Chain Slings
A. Noble & Son Ltd. is a leading manufacturer of Grade T
chain slings in Australia. Nobles chain slings comply with AS 3775
and all chain slings manufactured by Nobles are proof load tested
to twice the WLL.
The Grade T alloy steel chain is manufactured to AS 2321 'Short
Link Chain for Lifting Purposes'. This chain is electrically
welded, fully heat treated and tested at manufacture. Testing
incorporates non-destructive (proof) testing for the entire chain
and destructive type (breaking load and elongation) tests on
selected samples.
Nobles Grade T components comply to AS 3776 'Lifting Components
For Grade T Chain Slings'.
Nine of Nobles branches throughout Australia are NATA Accredited
Testing Laboratories with facilities to carry out proof and
destruction type testing of chain and chain sling components.
Nobles chains may be supplied with the following markings T, 8,
80 or 800.
WLL Tonnes
Working Load Limit (WLL) is the maximum load that can be
supported by a sling under general conditions of use.
General conditions of use are equivalent to a group
classification of crane mechanisms of M3 as specified in AS
1418.1.
Under other than general conditions of use (e.g. severe
conditions, hazardous conditions involving safety of personnel),
the WLL shall be derated to conform to the group classifications of
crane mechanisms as specified in AS 1418.1 for conditions of use
that apply.
(a) Endless Slings
The WLL of endless chain slings shall be not more that 1.5 times
the WLL of the chain.
(b) Non-vertically orientated leg of a sling
The WLL of a non-vertically orientated leg of a sling shall
allow for its inclination to the vertical.
(c) Adjustable Slings
The WLL of adjustable chain slings shall be as follows:
Where a special purpose hook (e.g. a shortening hook or a cradle
grab hook) that fully supports the chain link and attains a 100%
efficiency is used, the WLL shall be not more than the WLL of the
chain to which it is attached.
Where (i) above does not apply, the WLL shall be not more than
0.75 times the WLL of the chain to which it is attached.
(d) Multi-Leg Slings
The WLL of a two-leg sling assembly shall not exceed that for an
included angle of 60º between the two legs.
WLL of a multi leg sling assembly with more than two legs shall
not exceed that for the sling with only two of its legs used with
an included angle of 60º between these two legs. That is, the WLL
of multi leg slings comprising more than two legs shall be not more
than the WLL of the sling used as a two-leg sling.
Where a sling is not symmetrically loaded, the WLL shall be
based on an included angle equal to twice the largest angle from
the vertical.
The WLL for a multi leg sling having an included angle of 60º
between the legs is the maximum WLL for the sling and shall not be
exceeded, even where the included angle between the legs is less
than 60º.
Under no circumstances shall the included angle between the legs
of a multi leg sling be allowed to exceed 120º.