Safety regulations on chain

[Matt Matt]

I'm not sure if there is a national standard on stretch allowances. I do know that most certified chains have a weight rating. But at what point does the weight rating become void? And chain need to be replaced?

Heck, maybe for the elevator mechanics, when does aviation cable need to be replaced??? and how should it be inspected??? This would probably be applicable for anybody who has a car hoist in the shop.

I asked Ryan to do an edit to the title.

 

[Mikeske]

I'm not sure if there is a national standard on stretch allowances. I do know that most certified chains have a weight rating. But at what point does the weight rating become void? And chain need to be replaced?

Heck, maybe for the elevator mechanics, when does aviation cable need to be replaced??? and how should it be inspected??? This would probably be applicable for anybody who has a car hoist in the shop.

I asked Ryan to do an edit to the title.

Most aviation cable is normally replaced during their 5-6 year inspections (D Check). Almost all aviation cables on new aircraft is no longer used except in backup uses as most modern aircraft are fly-by-wire. I do know that the 747-8 (earlier models of the 747 were cable planes), all models of the 777, all models of the 787, and I believe the newest models of the 737 are all fly-by-wire.

 

[bad_idea]

Perhaps some more info would net more answers. Why do you ask? What use do you have in mind that warrants such concerns?

 

[PCustoms]

Theyake chain stretch gauges for each size and grade of rated chain. If the norch on the gauge fits the link, the link has elongated, narrowing the cross section, and it's no longer capable of holding the rated load.

Off the top of my head I don't know the spec (ANSI?) That these follow, but the engineering is there and sure as heck don't get caught by OSHA using am unlisted/rated chain or one that fails an annual inspection.

Cables can be measured for cross section as well. Those carrying people (I have some experience with ski lifts) are also x rayed and/or periodically load tested.

 

[jubilee]

X2 on chain stretch gauges. You can do the same thing with a micrometer. You can fab your own gauge easily.
Years ago when I worked in the oil field, the drilling line (cable) on a rotary drilling rig load/wear was tracked in a logbook in ton/miles. So many trips in/out of hole, connections and ect. When the ton/mile limit was reached, a calculated amount of line was pulled off the supply spool, though the blocks and crown sheaves and off the drum. The line was then cut and reattached to the drum. Obviously, this changed all the stress points on the line. I'm not sure if it's still done that way today or not. Probably involves a computer today.

 

[maxpower_hd]

I don't remember the reg exactly but I do remember getting some training on hoists many years ago. The gauge is called a go-no-go caliper from what I remember.