Friday, November 23, 2012

Accidents On Low-Rise Buildings

Falls are the most frequent accidents that occur on low-rise buildings and low-rise construction sites.  OSHA data shows that fall accidents on low rise buildings are the cause of many serious injuries and fatalities.

At the same time, the data shows that falls have certain properties, which may help designers to devise preventive approaches on low rise buildings.  OSHA data shows that nearly half of the fall accidents occur on projects involving commercial buildings and single family dwellings.  However, whether it is a commercial building, multi-storey building or even a single storey building; the potential for falls remains a significant hazard on low-rise buildings and construction sites.

OSHA data shows that falls occurred at what some would consider relatively low elevations.  About 75% of falls occurred at elevations of less than 30 feet, and 45% were less than 20 feet.

Environmental Concerns

Over half of the fall injuries are related to environmental factors involving the working surface (icy or wet conditions for example) or building layout conditions (awkward or inconvenient roof layouts).

Human Errors Resulting In Falls

Analysis of human errors showed that “misjudgement of the hazardous situation” is the most frequent type of error involving falls, accounting for 30% of all the accidents.

Location Of Falls

80% of all building fall accidents took place:
 
  • from roofs,
  • from or with scaffolds,
  • from or with ladders, and
  • through openings.   
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These falls can be effectively prevented with adequate safety equipment, proper training, and suitable fall protection.  Without fall protection, workers may not be aware of their surroundings and ignore hazards.

The bottom-line is; fall protection equipment is need:

  • In Canada, where any section of the parapet wall is less than 36 inches (and someone is subject to a 10 foot fall)

  • In the USA, where any section of the parapet wall is less than 42 inches (and someone is subject to a 4 foot fall)

Tuesday, November 13, 2012

Early Fall Protection


Falls are the leading cause of worker deaths in construction (and have been for many years).

Why is this so?  We have a fall protection standard (29 CFR 1926, Subpart M).

Are we ignoring the codes, standards, and regulations?

Have we learned ways to "outsmart" them for production's sake?

When the standard calls for fall protection are we simply putting the worker into a harness and lanyard and calling it "fall protection" (to meet the minimum requirements)?  And is this the best way to ensure the safety of the worker?

Can we do more; such as engineer the hazard out with guardrail systems or some other means of protection?

One of the marvels of early 20th century construction is a testament to safe work practices and fall protection.

In 1933, (during the middle of the Great Depression), work began on the eventual 4 year project to build the world's longest suspension bridge at a cost of $35 million.  The workers who were hired to perform this dangerous work at great heights, (in strong winds over rolling water and with fog moving in and out regularly), largely were inexperienced with steel erection or with construction in general.

Because of the economic situation in the country at the time, a well paying job like this was much sought after, (even if it was one of the most dangerous jobs in the world).  Those who claimed to be ironworkers often came from very different backgrounds, but would buy identification from local residents so they would be allowed on the job.  They would, however, claim to be "experienced" ironworkers, and therefore didn't need any training.

At the time, contractors estimated one fatality for every $1 million.  As this was a $35 million project, 35 deaths were "budgeted" from the start.

The man charged with the design and engineering of the bridge was Joseph Strauss.  He was a pioneer in the world of safety and the fall protection methods he used on the bridge have been refined into state of the art systems.  He required workers to tie-off with a lifeline, and those who didn't were fired.

Today, one may even purchase ready to install systems that can be set up in minutes and systems have become comfortable to wear and easy to use.

The best known engineered fall protection device on the project was the safety net Strauss had installed prior to beginning work on the roadbed segments.  This cantilevered net ran the entire length of the roadway and extended 10 feet out from either side (protecting workers from falling to certain death in the choppy waters of the bay).   

Unfortunately, on February 17th, 1937, (just months away from final completion and opening the bridge to traffic), a scaffold carrying 10 men gave way and actually fell through the net.  Along with another worker who had fallen earlier, these were the only reported fatalities during the project.

This net was installed at a cost of 130,000 Depression-era dollars.  But the value added in saving lives proved worth it.  Of the 19 men who fell into the net, (and were later dubbed the "Halfway to Hell Club"), anyone of those who hadn't been saved by that $130,000 net could have cost the project considerably through delays, work slowdowns, and morale.

The Golden Gate Bridge opened 73 years ago; almost 40 years before OSHA mandated that these safe practices routinely be included for these hazardous activities.