Ropes and knots Flashcards
Uses for rope
halyards, swift water rescue, high angle rescue confined space rescue, hoisting, and many more
life safety rope make
100% nylon
Swift water rescue make
polypropylene
utility rope make
usually nylon
Types of rope
“a. Kernmantle
b. Laid (twisted)
c. Braided
d. Braid-on-braid
e. Nylon webbing”
Dynamic kernmantle
has twisted bundle construction- normally 8% stretch with 200lb. load, 60% near failure
Static Kernmantle
“core has parallel bundle construction
Elongation: Normally 1% minimum- 10% maximum of 10% of the rated breaking strength”
Strength of kernmantle is found where?
“c. Kern: Core, containing approximately 75% of strength
d. Mantle: Sheath, containing approximately 25% of strength”
Sheath of kernmantle can be either ____ or ____
“i. ‘Tight” weave- better abrasion resistance but harder to tie into knots.
ii. “Loose” weave- easier knot tying but less abrasion resistance. “
NFPA for ropes
1983
Stats for TFD kernmantle use
“i. ½” diameter
ii. Minimum breaking strength: 9000lbs.
iii. Maximum working load: 600lbs.
1. Ropes hold to 15:1 safety ratio, ie 9000lb max load to 600lb working load.
iv. Weight: approximately 7lbs. per 100’.
v. Suppression units carry 150’ in length.
vi. TRT/RRT carry up to 600’ in length”
Laid
“a. Natural fibers (Manila hemp) – three twisted fibers (yarns) bundled together to form strands.
b. Rope will twist in the opposite direction of lay when under load.
c. All fibers are exposed.
d. High stretch characteristics.”
Braided
“a. No core or outer sheath.
b. Load-bearing fibers are exposed to direct abrasion and damage”
Braid on braid
“a. Synthetic- Nylon and polypropylene.
b. Braided fibers through each other.
c. Less abrasion resistance than kernmantle.
d. High stretch characteristics.
e. Load is share- 50% with core and 50% with sheath”
nylon webbing
“a. Issued to all uniformed members.
i. Recruits will be issued enough red to make a Hansen seat, and enough blue to lift items.
b. Red: Used exclusively for class 3 rappelling harness (Hansen Harness).
c. Blue: Utility purposes only.
d. Constructed of continuous nylon fibers woven in a spiral weave to produce tubular shape.
e. Minimum breaking strength of 4000lbs.
i. 15:1 ratio is about 250lbs.
ii. Used only in an emergency because SCBA FF is normally +250lbs”
Manila Hemp
Has been replaced by ropes made from synthetic fibers, though there may be a few left
Define Newton
The amount of force needed to accelerate 1 kilogram of mass at the rate of 1 meter per second squared
1 N=
.225 lbs thus one kN = 225lbs
OATH rope signals
"O = OK – 1 tug A = Advance – 2 tugs T = Take up slack – 3 tugs H = Help – 4 tugs
NFPA 1983 requirements
- Standard on Fire Service Life Safety Rope, Harness, and Hardware
- Class I load— 300lbs.
- Class II load— 600lbs.
- Minimum 15:1 safety margin.
Class I
Fastens around the waist and around the thigh or under the buttocks. Intended to be used for emergency escape with a load of up to 300lbs. (136kg.)
Class II
Same a Class I, but rated for loads up to 600lbs. (272kg.)
a. Looks exactly like Class I harness, so attached label must be used to verify its rating.