The Highs & Lows

Materials Falling

Lessons Learned

Work at Height Workshop

• Held on 9th October 2009 due to several problems with scaffolding on Blackfriars & Farringdon

• Materials/tools falling from height

• Attended by members of the Blackfriars & Farringdon project teams

• Encourage knowledge and best practise sharing across Station & Civils projects

9th June & 12th July 2009 (Blackfriars Bridge)

What Happened

1. Scaffold base plate fell from Blackfriars bridge and struck a passenger

boat. No persons injured and no damage to boat

2. Report of an object falling from the bridge, hitting a passing boat and

bouncing into the river Thames.

No persons injured and no damage to boat

Base Plate / Bolt

Investigation Identified

Scaffold base plate fell from underside of

bridge, possibly through opening in crash

deck. Other openings (areas of weaknesses)

in scaffolding

Base Plate / Bolt

Actions as a Result of Incident1. Purge of the bridge and scaffolds to identify ‘hotspots’ gaps

closed in areas of weakness on scaffolding

2. Bridge housekeeping, edge and side protection and scaffold in the

regular monitoring regime

3. Tally system for access to authorised personnel only

4. Bridge scaffolding inspected on a weekly basis by the

construction team and the Port of London Authority

Photographs of remedial work follow………….

Bolt / Base Plate

Remedial workEnclosed walkway

including roof and

full height sides

“Brick guards” and

netlon to support and

reinforce sheeting

Bolt Base / Plate

Remedial work

Plywood infill decking to

eliminate gaps. Expanding

foam also used to plug

gaps

29th June 2009(Blackfriars – Hopton Street)

What HappenedThe scaffolders dropped a hammer through the boards onto the floor

underneath.

Investigation Identified

Birdcage scaffold wider than original so extended outside original scaffold

structure. Not close boarded or fitted, loose equipment fell down gap.

29th June 2009(Blackfriars – Hopton Street)

Actions as a Result of Incident

Scaffolding boarded out with no gaps

22nd September 2009(Farringdon – Cardinal Tower)

What Happened

Scaffold spanner became dislodged from scaffolders belt.

No persons injured, no damage occurred.

Area where

scaffolder was

situated

Position of

spanner

Podium roof where spanner

believed to have bounced

Final

landing

point of

spanner

22nd September 2009(Farringdon – Cardinal Tower)

Investigation Identified

• Deviation to scaffold design

• Failure to review the WPP and recognise that by re-sequencing the scaffold erection

works introduced a new risk

Actions as a Result of Incident

• Tethered tools

• Combisafe netting introduced during scaffolding construction

• Fully boarded lifts during scaffolding construction

See following slides…….

Farringdon – Cardinal Tower

Spanner

Tethered tools

used by scaffolders

Farringdon – Cardinal Tower

Spanner

Plywood infill decking to

eliminate gaps

Combisafe netting to prevent

debris/tools falling in work and

pedestrian areas during

construction

Best Practice Examples

• Documentation

– WPP review if in use for 8 weeks - check risks & methodology still relevant

– WPP compliance and safe working practice checks on site during tours/inspections

– Engagement of workforce/site supervisors in writing WPP and defining work sequence and methodology

Best Practice Examples

• Checks on site

– Regular temporary works inspections to ensure design compliance

– Daily/twice daily inspections of netting and screens during works/demolition activities

– Use of 16ft scaffold tubes over 21ft tubes, and rope tethered during installation

Best Practice Examples

• Physical Controls– Lanyarded (tethered) tools

– Fall arrest netting during scaffold construction

– Netting over specified walkways

– “Brick guard” type mesh used to reinforce lower areas of debris netting/dust sheeting

– Full boarded lifts as the scaffolding is constructed

– Plywood decking on top of scaffold boards - prevent debris falling in gaps

– Double encasement/bagging of materials when accessing the scaffold i.e. need 5 bolts, take 5 bolts not a box of 40

– Lookout on scaffolding (in a similar way to a lookout on the railway)

– Use of expanding foam to block ALL gaps in scaffold decking

– Restricted access – tally system

Have we learned?

3rd November (Borough Viaduct)

What Happened

A socket wrench was dropped from the 2nd level

scaffolding to the road below.

No injuries or damage, Exclusion Zone in place.

Investigation currently underway to identify issues

and actions required.

Borough High Street

Lack of protection for members of public

Socket wrench dropped from 2nd level, landed in exclusion zone

See next slide for depth of exlusion zone that was operational when incident occurred

Borough High Street

Exclusion Zone