OHS Code Explanation Guide

Published Date: February 23, 2012
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Part 21 Rigging

Section 297 Sling standard

ASME Standard B30.9-2006, Safety Standard for Cableways, Cranes, Derricks, Hoists, Jacks and Slings, applies to slings intended for lifting, made from alloy steel chain, sewn synthetic webbing, wire rope, metal mesh and synthetic fibre rope. The Standard describes technical requirements for construction, load rating, proof testing, identification, maintenance, environmental effects, end attachments, inspection, repair and use. Figures 21.2 to 21.7 show a variety of different types of slings. The Standard specifies that inspections be conducted as described in Table 21.1.

Figure 21.2 Example of metal mesh fabric

Figure 21.3 Example of metal mesh sling

Figure 21.4 Chain sling major components

Figure 21.5 Synthetic webbing slings

Figure 21.6 Wire rope slings

Figure 21.7 Synthetic roundsling configurations

Table 21.1 Sling inspections based on sling type

Type of Sling

Inspection

Type

What to Look For

How Often

Chain Frequent
  • Chain and attachments for wear, nicks, cracks, breaks, gouges, stretch, bends, weld splatter, discoloration from excessive temperature, and throat opening of hooks
  • Missing/illegible markings
  • Seating, free hinging, distortion of hooks/latches
*Normal service – monthly

*Severe service – daily to weekly

*Special service – as recommended by qualified person

Periodic
  • Same as "Frequent" inspection, link by link
  • Inner surfaces of each link
  • Wear not to exceed manufacturer’s specifications
*Normal service – annually

*Severe service – monthly to quarterly

*Special service – as recommended by qualified person

Wire Rope Frequent
  • Distortion such as kinking, crushing, unstranding, birdcaging, main strand displacement, core protrusion, loss of rope diameter, unevenness of outer strands
  • General corrosion
  • Broken or cut strands
  • Number/distribution/type of visible broken wires
  • Missing/illegible markings
Daily
Periodic
  • Deterioration warranting removal
  • 10 randomly distributed broken wires in one rope lay, or 5 broken wires in one strand in one rope lay
  • Severe localized abrasion or scraping
  • Kinking, crushing, birdcaging, or other distortion
  • Evidence of heat damage
  • Cracked, deformed, worn attachments
  • Severe corrosion
Based on how often the sling is used and severity of service conditions, but at least annually
Metal Mesh Initial Verify correct sling is being used Prior to first use as new or repaired
Frequent
  • Broken weld or brazed joint along edge
  • Broken wire in mesh
  • Reduction in wire diameter of 25 percent due to abrasion or 15 percent due to corrosion
  • Distortion in the mesh
  • Distortion of the slot in choker fitting by more than 10 percent
  • Distortion of end fittings
  • 15 percent reduction of original cross-sectional area at any point around hook opening or end fitting
  • Cracked or visibly distorted end fittings
  • Missing/illegible markings
Daily
Periodic Same as for "Frequent" inspection Based on how often the sling is used and severity of service conditions, but at least annually
Synthetic Rope Initial Verify correct sling is being used Prior to first use as new or repaired
Frequent
  • Cuts, gouges, extensive fibre breakage along the length, abraded areas
  • Reduction of rope diameter by more than 10 percent
  • Uniform fibre breakage along major part of the length of the rope such that the entire rope appears covered with "fuzz" or "whiskers"
  • Fibre breakage or melted fibre involving 10 percent of the fibre in the strand at any point
  • Discolouration, brittle fibres, chemical or ultraviolet damage
  • Foreign matter permeated in the rope attracting and holding grit
  • Kinks/distortion
    Melted or charred areas that affect more than 10 percent of rope diameter or affect several adjacent strands to more than 105 of individual diameters
  • Corrosion, cracks, distortion, localized wear of thimbles or other fittings
  • Other visible damage
  • Missing/illegible markings 
Daily
Periodic Same as for "Frequent" inspection Based on how often the sling is used and severity of service conditions, but at least annually
Synthetic Webbing Initial Verify correct sling is being used Prior to first use as new or repaired
Frequent
  • Acid or caustic burns
  • Melting or charring
  • Holes, tears, cuts, snags
  • Broken/worn stitching in load-bearing splices
  • Excessive abrasive wear
  • Knots
  • Excessive pitting or corrosion, or cracked, distorted or broken fittings
  • Other visible damage
  • Missing/illegible markings
Daily
Periodic Same as for "Frequent" inspection Based on how often the sling is used and severity of service conditions, but at least annually
Synthetic Roundsling Initial Verify correct sling is being used Prior to first use as new, altered, modified or repaired
Frequent (records not required)
  • Melting or charring
  • Holes, tears, cuts, abrasive wear, snags, exposed core yarns
  • Damaged, stretched, cracked, worn, pitted, distorted fittings
  • Knotting
  • Other visible damage
  • Missing/illegible markings
*Normal service – daily

*Severe service – each use

*Special service – as recommended by qualified person
Periodic (recorded as basis for continued use) Same as for "Frequent" inspection *Normal service – daily

*Severe service – each use

*Special service – as recommended by qualified person

* Type of sling service:

  • Normal – involves use of loads within maximum load rating
  • Severe – involves normal service coupled with abnormal operating conditions
  • Special – involves operation, other than normal or severe, that is recommended by a “qualified person” (a person who, by possession of a recognized degree in a relevant field or certificate of professional standing, or who, by extensive knowledge, training, and experience, has successfully demonstrated the ability to solve or resolve problems relating to the subject).

Subsection 297(2)

A below-the-hook lifting device is a device used for attaching loads to a hoist. ASME Standard B30.20-2006, Below the Hook Lifting Devices, presents requirements that apply to the marking, construction, installation, inspection, testing, maintenance, and operation of such devices. These include

  • structural and mechanical devices e.g. plate clamps, bar tongs, spreader bars,
  • vacuum devices e.g. single pad, multiple pad,
  • close-proximity operated machines e.g. electrically-controlled, manually-controlled,
  • remotely operated magnets e.g. circular, rectangular, and
  • scrap and material-handling grapples e.g. orange peel grapple, magnetic grapple.

The Standard requires that each device be marked with its related load limit, manufacturer name and address, serial number, lifter weight and other information as noted, directly on the device or on a tag attached to it.

The Standard specifies the following inspection intervals:

  • Visual examination before and during each lift
    • Surface of the load for debris
    • Condition/operation of controls
    • Condition/operation of indicators or meters
  • Frequent visual examinations reflecting the degree of use
    • Normal service – monthly
    • Heavy service – weekly to monthly
    • Severe service – daily to weekly

Inspectors are to look for the following:

(a) deformation, cracks, or excessive wear in structural members;
(b) loose or missing guards, fasteners, covers, nameplates;
(c) proper function/alignment of operating mechanisms;
(d) proper operation of vacuum generators;
(e) vacuum pad seals for cracks, tears, excessive wear, leakage, cuts, kinks of vacuum lines and connections;
(f) appropriate levels in the entire vacuum system;
(g) condition of magnetic device face, lifting bails, control handles, indicators, electrical conductors, battery (where applicable); and
(h) condition of hydraulic lines and cylinders.

The Standard requires complete inspection based on the degree of use

  • Normal service – yearly
  • Heavy service – semiannually (quarterly on magnetic devices and grapples)
  • Severe service – quarterly (monthly on magnetic devices and grapples)
  • Other as noted in the Standard or in the manufacturer’s specifications or instructions

Inspectors are to look for the following:

(a) all items under “Frequent” inspections;
(b) loose bolts, fasteners;
(c) cracked/worn gears, pulleys, sheaves, sprockets, bearings, chains, belts;
(d) excessive wear at hoist hooking points and support shackles or pins;
(e) damage to motors, controls, auxiliary components;
(f) condition of electrical motors and components;
(g) condition of hydraulic motor; and
(h) other components as noted in the Standard or in the manufacturer’s specifications or instructions.

Subsection 297(3)

Many spreader bars are extendable and their load capacity varies with their length. Table 21.2 provides an example of a capacity data sheet for a spreader bar. If such a data sheet is not available from a device manufacturer, it is important to have one prepared by a professional engineer.

Subsection 297(4)

Where a capacity data sheet is used in accordance with subsection (3), an employer must ensure that the correct and corresponding sheet is used with each spreader bar. This is accomplished by ensuring that the data sheet and corresponding spreader bar are identified by a unique numbering system. Procedures for use of the bar should include an initial check to ensure that the correct data sheet is being followed.