tower crane compliance campaign report 2005

7/30/2019 Tower Crane Compliance Campaign Report 2005

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Tower craneCompliance campaign 2005 report

Workplace Health and Safety QueenslandMarch 2006


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Executive summary

Between J uly and August 2005 a compliance campaign focusing on safety in the towercrane industry in Queensland was undertaken by Workplace Health and SafetyQueensland. In total, 108 audits of tower cranes on construction sites across the state

were undertaken. In addition to the enforcement activity associated with unsafe cranesand their use, tower crane operators were interviewed and asked about a number ofkey safety issues. At the end of the compliance campaign a total of 343 individual non-compliance items were identified in relation to safety. As a result, 94 directions wereissued to obligation holders.

The tower crane compliance campaign has identified the following as key safety issuesrequiring attention:

safe access on cranes.

crane condition and safety features.

crane safety documentation.

crane customer input.

operator training and competence.

Responses from the crane industry indicate the tower crane compliance campaign hasbeen a success. As a result of the actions of inspectors during the compliance

campaign, safety associated with tower cranes has achieved a greater profile.Significant data has also been collected through the tower crane operator surveyadministered during the compliance campaign, which will allow the industry andgovernment in partnership to plan future safety improvements.


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1. Table of contents

Section Page

Introduction 4

Background 4

Strategy 6

Results 9

Discussion 13

Conclusions 18

Recommendations 20

Appendix 1 - Tower crane audit checklist

Appendix 2 - Tower crane audit issues(cranes used at construction sites)

Appendix 3 Tower Crane audit: operatorquestionnaire


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Introduction

Between J uly and August 2005 a compliance campaign targeting tower cranes wasundertaken by Workplace Health and Safety Queensland (WHSQ). In the two monthsprior to this, a compliance campaign focusing on mobile cranes was also undertaken

by WHSQ. Both crane compliance campaigns were in response to an increasingnumber of serious crane incidents in Queensland and form part of a WHSQ strategy toreduce the number of these incidents.

During the tower crane compliance campaign 108 tower cranes around the state wereaudited by WHSQ inspectors and the results of this compliance campaign are includedin this report. In addition to the application of compliance instruments, the compliancecampaign also included interviewing tower crane operators to gain greater insight intothe safety issues related to this industry. A number of conclusions andrecommendations relating to the tower crane industry are included in this report.

Background

Cranes are an integral part of construction work in Queensland. This is particularlyevident in the commercial construction sector, where the construction of multi-storeystructures is achieved through the extensive use of tower cranes. The construction oflarger, more complex structures has only been possible through the development oflarger, more complex cranes.

Since the late 1990s there has been a boom in Queensland construction and aproliferation of cranes of all types and configurations. All types of cranes used in theconstruction industry are being exposed to more frequent and sustained use than everbefore. There has also been a corresponding increase in serious crane incidents.

Table 1 shows the number of crane incidents from the beginning of 1999 through toAugust 2005.

Period 1999 2000 2001 2002 2003 2004 2005(up to20August )

*

Number ofQld craneincidents

10 12 8 15 12 20 23

Total 100*Reported to Workplace Health and Safety Queensland

Table 1: Total number of serious crane incidents in Queensland, 1999 20 August2005


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At the time of writing this report, most crane incidents reported to WHSQ have notresulted in fatalities or serious injury to persons. This fact should not signalcomplacency within industry. Due to their physical size and mass, and their propensityto be used in built up areas, any adverse event has the potential to result in acatastrophic outcome.

From the events notified to WHSQ, the total number of serious crane incidents for bothmobile and tower cranes can be further broken down into incident types as indicatedby Table 2 below.

Incident type

Number of incidents

Percentage of total

Crane overturn(mobile cranes only) 44 44%

Contact with overheadpower lines 20 20%

Falling object

8 8%

Other types ofoperational incidents notincluded above

13 13%

Crane collapse orstructural damage

15 15%

Total 100 100%

Table 2: Queensland crane incident types, 1999 20 August 2005(Compliance and Investigation System data base - CIS)

The Construction Industry Action Plan 2004 2007 highlights cranes as one of the

areas in the construction industry requiring intervention by WHSQ. Cranes used in theconstruction industry predominantly fall into two categories - mobile cranes and towercranes. As there are a number of fundamental differences in the nature of hazardswithin the tower crane and mobile crane industries, a separate compliance campaignwas conducted for each sector. This report solely references the tower cranecompliance campaign. The report of the mobile crane compliance campaign can beaccessed at www.dir.qld.gov.au.


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Strategy

Audit criteria

Incident data on cranes reported to WHSQ indicates that operational issues are one ofthe primary causes of crane incidents in Queensland. In recognition of this information,the compliance campaign addressed operational issues in addition to the condition andsafety features of the crane itself. Items to be audited were divided into two primarygroups: the crane itself and the crane use. Tower cranes were inspected atconstruction sites whilst involved in actual crane operations.

For the actual crane, the key issues for consideration were:

structural integrity boom, tower, A-frame, slew ring bolts, welding etc foundation integrity traditional crane bases and self erecting crane support mechanical integrity drive systems, wire ropes, hydraulic systems etc safety systems load indicators, rated capacity limiters, limit

switches etc documentation load chart, operators manual, maintenance records and log book.

For crane operations, the key operational issues for consideration were:

crane set up proximity to overhead power lines crane proximity to persons (crushing and falling object risk)

crane crew certification operator and dogger

crane loading (including load chart interpretation).

An audit checklist was developed for the compliance campaign to reflect both craneand crane use issues and a copy is included in Appendix 1.

The following Australian Standards were used as a reference for the audit criteriaemployed during the compliance campaign: AS 1418.4 Cranes, hoists and winches - Tower cranes AS 2550.1 Crane, hoists and winches - Safe use: General requirements AS 2550.4 Safe use: Tower cranes.

In addition, the WHSQ document, Tower Crane Industry Compliance Guidelinesdated 28 June 2005, was used by inspectors (see Appendix 2). This documentprovides guidance on a number of key safety issues associated with tower cranes andalso indicates benchmarks that are to be applied to older crane models manufacturedbefore the current series of Australian Standards. It should be noted that Queenslandworkplace health and safety legislation is not retrospective and not all currentrequirements in Australian Standards can be applied to older cranes. However, in anumber of high risk situations the principles are applied to older cranes. An example isthe provision of rated capacity limiterson tower cranes, in comparison to loadindicators that only provide the operator with an indication of how much load is

suspended on the hook. Due to high level of risk associated with the operation of tower


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cranes, rated capacity limiters have been a standard feature of tower cranes operatingin Queensland for a number of years.

A goal of 96 state-wide tower crane installations was nominated and the audits werecarried out on building and construction sites. Based on plant registration statistics,

there were approximately 180 tower cranes in use in Queensland at the time of thecompliance campaign. The final sample size of 108 therefore equates to more than 50percent of all tower cranes in Queensland, and provides an accurate indication of thesafety performance of the tower crane industry.

Crane operator questionnaire

Most safety initiatives carried out by regulatory authorities tend to focus on theworkplace health and safety inspectors observations, relating to both plant and worksystems. While such information is important, feedback from workers in the industrycan also be invaluable. Therefore the tower crane compliance campaign also obtained

feedback from the crane operators about their views on crane incidents they wereaware of. This is considered an important tool because crane operators as a grouphave a wealth of knowledge regarding the culture and constraints that have an impacton safety in this industry. A questionnaire was developed which, in addition toobtaining data on the views of operators, also obtained crucial information with respectto the experience of, and training received, by crane operators (see Appendix 3).

Inspectors

A total of 12 WHSQ inspectors were involved across the state. Inspectors wereselected based on their competency and knowledge of the tower crane industry andtheir ability. This was supported by an extensive information and learning sessiondelivered by in-house technical and construction experts. The following subject matterwas canvassed:

crane design standards maintaining consistency ofapproach

crane maintenance appropriate enforcement tools

crane use campaign reporting systems.

campaign audit tools


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Reporting and technical support

The compliance campaign was scheduled to run for six weeks and commenced on 4J uly 2005. At the end of each two-week period, compliance campaign report summarysheets were forwarded to the Construction Strategy Group (CSG). In addition,

inspector directions such as improvement notice information was entered into theWHSQ electronic reporting system and the results were collated by the CSG.

During the compliance campaign, continuous technical and procedural support wasprovided to field inspectors, both by representatives of the Technology Services Unitand the Construction Strategy Group. This support was both verbal and written andalso included a number of joint visits on crane audits.

Industry consultation and support

Extensive consultation was undertaken before the compliance campaign commenced.

WHSQ held a number of information sessions with both the tower crane industry andthe building and construction industry.

As a result of this consultation, the tower crane owners involved in the consultationwelcomed and actively supported the proposed compliance campaign. This commentis reinforced by the fact that very few complaints were received by these participantsduring the compliance campaign. Additionally, employer and union representativeswere also consulted on the proposed compliance campaign and they also activelysupported, through their newsletters etc, the promotion of the compliance campaign.WHSQ intends to build on this working relationship and will consult with these groupswhen future opportunities are presented.


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Results

Compliance issues

A total of 108 tower cranes were audited across the state. Table 3 shows the total

number of cranes audited and non-compliances for the various regions in Queensland.

Directions issuedRegion No.auditstargeted

No.auditscarriedout

Noted non-compliances*

Improve Prohibition

NorthQueensland 7 9 30 14 -

Wide Bay(incl.

SunshineCoast)

14 17 34 10 2

BrisbaneNorth 36 42 154 32 1

BrisbaneSouth (incl.Gold Coast)

34 35 112 31 2

South West5 5 13 2 -

Total 96 108 343 89 5

Table 3: Total number of cranes audited and non-compliances identi fied.

As demonstrated in the above table, a total of 343 non-compliances were recordedduring the compliance campaign.

The highest level of non-compliance was in the area of access issues at 28.5 percent

and is closely followed by safety features at 26.5 %. Table 4 includes a breakdown forall non-compliance issues reported. The non-compliance issues listed in Table 4 areissues set out in the Tower Crane Audit Checklist employed during the campaign(see Appendix 1).

* Noted non-compliance describes the number of non-compliance issues with respect to the auditcriteria used during the compliance visits. Each noted non-compliance did not necessarily result in aninspector issuing a written direction because the non-compliance may have been remedied during thevisit.


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ACCESS STRUCTURAL AND

MECHANICAL

OPERATIONAL

ISSUES

SAFETY

FEATURES

CRANE

DOCUMENTATION

A-frame access

9.9%

- ladders- platform- condition

Tower access

9.3%


Machine deckaccess

6%


Other access

3.3%

- boom- saddle bag

Bolt

8.8%

- type- corrosion- torque

Other structural/mechanical

5.7%

- hydraulic leaks- general

lubrication- counterweight

bolts Rope sheaves

2.4%- condition- rotation- wear

pads/rollers- rope keeper

bar

Crane structure

2.1%

- straightness- deformation- cracks- corrosion- welds- play

Ropes

1.6%

- damage- wear- lubrication

Pins (jib, etc)

0.9%

- located- split pins- wear

Proximity other plant

4.2%

- provided- suitable

Load handling

1.8%

- sling type- sling condition- wind effect

Power lines

1%

- location- control measures

Operator and doggerissues

0.3%

Crane cabin

11.8%

- seating- visibility- noise- fire extinguisher- clean (not

slippery)

Controls & limits

7.5%

- correctly labelled- operable- deadman levers

and pedals

- radius gauge- boom angle

indicator- hoist limit- luff (upper limit)

Rated capacity limiter

4.5%

- operable- calibrated- cut out

operational

Guarding

2.7%

- sheaves- exists- adequate

Documentation12.6%

- operatorsmanual(English)

- NDT reports- logbook

provided

- commissionreport

- majorinspect-10yr

load charts

3.6%

- supplied

- correct forcrane

- comply withAS 1418

- legible andin English

- visible

ACCESS

Total : 28.5 %

STRUCTURAL ANDMECHANICAL

Total: 21.5 %

OPERATIONALISSUES

Total: 7.3 %

SAFETYFEATURES

Total: 26.5 %

CRANEDOCUMENTATION

Total: 16.2 %

Table 4: Breakdown of non-compliance issues

During the campaign inspectors recorded data on the characteristics of the cranesincluding basic crane type and crane age. The percentages of different crane types


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audited are included in Table 5. To simplify the data, the age of cranes audited hasbeen divided up into seven different categories ranging from less than one year old tomore than 25 years old. This information is depicted in Table 6.

Breakdown of tower crane types

Region No. towercranesaudited

Luffing Non-luffing(hammerhead)

Self erecting

NorthQueensland 9 3 5 1

Wide Bay (incl.Sunshine

Coast)

17 4 11 2

Brisbane North42 18 20 4

Brisbane South(incl. Gold Coast) 35 18 17 -

South West5 4 1 -

Total 108 47 54 7

Table 5: Breakdown of tower crane types audited

Crane age Percentage

Less than 1 year 9 %

2 5 years 6 %

6-10 years 11 %

11-15 years 12 %

16 20 24 %

21 25 12 %

More than 25 years 26 %

Table 6: Age of tower cranes audited


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Tower crane operator questionnaire

A total of 97 completed tower crane operator questionnaires were returned to theConstruction Strategy Group. This number is less than the total number of total craneaudits performed because in some cases the operation of the crane could not beinterrupted and the operator could not be interviewed.

The findings of the questionnaire are included in the Discussion section of this report.


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Discussion

The information gathered during the tower crane compliance campaign providesinsight into the nature of the industry and key safety obstacles that exist. This sectionof the report discusses compliance issues and the results of the survey questionnaire.

Compliance issues

A total of 343 non-compliances were recorded during the compliance campaign.Feedback received from inspectors during the campaign alluded to the poor conditionof some tower cranes in the industry. This comment often focused on the older towercranes in service.

To assist in drawing conclusions from the data, it is necessary to group the non-compliance issues into major groups and this is illustrated in Figure 1.

Figure 1: Breakdown of tower crane non-compliances issues

The highest level of non-compliance was in the area of access issues at 28.5 percent.

Access issues related to a number of areas including tower, machine deck, A-frameand boom access. Many of the cranes audited were manufactured in the 1960s andearly 1970s when safety features on ladders and platforms, such as guardrails andlandings, were simply not provided by the crane designer and manufacturer. Theability of workers not to fall to their death was largely left up to their skill and not beingin the wrong place at the wrong time. Over the last three decades safety standardshave progressively improved and additional features have been added to the accesssystems. However, the additions have often been less than ideal and have not beenconsistent from crane to crane. The results of the tower crane campaign illustrate thislater point.

Tower crane non compliance

28.5

21.5

7.3

26.5

16.2

0

5

10

15

20

25

30

35

Access Structural &

Mechanical

Operational

Issues

Safety Features CraneDocumentation

Issue

Percentage


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Most of the newer tower cranes have excellent safety provisions on ladders andplatforms and require very little reliance on fall arrest systems. However, oneexception to this general rule is on tower cranes with narrow, slender towers. Some ofthese do not have adequate room for the ladders to be staggered such that ladderlandings will prevent a person falling for more than 4 to 6 metres. Instead these

cranes have continuous vertical ladders and it is feasible that a person could fall for theentire length of the tower. Considering that the total fall distance could be in excess of40 metres, there would be very little chance of a person surviving such a fall. Sometower crane manufacturers and owners have attempted to remedy this issue byproviding trapdoors at landings to limit a persons fall. However, trapdoors areunacceptable in this application for the following reasons:

1. Trapdoors can increase the risk of a person falling off the ladder becausethey regularly require the person to hold the trapdoor open as they areclimbing or descending the ladder.

2. A closed trapdoor can impede the rescue of a person from the tower crane.This is especially the case if the worker is unconscious on top of a closedtrapdoor.

3. Persons climbing a tower may be tempted to leave the trapdoors open andhence will not reduce the potential fall distance.

In view of the above, trapdoors should not be provided in tower crane towers, except atthe crane cabin. Where there is no alternative for a continuous vertical ladder to beprovided on a tower crane, vertical rail or steel wire rope fall arrest systems may beused. These systems lock in the event of a person falling from a ladder and onlypermit a minimal free fall distance (i.e. less than 600 mm).

The next key area of non-compliance is related to the provision and operation of safetyfeatures, and this makes up 26.5 percent of the total. Included within safety featuresis the provision of indicators, motion limiters and crane controls. While the newer,state of the art, tower cranes have comprehensive operating and monitoring systemsthe safety features in older cranes are more prone to breakdown and malfunction.While some older tower cranes are maintained in excellent condition and have beenupgraded with newer control systems, this is generally not the case. This serves asa reminder to the tower crane industry to ensure safety features are both provided on

the cranes and their continued operation is monitored.

Structural and mechanical issues accounted for 21.5 percent of the total number ofnon-compliances. A large proportion of the structural and mechanical issues applied tohydraulic oil leaks and corrosion on the towers and booms of the cranes. In somecases it appears that the tower cranes have been sent from job to job without beingsent back to the crane yard for adequate inspection and maintenance. It should benoted that the time that a tower crane can be located on site may be in excess of twoyears in some situations, although the average is generally about 10 months. Mostexamples of structural and mechanical non-compliances were not enough to justifystopping the operation of the crane. However, the results of the compliance campaign

demonstrate there is a need for the industry to ensure structural components andhydraulic systems are regularly checked and maintained.


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Figure 1 shows that crane documentation issues accounted for 16.2 percent of non-compliance. Crane documentation includes commissioning paperwork, non-destructivetesting records for critical crane components and 10 year major inspection reports.While the percentage is not particularly high, it indicates that there is room for

improvement in this area and not all crane owners are applying the safety inspectioninstructions of the crane manufacturer and Australian Standard AS 2550. In particular,there was a lack of 10 year major inspection reports on some of the older towercranes.

Operational issues had a relatively low percentage (7.3 %). When taken at face value,this is not consistent with the data in Table 2, which indicates that most crane incidentsin Queensland are attributed to operational issues. However, it must be noted that thedata in Table 2 applies to both mobile and tower cranes. In the case of mobile cranes,most incidents relate to operational issues and specifically to incidents where themobile crane has overturned. Tower cranes are nearly always anchored to their

supporting structure and instances of the tower crane overturning are extremely rare.Incidents with tower cranes are more likely to relate to non-operational issues, such asmechanical failure or malfunction of a safety system. The low percentage of non-compliances relating to operational issues during the tower crane compliancecampaign is therefore reasonable.

The data obtained on tower crane age is of interest. The data on crane age has beencategorised into three main groups and these are illustrated in Figure 2. Only 15percent of tower cranes audited are less than 6 years old. A large percentage (62%)of cranes are more than 15 years old. Of this latter group, Table 6 shows that 26percent of cranes audited are more than 25 years old. This group is mainly made upof the Favco type hydraulic luffing cranes manufactured during the 1960s. Thesample size of more than 100 cranes audited shows that this data gives an accuratepicture of the age of tower cranes operating in Queensland. The information illustratesthe need for increasing levels of maintenance on older cranes. While the older towercranes have given many years of safe operation, some of these cranes are beginningto show their age and are nearing the end of their practical design life. While it ispossible to upgrade the older cranes by replacing mechanical and structuralcomponents, this option is becoming increasingly impractical with the introduction ofnewer, more sophisticated tower cranes.


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Tower Crane Age

15%

23%

62%

under 5 years 6 to 15 years over 15 years

Figure 2: Tower crane age

Tower crane operator survey questionnaire

As previously mentioned in this report, the tower crane operator survey questionnairehas provided invaluable information that would not have been obtained if the campaignhad only been compliance focused. Two important issues that the questionnaire hashighlighted are the concern over tower crane customers and perceived crane crewcompetency in the tower crane industry. One of the questions operators were askedwas:

What do you believe is the main reason for the increase of crane incidents over thelast few years?

The answers to the question are graphically shown in Figure 3 of this report.

The largest percentage of responses to the question above relate to tower cranecustomers. The following three responses accounted for 47 percent of all responses:

Pressure from customers to complete jobs quickly - 35%

Pressure from customers to complete jobs with the wrong size or type of crane - 10%

Customers providing poor set up areas for the crane - 2%

Total: 47%


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The combined total of customer related issues (47%) indicates that this is an extremelyimportant issue that needs addressing. It demonstrates operators concerns that theyconsider customers not only have a poor understanding of safe crane operation butthat crane customers are also applying considerable pressure to the tower craneindustry to get the job done without considering the correct type of crane for the task.

The second most common response to the above question waslack of experiencedoperators in the industry and accounted for nearly one in five responses. This wasfollowed by the statement operators dont receive adequate training (12%). Both ofthese responses relate to operator competency and when combined (31%), it isevident these issues are one of tower crane operators primary concerns and deservefurther consideration.

The large percentage of responses relating to operator competency also helps todispel the misconception that operators do not care about the safety performance oftheir industry. The response is an excellent indication of the candidness of the crane

operators and, more importantly, their desire for the level of operator competency to beraised and consequently, safety within the industry increased.

What do you believe is the main reason for ther increase of crane incidents over the last few years?

6

19

12

1

35

10

2

9

6

0

5

10

15

20

25

30

35

40

Large amount

of work in the

crane industry

Lack of

experienced

operators in

the industry

Operators

dont receive

adequate

training

Cranes are

becoming

more difficult

to operate

Pressure from

customers to

complete jobs

quickly

Pressure from

customers to

complete jobs

with the wrong

type or size of

crane

Customers

providing poor

set-up areas

for the crane

The wrong

type of crane

being used for

the job

Other reason

Range of responses

Percentage

Figure 3: Responses to operator question main reason for incident increase


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Conclusions

The tower crane compliance campaign was successful for the following reasons:

The campaign has enhanced the safety of the industry by improving the safety

of tower cranes themselves and the safety systems associated with crane use.

The data received, particularly from the tower crane operator surveyquestionnaire, has given an excellent indication of where further attention isrequired in this industry to help reduce the potential for future crane incidents.

The increased profile of Workplace Health and Safety Queensland inspectorshas served as an incentive for crane owners, crane crews and principalcontractors to make safety improvements in this industry.

A number of specific safety issues have been raised by the campaign. While the towercrane industry in general is safety conscious, there are a number of areas whereimprovement can be made. The key areas below summarise the most important issueshighlighted by the campaign.

Safe access on cranes: safe means of access on tower cranes is required for avariety of workers including operators, maintenance workers and crane erection crews.The latest tower cranes generally provide a very high level of safety in relation to fallsfrom heights issues and a very low reliance on personal fall arrest equipment (i.e.safety harnesses). However, many of the older tower cranes have relatively pooraccess systems and require a high reliance on fall arrest equipment, particularly for

maintenance and crane erection crews. In addition, some of the newer tower craneswith slender towers have poor access provisions on the tower ladders. There is aneed for continual improvement on access provisions in the tower crane industry.

Crane condition and safety features: Limiting and indicating devices on aconsiderable number of older cranes were either not operational or requiredcalibration. A large percentage of older cranes also had hydraulic leaks, rustedstructural components, and worn mechanical parts. In some relatively rare situations,it appears that the tower cranes have been sent from job to job without being sent backto the crane yard for adequate inspection and maintenance. There is an ongoingrequirement for tower crane owners to ensure their cranes are supplied with all

relevant safety features required by Australian Standards and to ensure that cranesare regularly and adequately maintained.

Crane safety documentation: Crane documentation on some tower cranes wasfound to be lacking. This included, commissioning paperwork, non-destructive testingrecords and 10 year major inspection reports. While the percentage is not particularlyhigh, it indicates that there is room for improvement in this area and not all craneowners are applying the safety inspection instructions of the crane manufacturer andAustralian Standard AS 2550. Particular improvement is required in the area of 10year major inspection reports. This issue has been addressed in recent amendmentsto the Workplace Health and Safety Regulation 1997. The Regulation require the

mandatory submission of a yearly statement from tower crane owners stating thecrane has been inspection and maintained so as to be in safe condition. Further


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amendments to the Regulation, due to take effect in February 2007, will prescribe 10yearly major inspections for tower cranes and these are to be overseen by aProfessional Engineer. The Tower Crane Code of Practice will provide furtherguidance on this issue.

Crane customer input: 48 percent of crane operators consider that crane customers,including principal contractors, have had a direct influence on the increase in craneincidents in Queensland. This feedback indicates that the issue requires furtherinvestigation and that crane customers may be unknowingly contributing to craneincidents. It is considered that the construction industry requires further educationregarding the safe operation of cranes and the need to comply with guidance providedby the crane owner and operator.

Operator training and competence: Crane operators have highlighted the need forimproving their competency as a group and consider this to be a major factor in theincrease of crane incidents. It is considered that training systems, in addition to those

addressed by the National Certification System, need to be introduced in the craneindustry. This issue has already been identified by both the Tower Crane and theMobile Crane Code of Practice Reference Groups and the codes identify the need forboth familiarisation and refresher training of crane operators. It should also be notedthat recent amendments to the Workplace Health and Safety Regulation 1997prescribe a separate, specific type of tower crane certificate for operators of selferecting tower cranes.

Workplace Health and Safety Queensland greatly appreciated the support of the towercrane industry and welcomes future industry cooperation to promote a safer industry.


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Recommendations

A number of recommendations have been provided in theMobile Crane ComplianceCampaign 2005 Report, previously prepared by WHSQ. These recommendationsgenerally apply to both the mobile and tower crane industries and have largely been

implemented. In view of this the only recommendation remaining to be implemented isas follows:

The level of understanding of tower crane customers, with respect to safe craneoperation, be investigated to determine if there is a deficiency in this area. If thisis the case, it is recommended that an effective education initiative beundertaken.

It should be noted that the Mobile Crane Compliance Campaign 2005 Report includesan identical recommendation to the above. The strategy to address bothrecommendations can apply to both the tower crane and mobile crane industries.

It is intended that WHSQ will enter into discussion with all parties within the industrywith the intention of implementing the recommendation above.

Appendices

1. Tower crane audit checklist

2. Tower Crane Industry Compliance Guidelines

3. Tower Crane blitz Operator questionnaire


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Tower Crane Audit Checklist

One checkl ist per crane set-up

Crane Details : Date:

Inspector: Time:(1) Type(luffing, hammerhead,self erector)Manufacturer & model

Serial No.

No. of towers

Boom length

Location & builder

(2) Manufacture date

Plant Reg No.

Crane owner

Crane Driver

Dogger

Cert. No.

Cert. No.

CRANE

Item C

(3) Ropes (or luff rams)

Hoist

a) condition

b) lubrication

Luff/trolley (or luff rams)

c) condition

d) lubrication

Counterweight

e) condition

f) lubrication

(4) Pins

a) Correctly located

b) Split pins

c) Cheek plates(where required)

d) Wear


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Item Comments

(5) Crane structure(Deformation, rust, damage, etc)

a) Tower

b) Boom

c) A-frame

(6) Rope sheaves & wearpads

a) Condition

b) Sheaves rotate

c) Wear pads/rollers(boom/jib protection)

d) Rope keeper bar/plateon sheaves

e) Bar clearance correct

(7) Bolts

Tower

a) Tightened

b) Correct type

Slew ring

c) Tightened

d) All of one type

e) Washers

(8) Counterweights

a) Fixed will notsway

b) Moving connectingbolts

(9) Other structural/mech

a) Anti cavitation

b) Fluid leaks

c) Hook latch


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(10) Guarding (accessibleareas)

a) Provided

b) Fixed

(11) Load indicator & Ratedcapacity limiter

a) Load indicatoroperational

b) Load indicatorcalibrated

c) Cut-off operates

d) Other means ofverifying cut-off

(known weight older selferectors)

(12) Other indicators

a) Radius indicator

b) Height indicator(where required)

c) Wind indicator

(13) Limiters

a) Hoist limiter

b) Trolley limiter

c) Luff limiter &buffers

(14) Crane cabin

a) Seating

b) Visibility

c) Noise

d) Fire extinguisher

e) Controls labelled

f) Controls deadman

(15) Load charts

a) Provided

b) Displayed

c) Legible


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(16) Tower access

a) Ladders

b) Fall risk controlled

c) Platform guardrail

d) External fall control

(17) Machine deck access

a) Edge protection

b) Clean

c) Trip hazards

(18) A-frame access

a) Ladder cage

b) Ladder

c) Trapdoor opens

d) Edge protection

(19) Saddle bag access

a) Ladder access

b) Guardrail

(20) Boom/jib access

a) Walkway

b) Static line

c) Trolley platform(larger hammerheads)

(21) NDT

a) Boom crack testing

b) Chord thickness

c) Slew ring bolts

d) Tower bolts

e) Other NDT

(22) Other Documentation

a) Base drawing

b) Logbook providedcomplete

c) Plant registration

d) Commissioningdocumentation


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CRANE USE

(23) Load handling andslings

a) Load balanced

b) Slings adequatecapacity

c) Slings correct type

d) Sling condition

e) Slings tagged

f) Sling hooks

g) Materials restrained

(24) Proximity to otherplant/structures

a) Documented system toprevent collision

b) Operator okay withsystem

c) Co-ordinator listed

d) If warning devices(adequate reliability)

(25) Power lines

a) Documented system toprevent contact

b) Clearances adequate(during audit)

c) Safety observer(where required)

d) If warning devices(adequate reliability)

(26) Wind (if greater than 15m/s used on site)

a) Written procedures

b) Co-ordinator listed

(27) Crane climbing

a) Procedures exist

b) Risks addressed

(28) Personnel issues

a) Adequate number

b) Communication


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APPENDIX 2

Workplace Health and Safety QueenslandTower Crane Industry Compliance Guidelines

28/6/2005

Section Page

Introduction 2Structural and mechanical issues

Rope wear 3Pivot pin wear Luffing cranes 3Structural damage, modifications & repairs 4

Pin restraint Provision & use 5Correct towers in use Favcos & Favelles 6Correct towers in use Liebherrs 7Tower bolts - Torque 7Tower bolts - Identification 8Slew ring bolts - Torque 8

Indicators and motion l imiters

Load indicators: Non-self erecting tower cranes 9Load indicators: Self erecting tower cranes 9Rated capacity limiters: All tower cranes 9

Radius indicator 10Hook height indicators 10Wind speed indicators (anemometer) 10Upper hoist limit 11Luffing buffers & limit switches Rope luffing towercranes

11

Trolley limits all tower cranes with horizontal jibs 12Access issues

Tower ladders: Non-self erecting tower cranes 12Tower ladders: Self erecting tower cranes 13Internal guardrail on tower landings 13

External fall protection (primarily older Liebherr towers) 14Guardrail on machine deck & A-frame platform 14A-frame ladder cage 15Saddle bag access Favcos 15Crane jib access: Non-self erecting tower cranes 16

Non-destructive testingBoom crack testing: All non-self erecting booms 17Boom crack testing Favco & Favelle booms 17Band brakes Favcos 18Chord thickness testing all tower cranes lattice booms 18

Slew ring bolts - NDT 18Tower bolts 19


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Other documentation

Design and plant registration 19Crane base certification 19Verification of tower bolt torque Liebherrs 20

Commissioning documentation All tower cranes 20Operational Issues

Cabin glass 21Operational wind speed 21Avoiding collision 21Proximity to overhead power lines 22

Note: this document does not discuss all safety issues on tower cranes

Introduction

This document provides guidance to industry on the standards implemented byWorkplace Health & Safety inspectors when performing tower crane audits. Thisdocument does not discuss all issues relating to tower cranes and their safeoperation, but highlights the principal issues that can be audited during tower craneaudits. It focuses on more obvious safety issues that can be audited during aninspector visit to a site. This document is intended to be a guide and an inspectormay issue other directions based on considerations at the time of the inspection. Thisdocument applies to all tower cranes that are used on construction sites inQueensland including self erecting tower cranes.

The information in this guide is based largely on information detailed in AustralianStandards, principally in AS 1418.4, AS 2550.1 and AS 2550.41. The Plant Code ofPractice 2005 lists AS 1418 and AS 2550 and states that these standards should beapplied. Both standards are periodically revised and the requirements of thestandards are gradually increasing. The newer requirements of the standards arenot always applied retrospectively. However, where the newer requirements areconsidered to be important safety issues, WHSQ has required compliance. Oneexample is the provision of rated capacity limiters systems on early model Favcotower cranes. This requirement did not exist when these cranes were introduced butwas retrospectively applied in Queensland a number of years ago. Where arequirement of the current standard is considered to be an important safety item, this

document will generally advise the provision of that item on both older and newercranes.

1Note: AS 1418.4-2004 and AS 2550.1-2002 have been used in the preparation of thisdocument.


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Structural and Mechanical Issues

Rope wear

1. Issue: Guidance on the inspection of steel wire ropes is provided in section

12 of AS 2759 and A Guide to Rigging. This standard lists a number ofdiscard criteria for when the rope wear becomes excessive or the rope isdamaged.

2. Action: Wire ropes that fail the discard criteria set out in AS 2759 should bereplaced. Obvious examples of reasons for discard include a complete brokenstrand, excessive number of broken wires in one rope lay (see table 12.3.1 ofAS 2759), bird-caging, a severe bend, and a kink. As an indicator, themaximum number of broken wires permitted is 10% of the total number ofwires over a length 8 times the diameter of the rope. A small degree ofwaviness in the rope is permitted and this can sometimes be confused with

kinking. In cases of waviness, the rope should be discarded if:

d1 4d 3

where d is the nominal diameter of the rope and d1 is the diametercorresponding to the envelope of the deformed rope (see clause 12.12.10, AS2759 for more detail).

Waviness diagram showing d and d1

In the case of a hoist rope or luff rope, the crane should not be operated where acomplete strand of the rope has failed.

Pivot pin wear luffing cranes

1. Issue: The boom pivot pins (heel pins) on luffing tower cranes are extremelyimportant because they support most of the weight of the boom. These pins arerelatively large but experience wear as the boom is luffed up and down. There isa need to lubricate the pins. Any major wear will usually be evident when theboom is luffed down at moderate speed, with a load, and then stopped. If theboom is luffed up and down, in the vertical plane, the amount of slop in theconnection can generally be seen (caution should be exercised when slewing theboom back and forth because of the booms limited strength in the lateral plane).It can be difficult to measure the actual clearance between the pin and sleevewhile the pin is inserted in place. However, an indication of the degree of wearcan be determined by observing the crane in operation. Note: on hydraulicluffing Favcos the hydraulic ram pins should be observed to see if there is anyobvious wear in the ram pins.


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2. Action: Any excessive wear in the pivot pins should be investigated by acompetent person and a written report stating the amount of wear is permissibleshould be provided if the competent person is not prepared to do this the craneshould not be operated. The competent person is to measure the actual wear inthe pin where it is practicable to do this. Note: this issue is rarely a problem

because the pins take a considerable amount of time to wear. If the crane isproperly maintained the crane owner will make sure the wear is within toleranceprior to erecting the crane. It can be major exercise to replace the pivot pins whilea tower crane is erected.

Structural Damage, Modifications & Repairs

1. Issue: A tower crane is sometimes damaged during transportation and erection,or during use. Parts of the crane are also prone to corrosion or wear. As anexample, lacings on the boom are sometimes damaged by the hoist ropebecause the timber wear pads are worn through or damaged during transport.

The consequences of the damage will vary in potential risk depending on thedegree and location of the damage. For instance, surface rust is not seriouswhile rust that has caused pitting in a major structural component can haveserious consequences. Damage to boom lacings is generally much less criticalthan to chord damage, because lacings are secondary structural members. Anydamage that appears to be from overloading is very serious (eg bent boom orbuckled A-frame) this type of damage is fairly rare because tower cranes aregenerally fitted with rated capacity limiters. All tower cranes should be maintainedin good condition but the remedial action for some types of damage is morecritical than for other types.

2. Action:Damage: Deformed lacings where the number of bent lacings is small (i.e. 2 or3) the crane does not have to be stopped unless the bent lacings have pulled thechords out of alignment. However, if the lacings cannot be repaired until thecrane is next dismantled (i.e. access problems with the boom), a competentperson should provide a report on the lacings relating to on-going operation of thecrane.

Lacings cut - where a lacing has been totally cut through, the capacity of thecrane should be reduced based on a competent persons report. If two or more

consecutive lacings have been cut through, the crane should not be operated untilthe lacings have been replaced.

Chords bent where a chord is deformed the crane should not be operated.However, if a suitably qualified and experienced professional engineer makes astatement that the crane is safe to operate, at a de-rated capacity nominated bythe engineer, the crane may continue to operate under these conditions.

Corrosion where the corrosion only appears to be on the surface, corrosion is tobe removed and the surface repainted with suitable painting process. Substantialcorrosion will require the input of a competent person. Where internal corrosion

in chords is substantial, the chord section is to be replaced. Note: sometimes thereadings on ultrasonics thickness testers may not be accurate due to incorrect


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operation of the probe, difficulty of accessing the test location or providing asuitable transfer medium (i.e. couplant or jelly).

Modifications and repairs: Where the crane has been modified or repaired, sometype of certification or evidence of a repair procedure should be available. The

crane owner should also be able to verify competence of persons who havecarried out repairs to a crane. This particular information does not have to becarried on the crane but should be available at the crane yard. Wherever thecrane design has been altered, certification from a competent person (such as asuitably qualified and experienced professional engineer) should be available,unless the crane has been altered in accordance with instructions from the cranemanufacturer. Where the crane has been repaired, and the design not altered,certification from an engineer may not be required provided the owner canprovide a repair procedure authorised by the crane manufacturer or competentperson. The crane owner would need to demonstrate that the tradespersoncarrying out the work is competent. A report on the repair of the boom should

identify the steel type and any special welding procedures required. For example,the repair of T-1 type steel, from which some boom chords are constructed,requires the use of specific welding electrodes and heat treatment techniques.

Pin restraint provision and use

1. Issue: Effective restraint of pins. Two types of restraint can be provided on pins a device to prevent pin rotation and a device to prevent the pin becomingdislodged. Devices to prevent pin rotation, such as cheek plates, are providedwhere one of the pinned parts rotates. Pin rotation is prevented in this situation toreduce wear on the non-moving parts and to negate the need to lubricate both ofthe pinned parts. Where both of the pinned parts are static, there is no need toprevent pin rotation. However, all pins must be prevented from becomingdislodged by means of split pins, R-clips or another effective means.

2. Action: All pins require a locking device to prevent unintentional pindislodgement. However, cheek plates or similar are to be provided to prevent pinrotation wherever one of the pinned components is required to rotate (i.e. the heelpins connecting a luffing boom to the machine deck and pins provided onhydraulic rams). Split pins are to be opened and cheek plates are to be fitted withall bolts tightened.


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Correct towers in use Favco & Favelles

1. Issue: Each model of Favco and Favelle tower crane has specific tower sectionsthat are designed to withstand the loadings applied to that type of crane andthese are specified in the design registration. Some Favco towers have similar

external dimensions and it is possible to bolt different models of tower together.As an example, Favco STD 350 tower sections are usually constructed from steelwith a yield strength of 250 MPa and look similar to STD 750 towers, which areconstructed from Grade 350 steel. Although the STD 350 towers can be bolted toa STD 750 tower crane they should not be, unless they have been strengthenedin accordance with an amended design that has been registered with WHSQ.Some tower sections have been strengthened by the addition of steel plate orangle that runs along the chords. Three examples of strengthening to towers thathave been design registered are as follows:

a) The addition of two lengths of 150 mm wide, 10 mm thick plate welded

to each chord of a Favco 350 tower modified tower may be used on aFavco 750 type tower crane (design registration number: CH 12361).

b) The addition of a 150 mm x 150 mm, 12 mm thick steel angle to eachchord of a Favco 750 tower modified tower may be used on a Favco1000 type tower crane (CH 14176).

c) The addition of two lengths of 150 mm wide, 12 mm thick plate weldedto each chord of a Favco 750 tower or the addition of a 150 mm x 150mm, 12 mm thick steel angle to each chord modified tower may beused on a Favco 1000 type tower crane (CH 11948).

Where different towers are used they should at least have the same or greaterstrengths than the original towers designed for that crane.

2. Action: Tower sections should be clearly and permanently identified with theirmodel type. Only tower sections of the correct model or a model of greaterstrength should be used. With Favcos this will generally mean that tower sectionsof the same or a higher model number should be used (ie acceptable to use STD750 towers with a STD 350 tower crane). The tower sections actually used onsite are to be the same as specified on the engineers crane base drawing on site.

Note: Favelle 230D and 300D tower cranes - STD 750 towers or stronger may beused.


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Correct towers in use Liebherrs

1. Issue: Each model of Liebherr tower crane has specific tower sections that aredesigned to withstand the loadings applied to that type of crane. The four maintypes of towers below are used. These should not be interchanged unless an

engineer certifies this is acceptable and it is highlighted on the crane basedrawing on site.

71 EC towers. 120 HC towers (90 ECs are used on these towers). 185 HC towers (in USA - 200 HC). 256 HC towers (in USA - 290 HC. 280 EC-H used on 256 HC

towers).

The towers for the 185 HC and 256 HC have similar external dimensions, but thechord thickness on the 256 HC tower sections is much greater. Where different

towers are used they should at least have the same or greater strengths than theoriginal towers designed for that crane, if a professional engineer provides writtencertification.

2. Action: Tower sections should be clearly and permanently identified with theirmodel type (Liebherr uses symbols). Only tower sections of the correct model ora model of greater strength should be used. Where Favco towers are used thisshould be clearly identified on the engineers crane base drawing for the particularinstallation. Note: Liebherr 120 HC and 185 HC tower cranes may be erectedon Favco STD 350 or stronger tower sections.

Tower bolts - torque

1. Issue: Tower bolts serve a very important function and should be tightened to themanufacturers specification. Tapping the bolts with a small hammer will give anindication of whether the bolts are loose this is an indicator only, it will not verifythat bolts have been tightened to the specified torque. When tapped, loose boltswill give a lower or duller pitch than tighter bolts. However, the tone will also beeffected by the amount of steel or around the bolt the more material, the dullerthe tone.

Favco and Favelle: Favco towers generally have six bolts on each corner of thetower. On these cranes it is fairly common to find at least one tower bolt loose onan installation. Tower bolts serve a very important function and should betightened to the manufacturers specification. Tapping the bolts with a smallhammer will give an indication of whether the bolts are loose this is an indicatoronly, it will not verify that bolts have been tightened to the specified torque. Whentapped, loose bolts will give a lower or duller pitch than tighter bolts.

Liebherr: On Liebherr towers it is extremely rare to find a loose bolt but if everfound it is much more critical because there are only two bolts on each corner.Impact wrenches (rattle guns) are used to tighten bolts on both Favcos andLiebherrs. However, bolts on Liebherr towers should be tightened with a torquemultiplier because the required torque is usually higher than the maximumachieved with a rattle gun (see testing and documentation section).


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2. Action:

Favco and Favelle: All tower bolts should be tightened. As a general guide itbecomes critical when more than two bolts on any one corner of a Favco towerare loose. In these critical situations occur the crane should not be operated until

the bolts have been tightened. In other situations, the crane may continue to beoperated but the loose bolts should be tightened as soon as possible.

Liebherr: If there are any obviously loose bolts on a Liebherr tower, operation ofthe crane should cease until bolts are checked and tightened to themanufacturers torque specification.

Tower bolts - identification

1. Issue: Sometimes different types of bolts are used to connect the tower sections this is generally only an issue on Favco towers. Favco type bolts can be clearly

identified with the word favco or FAV.L marked on the head. Other bolts canalso be used but there should be some verification or marking available to showthe bolts are at least grade equivalent to the grade specified by the manufacturer.Liebherr tower bolts are generally grade 10.9 bolts although grade 12.9 bolts areoften used on the tower base (Liebherr 256 HC crane towers require grade 12.9bolts throughout).

2. Action: Tower bolts of the correct type and grade should be used. The mixingand matching of bolts on any one corner should be discouraged. Any bolts usedshould be long enough to protrude through the nut so that all threads of the nutare engaged. Tower bolts with extensive damage from hammering on the bolthead should not be used.

Slew ring bolts - Torque

1. Issue: Slew ring bolts are extremely important because they ensure the machinedeck and boom do not fall off the crane tower. Tapping the bolts will give anindication of whether the bolts are loose this is an indicator only, it will not verifythat bolts have been tightened to the specified torque. Slew rings can have morethan 50 bolts on the upper and lower parts of the slew ring. This gives a highnumber of bolts over which the load is distributed. However, when one bolt fails

or is loose, this places additional load on the bolts adjacent to this bolt andincreases the likelihood of other bolts failing.

2. Action: All slew ring bolts should be torqued to within the manufacturersspecification. An audit will not be able to quantitatively verify this but it shouldlocate any loose or failed bolts in the slew ring. Note: not all slew ring bolts canbe tapped because they are not easily accessible. Where a bolt has failed in theslew ring, it can indicate that the slew ring bolts have not been installed correctlyor are damaged in this situation all of the slew ring bolts should be removed andchecked for cracks by NDT or be completely renewed.


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Indicators and Motion L imiters

Load indicators: Non-selferecting tower cranes

1. Issue: a load indicator measures and displays the mass of the load being lifted.

This indicator assists the crane driver to stay within the load chart and SWL of thecrane, and assists with checking correct operation of the rated capacity limiter.

2. Action: load indicators are to be fitted to all non-self erecting tower cranes. Theload indicator is to operate at all times that the load is suspended on the hook (theoriginal Favco hydraulic gauges do not display the load when hoisting down).Note: The allowable tolerance of the load indicator should be within 97 to 110 %of the actual load (see section 4.2.2.2 of AS 1418.4).

Load indicators: Self erecting tower cranes

1. Issue: a load indicator measures and displays the mass of the load being lifted.This indicator assists the crane driver to stay within the load chart and SWL of thecrane, and assists with checking correct operation of the rated capacity limiter.Newer self erecting tower cranes are generally fitted with digital load indicators onthe remote control. However, older self erectors are not always fitted with suchdevices.

2. Action: wherever the self erecting tower crane was originally provided with a loadindicator (i.e. at manufacture), the indicator must not be removed and is tooperate correctly. If the crane is not provided with a load indicator, there must bea means of verifying the rated capacity limiter of the crane is functioning correctly.For example, a calibrated weight is to be kept on site, and when lifted will causethe relevant crane functions to shut down at the correct radius positions on theboom. Note: The allowable tolerance of the load indicator should be within 97 to110 % of the actual load (see section 4.2.2.2 of AS 1418.4).

Rated capacity limiters: all tower cranes

1. Issue: A rated capacity limiter prevents overloading of the crane by stopping allrelevant crane functions when an overload is detected (ie stops hoisting up andincreasing the radius of the load). Capacity limiters generally allow a slight

overload on the hoist function to account for dynamic factors (if they are set at100% it is difficult to operate the crane at its full capacity).

2. Action: Rated capacity limiters are to be fitted and functioning on all towercranes. The limiter should prevent hoisting of a load exceeding 110% of themaximum rated capacity and should prevent the radius being increased when theload exceeds 100% at the particular radius (clause 3.4.1.2 AS 1418.4). If the loadindicator and capacity limiter are not operating, the crane is not to be used.


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Radius indicator

1. Issue: A radius indicator displays the radius of the suspended load generallymeasured from the centre of the slew ring.

2. Action:Tower cranes with cabins: Operational radius indicators should be fitted and bedisplayed in metres. The indicator is to be accurate to + 10%, -3%. It should benoted that if the radius indicator is not providing accurate readings, the ratedcapacity limiter may be malfunctioning if this is the case the radius indicator is tobe repaired immediately. Note: on luffing tower cranes the radius indicator willgenerally be connected to the capacity limiter on hammerhead type Liebherrtower cranes the overload system is usually separate from the radius indicator.

Tower cranes with remote control only: Provided the jib can only be operatedhorizontally and all of the jib is clearly visible to the operator the indicator may

consist of 1 metre graduations marked on the jib with numbers written at intervalsthat are not excessive (eg every 5 metres).

Hook height indicators

1. Issue: Hook height indicators usually display the height of the hook aboveground level and are particularly useful where the operator is lifting blind (cannotsee where the hook is). These devices are important on high rise buildings. Thedevices are also known as rope payout gauges.

2. Action: Hook height indicators should be provided on high rise jobs where thehook is regularly outside of the operators view. These devices should also beprovided where a job exceeds 5 -10 floors, or if loads are lowered below groundlevel. However, hook height indicators should always be provided where thecrane operator considers that absence of the indicator may make the craneoperation unsafe.

Wind speed indicators (anemometer)

1. Issue: Wind speed indicators are provided as an aid to tell the operator when touse caution when moving a load that is susceptible to wind loading. These

devices also indicate to the operator if the wind speed is excessive and thedecision can be made to shut the crane down.

2. Action:Non-luffing tower cranes (non-self erecting): Operational wind speed indicatorsshould be provided and mounted where a true wind speed will be obtained.However, because there is not a large power pack on hammerhead cranes, it isgenerally acceptable to position the wind gauge on the guardrail above theoperators cabin. On these cranes it is not necessary to mount the wind gauge ontop of the A-frame.

Luffing tower cranes: On luffing tower cranes the wind gauge should be mountedon top of the A-frame. If mounted on the machine deck, the power pack cancause substantial wind shielding and the wind speed reading will be inaccurate.


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Self-erecting tower cranes: It is preferable for the wind gauge to be mounted ontop of the tower. However, it is acknowledged that on self erectors it is generallymore difficult to prevent damage to the gauge (i.e. during erection and collapsing)and it may be impractical to maintain the gauge if it malfunctions. If there is an

effective way of measuring wind speed on site (i.e. by providing a wind gauge ona nearby structure) there may be adequate justification not to fit a wind gauge tothe crane.

Upper hoist limit

1. Issue: When activated, an upper hoist limit stops all crane functions whosemovement can cause the hook block or ponder weight (headache ball) to contactthe boom or head sheave. On hydraulic luffing Favcos the hoist limitarrangement will consist of both a hunting tooth limit and a mechanical device onthe boom head often called a banana. Both of these devices should be

operational. Rope luffers are not fitted with mechanical devices on the boom tipbut the limit switch is incorporated on the hoist rope drum. Liebherr tower cranesare fitted with an initial limit that slows the hoist speed prior to contact with thefinal limit.

2. Action: Upper hoist limit devices should be fitted to all tower cranes and shouldbe of the motion cut type (not indicators). If the crane was originally fitted with twolimits on the hoist up function, both limits should be operational.

Note: a lower hoist limit is rarely a mandatory requirement on tower cranes.However, if the crane is being used to lower materials below ground level, a lowerhoist limit should be fitted. One example is where the crane is lowering materialsdown a shaft.

Luffing buffers & limit switches Rope luffing tower cranes

1. Issue: Luffing limit switches and buffers ensure the boom is not luffed up or downbeyond the design limitations and prevent the boom being damaged or collapsingover the back of the crane. The luff limit switches are extremely importantbecause the presence of buffers alone will not prevent the boom being pulledover backwards. The luff rope winch has more than enough power to pull the

boom past the buffer limit.

2. Action: Luffing limit switches and buffers must be fitted to all rope luffing towercranes. These cranes are usually fitted with an initial deceleration (decel) limitthat slows the luff speed of the boom prior to the final limit (see clause 3.4.2.3 AS1418.4). The luffing limit switch is to be set to the manufacturers specifications(the limits on final luff limit for Favco tower cranes varies between 74 and 82degrees depending on the boom length set up on the crane). A rope luffing towercrane is not to be used when the luff limit switches are not operating.


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Trolley limits all tower cranes with horizontal jibs

1. Issue: Trolley limits ensure the trolley does not travel beyond the designlimitations and prevents it going through the end stops. The end stops areprovided as an additional safety feature and to prevent the trolley falling off the

end of the boom when the crane is being rigged (applies to Liebherr, Potain andKaiser tower cranes).

2. Action: Trolley limits and end stops should be fitted to both ends of the jib. Mostnon-luffing tower cranes are fitted with an initial limit that reduces the trolleyspeed to low speed prior to approaching the final limit (see clause 3.4.2.3 AS1418.4). The crane should not be used where the final limit switches are notoperating.

Access Issues

Tower ladders: Non-self erecting tower cranes

1. Issue: The type of ladder access in tower cranes is often determined by theamount of available space in the tower. AS 1418.4 provides information onminimum requirements for the ladders. However, it may be impractical to complywith the design principles in AS 1657, Fixed platforms, walkways, stairways andladders. The provision of landings, with changes in direction of the ladder,should be provided where there is available space. This system will minimise theinjury to workers, in the event of them falling off the ladder. It will also allowworkers to take rest breaks.

AS 1418.4 states that the first ladder in the tower shall not exceed 12.5 m inheight and subsequent ladders shall not exceed 10 m. However, the standardalso permits the use of longer vertical ladders where there is a control thatprovides at least an equivalent level of safety. Favco and Favelle type towercranes are generally provided with vertical ladders with landings at 4 m intervalsalthough this can increase to 6 m on some towers. Liebherr tower cranes, otherthan the 71 EC towers, are generally provided with sloping ladders with landingsand the ladders change direction every 4 m. Potain City cranes, and smallerLiebherr cranes are often fitted with a continuous vertical ladder.

2. Action:

Larger towers (Favco, Kaiser, Liebherr larger than 71 EC).

Favco, Favelle and the larger Liebherr type tower cranes are to be provided withladders and landings that complying with the principles in AS 1418.4 and themanufacturers specifications. AS 1418.4 permits the use of 12.5 m high and 10m high ladders for the first and other towers respectively however, wherepracticable the distance between landings should not exceed 6 m.


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Smaller towers continuous vertical ladders

The use of continuous vertical ladders for the total length of the tower is to bediscouraged. Where it is impractical to provide anything but a continuous verticalladder, a fall arrest system that does not require the climber to constantly hook on

and off, is to be provided. This device could incorporate a vertical rope or dropline with a locking cam device. The lanyard length is to be minimised so as toreduce the likelihood of injury in the event of the climber falling off the ladder. Anyfall arrest system is to comply with the directions of a person competent in thistype of equipment. Note: the provision of rest platforms beside the vertical ladderis not adequate on its own because these will not reduce the potential falldistance of the climber. The use of fold down type platforms is discouragedbecause they can hinder rescue procedures (if the operator collapses on top ofthe platform), and create procedural difficulties.

Tower ladders: Self erecting tower cranes without cabins

1. Issue: The towers on most self erecting tower cranes do have to be climbed byworkers while set up on construction sites. Any maintenance that must beperformed on site can often be carried out by collapsing the crane. However,some self erecting tower cranes are provided with ladders on the towers formaintenance access.

2. Action: If a ladder is provided for maintenance activities only, the ladder can bevertical and the twin lanyard access system may be used by persons climbingthe ladder. No person should be permitted to climb the ladder without fallprotection. The use of work platforms, such as elevating work platforms, shouldbe considered for performing maintenance activities. Note: any self erectingtower crane fitted with a cabin is to comply with the access principles for non-selferecting tower cranes above.

Internal guardrail on tower landings

1. Issue: Internal guardrails on landings reduce the risk of persons falling internallydown the tower. On Favcos, it consists of either a guardrail on the internal side ofthe manhole or a rail that also extends around the back of the manhole. OnLiebherrs it consists of a short section of guardrail that is located on the internal

side of the landing there needs to be adequate room for a person to climb offthe ladder and onto the platform.

2. Action: Both Favco and Liebherr tower cranes should be provided with internalguardrail on tower landings. The same principal applies to other types of towercrane. Note: on Favcos, it is impractical to provide an internal guardrail on the toptower landing because this can obstruct the machine deck ladder as the craneslews.


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External fall protection (primarily older Liebherr towers)

1. Issue:a) Ladder next to side of tower: On some tower cranes the internal ladder may

be provided next to the outside of the tower. In some cases the lacings may

not provide adequate protection to climbers from falling out of the tower. Inthis situation modifications to the tower access need to be carried out. Note:in normal circumstances it is considered very unlikely that a person could fallfrom the tower on an unmodified tower. However, in high winds and theperson is small there is still a risk of this occurring.

b) Favco and Favelle towers: On these towers there is a triangular opening onthe four sides of each tower at platform height. Two of the openings haveladders in front of the openings and do not require additional edge protection.However, with the two other openings there is a risk of falling out of the tower.Note: some of these towers also have guardrail provided next to the

triangular openings below the tower bolts. However, this guardrail can maketightening of the tower bolts, with a rattle gun, difficult as the rigger has toclimb over the rail. The substantial kickboard also minimises the risk of fallingthrough this gap. There does not appear to be adequate justification to makethis guardrail mandatory (riggers installing tower bolts need to use fall arrestharnesses, unless the opening is covered).

2. Action:a) Ladder next to side of tower: Parallel rails (one or two), or other alternative

means such as a ladder cage, should be provided adjacent to access ladderswhere there is a risk of falling out of the tower. A horizontal bar, or othereffective means to prevent persons falling off the tower, is to be provided atthe top of each tower ladder, if there is an external fall risk.

b) Favco and Favelle towers: The two triangular openings, other than thoseprotected by access ladders, require a single horizontal bar to be fitted tocontrol the risk of falling out of the tower.

Guardrail on machine deck and A-frame platform

1. Issue: Guardrail on the machine deck and A-frame platform of tower cranes

prevents the operator and maintenance personnel falling to the ground.

2. Action: Accessible machine decks on tower cranes are to be provided withperimeter edge protection that extends around the machine deck. The edgeprotection should consist of a top rail between 900 and 1100 mm high, a mid-railand a kickboard at least 100 mm high. The guardrail should comply with AS 1657(the standard edge protection provided on these cranes is generally acceptable).


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A-frame ladder cage

1. Issue: The ladder cage on the A-frame ensures that if a person falls off a ladderthey will be confined within the cage and will fall onto the machine deck (not offthe tower crane). Where there are an inadequate number of vertical rails on the

ladder cage, or the ladder cage is too high above the lower platform, this may notoccur.

2. Action:

a) The lowest part of the ladder cage should be between 2 and 2.2 metres abovethe lower deck (see section 5.6.7, AS 1657).

b) The horizontal spacing between vertical bars on the ladder cage should notexceed 150 mm. It is acceptable to use a mesh infill in place of rails.

Saddle bag access Favcos with moving counterweights

1. Issue: Saddle bag platforms are provided on Favcos with moving counterweightsand provide access for riggers erecting cranes and for persons carrying outmaintenance. Some of these cranes have very poor access to the platforms andrequire a person to climb over the machine deck guardrail and down a ladder ontothe saddle bag platform. On such cranes the person can fall to the ground if theyslip off the ladder and are not using a fall arrest harness. In addition someplatforms are not fitted with an internal rail. It is sometimes argued that personsare only required to be on the platform while the counterweights are located nextto the platforms and there is no risk of falling off the internal side. However,maintenance workers are required to stand on the platforms to check that thecounterweights are moving correctly for their entire travel so that argument is notvalid.

The provision of fall arrest harnesses is one control measure used on saddlebags with poor access provisions. However, it is a lower order control and it isconsidered practical for crane owners to modify saddle bags such that the use offall arrest harnesses is unnecessary.

2. Action:

a) Access to saddle bag platforms should ensure a person cannot fall off thetower crane when getting onto the ladder or while climbing down the ladder.This can sometimes be done either by providing a trapdoor in the machinedeck or a ladder cage on the saddle bag ladder depending on the saddlebag design.

b) The saddle bag platform should be provided with a top rail, mid-rail andkickboard. On the inside of the saddlebags the provision of a removable toprail and mid rail is an option (permanent rails may interfere with installation ofthe counterweights).


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Crane jib access: Non-self erecting tower cranes

1. Issue: Non-self erecting tower cranes require riggers and crane operators toaccess the jibs during erection, inspection and maintenance. Both luffing andnon-luffing are usually fitted with a narrow platform (riggers run) and a number of

wire rope static lines running the length of the jib (the jib consists of a number ofsections and each section is fitted with a static line). Workers walking along thejib need to use two lanyards, or a twin-tail lanyard, to ensure they are connectedto the jib at all times. A length of guardrail, on one side of the riggers run mayalso be provided on some crane jibs. Hammerhead tower cranes are often fittedwith a small platform with guardrail, attached to the hook trolley.

2. Action:

a) All non-self erecting tower cranes should be fitted with a riggers run and staticlines that extend for the complete length of the jib. The crane owner may be

able to provide engineering certification (AS/NZS 1891.2 provides guidance)for the static line system that justifies lower design loadings than stated below(ie possibly by using static line energy absorbers). However, as a generalguide the following specifications are satisfactory galvanised or stainlesssteel wire rope minimum diameter 10 mm, with machine swaged terminationsor a minimum of three bull-dog grips correctly fitted at each end. The staticline termination should also be fitted with thimbles. The line should generallynot extend more than about 8 metres between intermediate supports. Endanchorages and steel wire rope should have a failure load of at least 40 kN.Shackles and turnbuckles (rigging screws with open hooks not permitted)should have a failure load of at least 40 kN this corresponds to a workingload limit of 1 tonne if the components are manufactured to an AustralianStandard for lifting gear (these specify a factor of safety of 4 to 1).

b) Trolley platforms on hammerhead cranes these should be provided on alltower cranes other than the Liebherr 71 EC and 90 EC models (it isimpractical to fit platforms to these due to size).


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2. Action: NDT crack testing of the following parts of Favco and Favelle booms is to

be performed prior to erection:

a. Counterweight sheave bracket welds.

b. Welds in the cruciform area.c. Butt heal bosses.

Band brakes Favcos

1. Issue: The older designed Favco tower cranes are provided with band brakes.On some of these cranes the steel band is welded to an end fitting, that in turnhas a pin passing through it. These welds have been known to crack.

2. Action: All Favcos fitted with band brakes are to have the weld between theband and end fitting tested by NDT each time the crane is erected(note: on some

brake bands there may be no weld).

Chord thickness testing all tower cranes with lattice booms

1. Issue: Chords on boom can be attacked both by internal and external corrosionand this can greatly reduce the strength of the boom. In addition abrasiveblasting of the boom can reduce chord wall thickness. Ultrasonic thicknesstesting is one method of verifying there is adequate strength in the chords of theboom.

2. Action: All main chord sections on booms of all tower cranes should bethickness tested at intervals not exceeding 8 years (based on section 8.3(c) of AS2550.4-1994).

Slew ring bolts - NDT

1. Issue: The integrity of slew ring bolts is critical because this ensures that themachine deck and boom remain attached to the tower. Slew ring bolts canbecome damaged, and their effective life is reduced if the bolts are either under orover torqued. In addition the prescribed amount of applied torque will varydepending on the type of lubricant that has been used.

2. Action:

a. All tower cranes: all slew ring bolts are to be non-destructively tested at leastevery five years. The preferred system is to remove the bolts completely andexamine the bolts by magnetic particle NDT. This applies to both self erectorsand non-self erecting tower cranes. Note: if selected bolts are removed, all ofthe bolts should be removed from the slew ring, unless the cranemanufacturer states otherwise.

b. Where the slew ring is separated: on some tower cranes the slew ring must

be split when the each time the crane is moved (e.g. Favco 1500). Whereslew ring bolts are disturbed, 10% of slew ring bolts are to receive NDT cracktesting. The bolts to be crack tested shall be selected from the slew ring at


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random locations, and the locations of the bolts marked. If any cracked boltsare found, all bolts are to be tested.

Tower bolts

1. Issue: Tower bolts are a critical part of the crane and permit the effective transferof load from the crane boom to the crane base. Slew ring bolts can becomedamaged from job to job, and their effective life shall be reduced if the bolts areeither under or over torqued. While all tower bolts are high tensile bolts somebolts are of extremely high steel grade and may be more susceptible to cracking.

2. Action: a minimum of 10% of tower bolts to be checked for cracks by NDT. Thetested bolts should be identified by marking on the bolt head by a method thatdoes not damage the bolt.

Other Documentation

Design and Plant Registration

1. Issue: The Workplace Health and Safety Regulation 1997 requires all towercranes to be design registered and the cranes should preferably comply withAustralian Standard AS 1418.4, Cranes: Tower cranes. The original cranedesign requires registration on a one off basis. However, the crane base designmust be registered for each installation other than for static bases where there isno moment connection between the tower and base (i.e. the crane relies onweights placed on the tower base for stability). All tower cranes are also requiredto have plant registration and this is to be renewed on a yearly basis.

2. Action: The tower crane should not be operated until design and plantregistration from WHSQ are obtained. However, the absence on these itemsalone does not demonstrate risk.

Crane base certification

1. Issue: The size and design of tower crane bases will vary depending on factorssuch as tower height, wind speed and terrain type, ground type and bearing

capacity, boom length and crane lifting capacity. Bases may consist of staticbases that rely on dead weight only, re-enforced concrete that is buried in theground and may be anchored to piers, or structural steel that is anchored to astructure. All tower crane bases should be designed by a suitably qualifiedengineer and are to be design registered with WHSQ.

2. Action: For every tower crane installation the crane base configuration is to becertified by a professional engineer and a signed drawing showing the towercrane configuration and the crane base specification is to be available. Thedesign registration number should be noted. Concrete strength test results,verifying the base has achieved its design strength, should also be available. The

base should be inspected by a competent person, prior to concrete placement, toverify steel content is as specified. Note: Static crane bases do not require


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design registration, but engineering input is required for the design of thefoundations underneath the crane.

Verification of tower bolt torque Liebherrs

1. Issue: Bolts on Liebherr towers should be torqued up with a torque wrench ormultiplier because the required torque is usually higher than the maximumachieved with a rattle gun (impact wrench). Liebherr specifies that torqing boltsup with an impact wrench can lead to a dangerous situation. The torque specifiedby the manufacturer is very high and this can usually only be achieved with atorque multiplier or other calibrated device (i.e. M 45 10.9 grade bolt torque is4693 Nm).

2. Action: The toque of Liebherr tower bolts should be checked with a torquewrench or torque multiplier to the manufacturers torque specification. Note: thenut can be initially done up with a rattle gun.

Commissioning documentation All tower cranes

1. Issue: Commissioning documentation helps to verify that the crane has beencorrectly assembled and tested in accordance with the manufacturersspecifications. The commissioning process requires input from riggers,technicians, engineers and electricians (for electric cranes with lethal voltage).Guidance on the process is provided in AS 2550.4.

2. Action: Prior to use, commissioning documentation is to be completed for eachtower crane installation. The sign off pro-forma in Appendix A of AS 2550.4should be completed. The person signing off the certificate is to be competent while the person does not have to be a professional engineer, he or she needs tohave experience in commissioning tower cranes. Where commissioning of thetower crane requires electrical work with lethal voltages (i.e. for Liebherr towercranes), the electrical installation is to be signed off by a qualified electrician.

A commissioning checklist should be completed for the tower crane and beappropriate for the type of tower crane. A

tower crane compliance campaign report 2005

Documents