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Has been replaced by ropes made from synthetic fibers, though there may be a few left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.
Class III
Fastens around the waist, around the thigh or under the buttocks, and over the shoulders.
a. Rated for loads up to 600lbs. (272kg.)
b. Also known as ‘full body’ harness.
Carabiners
a. Aluminum or steal connectors that link the rapeller’s webbing to the rope
i. Aluminum – rated to 6000lb (personal load 300lb, max 400)
ii. Steel – rated to 9000lb, rescue load 600lb
Figure 8 descenders
used for descending
a. Same specs for steel and aluminum carabineers
OATH rope signals
O = OK – 1 tug A = Advance – 2 tugs T = Take up slack – 3 tugs H = Help – 4 tugs
Types of damage to rope
Abrasion Chemical Heat/fusion/friction UV Moisture Shock Loading
Abrasion
(90% of all damage)
a. Stepping on, driving over, chaffing
b. Do not step on, place on sharp edges, rope sharp stuff, swing around while rappelling
Chemical damage
If it can hurt you, it can hurt the rope
heat friction/heat fusion
a. Heat fusion is when rope rubs against rope
b. Heat friction is when rope rubs against other stuff
Kernmantle heat damage stats
i. Will yellow after 5 consecutive hours of 300 degree heat
ii. Becomes sticky at 445
iii. Melts at 480 (per NFPA 1983, life safety rope must have a minimal melting temp of 400)
Manila hemp heat damage stats
i. Progressive heat loss above 180 degrees
ii. Sunlight also greatly weakens rope
UV damage
Duh. The sun burns stuff.
Moisture damage stat
a. Kernmantle – water weakens the rope by 10-15% but it recovers HP when dried
b. Manilla Hemp – irrevocably loses 50% tensile strength when wet
Shock loading
a. Excess G forces damage internal rope tensile strength.
How are webbing and polypropylene affected by rope damage?
- Webbing and polypropylene rope are affected similarly, but polypropylene is more easily damageable.
When and what do you inspect on ropes?
a. Inspect quarterly and after each use
b. Information is kept in rope history log (on trucks)
i. List ID info, manufacture info, what the rope is used for, date/location/reason for use, comments on exposure/damage.
c. Inspect ladder halyards monthly during ladder inspections
What should you look for during inspection?
i. Discoloration
ii. Glossy marks
iii. Cuts/tears in sheath
iv. Obvious changes in diameter
v. Fraying
vi. Chemical contamination
vii. Other evidence of damage (burns, etc)
How do you clean a rope?
e. Clean rope by chaining it and putting it in washing machine with a mild soap
NO BLEACH
A good knot is _____
a. Easy to tie
b. Easy to untie
c. Remains tied
d. Easily identifiable
e. Minimal reduction of breaking strength of rope
f. Resistance to jamming under load
Define knot
Rope tied to self
Define bend
Rope tied to other rope
Define hitch
Rope tied to thing
Define working end/bitter end/tag end
the end of the rope used to tie the knot
Define standing end
The other end, the one with all rope
Define bight
The U shape section of the rope
a. Overhand knot and double overhand
Stopper and back up knots
Slip knots
Used to draw tight on something
Square knot
i. Connects two ropes of equal diameter
ii. Decreases tensile strength by 50%
Family of eights
i. Figure eight
1. Decreases tensile strength by 20%
2. Stoppers and basis for many other knots
ii. Figure eight on a bight
1. anchor
iii. Figure eight follow through
1. anchor
iv. Rescue eight
1. Two loop eight
2. Used for rescue. Hence the name.
Bowline family
i. Bowline
1. Decreases tensile strength by 33%
2. Used for anchoring
ii. Bowline on a bight
1. Rescue knot similar to rescue 8
iii. Running bowling
1. Used to tighten down on an object
Butterfly knot
i. Used to make an anchor point in the middle of a rope
ii. Decreases the tensile strength by 30%
Half hitch
i. Used to secure line to object
ii. Basis for other knots
iii. Not sufficient to use by self
Clove hitch
Secures line to object
Munter Hitch
Used with carabiners for emergency rappels
Becket (sheet) bend
i. Reduces tensile strength by 50%
ii. Used to tie two ropes of unequal diameter together
Water Bend
i. Used to tie ends of webbing together
ii. Not to be used on rope!
