When Should I Replace My Crane's Wire Rope?

Your crane's wire rope works hard. (Almost as hard as you do.) It can deteriorate more quickly than you might think, posing a real danger for you and your crew. In this article, we'll answer the following questions. 

• What kind of inspections can or should be done?
• When/how often should crane wire ropes be inspected?
• When does your crane wire rope need to be replaced?
• Who should conduct inspections?
  
  

Before we get into that, let's take a brief moment to go over the proper wire terminology and a coffing hoist wire parts breakdown. Understanding the make-up of the wire rope allows you to have a clear understanding of when the rope needs to be replaced. 

Flexible Steel Wire Rope Terminology

Flexible steel wire rope is made up of individual wires that make up a strand; these strands are then wrapped around a central core to make up a rope. 

Understanding the difference between a wire and a strand is critical. If a strand (grouping of wires) in the rope breaks, the crane wire would need to be replaced. However, if a single wire in the strand breaks, the rope itself may still be usable.

What Kind Of Inspections Should Be Done?

External Crane Wire Rope Inspections 

Visual Inspections: Visual inspections are simple routine surface inspections checking for any visible defects. 

Rag & Visual Inspections: In this method, you use a rag in your inspection, pulling it slowly across the strand, stopping for a closer and more detailed inspection wherever the rag gets caught on a wire. 

The Diameter Measurement Method: This method involves comparing the diameter of your rope at various intervals with the rope's official diameter per the manufacturer's guidelines. A variation in the rope's diameter can alert you to potential interior damage that a visual inspection would miss. 

Internal Crane Wire Rope Inspection Methods

Localized Flaw Inspections (LF) vs. Loss of Metallic Area Inspections (LMA) - Both methods use electromagnetics to search for a wire rope's internal damage. 

LF inspections search for individually broken strands. 

LMA inspections detect and measure the change in diameter that damaged internal wires have caused.

How Often Should You Inspect Your Crane's Wire Ropes? 

According to OSHA's safety regulations, you're required to inspect your crane's wire ropes at least every 12 months by qualified professionals. However, OSHA and other experts also recommend inspecting your wire ropes more frequently, such as after every initial installation or repair, or daily before each shift to ensure a safe work environment.  

When Should You Replace Your Crane's Wire Rope?

As discussed at the very beginning of this article, we can break down wire rope into three parts. First, wires, which make up strands, and then the strands wrapped around the central core make the rope. Of your total number of wires, you never want more than 10% to be damaged before you need to look into crane wire rope replacement. 

Example

5 wires = 1 strand 

10 strands = 1 Rope 

10 strands x 5 wires = 50 wires

50 wires x 10% = 5 wires

So in this example, you wouldn't want more than five broken or damaged wires in the given diameter specified by the rope's manufacturer. 

Who Should Conduct Your Crane's Wire Rope Inspections?

According to OSHA, only "trained personnel should carry out inspections," and according to the Crane Manufacturers Association of America, a certified crane inspector should get 2,000+ hours of field experience and training. 

We at Americrane & Hoist Corporation are just the experts you need, qualified to offer OSHA inspections and provide operator safety training classes to your employees. Contact us today!