The last months we noticed an alarming trend: the regular appearance of headlines related to incidents involving a suspended platform system or suspended scaffolds collapsing.
In the following blogs we will give insights in the possible explanations for such accidents and how to prevent them.
Common suspended scaffolding citations
Accidents with suspended platform systems can have various causes, ranging from technical issues to personal errors or negligence. To minimize the chances of incidents happening, we have put together a short checklist.
Make this assessment every day, and every time the situation has altered. This way, you can determine if the system (still) complies to the requirements and it is safe to use.
For one, confirm there is a secure anchorage system present from which the platform will be suspended. Possible methods are Davit arms, parapet clamps and outrigger beams. Before installing the platform, make sure the system you use, is able to withstand the intended load. You can read more about this subject in our previous blog: suspended scaffold rigging.
Outrigger beams come with an added warning. Always be sure they are provided with sufficient counterweights, made from the correct material and protected from displacement or removal by unauthorized persons.
If suspension equipment were to fail, there is an increased risk of the equipment falling down. This will endanger both the workers on the platform, as well as the people below. To prevent this risk, make sure tiebacks are in place. The strength of the wire ropes used should be equal to that of the suspension ropes. In case of outrigger beams, tiebacks are not needed if they are directly connected to the floor or deck using bolts.
2. Fall Protection
“Each employee on a scaffold more than 10 feet (3.1 m) above a lower level shall be protected from falling to that lower level”. In case of a suspended platform system, workers always need to be protected by both a guardrail system as well as a personal fall arrest device.
The guardrail system should be installed along all edges of the platform. It has to consist of a top rail installed between 38 inches and 45 inches above the platform surface. Between the toprails and the platform, midrails should be installed.
A personal fall arrest device also needs be used, consisting of a harness, connected to a safety line (tie up) with the help of a lanyard. The safety lines must be fastened to a fixed safe point of anchorage, independent of the scaffold. Check if the ropes are protected from sharp edges and abrasion. Furthermore, they need to be equal in strength to the suspension ropes of the scaffold.
In addition, when parapet hooks are used to anchor the safety lines, make sure they are secured with tiebacks as well.
Before using the suspended scaffold, make sure the hoists are maintained properly and timely. Also, they should be connected to the right power source. For safety measures, a secondary break and an overload detection are required on each hoist.
In the United States, an overspeed device is the commonly used secondary brake. This device is activated when the hoist experiences an instantaneous change in momentum or an accelerated overspeed.
The overload detection is activated when the load exceeds the WLL. It will then prevent the hoists from being used. This prevents dangerous situations. However, when using an external device, always check whether it is calibrated correctly. If the overload detection is integrated and if it’s maintained properly and logged as such, this check is no longer needed on-site.
One of the most critical variables when using a swing stage is the load. One of the most obvious safety measures, is not to overload the system. Users should be aware of the Working Load Limit (WLL) of all the components that are being used in the system. This means the WLL of the suspension point and the hoist should be known. Whichever number is the lowest, that is the maximum allowable weight. But there is more to keep in mind. Also make sure the load is distributed evenly. Placing the majority of the load on one side of the platform can cause the platform to tilt or even fail and collapse. So always assess the WLL, the intended load before use, and make sure the load is distributed evenly during operation.
5. Wire rope
Wire rope of insufficient quality will almost certainly cause an incident and possible injuries, or worse. Take the right measures to ensure the wire rope is safe:
- Check if wire rope is used as specified in the manufacturer’s manual
- Check whether the wire rope is damaged or repaired. If so, replace the wire rope
- Check if the wire rope is slippery. If so, replace the wire rope
- Check the wire rope for corrosion
6. Falling objects
To prevent tools, materials, debris or equipment falling from the platform onto employees or pedestrians below, they must be protected from falling objects. One of the options is installing toeboards along all edges of the platform, when it’s suspended 10 feet or higher above the lower level. They have to be solid and at least 3.5 inches high, measured upwards from the level of the platform. When the load is piled higher than the top edge of the toeboard, they should be prevented from falling by paneling or screening reaching to the top of the guardrail.
Another measure that should be taken is barricading the area below. This prevents unauthorized persons to walk under the scaffold. Another effective way to protect people, is using a canopy structure, debris net, or catch platform. This will allow employees to reach certain areas underneath the scaffolding, whilst still protecting them.
If the suspended platform complies to all requirements and is safe to use, workers still need to be cautious. Extreme weather or damaged components of the structure can affect a platforms’ stability. Always check if the circumstances allow safe use of the suspended platform system.
For example, temperatures below -10° C and above +50° C and wind forces exceeding 6 Beaufort (45 ft/s) mean the circumstances don’t allow safe use of the suspended platform system.
Safety assessment checklist
We have incorporated the items above in one overall checklist for assessing the safety of a suspended platform system. Although there is much more to safe work at height, the above article, and the downloadable checklist, will help you avoid the hazards which are common near construction sites. If you’d like to receive more information, please contact us. One of our scaffolding experts will gladly help you along.