How to Choose the Proper Safety Line for Your Search & Rescue Team

Ropes are some of the most versatile tools in any safety arsenal—from assisting escapes, hauling and rigging, as part of a fall arrest system, or as part of a rope descent device. When it comes to selecting the right one for your team, there are some key characteristics to consider. 

Equipment Compatibility

Sometimes the choice of rope is already predetermined by your equipment. While there are many types of ropes and lines used in rescue operations, it is absolutely essential to be aware that certain safety equipment (particular fall arrest devices, for example) require specific types, sizes, and even brands/models of rope or line. If a device specifies a particular line, use only that line. Any substitutions or variations can lead to serious injury or death.

Rope Material & Construction

There’s evidence of rope use dating back to the dawn of civilization, but fortunately today’s ropes have come a long way in terms of durability and function. For search and rescue, synthetic ropes are the standard; synthetic materials have longer, more consistent strands resulting in a stronger end product.

Common materials include:

Nylon:

Generally the most preferred, and it’s easy to see why. It’s strong, resistant to heat, friction, UV rays, moisture, and chemicals, making it an all-purpose choice for active fall protection as well as a wide range of environments. 

Polyester:

Also widely used, and can withstand heats almost as high as nylon, and has excellent shock absorption—but isn’t as strong as nylon and sinks faster in water. Polyester does have one distinct advantage—its slickness allows for faster rappelling and better handling.  A kernmantle rope (see below) made of a nylon core with polyester sheath offers the best of both worlds. 

Polypropylene:

Another common material. While it is stronger than nylon, it is more susceptible to UV damage, chemicals, and other forms of rot. Polypropylene is, however, highly buoyant, making it a good choice for water rescue operations. 

When it comes to the construction of the rope itself, the most common types are:

Twisted/Laid:

Twisted (aka laid) ropes are made by twisting bundles of individual yarns. These ropes are easily spliced, but can catch easily on obstructions, and have a tendency to kink or rotate under a load—making them a poor choice for active fall protection, for confined space safety, or with a rope descent device. 

Diamond Braid:

These are made by weaving half the yarn strands in one direction, while the other half are woven the opposite way. They can be left hollow, or they can have a center core of parallel fibers for added strength. 

Double Braid:

Double braided ropes are made with an inner hollow single-braided rope at the core, with another hollow single-braided rope around its exterior—essentially a rope within a rope. While these ropes are strong and easy to handle, they tend to snag, abrade, and bunch up when run through hardware or pulleys found in a typical fall arrest system or rope descent device. 

Kernmantle:

Considered to be the gold-standard for search and rescue, kernmantle ropes are made by braiding a cover (mantle) over a core (kern). This design allows the inner core to take the load while the outer sheath protects against abrasion, dirt, and environmental elements. Most high-quality ropes on the market today use kernmantle construction.

Elongation

Elongation is one of the most critical elements of any rope: knowing how much a rope stretches under varying degrees of load helps decipher which is the right one for the job. Ropes with high elongation are known as dynamic ropes, while ropes with reduced elongation are known as static. With dynamic ropes, the greater the elongation, the less force of impact is felt by the system—and, at first glance, may seem a better choice. 

Unfortunately, dynamic ropes require more distance to come to a stop, making it far less versatile for rescue operations—and in some instances, more dangerous. Likewise, the more a rope elongates, the more distance is created between the rescuer and the anchor, raising the risk of the rescuer losing control. If used as a part of a fall arrest system, you’ll need to ensure there is ample distance to mitigate any rebound effect. Lastly, when used as part of a system like a rope descent device, dynamic ropes also reduce efficiency—making static ropes the better choice for operations like tower rescue or confined space safety, which may require a controlled descent and ascent. 

Minimum Breaking Strength

Sometimes referred to as ultimate load or tensile strength, minimum breaking strength measures the amount of force a length of rope can be exposed to until it breaks. Always check with your local regulations to ensure safety and compliance and select a rope that meets or exceeds these standards. 

Diameter

Diameter is directly proportional to strength, and rope should be chosen depending on the likelihood of there being heavier loads in the rescue scenario. Common sizes include:

• 3⁄8 in. (9.5 mm) - smaller, easily handled size for carrying and use with controlled descent devices

• 7⁄16 in. (11 MM) - a standard-size for search and rescue operations

• 1⁄2 in. (12 MM) - a standard-size for search and rescue operations

• 9/16 in. (14mm) - works well with individual sliding fall arrester devices

• 5⁄8 in (16 MM) - for standard lifeline applications

Keep in mind, however, that bigger isn’t always better. As diameter increases, so does the weight of the rope, making it difficult to carry, handle, and use with certain rescue equipment. This should be considered when choosing the right rope for the specific rescue. 

Rope Descent Devices

A rope descent device provides a controlled lowering along a synthetic rope, and it is commonly used for work positioning (like window washing). But they are also an integral part of search and rescue equipment, allowing rescuers to bring people to safety at a controlled pace. 

Generally speaking, a rope is fed through or around a descender, which is then controlled by the user to pace their descent speed. For confined space safety or other rescue operations where a subject must be lifted, a descent device that also offers the ability to ascend can be an invaluable asset. These usually include a hand wheel winch that allows the unit to operate as a lifting device as well.

While there are many descent devices on the market, it’s important to note the differences between devices made for recreational use (like climbing and spelunking) to those made specifically for rescue operations. Rescue devices should be capable of multiple evacuations and ready for consecutive descents. Furthermore, rope descent device systems often come complete with the appropriate rope and other accessories needed, which helps ensure compatibility and usability. 

Choosing the Right System

Given the importance of having the right equipment, it’s clear that the right rope is less about personal preference and more about understanding its functionality—and the type of rescue it’s needed for. Contact the safety experts at Tractel® today to discuss your rescue concerns. We'll help you choose the most appropriate rope, descent device and other active fall protection for the type of rescues you perform. You can count on our staff of qualified safety experts to guide you for all your search and rescue needs, and to provide the best worldwide support and service in the industry.