Researchers from the University of Greenwich’s Fire Safety Engineering Group have found that high rise construction workers are ‘risking their lives’ by not treating evacuation alarms seriously enough.
The research, funded by the Institution of Occupational Safety and Health (IOSH), significantly found that of the 932 workers who took part only half of the workers’ first actions when they heard an alarm was to evacuate, even though 82% said they knew they were meant to evacuate immediately.
Alarmingly many of those who took part in the evacuation trials believed their employer viewed finishing the task as more important than evacuating immediately as the alarm sounded.
The research, named Construction site evacuation safety: evacuation strategies for tall construction sites is the first of its kind and evacuations took place unannounced at two Multiplex sites, 22 and 100 Bishopsgate.
The primary goal was to understand the difference in evacuation times for workers at height in case of an emergency in a high building, such as a fire, severe unexpected weather, earthquake or partial building collapse.
Key findings of the report are
- 32% of workers spent over a minute finishing the task they were working.
- The longest time to respond to an alarm was six minutes.
- Four in five said they were prompted by an alarm, but video evidence taken during the trial evacuations shows 43% required supervisor intervention to leave the site.
- Once workers completed their tasks, a further 23% carried out four or more other activities, such as collecting tools and belongings, before leaving the site.
- Evacuation times from the buildings ranged from nine minutes and 14 seconds to 20 minutes and 47 seconds depending on the number of workers involved and what height they were at.
- Workers at a height took longer to evacuate as they often had more work to do to finish a task safely, compared to workers on lower floors.
- Those working at height using ladders were the slowest to evacuate. The average descent on ladders takes twice as long (52%) as normal building stair speeds.
- It was found that workers located within the formworks of a building respond to an alarm differently to those in the main building; the mean time to respond to an alarm for those working in the main building was 71 seconds, while in the formworks it can be as low as 30 seconds.
- One unexpected finding was that workers were not impacted by construction height. This means that people on higher floors and those on lower floors had similar response times. A worker on the 30th floor did not necessary respond to an evacuation alarm any quicker than a worker on the fourth floor.
Duncan Spencer, head of advice and practice at IOSH, said: “The outcomes from the research will help to improve the safety of construction workers in emergency evacuation when operating in tall building construction environments, by providing a series of suggested improvements and recommendations to be followed by businesses and safety and health practitioners.
“From the research, it is clear that these improvements are needed considering that this is one of the most challenging scenarios particularly given the ever-changing nature of the construction site. Response times are slow in many cases. Workers should be evacuating immediately when they hear an alarm, rather than wasting precious seconds on finishing a task. If they don’t do so, they are risking their lives because every second counts in an emergency.”
The report recommends enhanced training and greater enforcement of evacuation policies to ensure workers react promptly to alarms, as they speculate that workers may not be entirely sure what is meant by ‘evacuate immediately’.
The researchers said in a statement at the end of their report that they would “ideally” have carried out other trials involving different contractors and with different-sized buildings.
They also suggested exploring the issue on an international scale.
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