Chain

 

Dimensioning of Chain Slings

Calculation of working load limit (WLL) for chain slings
When the exact information about weight, lifting angle and  position of the centre of gravity is known, you are able  to calculate the working load limit using the trigonometric method as follows:

2-leg sling
WLL (ton) = 2 x WLL for single leg sling x cos ß.

3-4-leg sling
WLL (ton) = 3 x WLL for single leg sling x cos ß.

Note: If the load is unform on all 4 legs in a sling the following formula can be used in exceptional cases:

WLL (ton) = 4 x WLL for single leg sling x cos ß.

ß = the legs angle against the vertical surface.

Sharp edges
Edge protectors should be used to prevent sharp edges from damaging the lifting equipment. As a general rule the radius (R) of the edge should be > 2x the chain diameter. When lifting with chain directly on lugs it is recommended that lug diameter greater than  3x the pitch of the chain should be used. If a lug diameter is less than this, the WLL must be reduced by 50%.

R > 2x chain ØR > than chain ØR = chain Ø 
10,70,5

Working Load Limit (WLL) - Grade 10

General: Tables specify the maximum load for common chain dimensions in grade 10 for use in slings.

 

ChainWLL in ton for chain grade 10
ØSingle
2-leg & Basket*
3-4-leg*
Endless

16613

16603

16605

16640

16641

16643

16638

16614

mm 

Straight

Choked

Basket0°-45°45°-60°0°-45°45°-60°

Choked

61,41,122,821,432,122,24
71,91,53,82,651,942,83
82,5253,552,55,33,754
1043,1585,64866,3
136,75,313,49,56,7141010,6
1610820141021,21516
191411,22820143021,222,4
2219153826,519402830
2626,521,25337,126,555,639,742,4
Factor (KL)10,821,412,11,51,6
*When multi-leg chain slings are used in choke hitch - reduce value by 20%

Use in Adverse Environments

Temperatureaffects on working load limit (WLL)

Account should be taken to the maximum temperature that can be reached by the chain sling in service. This is difficult in practice but underestimation of the temperature should be avoided. The table below summarises the necessary de-rated working load limit due to temperature.

Chain slings in grade 8 and 10 will not be negatively affected by temperatures down to -40 °C which result in the fact that no reduction of the working load limit are needed. When chain slings are to be used in temperatures below -40 °C CERTEX should be consulted.

The use of a chain sling in grade 8 and 10 within the permissible temperatures ranges given in the table does not require any permanent reduction in working load limit. Working load limit are valid again when the chain sling is used in normal temperature again. If the chain sling reach temperatures that highly exceed the maximal allowed according to the table it should be discard or be returned to CERTEX for measure.

Allowed load expressed in % of working load limit (WLL)
temperature (t) Cº
-40 - 200201 - 300301 - 400401 - 475
1009075Not allowed
100Not allowedNot allowedNot allowed
100100100*Not allowed

Acidic conditions

Chain slings in grade 8 and 10 should not be used either immersed in acidic solutions or exposed to acid fumes.

Chain slings should, for the same reason, not be warm-galvanized or exposed to electroytic finish without permisson from CERTEX.

 

Chemical affects

CERTEX should be consulted in case the slings is to be exposed to chemicals combined with high temperature.

Working Load Limit (WLL) - Grade 12

General: Tables specify the maximum load for common chain dimensions in grade 12 for use in slings.
ChainWLL in ton for chain grade 12
ØSingle
2-leg & Basket*
3-4-leg*
Endless

31470

 31469

31474

16640

16641

16643

16638

16614

mm 

Straight

Choked

Basket0°-45°45°-60°0°-45°45°-60°

Choked

72,361,94,723,352,3653,553,75
832,3664,2536,34,54,75
1054107,1510,67,58
1386,31611,281711,812,5
Factor (KL)10,821,412,11,51,6
*When multi-leg chain slings are used in choke hitch - reduce value by 20%
Chain
lyftplansch_stor_2

Multi Leg Slings

The working load limit of any master link should be at least equal to that of the sling. The working load limit of any intermediate link fitted to a 3-leg or 4-leg sling should be at least equal to 1,6 times the WLL of the current chain.

WARNING! If the sling is to be used in an anticipated lift with a lifting angle less then (ß) 45° and with a higher working load limit than usual, it should be specified at time of order.

Chain
2-leg sling

Length

Tolerance of length
The length (L) should be measured between the "bearing points" or the circumference for endless slings.

The length on each leg should be nominal length with a tolerance of -0/+2 chain link lengths.

The difference in length (usally the same for all legs) between the shortest and longest leg in a mulit-leg sling, assembled with connecting links, should not exceed 10 mm if the sling is 2 m or less, for longer slings a value of 5 mm per metre should be used.

Marking

Slings are provided with a marking plate with the manufacturer's identifying mark, working load limit (WLL), length, date of manufacture and CE-marking.