0
$\begingroup$

I found a 40ft. length of rope for sale at the dollar store. Not having high expectations to start with, I examined the packaging closer out of curiosity. The front of the label states that the rope has 200lbs of tensile strength... Not all that much, but okay, in line with expectations. Turning it over to read the fine print on the back, "misuse... serious injury or death" mhm, alright... "Do not use to..." uh huh, okay, nope, no, nuh uh, wasn't planning to, and wh...? "The tensile strength and minimum breaking strength of this product have NOT BEEN RATED." (Emphasis original)

From a professional engineering standpoint, what must occur for a product such as this to be formally rated? As it stands with the disclaimers, that 200lbs figure on the front sounds like it was pulled out of someone's wazoo.

Improve this question
$\endgroup$
3
  • 3
    $\begingroup$ Rated means it has actually been tested to that in some sense (such as a sample), but not to the point of that specific individual item you are holding being tested and certified. Otherwise the number is just theoretical calculations based on cross section using numbers pulled from material strength table. $\endgroup$
    – DKNguyen
    Commented Mar 12 at 16:03
  • $\begingroup$ If you bought it from the dollar store, stuff on the package doesn't mean anything at all. More generally, ratings imply a controlled manufacturing process, and at a minimum, a specific and repeatable and published test procedure - which hopefully lets you deduce that it's fit for purpose - but without the manufacturer having made that claim to you. $\endgroup$
    – Pete W
    Commented Mar 12 at 16:22
  • $\begingroup$ Because safety is involved, for them to sell it and claim - or even imply - that it's fit for purpose, may violate laws regulating commerce (safety, professional licensing requirements, etc) and would put the manufacturer, suppliers, and the store all at risk of being sued $\endgroup$
    – Pete W
    Commented Mar 12 at 16:24

1 Answer 1

Reset to default
2
$\begingroup$

"Rated" means it has been proof-tested by an independent lab (like UL or CSA) according to a published standardized test protocol invented by a standards organization (like ASTM) and sufficient trials have been conducted to achieve statistical significance.

This costs money, and cheap product manufacturers skip this step whenever possible. Note that with electrical consumer goods in the USA, you cannot skip this step and must apply for, pay for, and obtain UL approval.

Improve this answer
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.