The Cordage Institute is the only organization in the USA dedicated
solely to rope manufacturing and raw materials.
It is important to note, however, that not all Cordage Institute standards
are relevant to Life Safety ropes. For example, CI-1201 – CI-1313 standards
are relevant to COMMODITY ropes, and not to LIFE SAFETY ropes.
“Resulting in much greater confidence”
The Cordage Institute standard that applies to Kernmantle Life Safety ropes is CI-1801.
This is important, because the tolerances, test methods, and reporting requirements in CI-1801 are much more stringent than in non life-safety standards.
For example, commodity rope standards typically derive an inferred diameter based on mass per unit length,
and an inferred strength based on diameter… whereas the life safety rope document dictates
very specific test methods for actual diameter (important for equipment compatibility)
as well as actual strength testing of multiple samples. CI-1801 also specifies
that the reported minimum breaking strength (MBS) be at least 3 standard deviations
below the mean of all test results… resulting in much greater confidence in those numbers.
CI-1801 is used as a reference document and as a baseline for other standards related to specific work at height.
While people who sit on such user based standards committees, such as NFPA, ASTM, ANSI, SPRAT, etc,
tend to be experts in those areas, it is recognized that deferring to rope industry experts – such as Cordage Institute –
is the prudent approach when it comes to testing for ropes. Therefore these industry standards usually reference
the CI-1801 document as a baseline for testing ropes for their application, but then place some
additional use-parameters on those ropes.
For example, while CI-1801 covers a wide range of rope diameters and properties,
NFPA 1983 narrows the range of what they accept to only those above a certain minimum breaking strength,
for specific applications. You may also find ANSI Z359 marks on ropes.
CI-1801 also clarifies the difference between what is known as a “static life safety rope”
(less than 6% elongation at 10% MBS) as compared with “low stretch life safety rope” (6-10% elongation at 10% MBS).
“EN 1891 is a European standard”
Another standard to which low stretch life safety ropes are sometimes marked is EN 1891.
This is a European standard. The US government does not officially recognize EN standards
(nor the CE mark) but on some occasions the EN standards and CE mark
may be accepted by private companies within the USA. This standard specifies slightly different
test methods and performance requirements than CI-1801, so the two are not the same.
For example, EN 1891 does not acknowledge ‘static’ rope at all – which can be problematic for rescuers
and others for whom low bounce and consistent positioning of loads is important; still, EN 1891 is an acceptable standard for some life safety applications.
In short, when specifying ropes for life safety applications, always and only accept ropes that meet standards
that are specifically designed and intended for life safety use. Standards used for commodity ropes simply
do not contain specific enough guidance nor tight enough tolerances on test methods and performance requirements
such as strength, diameter, and elongation.