March 26th, 2009
A lot of people are confused on how to calculate fall arrest shock force… here’s a simple equation to determine the average impact or shock force during fall arrest:
Average impact force, F = mg(h + x) / x
m = mass
g = gravity
h = free fall distance (from initial position to just before deployment of energy absorber or other energy absorbing component)
x = stretch or extension of the fall arrest system during fall arrest
Note that there are lots of assumptions in this equation. The Canadian standards has good information on design of fall arrest systems.
Tags: calculation, energy, equation, fall arrest, impact force, shock force
Posted in Fall Protection, Safety Technology/Hazard | No Comments »
March 26th, 2009
Safet at work blog (a very useful and active safety blog) reported a list of recent BHP fatalities. One quick observation of the BHP fatalities is that they are primarily personal accidents, not catastrophic accidents (e.g. Beaconsfield rock fall fatality).
A recent special issue of Safety Science (Vol. 47) discusses the confusion about process safety indicators and personal safety indicators. I think some of the discussions are relevant to the mining industry or other geotechnical industry (e.g. construction of tunnels). Process safety indicators are essentially major hazard indicators, which may not correlate with personal safety indicators (e.g. LTI, MTI). In Beaconsfield there appears to be a lack of attention on major hazard indicators. There were rock falls in October 2005, March 2006 and days before the day of the accident (26 April 2006), but the response appears to be inadequate.
One possibility is to require mines to report such major hazard indicators to relevant safety regulators (e.g. Workplace Standards Tasmania) periodically so that the mines will pay more attention to these indicators and the regulators can step in when necessary.
Tags: accident, geotechnical, indicators, Mining, process safety, safety
Posted in Incidents, OSH News | No Comments »
March 16th, 2009
Saw a post on Kevin Jone’s SafetAtWork blog (see my blog roll) on an accident involving a scaffold collapse.
The accident is reported in this website. Note that there had been a scaffold incident just weeks before this accident.
The victim did not put on his harness, the other painter that did survived. Based on the report, it seems like a scaffold connection failed… fall arrest system harnesses is a last line of the defence that should never be neglected.
Apparrently the painter that survived was hanging on the harness for about 45 minutes, luckily he was able to stand on a window ledge, if not suspension trauma could have set in.
Tags: accident, collapse, falling from height, harness, scaffold, suspension trauma, sydney
Posted in Fall Protection, Incidents, Industry, Safety Technology/Hazard, construction | No Comments »
March 3rd, 2009
A Straits Times (Singapore; 3 March 2009) article has the above title. The article reports on a roundtable discussion on the possibility of nuclear energy in South East Asia. Experts were reported to advise that, “investment in a safety culture among human operators is just as important as physical infrastructure to prevent catastrophes”.
Seeing human error as the source of safety problem is futile. Like what a famous safety professor, T. Kletz once said, seeing human error as the problem is like blaming gravity for falls. It is true but does nothing to help prevent.
I hope it is the reporters that have misinterpreted the experts…
Tags: experts, human error, nuclear, Safety Culture
Posted in OSH News | No Comments »