got some info from pirate 4x4
Chain
Another piece of gear you see on the trail all the time. It can be extremely useful and versatile, but is very often misused. If chain is going to be used anywhere in a recovery operation (and personally, I think this should be avoided if possible, because of the hazards, and most importantly because often grade, strength, and condition are difficult to verify), it should only be Grade 80 Alloy Steel chain of a size suitable for the task.
Chain for alloy steel chain slings shall conform to the requirements of ASTM A391/A 391M, Standard Specification for Grade 80 Alloy Steel Chain. Rated
loads for alloy steel chain slings shall be based on a minimum design factor of 4
Requirements for attachments to alloy steel chain slings follow:
1. Hooks, rings, oblong links, pear-shaped links, mechanical coupling links, or other attachments shall have a rated load at least equal to that of the alloy steel chain with which they are used.
Inspection:
Chain and attachments should display no wear, nicks, cracks, breaks, gouges, stretch, bends, weld splatter, discoloration from excessive temperature, or excessive throat opening of hooks. Chain links and attachments shall hinge freely with adjacent links. Latches on hooks, if present, should hinge freely and seat properly without evidence of permanent distortion.
Operating Practices.
Operating practices and guidelines for the use of alloy steel chains are as follows:
1. Chain having suitable characteristics for the type of load, hitch, and environment shall be selected.
2. The weight of the load shall be within the rated load (working load limit) of the chain.
3. Chains shall not be shortened or lengthened by knotting, twisting, or other methods not approved by the chain manufacturer.
4. Chains that appear to be damaged shall not be used unless they are inspected and accepted as usable in accordance with the periodic inspection requirements stated above.
5. The chain shall be hitched or rigged in a manner providing control of the load.
6. Sharp corners in contact with the chain should be padded with material of sufficient strength to minimize damage to the chain.
7. Portions of the human body should be kept from between the chain and the load and from between the chain and the winch hook.
8. Personnel should stand clear of the recovery.
9. Shock loading is prohibited.
10. Chain should not be pulled from under a load when the load is resting on the chain.
11. Chains should be stored in an area where they will not be subjected to mechanical damage, corrosive action, moisture, extreme heat, or kinking.
12. The load applied to the hook should be centered in the bowl of hooks to prevent point loading on the hook, unless the hook is designed for point loading.
13. Chains should not be dragged on the floor or over an abrasive surface.
14. When used in a choker hitch arrangement, chains shall be selected to prevent the load developed on any portion of the chain from exceeding the rated load of the chain sling components.
from here
http://www.pirate4x4.com/tech/billavista/Recovery/index.htmlafter reading the article I agree that chains are almost impossible to verify their strength/ load cap. therfore clubs would rather not allow them then be liable for breakage. so it is safer by "idiot proofing"
