Rope
Fiber Selection Guide:
Fiber Properties and Typical Values
STRENGTH:
Manila
Sisal
Cotton
Nylon
Polyester
Poly-
propylene
Poly-
ethylene
Kevlar1*
Spectra2*
Breaking Tenacity– (grams/denier)
5.0-6.0
4.0-5.0
2.0-3.0
7.0-9.5
7.0-9.5
6.5
6.0
18-26.5
30.0
Wet
Strength vs. Dry Strength
Up
to 120%
Up
to 120%
Up
to 120%
85-90%
100%
100%
100%
95%
100%
Shock-load
Absorption Ability
Poor
Poor
Very
Poor
Excellent
Good
Very
Good
Fair
Poor
Fair
WEIGHT:
Specific Gravity
1.38
1.38
1.54
1.14
1.38
0.91
0.95
1.44
0.97
Floats
No
No
No
No
No
Yes
Yes
No
Yes
ELONGATION:
Percent at Break
10-12%
10-12%
5-12%
18-25%
12-15%
15-25%
15-25%
1.5-3.6%
3.5%
Creep
(extension under sustained load)
Very Low
Very Low
Very Low
Moderate
Low
High
High
Very Low
Moderate
EFFECTS
OF MOISTURE:
Water Absorp. of Individual Fibers
Up to 100%
Up to 100%
Up to 100%
2-8%
< 1%
None
None
3.5-7.0%
None
Dielectric
Properties
Very
Poor
Very
Poor
Very
Poor
Poor
Good
Excellent
Excellent
Poor
Excellent
DEGRADATION:
Resistance to UV in Sunlight
Good
Good
Good
Good
Excellent
Poor
(black is best)
Fair
(black is best)
Fair
Fair
Resistance
to Rot and Mildew
Poor
Poor
Poor
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Storage
Requirements
Dry
only
Dry
only
Dry
only
Wet
or Dry
Wet
or Dry
Wet
or Dry
Wet
or Dry
Wet
or Dry
Wet
or Dry
ROPE
ABRASION RESISTANCE:
Surface
Good
Fair
Poor
Very Good
Excellent
Good
Good
Fair
Very Good
Internal
Fair
Fair
Fair
Excellent
Excellent
Good
Good
Poor
Excellent
THERMAL
PROPERTIES:
Melts
at
Does
not melt, Chars at 350°
Does
not melt, Chars at 350°
Does
not melt, Chars at 350°
420-480°
490-500°
330°
275°
800°
-Begins
to de-
compose
297°
RESISTANCE
3*:
Resistance to Acids
Poor
Poor
Poor
Fair
Good
Excellent
Excellent
Fair
Excellent
Resistance
to Alkalis
Poor
Poor
Fair
Very
Good
Fair
Excellent
Excellent
Fair
Excellent
Resistance
to Oils
and Gas
Poor
Fair
Poor
Very Good
Very Good
Very Good
Very Good
Very Good
Very Good
1*
Based on DuPont KevlarŽ data
2* Based on Allied-Signal SpectraŽ
data-Type 900
3* Resistance is relative to the
length of exposure, percent of concentration and temperature.
CAUTION: Use of Working Loads
Because of the wide range of rope use, rope condition, and exposure
to the various factors affecting the rope, it is impossible
to make blanket recommendations as to the correct choice of
rope to use. However, we have provided the tensile strength
for each diameter and type of rope. These strengths are based
on tests of new and unused rope, with appropriate splices. Proper
choice, care and inspection of the rope are essential for reasonably
safe use of the rope. Consult your cordage vendor for proper
use.
Dynamic Loading Voids Normal Works Loads
Dynamic Loading occurs when rope is subjected to sudden or extreme
stress. Figures given as working loads are void if rope has
been subjected to dynamic loading, high temperatures, long periods
of load, extreme stress, improper use or storage.
Effect of Temperature on Tensile
Strength
The tensile strength charts apply to ropes tested at normal
room temperature (70°F). Ropes have lower tensile strength at
higher temperatures. Continued exposure at elevated temperatures
causes permanent damage.
WARNING! MISUSE OF ROPES COULD RESULT IN SERIOUS INJURY.