Unique Rigging Applications for Suspended Scaffolding

Presented by: Clint Ramberg – Director, Spider Systems Group

• This webinar will detail the basic requirements of a safe effective suspended access system.

Scope

Lion’s Gate Bridge, Vancouver, BC, Canada

Circa 1950

Introduction

• Any time a suspended scaffolding is used, one key element is to determine if the system includes the development of an adequate safety and rigging plan.

Introduction (cont’d)

• When accessing work higher than 10 ft or within 6 ft of an unprotected edge the contractor needs a safety plan that addresses fall protection and fall restraint.

ACE Strategy

• Anchorage• Conditions (site specific)• Equipment

Anchorage – Personal Fall Protection

• Fall protection anchorage must:– Be independent of other

suspension points– Support only one worker – Be capable of 5,000 lbs load– Allow safe deceleration and

support of the worker

Anchorage (cont’d)

• To determine which anchorage system to use:– Evaluate structure’s

construction– Consider load capacity of the

anchorage system

Anchorage (cont’d)• Evaluating the structure

– Have a structural engineer assess structure’s steel or concrete construction to determine where it can handle the load of the anchors and craftworkers once connected to it

– Typical for structure load to include several fall protection anchors, craftworkers, and access equipment

• Example: For a 2-point suspended scaffold with 1000 lbs rated scaffold hoists and 2 independent lifelines, the combined load would be 18,000 lbs

2 hoists x (1000lb x 4) + 2 lifelines x 5000lb = 18,000 lbs

Anchorage (cont’d)

• Avoid using wood framing, hollow walls, bar joists, glazing, hand rails, conduit, or any other light weight structures

Conditions (Site Specific)• One of the largest variables in construction

access is the condition of the jobsite. You need to be cognizant of the surroundings and situations that exist

• Common site conditions:– Indoor /in containment (confined space?)– Outdoor (atmospheric)– Environmental (toxic or explosive, etc)– Traffic around or below

Indoor

• Challenges for working inside a structure – Confined space

• Requires specific monitoring and prompt rescue requirements

– Lighting– Access– Structural obstacles– Lock out/tag out procedures

Indoor Example: Stacks – Internal Float Platforms

Indoor Example: Nuclear Reactors

Outdoor• Weather can be a significant and sometimes an

unpredictable obstacle– Temperature, precipitation, wind, and lightning

• High winds play havoc on platforms and lifelines• Areas prone to lightning strikes requires early

warning and quick egress plans• Build up of ice on lifelines and equipment can

cause system to malfunction or increase the load

5ft BAP

6.7ft BAP

TAP

360° BAP

Extreme Winds

Coatings contractors use Tower Access Platforms (TAP) for inspection, cleaning and preservation of wind towers up to 120 meters tall

Chemical Environment

• Be aware of exposure to chemicals at the worksite• Many chemicals and processes will degrade the

integrity of the fall protection equipment– Acids and alkaline chemicals

• Can be explosive or highly corrosive

– Abrasives– High pressure water– High heat during processing or cleaning – Intense light sources

Environmental

Traffic

• In high traffic areas special consideration should be given to minimizing fall distances, protecting others in the overlapping work zones or under the elevated work area, and controlling the portions of the system that will hang into high traffic areas. Common areas of concern are:– Over roadways, waterways and pedestrian traffic

Traffic

Example of Traffic

Equipment

• Identify the fall protection equipment best suited for the worksite/structure

• Equipment related conditions are:– Location of anchor– Resistance to elements– Unrestricted movement

Fall Protection - Resistance to Elements

• Kevlar harnesses and lanyards are resistant to weld slag and melting

• Wire rope lanyards are resistant to abrasive blasting

• Harnesses are available to protect from chemicals, moisture, or weather

Unrestricted Movement- Example of Correct Sourcing

• Most people assume that any powered suspended scaffold system requires the use of a lifeline. It is possible to design an access system that will allow the user to be tied off to the platform with a horizontal dogline system, allowing the worker to move quickly along the length of the platform, not having to tie up the hand managing the rope grab.

Examples of Unique Scaffolding Applications

John James Audubon BridgeLouisiana

Project Scope: Provide access for the construction and painting of the 500 ft towers of the 2.5 mile, 4-lane elevated John James Audubon Bridge, the longest cable-stayed bridge in North America.

Challenges: Working over vast Mississippi River Accessing the remote 500 ft towers that support the bridge’s cables Custom rigging required

Solutions: Adding to the ST-17 work baskets in the contractor’s fleet, four ST-17s were supplied and equipped with 3 ft fly decks for the initial construction of the towers. Three custom U-shaped platforms were also engineered, each powered by four air traction hoists for the painting of the towers. Services provided included initial rigging labor, Competent Person Training as well as hands-on Operator Training. These solutions assisted the contractor in completing the project on time and within budget.

Route 81 BridgePennsylvania

• Project Scope: Repair of two piers

• Challenges: – 360 degree access required at various

work levels– Continually changing project scope as

work progressed

• Solution: Two custom-designed float platforms powered by twenty-four SC40 1,500-lb. traction hoists, on-site supervision and re-engineering to increase the load capacity and functionality according to the customer’s needs

Stack – External – Mid-Air Transfer

800’ stack

Hoist Travel Speed 30 FPM

25 minute travel time / one way

Stack – External – Mid-Air Transfer

Stacks – Rigging Star

Stack Rigging – Rigging Star w/Material Hoist

350-ft to Top

Summary

• There are many factors to consider when planning an effective fall protection system. The signs of a good system are that the workers are always safe and that the task can be completed on schedule, on budget and without excessive risk