Roundsling, Websling, Cloverleaf Slings - Man-Made

 

MAN-MADE FIBRE SLINGS

INTRODUCTION

1 This circular describes the different types and legal requirements for man-made fibre slings. They are in widespread use in the manufacturing, construction and dock industries.

BACKGROUND

2 There are three types of man-made fibre sling in common use; the roundsling and flat woven webbing slings which are designed and constructed for repeated use and a disposible sling which is for one trip and then disposed of. These latter slings are encountered on bagged cargoes such as fertilisers, cement and plastic granules, where they are woven into the bag material but they are also becoming more widely used for items that only require to be lifted once or twice, for example:- sections of timber framed houses or packs of metal work (Pipework or sections).

3 The standards for repeated use slings are BS EN 1492:2000 Parts 1 and 2 “Specification for lifting slings for general service made from man-made fibres”. There is no standard for single use slings. (see note 12 below)

ROUNDSLINGS

4 Roundsling is the term generally used to describe an endless man-made fibre sling formed by winding a hank of many individual continuous fibres of polyester yarn many times round a former of suitable diameter to produce a skein of many turns, and with the ends of the hank joined together by a knot. The roundsling is placed inside a protective woven man-made fibre tubular sleeve. The makers claim that roundslings are half the weight of other fibre slings, have greater flexibility, are softer to handle, will not harm delicate surfaces, resist edge damage and dragging-out damage, are non-sparking, and have a very low stretch (3% at safe working load).

5 At present there are several types of roundsling. The main difference in the products is the sleeve, which may be of polyamide (nylon) or polyester with edge stitching around the circumference or in the case of polyester, made from a continuous woven tube.

6 BS EN 1492-2: 2000 “Specification for roundslings made of man-made fibre for general service” covers the manufacturing specifications for this type of sling and gives advice on selection, use and maintenance.

FLAT WOVEN WEBBING SLINGS

7 Flat woven webbing slings are made from either nylon or polyester material and can be treated to withstand acids and alkalis. There is some elasticity in the slings which gives extra protection against shock loading.

8 As with the round slings the soft material of the sling does prevent damage to the goods being lifted and are lighter to use than conventional slings.

9 Any damage to the webbing can reduce the capacity of the sling dramatically and care should be taken when storing slings. .

10 Regular inspection is required to make sure any damaged items are taken out of use.

11 BS EN 1492-1: 2000 “Specification for flat woven webbing slings made of man-made fibre for general service” covers the manufacturing specifications for this type of sling and gives advice on selection, use and maintenance

DISPOSABLE FLAT BELT SLINGS

12 There are three types of materials used for disposable flat lifting slings, a polyethylene, a water resistant reinforced paper or a woven webbing outer layer to contain straight polyester fibres. They are made in several widths and strengths according to the intended use. The slings are designed for one load only (to enable that load to be despatched and received) and are not intended for repeated use.

13 They are normally used in the pre-slinging of bagged cargo and are assembled into a form known as 'cloverleaf' as the empty sling in plan view resembles a four leaf clover. Increasingly they are being used in the construction industry to lift sections of timber framed houses or roof trusses and in manufacturing for packs of steel, wood or plastic.

14 They are not used for general lifting purposes because, although they have a satisfactory but slightly lower factor of safety, they are not suitable for repeated use due to their comparatively light construction and low abrasive resistance. These slings should be disposed of once they have been detached from the load at the final destination.

15 Slings of this type are not individually proof tested, but any metal fittings, such as rings or links, should be proof tested in the normal way. This type of sling would not need to be subjected to periodic examination by a competent person, due to its disposable nature.

16 There is no specific standard for Disposable Flat Lifting Slings (the old Bristish standard has been withdrawn) therefore BS EN 1492-1: 2000 may be used as a guide to compliance with the Essential Safety Requirements of the Supply of Machinery Regulations 1992 Schedule 2 Part 4. There are however standards for the production of disposible bags, known as Flexible IBC’s BS EN 1898.2001 which should be used.