg 

1 584 

CG1 

CG3 

2 400 

1200kg 

CG2 

METHOD 2 

Sometimes it seems possible to calculate 

the sling load stress on each side of a 

non-symmetrical load as shown, by using 

the normal sling formula and applying it 

twice: once for one side, and again for the 

other side, using two different lengths of 

sling and different heights. 

1 920 

1600 kg 

Heavily 

loaded 

sling 

This method is not accurate, 

especially with extreme load 

distribution such as a heavy 

steel structure on one end and 

light steel framing on the other 

end. 

400 kg 

CG1 

2 400 

CG2



SECTION 2: 

KNOW YOUR TACKLE 

2.1 Know the Tackle Capacity 

2.2 The Riggers Chart - 1 

2.3 The Riggers Chart - 2 

2.4 Shackle Care 

2.5 Crane Hook Care 

2.6 Wedge Sockets 

2.7 Web Slinging Rights and Wrongs 

2.8 Web Slinging Capacity Details 

2.9 Blocks & Tackle 1 

2.10 Blocks & Tackle 2 

2.11 Blocks & Tackle 3



2.1 KNOW THE TACKLE CAPACITY 

Lifting any load with tackle which is inadequate for the job is just not an option. 

Commonsense tells you this is dangerous. 

Before carrying out any lift, there are TWO factors which MUST be known: 

The weight of the load, and 

The lifting capacity of the tackle. 

On the following sheets are some simple formulas which will show how to select the 

correct tackle for the job. 

Sheets 2.2 and 2.3 are quick-reference sheets for the common slings and shackles, 

with following sheets providing more detail, with information for checks of equipment, 

and the use of blocks and tackle. 

WLL 2.5T 

SWL 5.0 T



BASIC RULES ... 2 - QUICK REFERENCE CHART 1 

POLYESTER ROUND SLINGS: 

LISTED CAPACITIES 

INDICATIVE ONLY. 

One stitch row = 1 tonne 

Vertical 

Choke 

Parallel 

Basket 

Basket 

90° 

All lifting tackle has the 

SWL or WLL marked. 

Slings must NOT be used 

beyond their 6-month 

inspection date. 

1.0 

2.0 

3.0 

4.0 

5.0 

6.0 

0.8 

1.6 

2.4 

3.2 

4.0 

4.8 

2.0 

4.0 

6.0 

8.0 

10.0 

12.0 

1.4 

2.8 

4.2 

5.6 

7.0 

8.1 

Nip angle 

must NOT 

exceed 120°, 

square or 

round reeved 

(choked). 

120° 

8.0 

6.4 

16.0 

11.2 

CHAIN SLINGS 

Grade 80, Lifting chain only. 

Chain 

dia. mm 

Single 

Vertical 

Single 

Reeved 

2-, 3- and 4- legged Slings 

Straight 

Reeved 

10 mm 3.2 

13 mm 5.4 

16 mm 8.0 

19 mm 

23 mm 

Rope 

dia. mm 

13 mm 2.0 

16 mm 3.0 

19 mm 

22 mm 

24 mm 

11.5 

16.9 

WIRE ROPE SLINGS 

Single 

Vertical 

4.3 

5.7 

6.8 

2.6 

4.3 

6.4 

9.2 

13.5 

Single 

Reeved 

1.6 

2.4 

3.4 

4.6 

5.4 

0° - 90° 90°-120° 

2.8 

4.2 

6.0 

8.0 

9.5 

Grade 1770, Fibre core 

2-, 3- and 4- legged Slings 

Straight 

2.0 

3.0 

4.3 

5.7 

6.8 

2.2 

3.4 

4.8 

6.4 

7.6 

Reeved 

26 mm 8.0 6.4 11.0 8.0 8.8 6.4 

28 mm 9.3 7.4 13.0 9.3 10.4 7.4 

4.5 

32 mm 12.1 9.7 16.9 12.1 13.5 9.7 

7.6 

11.3 

16.2 

23.9 

3.2 

5.4 

8.0 

11.5 

16.9 

0° - 90° 90°-120° 

7 mm 1.5 1.2 2.1 1.5 

1.7 1.2 

3.6 

6.0 

9.0 

12.9 

19.1 

2.6 

4.3 

6.4 

9.2 

13.5 

1.6 

2.4 

3.4 

4.6 

5.4




2.3. QUICK REFERENCE CHART 2 

BOW SHACKLES 

High Tensile 

Screw pin type. 

Size mm 10 11 13 16 19 22 25 28 32 35 38 45 

Pin Ø mm 11 13 16 19 22 25 28 32 35 38 42 50 

SWL 

1.0 1.5 2.0 3.25 4.15 6.5 8.0 9.5 12.0 13.5 17.0 25.0 

SWIFTLIFT PINS 

Min. 20MPa concrete. 

3 x depth = dist. from edge 

Pin length. mm 

SWL 

35 50 55 65 75 85 90 95 120 

0.47 0.88 1.17 1.51 1.88 2.1 2.42 2.92 4.16 

170 

5.00 

EFFECT OF INCLUDED ANGLE 

ON SLING LOADS 

WEIGHTS OF CONSTRUCTION 

MATERIALS 

0.5 t 0.5 t 

Load 

in 

tonnes 

30° 

60° 

0.52 

0.58 

Brick 

Concrete (wet) 

Concrete (& precast) 

Sand / Gravel (wet) 

Steel 

Timber 

Water 

T /Cu.M. 

2.01 

2.40 

2.41 

1.92 

7.85 

0.610 

1.00 

90° 

0.7 

120° 

1.0 

150° 2.0 

170° 

1 tonne load 

6.0 

CONCRETE WEIGHTS 

0.5 cu.m. skip 

1.4 t 


2.7 t 


5.6 t 

HOLLOW CORE FLOORING 

200 thk series 

0.32 t / m 

300 thk series 

0.42 t / m




2.4. CARE OF SHACKLES 

Shackle size is usually given 

as the pin diameter, not the 

bow diameter. 

NEVER use a bolt in place 

of a proper shackle pin. A 

bolt is made of the wrong 

(weaker) metal. 

Tie the pin to prevent it 

coming undone with 

twitching wire through the 

eye and around the 

opposite part of the bow. 

WLL 2.5 T 

Where possible, use a 

shackle with the pin on the 

hook, and not upside-down. 

A rope being pulled across a 

pin could cause it to come 

undone. 

ALWAYS use a shackle for 

vertical lifts only. If you have 

to use a shackle with two 

chokers spread at a wide 

angle, go UP a size in rating. 

CHECK for wear on the 

shackle bow. Any more 

than a 10% reduction in the 

bow material - throw the 

shackle out. 

CHECK FOR: 

Damaged threads 

Nicks or flat spots on pin 

Worn or damaged shoulder 

Bending in the pin 

Opening or closing-up of 

the bow gap 

Flat spots on bow 

Wear on bow 

Eyes out of alignment 

WLL 2.5 T 

A pin should have ONE thread showing 

when tight. 

Any more or any less - the shackle has 

distorted and should be scrapped.




2.5. CRANE HOOK CHECK AREAS 

CHECK 

the swivel 

is working 

smoothly 

CHECK 

for signs 

of cracks 

and 

twisting 

CHECK for 

wear and 

cracks 

CHECK for 

wear and 

deformation 

CHECK for 

signs 

of the throat 

opening up 

CHECK 

the 

safety 

latch 

CHECK 

the hook 

rating 

is clearly 

shown 

CHECK 

for 

twisting 

ANY sign of a defect means the 

hook could be dangerous if used. 

DO NOT risk using it - have it 

checked over by our experts. Tag it 

as being "FAULTY". 

Other suspicious signs to check for: 

- Discolouration through heat. 

- Any signs of welding. 

- Any sign of the hook rating being altered or obscured. 

- Any sign of the hook having contact with power (arced areas) 

- Any deformations, even hammer marks, on the hook. 

YOU MAY BE THE ONE UNDER THE HOOK IF IT FAILS. 

YOU DON'T GET SECOND CHANCES.




2.6. WEDGE SOCKET CHECKS 

The wedge socket 

MUST be attached with 

the load line pulling in a 

straight line from the 

pin. 

RIGHT! 

WRONG!! 

METHODS OF SECURING THE DEAD END 

Always pull sufficient rope through the socket. 

The dead end is clamped to the 

load line - NOT too tight, or the 

load line may be damaged. 

Always allow a little slack. 

After loading the socket, the 

dogging clamp should be 

released and some slack 

forced into the dead end, 

otherwise the dogging clamp 

takes all the load until it fails. 

(A) 

Saddle on live end 

This is a common method - 

clamp a short length of line 

to the dead end. 

(B) 

Take care if 

considering this 

method - the loop 

can often snag on 

projecting materials. 

(C)




2.7. WEB SLINGING 

SWL 10 T WITH 6M SLINGS 

Lifting Beam 

10,000kg LOAD 

RIGHT!! 

This is the correct way 

to sling precast using 

mesh or nylon slings. 

Note the slings are 

vertical and the full 

width of the sling is 

taking the load. 

The greater the included angle, 

the greater the risk. 

10,000kg LOAD 

WRONG!! 

This is a common - and risky - method 

of slinging. The only thing preventing 

the slings being pulled together, is 

friction between the webbing and the 

load. 

The entire load is being 

borne by a thin edge of the 

sling. Failure is certain. 

Side force: 

2 900 kg @ 60° incl. angle 

5 000 kg @ 90° incl. angle 

The sling will 

tear at this point. 

FACTORS INVOLVED: 

1. Load is applied to the sling edge only. It 

must be shared by the entire sling width. 

2. The slings are being pulled in together 

by the weight of the load (Side force). 

3. If slipping starts, the slings will be destroyed 

by both abrasive friction, and heat. 

4. Once slipping starts, it cannot be halted.




2.8. WEB SLINGING 

FLAT EYE 

Used where 

minimum 

clearance is 

required 

for passing under 

load, and for use 

with lifting beams. 

REDUCED 

EYE 

For use with 

small hooks. 

REDUCED AND 

REVERSED 

EYE 

For choker lift, 

giving square lift 

to the load on the 

same plane as 

the webbing. 

METAL DEE 

(Plain and Choker) 

Best suited to lifts 

where the eye is 

subject to heavy 

wear. 

SAFE WORKING CAPACITY (S.W.L.) IN TONNES 

Slings as above 

Endless Slings 

Sling 

Width: 

No. of 

Plys 

38mm 

One 

Two 

0.75 

1.50 

0.60 

1.20 

1.05 

2.10 

1.50 

3.00 

1.50 

3.00 

1.20 

2.40 

2.10 

4.20 

3.00 

6.00 

50mm 

One 

Two 

1.00 

2.00 

0.80 

1.60 

1.40 

2.80 

2.00 

4.00 

2.00 

4.00 

1.60 

3.20 

2.80 

5.60 

4.00 

8.00 

75mm 

One 

Two 

1.50 

3.00 

1.20 

2.40 

2.10 

4.20 

3.00 

6.00 

3.00 

6.00 

2.40 

4.80 

4.20 

8.40 

6.00 

12.00 

100mm 

One 

Two 

2.00 

4.00 

1.60 

3.20 

2.80 

5.60 

4.00 

8.00 

4.00 

8.00 

3.20 

6.40 

5.60 

11.20 

8.00 

16.00 

150mm 

One 

Two 

3.00 

6.00 

2.40 

4.80 

4.20 

8.40 

6.00 

12.00 

6.00 

12.00 

4.80 

9.60 

8.40 

16.80 

12.00 

24.00 

200mm 

One 

Two 

4.00 

8.00 

3.20 

6.40 

5.60 

11.20 

8.00 

16.00 

8.00 

16.00 

6.40 

12.80 

11.20 

22.40 

16.00 

32.00 

300mm 

One 

Two 

6.00 

12.00 

4.80 

9.60 

8.40 

16.80 

12.00 

24.00 

Special endless slings 

available to specific design.




2.9. BLOCKS AND TACKLE ... 1 

A load of 500 kg is 

going to need a force of 

500 kg to shift it. Those 

TWO loads will be 

applied to the block 

rigging. 

Load on block rigging: 

(500 kg + 500 kg) = 1,000 kg! 

500 kg 

A snatch block is rated by 

the maximum line pull. 

Therefore, a 500 kg snatch 

block will have a 1,000 kg 

capacity hook. 

500 kg 

Load: 500kg 

The greater the included angle between the load rope and the pulling rope, the less the 

force on the block rigging. 

Yes, this is the opposite to slings, and can be confusing, BUT it is very important to 

remember the difference, and WHY that difference works. 

920 kg 705 kg 500 kg 

500 kg 

500 kg 500 kg 

500 kg 500 kg 

500 kg 

45° 90° 135° 

In a vertical,lift, the combined force of both the load AND the lifting force are applied to 

the block. If the load was being pulled at 180° - in effect a straight rope - the block 

would take NO load. The load on the block then decreases, as the included angle 

increases. 

The following sheet shows how these forces can be worked out, for a number of 

angles. All you need to do, is MULTIPLY the load by the factor shown for the nearest 

angle between the load line and lead line ("pulling" line).





TABLE OF MULTIPLICATION FACTORS FOR 

SNATCH BLOCK LOADS 

Angle between 

Lead and Load 

Lines 

Multiplication 

Factor 

10° 

20° 

30° 

1.99 

1.97 

1.93 

Lifting 

force 

Load 

40° 

1.87 

Angle: 

50° 

1.81 

60° 

1.73 

70° 

1.64 

80° 

1.53 

90° 

1.41 

100° 

1.29 

110° 

1.15 

120° 

1.00 

130° 

0.84 

140° 

0.68 

150° 

0.52 

160° 

0.35 

170° 

0.17 

180° 

0.00 

Examples: 

A load of 645 kg is to be shifted using a snatch block. The angle between the lead line 

and the load line is 80°. What force will be applied to the snatch block rigging? 

= (645 x 1.53) = 986.85 kg , say 987 kg. 

A load of 362 kg is to be shifted, with the angle between lines at 75°. What is the force 

applied to the block rigging? 

Here, you take a factor half-way between the 70° and 80° factors and use that. 

= (362 x 1.59) = 575.58 kg, say 576 kg.





"What is meant by mechanical advantage?" 

"Mechanical advantage" is a term to describe how 

any machine multiplies the force applied to it in order 

to lift or move a load. 

With a block and tackle, using a rope through several 

pulleys or sheaves, a large load can be lifted or 

moved with only a small effort. 

Diag. 1 

The top fixed sheaves, which do not travel up or 

down, serve no other purpose than to change the 

direction of the rope. The sheaves on the travelling 

block - the lower block - will create a mechanical 

advantage of 2:1 on each sheave. 

(Not counted) 

2 

3 

1 

4 

To calculate the mechanical advantage of a block 

system, simply count the number of lines supporting the 

load - except for the lead line (the one you pull on) when 

it comes down over the top block. 

Diagram 1 at right shows this set-up. 

Mechanical advantage is 4:1, which means that, to lift a 

load of 400 kg, an effort of only 100 kg is required on the 

lead line. 

However, if the lead line comes up to the 

winch or lifting force, it is counted as a 

supporting line, and the mechanical 

advantage in this case - as shown in 

Diagram 2 - becomes 5:1, which means 

that, for the same 400 kg load, only 80 kg 

of effort is required. 

Diag. 2 

1 

4 5 

2 

3



SECTION 3: 

KNOW ABOUT INCLUDED ANGLES 

3.1 Know about the "Included Angle" 

3.2 Effect of Included Angle on Sling Loads 

3.3 Load Angle Factors 

3.4 Finding the Included Angle




3.1. KNOW WHAT THE "INCLUDED ANGLE" IS ALL ABOUT. 

You know the weight of the load to be lifted. 

You have estimated the load's centre of gravity. 

You know what loads the slings can carry. 

You have information on the different types of slings. 

You are all set to lift, then. Right? 

No! 

There is still one very important factor to take into account - the "Included Angle" of 

the slings. 

Having the angle of the slings is so important that it gets a section all of its own. 

The included angle is the angle 

between the two legs of a sling system. 

The greater the included angle 

between sling legs, the less load can 

be lifted. 

If a single sling is taking a load 

vertically, the load on that sling is 

equal to the load weight. That's 

quite simple, and certainly 

sounds logical. 

1,000 kg 

It may sound odd, but if a sling 

has an angle between the sling 

legs of 150°, each sling leg will 

have a load equal to twice the 

total load weight. 

For a load of 1,000 kg, each sling 

will have a load of 2,000 kg. 

Sling load = 

2,000 kg 

1,000 kg 

Incl. angle = 

150° 

Should that angle increase to 

170°, each leg will be subject to 

a load that is six times the total 

load weight. 

For a load of 1,000 kg, each sling 

will be loaded with 6,000 kg. 

Sling load = 

6,000 kg 

1,000 kg 

Incl. angle = 

170°




3.2. THE EFFECT OF THE "INCLUDED ANGLE" ON SLING LOADS. 

30° 

520 

520 

60° 

580 

580 

90° 

700 700 

120° 

1000 

1000 

2000 

150° 

2000 

6000 

170° 

6000 

1000 kg load 

This shows the effect of increasing the included angle in slings.You 

will see that, with an included angle of 170°, the load on each sling 

is six times the actual weight being lifted. 

Do NOT exceed the 120° included angle which provides each sling 

with the same weight as the actual load.

Vert 




3.3. INCLUDED ANGLE FACTORS ON SLING LOADS. 

12,000 

11,000 

10,000 

This simple graph shows the dramatic increase in loading of 

slings as the included angle increases. 

It can be seen that an included angle of less than 120° 

is the best option. 

(BASED ON TWO SLINGS LIFTING A LOAD OF 2,000 KG.) 

9,000 

8,000 

7,000 

6,000 

5,000 

4,000 

3,000 

2,000 

1,000 

10 0 

20 0 

30 0 

40 0 

50 0 

60 0 

70 0 

80 0 

90 0 

INCLUDED ANGLE 

100 0 

110 0 

120 0 

130 0 

140 0 

150 0 

160 0 

170 0 

SLING 

LOAD 

IN KGs 

Actual load 

on sling 

1,154 

C L 

60° 

Angle off 

horizontal: 

Included 

angle of 

sling: 

Sling 

included 

angle: 

Load 

angle 

factor: 

1,414 

2,000 

2,924 

5,714 

11,490 

2,000 kg load 

45° 

30° 

20° 

10° 

5° 

60° 

90° 

120° 

140° 

160° 

170° 

170° 11,490 

160° 

150° 

140° 

130° 

120° 

110° 

100° 

90° 

80° 

70° 

60° 

50° 

40° 

30° 

20° 

10° 

5,714 

3,861 

2,924 

2,364 

2,000 

1,742 

1,555 

1,414 

1,305 

1,221 

1,155 

1,104 

1,064 

1,035 

1,015 

1,004

PAGE 24 



3.4. FINDING THE INCLUDED ANGLE. 

How do you work out or measure the "included angle" in a set of slings? 

As you will now be aware, an included angle of more than 120° is not an option. The 

stresses on the sling start to increase dramatically once the angle of 120° is exceeded. 

It is a good practice to keep the sling included angle at a maximum of 60°. 

60° is obtained when (L) - the distance between sling attachments - is 

EQUAL to (S) - the sling length. 

90° is obtained when L is 1.4 times S. 

120° is obtained when L is 1.7 times S. 

Included 

Angle: 

S 

L

good slinging practice - Site Safe

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