Climbing Self Rescue Course

Gear and Material Overview

Introduction: Understanding Climbing Gear Materials

Climbing gear is designed to ensure safety in challenging environments, and the materials used in its construction are key to its performance. Metals like steel and aluminum provide strength and durability, while textiles and polymers such as nylon, Dyneema, and Kevlar offer various characteristics, including flexibility, abrasion resistance, and heat resistance in ropes, slings, and harnesses.

Each material has unique properties that make it suited to specific applications. Understanding the properties of these materials can help you make informed decisions, recognize signs of wear, and use the correct piece of gear for the task at hand.

Broadly speaking, we can divide our safety equipment into two main categories:

• Hardgoods, which are made from metals, and
• Softgoods, which are made from textiles and polymers.

Metals

Steel

• High abrasion resistance, ideal for rugged use and frequent contact with rock or metal.
• Allows for thin cross sections, maintaining strength while reducing bulk.
• Corrosion or rust appears red and pitted, which follows our common intuition.

Aluminum

• Extremely lightweight, making it ideal for larger cross sections without adding excessive weight.
• Prone to wear; inspect for thinning or deformation over time.
• Corrosion appears white or green and powdery, which can weaken structural integrity.

Textile/Polymers

Nylon/Polyester

• The most common materials, suitable for a wide range of climbing applications.
• Durable, flexible, and reliable in knots and hitches.

HMPE (Dyneema/Spectra)

• A specialty material, exceptional for its strength-to-weight ratio.
• Slippery surface, making it unsuitable for safety knots, or dynamic systems.
• Low melting temperature ~135°C (275°F), unsuitable for applications like friction hitches or other high wear scenarios.

Aramid (Technora/Kevlar)

• Another specialty material, offering impressive strength relative to weight.
• High melting temperature, making it ideal for heat and friction applications, such as friction hitches.
• Degrades faster with high use; inspect frequently for wear or damage.

Strength Ratings (kN) Explained

In climbing, kN (kilonewtons = 1000 newtons) is a measure of force. Where F=ma or Force = Mass x Acceleration where the units are Newtons = kg * meters/second². It is used to indicate how much weight or force a piece of gear can withstand before breaking or failing. To give you an idea of what these numbers mean in everyday terms, here are some examples:

• 10 kN = ~2,248 pounds (~1000 kg). This is roughly the weight of a small car.
• 20 kN = ~4,496 pounds (~2000 kg). This is close to the weight of a medium-sized SUV.

What does this mean for climbers?

A carabiner or other climbing hardware with a 20 kN strength rating is strong enough to withstand significant force, such as the force generated by a lead fall. However, the actual forces involved in a fall depend on several factors, including the climber's weight, the rope's ability to absorb impact, and the type of fall.

For example:

• Lead fall forces commonly range in the 2-4 kN on the climber and belayer. With a common high end of~6kN on the anchor/piece catching the lead fall.
• A fall factor - which is a ratio of how far you've fallen to how much rope you have out - is one of the main contributors affecting the force. The higher the fall factor, the greater the force on the gear. For example, a fall factor of approaching 2 (falling twice the length of rope) can easily generate forces above 10 kN.

Carabiner Orientation and Strength

The strength rating of a carabiner varies depending on its orientation and the direction of the load applied:

• Major axis (when the load is applied from end to end) is typically the strongest orientation, and this is where you'll see the highest kN rating.
• Minor axis (when the load is applied side to side across the narrow axis) is much weaker, usually reducing the strength to about ⅓ the full strength of the carabiner. Some carabiners may only have a strength rating of ~5-7 kN on the minor axis.
• Gate open also reduces the carabiner strength to similar ratings as the minor axis.

When using climbing gear, make sure that the load will be applied in the correct orientation and that the carabiner will stay fully closed.