as 1576.4 scaffolding suspended scaf.pdf

AS 1576.4—1991

Australian Standard

Scaffolding Part 4: Suspended scaffolding

1 0 0 2 p e S 5 0 n o g n i r e e n i g n E h g u o l C y b d e s s e c c A

This Australian Standard was prepared by Committee BD/36, Scaffolding. It was approved on behalf of the Council of Standards Australia on 20 August 1991 and published on 7 October 1991.

The following interests are represented on Committee BD/36: A.C.T. Administration, Office of City Management Aluminium Development Council Australian Federation of Construction Contractors Confederation of Australian Industry Department of Industrial Affairs, Qld Department of Labour and Industry, Tas. Department of Labour, S.A. Department of Labour, Vic. Department of Occupational Health Safety and Welfare, W.A. Master Builders Construction and Housing Association, Australia Metal Trades Industry Association of Australia National Association of Scaffolding and Formwork Contractors Workcover Authority, N.S.W. Work Health Authority, N.T.

Review of Australian Standards. To keep abreast of progress in industry, Australian Standards are subject to periodic review and are kept up to date by the issue of amendments or new editions as necessary. It is important therefore that Standards users ensure that they are in possession of the latest edition, and any amendments thereto. 1 0 0 2 p e S 5 0 n o g n i r e e n i g n E h g u o l C y b d e s s e c c A

Full details of all Australian Standards and related publications will be found in the Standar ds Australia Catalogue of Publications; this information is supplemented each month by the magazine ‘The Australian Standard’, which subscribing members receive, and which gives details of new publications, new editions and amendments, and of withdrawn Standards. Suggestions for improvements to Australian Standards, addressed to the head office of Standards Australia, are welcomed. Notification of any inaccuracy or ambiguity found in an Australian Standard should be made without delay in order that the matter may be investigated and appropriate action taken.

This Standard was issued in draft form for comment as DR 90080.

AS 1576.4—1991

Australian Standard

Scaffolding Part 4: Suspended scaffolding

First published as AS 1576.4–1991. 1 0 0 2 p e S 5 0 n o g n i r e e n i g n E h g u o l C y b d e s s e c c A

Incorporating: Amdt 1–1992

PUBLISHED BY STANDARDS AUSTRALIA (STANDARDS ASSOCIATION OF AUSTRALIA) 1 THE CRESCENT, HOMEBUSH, NSW 2140

ISBN 0 7262 7102 0

PREFACE This Standard was prepared by the Standards Australia Committee on Scaffolding. It is one of a series of four Standards which collectively supersede and amalgamate AS 1575–1974, Tubes, couplers and accessories used in metal scaffolding and AS 1576–1974, SAA Metal Scaffolding Code which will be withdrawn on 30 June 1992.


 Copyright —

STANDARDS AUSTRALIA

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CONTENTS Page

SECTION 1 1.1 1.2 1.3

SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REFERENCED DOCUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 2 2.1 2.2 2.3 2.4 2.5

4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12 4.13


5.1 5.2 5.3 5.4

10 10 10 10 10 10 10 10

GENERAL REQUIREMENTS

GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GROUPING OF LIVE LOADS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WORKING LOAD LIMIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . STRENGTH OF SUPPORTING STRUCTURE . . . . . . . . . . . . . . . . . . . . . LOAD–LIMITING DEVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VERTICAL SPEED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ROPE TENSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . STABILITY OF CANTILEVER SUSPENSION RIG . . . . . . . . . . . . . . . . . CRADLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ROPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SUSPENSION AND SECONDARY ROPES . . . . . . . . . . . . . . . . . . . . . . . . SUSPENSION RIG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SUSPENSION RIG COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 5

8 8 8 8 8

MATERIALS AND COMPONENTS

STEEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ALUMINIUM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SCAFFOLD TUBES AND COUPLERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . SUSPENSION AND SECONDARY ROPES . . . . . . . . . . . . . . . . . . . . . . . . SCAFFOLDING HOISTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . COUNTERWEIGHTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . STRUCTURAL PLYWOOD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TROLLEYS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 4

4 4 4

DESCRIPTION OF SUSPENDED SCAFFOLDING

GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SYSTEM OF ATTACHMENT TO STRUCTURE . . . . . . . . . . . . . . . . . . . . HORIZONTAL MOVEMENT CAPABILITY . . . . . . . . . . . . . . . . . . . . . . . SUSPENSION SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TYPES OF CRADLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8

SCOPE AND GENERAL

11 11 11 11 11 11 11 11 12 12 12 12 12

ELECTRICAL EQUIPMENT AND CONTROLS

GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CONTROL BOX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ELECTRICAL CABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14 14 14 14

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STANDARDS AUSTRALIA Australian Standard Scaffolding Part 4: Suspended scaffolding SECTION 1 SCOPE AND GENERAL 1.1 SCOPE This Standard sets out requirements for the materials, and design, of suspended scaffolding including the supporting structure. This Standard does not cover building maintenance units. This Standard is to be read in conjunction with AS 1576.1. 1.2 REFERENCED DOCUMENTS The following documents are referred to in this Standard: AS 1170 SAA Loading Code 1170.1 Part 1: Dead and live loads and load combinations 1170.2 Part 2: Wind loads 1418 SAA Crane Code 1418.1 Part 1: General requirements 1418.2 Part 2: Serial hoists and winches 1444

Wrought alloy steels — Standard and hardenability (H) series

1538

SAA Cold-formed Steel Structures Code

1554

SAA Structural Steel Welding Code

1576 1576.1 1576.2 1576.3

Scaffolding Part 1: General requirements Part 2: Couplers and accessories Part 3: Prefabricated and tube-and-coupler scaffolding

1577

Solid timber scaffold planks

1578

Laminated timber scaffold planks

1594

Hot-rolled steel flat products

1664

SAA Aluminium Structures Code

1665

SAA Aluminium Welding Code

1720 Timber structures 1720.1 Part 1: Design methods


1734

Aluminium and aluminium alloys — Flat sheet, coiled sheet and plate

1866

Aluminium and aluminium alloys — Extruded rod, bar, solid and hollow shapes

1867

Aluminium and aluminium alloys — Drawn tubes

1874

Aluminium and aluminium alloys — Ingots and castings

2269

Structural plywood

2317

Collared eyebolts

3190

Approval and test specification — Residual current devices (current operated earth leakage devices)

3569

Steel wire ropes

3678

Hot-rolled structural steel plates, floorplates and slabs

3679

Hot-rolled structural steel bars and sections

4100

SAA Steel Structures Code

1.3 DEFINITIONS For the purpose of this Standard, the definitions given in AS 1576.1 and those below apply. 1.3.1 Articulated cradle — a cradle of several sections hinged together enabling workers to walk from one section to another (see Figure 1.2). 1.3.2 Bay length — the distance between any two longitudinally adjacent support points on a cradle measured horizontally. 1.3.3 Boatswain’s chair — a special purpose cradle comprising a seat. 1.3.4 Counterweight — a weight or series of weights used to counterbalance the forces on the suspension rig against overturning. COPYRIGHT

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AS 1576.4—1991

1.3.5 Cradle — that portion of the assembly incorporating a suspended platform. 1.3.6 Double rope suspension system — a method of suspending a cradle using two hoists and two suspension ropes at each support point. 1.3.7 Fixed cradle — a cradle which does not traverse horizontally but which is capable of being raised and lowered. 1.3.8 Fulcrum point — the point of pivoting nearest to the outside edge of the suspension rig about which the balancing moments of the suspension rig are calculated. 1.3.9 Inboard portion of the suspension rig — that portion of the suspension rig which is on the inside of the fulcrum point (see Figure 1.1). 1.3.10 Individual cradle — a cradle of one bay length (see Figure 1.3). 1.3.11 Lever arm — the distance between the fulcrum point and the centre of gravity of the suspension rig including any counterweights. NOTE: The projection length is the length which is used in the calculation of moments for stability.

1.3.12 Load-limiting device — a device that limits the lifting capacity of a scaffold hoist to a specific load below the stalling load of the motor. 1.3.13 Maximum total suspended load — the maximum force which can be imposed on the suspension rig including the working load limit on the platform, the self-weight of the platform and the suspension and safety ropes together with any portion of the means of suspension and the rope tensions, and any extra force resulting from the operation of the equipment and environmental loads. 1.3.14 Needle — a continuous structural member that extends from the suspension point to the extreme inboard end of the supporting structure. 1.3.15 Outboard portion of the suspension rig — that portion of the suspension rig which is on the outside of the fulcrum point (see Figure 1.1). 1.3.16 Prefabricated platforms — a framed assembly of one bay length, incorporating a walking surface, which is capable of connecting to its support structure in such a way as not to be inadvertently dislodged. One or more prefabricated platform units can be used side-by-side and end-to-end to form a working platform. 1.3.17 Projection length — the horizontal distance between the fulcrum point and the suspension point. NOTE: The projection length is the length which is used in the calculation of moments for stability.

1.3.18 Scaffolding hoist — a lifting appliance manually operated or power-operated through which the suspension rope passes. 1.3.19 Working load limit — the working load limit is the maximum live load which may be placed on the cradle per bay. 1.3.20 Protective device — a device which will arrest the descent and support a cradle or boatswain’s chair in the event of the failure of the suspension rope or the scaffolding hoist. NOTE: A protective device may also prevent an overspeed descent.

1.3.21 Secondary rope — rope not normally carrying the weight of a cradle and the imposed load, but rigged for use with a protective device. 1.3.22 Single-rope suspension system — a method of suspending a cradle using one hoist and a single suspensionrope at each support point. 1.3.23 Stop — the attachment at or near the end of a rail or track or at an intermediate point to prevent further traversing of the cradle.


1.3.24 Suspension-mounted hoist — a scaffolding hoist which is mounted on the suspension rig or trolley track with one end of the rope attached to the cradle. 1.3.25 Suspension gear — the assembly which joins the cradle to the suspension rig. 1.3.26 Suspension point — that point where the suspension rope is connected to the suspension rig. 1.3.27 Suspension rig — that portion of the structure (including the trolley track) mounted at a level higher than the cradle to support and position the cradle. 1.3.28 Suspension ropes — ropes carrying the weight of the cradle and the imposed load. 1.3.29 Travelling or traversing cradle — a cradle capable of being moved horizontally. 1.3.30 Traversing — moving laterally across the face of the building in a cradle. 1.3.31 Traversing ropes — ropes rigged for the purpose of traversing the cradle, but not carrying the weight of it. 1.3.32 Traversing suspension rig — a suspension rig mounted on wheels or castors and supporting a cradle. 1.3.33 Trolley — a wheeled mechanism intended to support a serial hoist and capable of travelling along a suspended track. 1.3.34 Trolley track — the suspended rail which supports and guides trolleys in traversing installations. 1.3.35 Work cage — a cradle which is supported by a single suspension rope. COPYRIGHT

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FIGURE 1.1 TYPICAL SUSPENSION RIGS

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FIGURE 1.2 TYPICAL ARTICULATED CRADLE


FIGURE 1.3 TYPICAL INDIVIDUAL CRADLE

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SECTION 2 DESCRIPTION OF SUSPENDED SCAFFOLDING

2.1 GENERAL Suspended scaffolding is described according to the system of attachment to the structure, the horizontal movement of the cradle, the suspension system, and the type of cradle. 2.2 SYSTEM OF ATTACHMENT TO STRUCTURE The system of attachment to the structure may be one of the following: (a) Systems which rely on counterweights for their stability. (b) Systems which are secured to the building or structure. (c) A combination of systems specified in Items (a) and (b). 2.3 HORIZONTAL MOVEMENT CAPABILITY The horizontal movement capability may be one of the following: (a) Fixed. (b) Traversing cradle. (c) Traversing suspension rig. 2.4 SUSPENSION SYSTEM The suspension system may be one of the following: (a) Hoist reeling — where the hoist reels the wire rope on to a drum within the hoist. (b) Hoist climbing — where the hoist ‘climbs’ upthe wire rope leaving the tail end of the rope hanging or reeled onto a separate device below the hoist. 2.5 TYPES OF CRADLES The cradles may be one of the following (see Figure 2.1): (a) Articulated cradle The working area can be a single deck or several decks beneath each other. (b) Individual cradle This type can have a single deck or several decks beneath each other. (c) Boatswain’s chair . (d) Work cage.


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FIGURE 2.1 TYPES OF CRADLE


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SECTION 3 MATERIALS AND COMPONENTS 3.1 STEEL Steel components shall be manufactured from steel complying with AS 1444, AS 1594, AS 3678, or A S 3679, as a ppr opr ia te. 3.2 ALUMINIUM Aluminium components shall be manufactured from aluminium complying with AS 1734, AS 1866, A S 1867, or A S 1874, as appropri ate . 3.3 SCAFFOLD TUBES AND COUPLERS 3.3.1 Tube S te el a nd a lumi ni um t ube s hal l comp ly w ith A S 1 576.3 . 3.3.2 Couplers and accessories Couplers and accessories shall comply with AS 1576.2. 3.4 SUSPENSION AND SECONDARY ROPES Suspension and secondary ropes shall comply with AS 3569. 3.5 SCAFFOLDING HOISTS Scaffolding hoists shall comply with AS 1418.2. 3.6 COUNTERWEIGHTS Counterweight material shall be durable, such that the weight shall remain constant und er w or ki ng c ond it i ons. Ba gs o f sa nd or s im ila r m at er ial s hal l n ot b e us ed. Th e m ass of t he c oun te rw eig ht, i n ki logra ms, shal l be ma rked o n it . 3.7 STRUCTURAL PLYWOOD Structural plywood shall comply with AS 2269. 3.8 TROLLEYS Trolleys shall comply with AS 1418.2 and the following requirements: (a ) Wh ere i nt ended for use wi th a cr adl e, t he t rol le y sha ll be des ig ned t o inc orpor at e a s pace bar. (b) The worki ng l oad li mit shal l be the gr eat er of — (i )

the maximum r ope t ension; and

(ii)

5 kN.


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AS 1576.4—1991

SECTION 4 GENERAL REQUIREMENTS 4.1 GENERAL The design of structural members and components shall comply with the relevant requirements of t he fo llo wi ng St and ar ds: AS 1 170 .1, A S 117 0. 2, A S 1 418, A S 153 8, AS 1554, AS 1 664, AS 166 5, A S 1720. 1 an d A S 410 0. Th e d esi gn s hal l t ake a cco unt of : (a ) Wi nd s ail c ond it io ns c re ate d b y a we at her c over, s af ety s cre eni ng, or ot her s hee ti ng m ate ri al at tac hed to a scaffold. (b ) Th e n eed fo r o ver hea d a nd s id e p ro tect io n fo r t he occ upa nt s. 4.2 GROUPING OF LIVE LOADS The design of all parts of the installation shall take account of the possible groupi ng of t he li ve l oads at one end of t he cradle . 4.3 WORKING LOAD LIMIT T he w or kin g lo ad l im it s hal l b e n ot l es s t han l i ght d ut y l oadi ng in ac cor dan ce wi th AS 1576.1. T he worki ng l oad l imi t, in kil ogr ams, shall be mar ked on t he cradle in each bay, in a place whe re i t i s cl ear ly v isi ble . 4.4 STRENGTH OF SUPPORTING STRUCTURE The structure supporting the suspended scaffold system sh all b e abl e t o s ust ai n t he ma xim um t ot al su sp ens ion l oad. F or mo bil e s yst em s, th is r equi rem ent a ppl ies t o a ll positions of its travel. Wh ere s pre aders or p ads a re u se d to d is tri but e a l oad on a r oof or par ap et, t he m ate ria l s hal l be s uch t hat a pr ope r di str i buti on of t he l oad is a chi eved, a nd t hat t he spr ea der o r pad w il l n ot a dve rs el y d et eri or ate in t he w ork ing environment. 4.5 LOAD-LIMITING DEVICE Electrically powered scaffolding hoists shall have a device to limit the lifting capaci ty of t he hoi st t o a ma xi mum 1.25 t imes th e r at ing of s uch hoi st . 4.6 VERTICAL SPEED T he v ert ic al s pee d o f a ny s uspe nded sc aff ol d s hal l n ot excee d 1 2 m /m in. 4.7 ROPE TENSION Ro pe te nsi on f or el ect ric al ly p owe red s caf fo ldi ng h ois ts i s th e sum ma tio n o f th e l oad which is limited by the load-limiting device in Clause 4.5, the gravitational load of the suspension rope and any tensioning weight. Ro pe t ens io n f or o ther th an e le ctr ic all y p ow ere d s caff old ing hoi st s shal l b e th e s umm at ion o f — (a ) th e self w eig ht of t he s uspensi on r ope and any t ensioni ng w eig ht ; (b ) th e se lf w eig ht o f t he s caff old ing hoi st a nd any s ec ond ar y ro pe dev ic e; (c ) th at por ti on of t he sel f w eig ht of t he cr adl e act ing on th e r ope ( or t he s elf w ei ght of th e boat swain ’s chai r) ; and (d) the rat ed li ve load f or t he cr adle taking i nto account grouping of l ive l oads or t he rat ed li ve load of the boatswain’s chair. 4.8 STABILITY OF CANTILEVER SUSPENSION RIG 4.8.1 General anchorage.

S tabi li ty of a canti lever suspensi on r ig a gai nst over tur ni ng shal l be by count er wei ght s or

4.8.2 Determination of stability Factors in the determination of stability shall include the following: (a ) Th ree t im es th e r ope t ensi on fr om C la use 4. 7. (b ) Th e g roup in g o f s uspens io n r opes re la tiv e t o a tt achmen t poin ts. 1 0 0 2 p e S 5 0 n o g n i r e e n i g n E h g u o l C y b d e s s e c c A

(c ) Th e o utb oar d p ort io n o f t he s usp ens io n r ig a nd any at tac hed t ra ver sin g t rac k. (d ) Th e i nboa rd por ti on o f t he s usp ensio n r ig in cl udi ng cou nt erw ei ght s i f used. 4.8.3 Lateral stability T he suspe nsi on r i g and c an til evers , and t ra ver sin g t ra ck i f u se d, sh al l h av e adequ at e lateral strength or be adequately braced against lateral sway in the longitudinal direction. NOTE: The forces producing lateral sway include wind forces, surge from braking, and the applied force from traversing lines.

Fo r a wi re r ope br aced su spen si on ri g, t he r es tra ini ng w ire ro pes s hal l be so ang le d i n p la n, o r sup pl eme nt ed b y additional angled wire ropes or other means that lateral stability in both directions is achieved. 4.8.4 Counterweights C ounte rweig hts s hall be f ix ed t o the s uspensi on r ig i n suc h a way as to pre vent th eir dislodgement under all expected conditions of operation of the equipment. 4.8.5 Suspension anchorage points S uspens io n anchor age poi nt s s hal l t ake i nt o acc ount the natu re of th e material into which the anchor is fastened. Dr ill ed-in anchor s, w het her expandi ng or chem ic al t ype, s hal l not be used in an anchorage syst em t o r esi st a tensile (pull-out) force. Bo lts u sed i n an a ncho ra ge s yst em s hal l b e fi tt ed w it h lo ckn ut s.

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4.9 CRADLE 4.9.1 Width T he wi dth of t he platf orm shall be not l ess t han 450 mm. 4.9.2 End extensions End extensions t o the cradle shall be l imit ed i n l ength t o t hat all owed by t he cr adle design. 4.9.3 Decking T he d ecki ng of t he pl atf orm shal l h ave a su rfa ce th at d oes not b eco me s lip per y under expec te d working conditions. It shall be fixed so that it cannot be accidentally displaced. Except to the extent necessary for drainage, the decking shall be closely boarded, planked, or plated. A prefabricated platform shall comply with the performance requirements of AS 1576.3. Sc aff old pla nks if used f or decki ng s hal l compl y w it h A S 1577 or A S 1578. 4.9.4 Guardrails, midrail, and toeboards Guardrails, midrails and toeboards shall be designed in accordance wi th A S 1576. 1 a nd fi t te d to t he per im ete r o f t he p lat for m. Wh ere t he cr adle i s t ied t o th e bui ldi ng and t he bui ldi ng f orm s a barr ier at t hat l evel, th e i nner guar dra ils m ay be r emov ed p rovi ded t hey a re n ot an i nte gra l c ompo nent o f th e c radl e desi gn. 4.9.5 Suspension link T he desi gn of t he li nk us ed t o at ta ch t he hoi st t o th e cr adl e s hal l ta ke in to account any fo rce s re sul ti ng fr om o ut of le vel o f t he cr adl e i n a ny d ir ect io n. 4.9.6 Buffers W her e f ace w al l r ol ler s or buff er s a re used, t hey shall be a tt ached to the c radle , and vi si ble t o the operator. 4.9.7 Articulated cradles A rt i cula ted c radl es s hal l be d es igned t o ta ke in to acc ount t he c onf ig ura ti ons and resulting loads. Th e h inge d a rea s hal l b e des ig ned t o m in imi ze g aps in t he d ecki ng, g uard rai ls a nd to eboa rd s. 4.9.8 Other shapes Various shaped cradles may be used, and such configurations shall be specifically designed and special attention paid to the required suspension rig. 4.9.9 Boatswain’s chair The scaffolding hoist fitted to a boatswain’s chair shall be capable of being manually ope rat ed by t he user, i n a saf e m anner , i n an emer gency or powe r fail ure. 4.10 ROPE Fi bre ropes shal l not be used f or the l if ti ng or suspensi on of scaff olding, but may be used for traversing. St eel w ire r ope of a con st ru cti on o ther th an th at re comm ended b y t he sc aff old in g h ois t man uf act ur er s hal l not be used w it h such a hoi st . NOTE: Galvanizing of steel wire rope is recommended.

4.11 SUSPENSION AND SECONDARY ROPES Suspension and secondary ropes each shall be terminated at t he r ig end wi th a th im ble e ye s pl ice , or f er ru le se cur ed e ye te rmi nat io n or o th er r ope c oupl ing devi ce w hic h doe s not damage th e ro pe a nd gi ves a str ength of not le ss t han 80% of t he bre aki ng l oad of th e rope. The r ope shall hang f reely fr om the suspension r ig by an eye w hich compl ie s wi th AS 2317 and shall not be reeved through the eye. Rope bullet end termination shall be suitable for its purposes and finished to prevent overlaying. Where appropriate, the tail end of the rope shall be fitted with a suitable rope clamping device to prevent the rope passing through the hoist. The r ope shal l be l ong enough so t hat the syst em does not run out of rope. A se condar y r ope s hal l h ave a st re ngt h o f n ot le ss t han t he r ele vant s usp ensi on r ope . 1 0 0 2 p e S 5 0 n o g n i r e e n i g n E h g u o l C y b d e s s e c c A

4.12 SUSPENSION RIG The fulcrum point for static suspension rig is shown in Figure 1.1. The fulcrum point fo r a mo bil e su spens ion r i g is th e c ent re -li ne o f t he fr ont w hee l. Ade qua te means s hal l b e p rovi ded t o ens ur e th at th e s uspen si on s yst em s hal l not sl i p o ff t he e nd of t he nee dl e. 4.13 SUSPENSION RIG COMPONENTS 4.13.1 Trolley track Suspension from a scaffold coupler designed for joining tubes is not permitted. St ops s hall be at ta ched to t he t rol le y tr ac k usin g a posi tiv e me th od (e .g. n ut a nd bolt ) . F ri cti on s to ps sha ll n ot be used. 4.13.2 Parapet clamps P ara pet c la mps s hal l b e used o nly wh ere th e para pet h as a dequ at e s tre ngt h. NO TE : P ar ap et c la mp s s ho ul d no t be u sed o n b ri ck pa ra pe ts .

4.13.3 Pulleys W her e a wi re rope pass es over pul leys or ar ound dr ums ot her th an i n w inches and cl im bing devices, such pulleys or drums shall have pitch circle diameters in accordance with AS 1418.1. Gui de pul le ys ext ernal to t he w inc h or cl im bing devi ce shall have pi tc h ci rcle dia met ers i n accordance wi th AS 1418.1.

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AS 1576.4—1991

4.13.4 Protective device A protective device shall be provided for each scaffolding hoist. The protective device shall operate on the suspension rope above the scaffolding hoist or on a secondary rope. A protective device shall comply with the following requirements: (a ) Th e d evi ce s hal l b e desi gned t o w it hst an d t he g re ate st of t he f oll owi ng: (i )

Th e c ombi ned l oadin g of th e w orkin g lo ad l imi t and m ass of t he e qui pment i n mot ion .

(i i)

Th e in er tia l-e ff ect lo adi ng of the combin ed l oadin g of maxi mum w ork ing l oad l imi t a nd m ass of th e equ ip ment i n mo ti on r es ul tin g f rom th e o per at ion of t he p ro tec tiv e d evi ce u nde r f re e- fal l st oppin g conditions for the rate of deceleration determined by rational analysis, without stressing any component in excess of 75% of i ts yi eld s tr ess.

(iii)

The inertial-effect loading of the combined loading of the working load limitand mass of the equipment in motion due to the operation of the protective device under overspeed stopping conditions for the rate of deceleration determined by rational analysis without stressing any component in excess of 75% of its yield stress.

(b ) Mea ns s hall b e pr ovi ded t o dea ct ivate t he d evi ce. (c ) Th e d evi ce s hal l be mou nt ed i n s uch a w ay th at t he st ab ili t y of t he cr adl e is not a dver sel y af fe cte d w hen th e device is activated. 4.13.5 Secondary rope A secondary rope, where fitted, shall be independently attached to the suspension rig.


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AS 1576.4—1991

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SECTION 5 ELECTRICAL EQUIPMENT AND CONTROLS 5.1 GENERAL E le ctr ic al e qui pme nt and c ont ro ls sha ll c om ply w ith AS 1 418. 2 and th e re qui rem ent s of t his Section. 5.2 CONTROL BOX Where a central control box is fitted, the main supply cable shall be plugged into the box. Fr om t his box s epar at e y oke s sha ll le ad t o t he wi nche s. The central control box, if fitted, shall include the following features: (a) Socket-outlets for winches. (b ) An e mer gen cy s to p but to n. (c) A power-on li ght . (d) A Ty pe I or T ype II r esi dual c urr ent devic e com pl yi ng w it h A S 3190. The control box shall be fully enclosed, lockable, shatterproof and weatherproof. It shall be removable for safety an d s ec uri ty b ut a t t he sa me t i me s hal l b e se cur el y a tt ached t o t he gua rd rai ls o f th e c ra dl e o n t he s id e a wa y f ro m th e buil din g fa ce wh en i n u se. 5.3 CONTROLS T he h oi sts s hal l b e oper ate d at t he h ois t, f ro m a c ent ra l c ont ro l b ox, o r by t he us e o f p en dant controls within the cradle in accordance with AS 1418.1. All operating buttons and levers shall be of the spring-loaded ‘dead-man’ type. Th e e le ct ric al c ont rol sys te m s hal l be des ig ned so t hat any e le ctr i cal fa ilu re or m alf unc ti on wo ul d ca use t he system to fail to safety. Protection shall also be provided against phase reversal in 3-phase systems. 5.4 ELECTRICAL CABLES Electrical cables shall comply with the following requirements: (a) Electrical cables shall be purpose designed. (b ) Ca ble s s hall only be su spen ded f ro m a dev ic e t hat d oes n ot d am age t he c or e w ire s. A b uil t -i n t him bl e i s one fo rm o f s uch dev ic e.


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