Thorough Examination and Discard Criteria

General

An thorough examination is a visual check, performed by an expert and, when required, complemented with other methods, e.g. measurement and/or tests with intent to identify any damage or deterioration that might affect the slings fitness for use.

A thorough examination should be carried out at intervals not exceeding twelve months. This interval should be less where deemed necessary in the light of service conditions.

To facilitate examination, slings may need to be cleaned so as to be free from oil, dirt and rust prior to examination. This can usually be accomplished by using a wire brush. Other methods may be used providing that the parent metal is not damaged. Methods to avoid are those using acids, overheating or removal of metal.

Records of such examinations should be maintained.

The sling should be withdrawn from service if any of the following conditions are present, reached or exceeded:

Product inquiry

Sling markings

The sling markings, i.e. information on the sling identification and /or the working load limit, are illegible.

Damaged upper and lower terminals

Wear, distortion or cracking of the upper or lower terminals.

NOTE Particular attention should be paid to signs of opening up, distortion or cracking of the hook, distortion and wear of links or the closing of the thimble, indications that the sling may have been overloaded.

Damaged rope terminations

Wear, distortion or cracking of ferrules or the pulling out of a splice.

Broken wires

Broken wires are detrimental because of
a) the possibility of injury to the user’s hands;
b) the loss of strength in the rope.

Broken wires are usually caused by mechanical damage, although corrosion may also be a factor.

The appearance of well distributed broken wires may have no marked effect on the strength of the sling but the discard criteria in below should be adopted for randomly distributed broken wires and concentrated broken wires respectively.

NOTE To prevent injury to the user’s hands, protruding broken wires can be broken off in the valleys between the strands by reverse bending the wire, with the help of pliers, until fracture occurs. Such actions should be recorded.

Randomly distributed broken wires

6 randomly distributed broken outer wires in a length of 6 d but no more than 14 randomly distributed broken wires in a length of 30d where d is the nominal rope diameter.

Concentrated broken wires

3 adjacent broken outer wires in one strand.

Rope distortion

Kinking, crushing, birdcaging or core protrusion or other damage which distorts the rope structure.

NOTE: The main thing to look for is wires or strands that are pushed out of their original positions in the rope. Slight bends in a rope where wires or strands are still relatively in their original positions would not be considered serious damage.

Rope wear

10% of the nominal rope diameter (d).

Corrosion

Pitting of the wires or loss of flexibility of the rope due to severe internal corrosion.

NOTE Corrosion may occur where slings have been improperly stored or have been used in particularly corrosive conditions, such as moving loads in and out of acid/alkali baths. The effect is readily identified through the loss of flexibility and roughness to the touch. While light surface rusting is unlikely to affect the rope strength, it may be indicative of internal corrosion, the effect of which is not predictable.

Heat damage

Heat damage as evidenced by discolouration of the wires, loss of lubrication or pitting of the wires caused by electric arcing.

Certex Finland Oy * Juvan teollisuuskatu 25 C * 02920 Espoo * Puh: 0201 550 220 * sales@certex.fi