Worksite Safety UpdatePromoting safety in road construction

No 117 March 2012

Are Bore Holes and Excavations Safe on Your Project?

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In this Edition: Excavation Safety Page 1 TMA Operations in the United Kingdom Page 2 Safe Work Australia Draft Model Codes of Practice Page 11 WorkSafe Victoria Construction Equipment Hire Yards Blitz Page 11

Excavation SafetyFall Risks

The potential for people to fall into excavations deeper than 2 metres is considered to behigh risk construction work under the OHS Regulations 2007. Risk assessment andcontrol is mandatory with Safe Work Method Statements (SWMS) required.

Despite the well known high safety risks presented by excavations issues are still foundon site in the areas of trenches, general excavations and bore holes.

Controls apply following the hierarchy of safety controls with preference given toelimination of the hazard or where this is not practical in practice passive fall preventionin the form of guardrails rather than administrative controls involving delineated No GoZones.

Bore Holes

Open unprotected Bore Holes for piles or structure foundations present a significant riskin terms of depth and potential for wall collapse should a person fall into the hole.Historically it is often the workers involved in the works who are aware of the presenceof the hole who fall into them. Other workers may not even be aware of the unprotectedhole so the risk to them further increases.

In one incident a worker involved in the auger operation lifted up the closest edge of asheet of material placed over a bore hole, stepped forward and fell into the hole –fortunately his elbows stopped him falling fully into the deep hole. Sheets of materialare problematic in that the hole underneath cannot be seen, overlapping sheets are notrecommended and sheets can be easily removed by anyone unless secured in place.

Specialist emergency response teams are necessary to retrieve anyone who falls intosuch a hole. Broken limbs or a fatality from earth collapse or drowning are likelyoutcomes – no one wants to go there.

VicRoads Safety Alert No 64 is appended to this report to highlight WorkSafeexpectations in this area.

Risk of Excavation Collapse

In addition to the fall risk, excavations may collapse without warning and the riskincreases as the depth exceeds 1 metre. 1.5 metres has been the depth beyond whichprotection from excavation collapse has been mandatory in the form of batters, shoringor shields, and the risk increases with depth. In addition to the risks presented to workspersonnel near unsafe excavations children may enter works areas after hours and needto be protected from the fall and collapse hazards.

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WorkSafe recently released a timely Alert for Trenching which is appended to thisUpdate. It may also be found at:

http://www.worksafe.vic.gov.au/wps/wcm/connect/57eaca8047cec4468abedb7e95a1f53e/Alert_trench_collapse1.pdf?MOD=AJPERES

The Safe Work Australia draft Code of Practice for Excavation Work is a good referenceprepared with input by the state OHS Authorities. A copy may be found at:http://www.safeworkaustralia.gov.au/Legislation/PublicComment/Documents/Draft%20Model%20Work%20Health%20and%20Safety%20Codes%20of%20Practice%20Public%20Comment/Draft%20Model%20Codes%20of%20Practice%20for%20Public%20Comment/Excavation-Work.pdf

TMA Operations in the United KingdomAustralian Truck Mounted Attenuator (TMA) Operations have adopted the equipment andoperational practices of the Americans (USA) in the first instance and continue to learnfrom operational experience solutions and best practice studies as the result of crashinvestigations and observed driver behaviour. TMAs were first introduced in Texas USAin 1972 – the Texas Crash Cushion, according to one source.

The use of horizontal illuminated arrow display boards are standard practice in Australia.Because drivers are familiar with their use for conventional lane closures their use onTMAs for mobile type lane closures should be seen by the public as a natural progressionwith the same meaning of merge left or right. The Europeans have adopted the 45degree downward pointing arrow (Refer diagram 1 forward) and New Zealand has alsofollowed this approach.

TMA Operations in the United KingdomIn England, Wales, Scotland and Northern Ireland the Traffic Signs Manual Chapter8,Traffic Safety Measures and Signs for Road Works and Temporary Situations, Part 2Operations (2009) details the functional and operation expectations for TMAs in the UKwhen used in live lane activities such as Mobile Traffic Management. The applicationmight also be described as a mobile taper utilising block / TMA vehicles deployed toprotect short term roadwork.

A vehicle with a crash attenuator fitted to it is known as a ‘Block Vehicle’ within themanual (note that they are referred to as ‘Barrier Vehicles’ in the USA). The UK Manualrecommends block / TMA vehicles to have an on–the-road weight of between 10 and 15tonnes. It also recommends that the block / TMA vehicle should not have an on-the-road weight of less than 10 tonnes. The choice of block vehicle should reflect theacceleration and manoeuvrability required of them by the method of working.

To minimise the risk of vehicles cutting between the works vehicle and the block vehicle,it is recommended that a large 45 degree arrow sign is to be displayed on the workvehicle or on a towed trailer if practical, or a “keep left or right” sign. However, thehigher visibility illuminated light arrow board is recommended for the block / TMAvehicle. The illuminated arrows are not to be displayed on a hard shoulder of a dualcarriageway or when on a two-way single carriageway road. This appears consistentwith Australian and American practice, except that in Australia illuminated arrows arealso displayed on work vehicles.

A reliable two - way radio communication system is required between all vehicles,including contractor’s vehicles (in reality they are always carried).

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Maximum allowable traffic flows are specified in the manual and when crossing slip roadsthe maximum flow on the slip road should not exceed 500 vehicles per hour.

Where there is no hard shoulder or the hard shoulder is of restricted width the vehicle ortrailer-mounted advance signs should be located on the verge where practical. Where itis not possible to find sufficient stopping points, then the use of static trafficmanagement is necessary.

Diagram 1Light arrow system for block / TMA vehicles

When works are conducted in the verge or hard shoulder a single block / TMA vehicle isused as is the practice in Australia (Refer Diagram 2 forward).

However, at least three advance warning vehicles parked on the shoulder or emergencylane are deployed over a kilometre maximum distance from the block / TMA vehiclewhen traffic lanes are blocked by block / TMA vehicles. In Australia only one TMAadvance or pre warning vehicle is generally used. They do not always appear to useattenuator equipped vehicles in this advance warning application, probably reflecting thelower risk when not occupying a traffic lane (Refer Diagram 3 and 4 forward).

These advance warning vehicles display lane status diagram signs with only the barrier /TMA vehicle displaying an illuminated arrow. There is a trend to use VMS displays forthis application in Australia, some taking advantage of colour capable displays.

The lane status signs show a red ‘T’ at the end of the blocked lane as may be seen inDiagram 3, 4 and 5 forward.

Additional TMAs are used where more than one lane is closed. They either occupy a laneor block the line between lanes and are located at 50 to 100 metres spacing (ReferDiagram 5 forward). They provide a mobile taper and is similar to the practice in theUSA.

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The clearance between TMA and work vehicles is given as 50 to 100 metres nose of TMAto nose of work vehicle. The actual clearance or No Go Zone between the two vehiclesdepends on the length of the work vehicle. This compares to 30 metres clearancegenerally applied in Australia without speed reduction.

Diagram 2Mobile Lane Closure, working vehicle on a hard shoulder

There are obvious consistencies in TMA deployment practices when comparisons aremade between UK / European, American and Australian / New Zealand. This probablyreflects the historical precedents and experience gained by those who first introducedthe concept of mobile worksite protection against high speed errant vehicle intrusions.

I believe that the concept of a TMA first originated in USA and they have provided a verypractical means of positively protecting short term worksites in a world where everincreasing traffic volumes and traffic risk exposure make road work one of the highestrisk occupations. The TMAs in conjunction with the Light Arrow signboard significantlyreduce the risk when compared with conventional bollard protected worksites facilitatinga very practical low risk work environment under traffic.

Developments in traffic management vehicles around the world also demonstrateinnovation, better protection for traffic management personnel and efficiencies in workpractices.

I wish to acknowledge the provision of photographs and information by Ben Duncker, theInternational Sales Manager for Highway Care and Adrian Bullock who are both based inthe UK. Adrian has been directly involved in some work regarding the use of TMAs andmobile traffic management.

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Diagram 3Mobile Lane Closure on a dual carriageway road without a hard shoulder

Are Bore Holes and Excavations Safe on Your Project?

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Diagram 4Mobile Lane Closure on a dual carriageway road with a hard shoulder

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Diagram 5Mobile Lane Closure of two near site traffic lanes with a hard shoulder

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North American Approach – Similar to UK

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The following photographs and captions illustrate some of the traffic managementequipment in use in the UK:

Two traffic management barrier / TMS trucks in high visibility yellow. The attenuator is shownelevated for transport on the left truck which also has its 45 degree arrow board lowered. These

vehicles also permit the deployment and retrieval of bollards / large cones for formal conventionallane closures on the longer duration works.

Cone deployment from vehicle. The traffic management worker is restrained by a low guardrail butdoes not appear to wearing any harness system to prevent them falling from the vehicle as is thepractice in Victoria. Note the crash barriers along the side of the truck to reduce impact severity.

Are Bore Holes and Excavations Safe on Your Project?

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Stacking cones on truck.

Arrow board elevated and attenuator lowered into protective mode.

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Safe Work Australia Draft Model Codes of PracticeSafe Work Australia has released five new draft Codes of Practice for:

1. Traffic Management in Workplaces

2. Formwork and Falsework

3. Working in the Vicinity of Overhead and Underground Electric Lines

4. Scaffolding Work

5. Safe Design, Manufacture, Import and Supply of Plant

Public Comment opened on Monday 2 April 2012 and will close on the Friday 22 June2012 5:00pm AEST.

The first four draft codes do not exist in Victoria at present as Codes of Practice,although industry standard and guidance material are currently available for 2, 3 and 4.They should provide useful guidance and reference where Victorian approved material isnot currently available and has received national input by stakeholders and public.

WorkSafe Victoria Construction Equipment Hire YardsBlitz

Much equipment used on project sites is hired from construction equipment hire yards sothis blitz by WorkSafe should be welcomed by our industry.

Ashley Bracken, WorkSafe Project Officer, in the latest WorkSafe Safety SoapboxNewsletter reports that earlier this year, WorkSafe inspectors visited constructionequipment hire yards to ensure they were meeting workplace health and safetyobligations.

There is a large amount of hired equipment in use across the construction industry andby people doing home renovations. This equipment can be a major health and safety riskif it is not in good condition, appropriately designed for the task, or if the user is notprovided with information on how to use the equipment safely.

WorkSafe is particularly concerned about the use of the following types of hiredconstruction equipment:

powered tools mobile plant and equipment scaffolding and formwork height access equipment (e.g. elevating work platforms, portable ladders) generators and compressors site sheds and portable toilets.

Inspectors issued a significant number of notices for contraventions of the OccupationHealth and Safety Act 2004.

About half of the notices were issued in relation to the hiring process, particularly withregard to poor storage of equipment, inadequate maintenance, testing and recordsmanagement, and failure to supply adequate safe use information.

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It is not enough to hire out this equipment and assume, or hope, the user knows whatthey’re doing.

Businesses hiring out construction equipment have clear obligations and:

must ensure the hire equipment is properly maintained, tested and safe for use must supply users with the appropriate information for safe use should advise customers of any licensing requirements for the operation of plant

and equipment must provide and maintain a workplace that is safe and without risks to their

worker’s health.

It has been several years since the previous WorkSafe blitz on hire yards and inspectorsnoted while there was a marked improvement in the health and safety standards acrossthe industry, there is still room for further improvement.

Hire yards that were not targeted in this round of visits will be the focus of anotherWorkSafe blitz towards the end of 2012. Do not wait until inspectors arrive on yourdoorstep; get your workplace in order today.

View WorkSafe’s Checklist for hiring out construction plant and equipment

Worksite Site Safety Update is produced monthly by VicRoads Major Projects Division tocommunicate industry safety information and initiatives within VicRoads and to ourcontractors. It is also circulated via the WorkSafe Safety Soapbox to industry. The contentreflects civil road construction and maintenance safety and includes works conducted on orbeside operational roads. The editor may be contacted at: michael.rose@roads.vic.gov.au

Safety Alert

Alert 64 – MPD 7/12/07 Page 13 of 12

GUARDING OF PILE BORE HOLES

A number of fatalities have occurred where workers involved with pile boringoperations have fallen into deep holes and the earth has either collapsed into thehole or water has drowned the person before they could be safely rescued.

This area is frequently an issue on site and some companies involved with thiswork need to improve their safety provisions for this activity.

Workers in the vicinity or even children have been known to fall into unguarded orinadequately guarded holes both during boring and when the holes are leftexposed. WorkSafe Victoria has previously highlighted the risks and provides thefollowing advice:

INCIDENT

A driller's offsider died after falling into and becoming trapped in a 600 mm wide x 2.5metres deep bored pile hole. The pile drill auger had been removed from the hole andslewed round by the drilling rig in order to dump spoil from the hole. The man lost hisfooting on loose fill and fell backwards into the hole, becoming trapped.

CONTRIBUTING FACTORSNo guarding was in place to prevent workers from falling down the hole.

The ground around the hole was rough fill and did not provide secure footing for workersin the vicinity.

MAKING IT SAFEPile-hole guards can be constructed simply from reinforcing steel formed into a cage.The reinforcing bars should be bent into an L shape at the bottom to form supports forthe footplate. Footplates can be made from steel mesh welded to the reinforcing steel.

Guards need to be a minimum of 900 mm high and be fitted with a footplate to preventpeople falling down the hole in the event of the top of the hole falling away. Note thatsections of steel pipe are often used for guards – if they are too small noprotection is provided against hole edge collapse allowing a person to side feetfirst into the hole. Where this is observed on site prompt action must be taken tocontrol the risk.

Alert 64 – MPD 7/12/07 Page 14 of 12

Before drilling commences place a pile-hole guard on the ground and drill the holeinside the guard when:

Unsleeved holes are drilled deeper than 1.5 metres. Sleeved holes are to be drilled deeper than 1.5 metres before the sleeve can be

inserted.

Where sleeves are used for fall protection the sleeve needs to extend a minimum of 900mm above the ground.

PLEASE COMMUNICATE THIS INFORMATION TO ALL RELEVANTSTAFF AND APPLICABLE CONTRACTORS

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