SurfaceFabrication.com |

In the surfacing industry, cranes and hoists are often used to aid in the movement of large materials or products. These types of equipment typically use slings to hold their suspended loads. Some shops may also use slings attached to fork trucks to move materials. Improper selection or use of slings can result in sling failure or load slippage, which in turn can lead to injuries or death along with property damage.

OSHA recently issued a new guide on the selection and use of slings for handling and moving materials. This document updates the 1975 OSHA standard by including information on synthetic round slings and newer grade materials being used in alloy steel chain and wire rope slings.

Because OSHA’s standard was not as current as other industry standards, sling manufacturers have begun manufacturing and marking slings in accordance with American Society of Mechanical Engineers (ASME) standard B30.9-2003, Slings.

The recent guidance document is a combination of OSHA’s sling standards, ASME’s consensus standard and other relevant information. Specifically, this guidance document includes information on synthetic round slings, which were not covered in OSHA’s sling standards.

Problems with sling use include improper choice of sling or attachments for the type of load or the environment; worn or damaged slings and attachments including cracks, kinks, bends, cuts, gouges and frayed fibers; improper storage of slings; and misuse of slings by resting loads on the sling, dragging of slings across abrasive floors or similar misuse.

The guide describes a variety of slings, including alloy steel chain, wire rope, metal mesh, natural fiber rope, synthetic fiber rope, synthetic web and the commonly used synthetic round slings. The latter is an important addition, since it is not covered in the current OSHA standard.

SYNTHETIC ROUND SLINGS

Synthetic round slings are popular because they offer strength, convenience, load protection and economy. The guide discusses the most commonly used synthetic round slings, which are made of nylon- or polyester-type yarns (Figure 1). Each synthetic material has its own unique properties. Certain synthetic materials perform better than others in specific applications and environments. Be sure to check with the manufacturer before using a synthetic sling in and around chemical environments.

Slings are labeled for the core material and the cover material if different from core material. Information will also be given for the rated load based on the type of hitch and the angle. Slings are also typically marked with the name or trademark of the manufacturer and the manufacturer’s part number or other numerical code.

Rated loads (capacities) for synthetic round slings are as shown in Figure 2. Rated loads are based on material strength, design factor, type of hitch, angle of loading and the diameter of curvature over which the sling is used. The closer the angle of use is to vertical, the higher the load rating. For angles not shown in the table, or for angles of choke less than 120 degrees, the guide recommends that you use the next lower angle or ask a qualified person to calculate the rated load.