Technical Response: From ladders to ropes

Demystifying tech rescue training angles

When talking about tech rescue in the fire service, you don’t have to look far to find a fire department that is promising a high level of technical response delivery. What is even more likely to be seen is a lot of those same departments struggling to meet those expectations or even planning for the proper training for their members to be able to provide these services. However, to sit back and criticize these departments and their training delivery plan will only hurt us as the members on the front line. Our customers’ safety—and the safety of the members serving alongside us—should always be at the forefront of our minds when it comes to our motivation to be proficient at these skills.

But how can we keep up? How is it possible to stay current and proficient in all of these rescue disciplines? The equipment, the safety and the procedures are all very daunting when looking from afar. Can there be a way to make it easier to understand? Not everyone is into the job like some of the experts in these fields and there is nothing wrong with that. What I’m going to try to do going forward with this column is to find similarities to close these training gaps. Where I see proficiency and the ability to perform all tech rescue disciplines is in our talent of simplifying and finding commonalities in each skill set.

First, let’s consider the angle—or in the easiest form, the triangle. This shape was introduced to us in our years of infancy and if you look at the fire service, and more specifically at tech rescue, the triangle and the angle at which it presents itself can help us identify many different advantages and disadvantages. Let’s look at one of the earliest examples we see in our early fire service careers: the ladder.

Angles are everywhere in the fire service, from the simplest of forms to the tech rescue fields.

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When placing a ladder, we all have been taught the 75-degree angle rule or some variation that gets us to that same angle. But what is the reasoning behind that specific angle? When we look closer, we must understand that as we place weight on the ladder by climbing or working off it, that same weight is being transferred to the ladder and down to the butt spurs. As that degree of angle becomes less – 60, 55, 50 degrees – that same weight being applied to the butt spurs is increasing, ultimately making a much better case for the ladder to slip out and/or fall.

A similar example could include a heavy lifting application. Consider an underride scenario where we are required to lift and stabilize a large vehicle that is on top of a smaller vehicle. While the weight we have calculated is a set amount, the placement of our lifting and stabilizing struts can tell another story. In this scenario, we may be supporting a load of 20,000 lbs. By placing the struts at a 75-degree angle, the actual weight being transferred to the strut and down to its base plate is 5,600 lbs. If the same strut angle is decreased to 60 degrees, that weight transfer becomes 11,600 lbs, and 20,000 lbs at 45 degrees. At these calculations, we must seriously consider the weight ratings of our straps or chains as failure will be likely.

Setting multi-point anchors at angles greater than 90 degrees can add considerable weight to our anchor points. Photo: Chad Roberts

Lastly, we’ll apply the theory of angles to a rope rescue. When I think of angles and try to make it relatable to rope rescue, while keeping it to the most basic but important part of our system, I recognize that we need to look at the anchor(s) – specifically multi-point anchors and re-directions. The jurisdiction I work in brings us to many calls that involve patients being stuck down river/cliff embankments, many of which are in wooded areas that require us to get creative with our anchor points. A better understanding of how to apply angle theories allows us to create safe anchors using multiple smaller trees and objects, or even those redirect anchors that we must utilize to create a better hauling field. When using multiple points to create one anchor for a 600 lb load, the resulting angle where they meet (connection point, anchor plate) should ideally never be greater than 90 degrees as this will put 70 per cent of the load, or 420 lb, on each anchor. At 120 degrees, which is our critical maximum, each anchor will take on 100 per cent, or in this case 600 lb each. Therefore, keeping the anchor points under 90 degrees will ultimately cause less stress on our multiple anchors.

Conversely, setting deviations or redirects at angles less than 90 degrees can place more force on our redirect than our original anchor points. Photo: Chad Roberts

The converse is true for redirects. When selecting redirects in our systems, we must remember that the angle at which the rope enters and exits the pulley at the redirect anchor should be greater than 90 degrees to cause less stress on the object you’ve chosen. While somewhat confusing, if the angle is 90 degrees it will be taking on one and a half times the total load and at 180 degrees it will be taking on two times the load. Therefore, when choosing our redirect anchors, we must utilize angles to understand the true forces we are creating.

The main takeaway when we are using angles is similar in many applications: Any time weight is applied and/or transferred from one point to another, the closer that we can keep that point-to-point transfer straight (or plumb), the better off we generally are. Any time we add angles we change how that same weight is magnified or retracted. Angles are everywhere in the fire service, from the simplest of forms to the tech rescue fields. Go out and train with these theories, draw them up on the whiteboard and truly get an appreciation for how angles can help us simplify our most complicated operations.

Chad Roberts is an Acting Captain on a Heavy Rescue in Oakville, Ont. He is a member of the Oakville Extrication Team and Vice President of the North American Vehicle Rescue Association. He also instructs at various colleges throughout Ontario and is a current member of the Canadian Motorsports Response Team. Contact Chad at chadroberts12@gmail.com.