Essential Guide to Rope Access Rigging Principles: Anchors and Tension

In the industrial rope access scene, your life hangs in the balance. Although ascending and descending are the overt skills of the trade, rigging is the intellectual backbone. A technician who climbs fast but rigs poorly is a liability; a rigger who rigs precisely, and even ahead of time, is an asset.

At Atlas Access Training, we stress that rigging is not all about knots, but also an exploration of physics, angles, and redundancy. In this guide, we cover the fundamental principles of anchors and tension that every Level 2 and Level 3 technician must understand.

Understanding Load Sharing and Load Distribution on Anchor Systems

A key building block of strong anchoring is the difference between load sharing and load distribution. In an equalised anchor, the load is shared between two or more anchor points. The classic example is the Y-hang.

The angle is the crucial factor here. We teach the ‘Critical Anchor’ rule – when the angle between the legs of a set-piece grows higher, the force on these multiple anchor points also increases. You want this angle ideally to be less than 90 degrees. If you get above 120 degrees, the force on each point of stability is greater than the load – a risky situation.

So, load distribution is typically a case of rigging such that one anchor takes the primary load and the others replace or share within the load under very specified deformation. For different structural geometries, knowing when or not to use a self-equalising system versus a fixed-focus system is essential for accommodating the various configurations.

Mandatory Anchor Selection: Primary and Secondary Points

The required choice of anchors is based on primary and secondary points, as well as the necessary choice. IRATA standards are also based on redundancy. Rope access systems have two separate, independent points of attachment – a first (working line) and a second (safety/backup line). ‘Bombproof’ is the industry slang when choosing anchors, but the technical requirement is ‘unquestionably reliable’.

Primary Anchors: These need to be able to carry the static load of the rope, as well as possible dynamic loads. Structural steel beams are best.

Secondary Anchors: They have to be as strong as the primary. One common mistake is to select the weaker secondary point because it won’t be used. It has to be strong – the secondary suffers a great shock load if the primary fails. Never use anything problematic, such as handrails (not certified), PVC pipes or rusting metalwork.

Mastering Advanced Rigging: Tensioned Lines and Work Restraint Systems

Beyond the usual vertical drops, you see tensioned lines. Tensioned lines (Highlines or Tyroleans) enable the horizontal movement or diagonal drop. The physics here are unforgiving. A highly tensioned rope is a kind of guitar string; a slight amount of weight in the centre can create large forces on the end anchors (vector forces). These loads must be accurately calculated by technicians so as to preserve safety factors.

Work restraint is a preventative rigging process. But rather than arresting a fall, the rigging keeps the technician from getting to the fall danger. This is usually best used for rooftop work, but it needs specific changes in lanyard lengths in order to be effective.

Rigging Best Practices in Confined and Difficult-to-Access Areas

Rigging in confined spaces (silos, shafts, ducts) has unique challenges. You’re not usually going to have headroom and standard structural beams.

Deviation Anchors: Use to divert the rope path from abrasive edges or obstructions.

Re-Anchors: Decreasing long drops into shorter ones by the aid of re-anchors (re-belays) not only minimises rope extension but also provides easier rescue management.

Edge Management: In the most unforgiving terrain, it’s crucial to protect the rope. If the rig is working, but the rope runs over a jagged steel edge without a protector, the integrity of the system is destroyed.

Daily Anchor Inspection Checklists for Safe Operations

Rigging is not a ‘set and forget’ job. Conditions change. Every technician must complete a daily inspection checklist:

• Integrity: Are the slings or karabiners worn or chemically damaged?
• Security: Are all karabiners screw-gated and locked? Are all knots properly dressed and stressed?
• Loading: Has the loading direction shifted? Is the angle still safe?
• Protection: Is rope protection still effective and within acceptable limits?

Ready to Upgrade Your Rigging Knowledge?

Are you looking to improve your rigging know-how? Advanced rigging is the core of the curriculum, whether you are moving from Level 1 to 2 or from 2 to 3. Book your training week with Atlas Access Training today.