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Good morning everyone!
Thank you for this opportunity to try to get a message across, that is...
we can do more.
Well, that's nothing new isn't it? We all know that we can always do more for safety.
Safety culture, design for safety and legislation are important tools for safety but today,
I would like to take a more micro approach to Work At Height safety, by looking at what
more can we do in evaluating active fall arrest systems.
Now active fall arrest systems refers to those that requires users to take a specific action,
for example, to wear it, to hook it up or to set it up. This will include horizontal
lifelines, vertical lifelines, harnesses with energy absorbing lanyards and so on.
We all know that Falls From Heights is unfortunately, still the number 1 killer in Singapore worksites.
Now, before a contractor can start working at height, safety professionals have to evaluate
their risk assessment, safe work procedures and their Fall Prevention Plan before approving
their Permit To Work.
And the safety officer or project manager will almost always find active fall arrest
systems being used as a control measure.
We are not going to discuss whether these RA, SWP or FPP works. That, we can have a
debate later. For now, let us ask ourselves, how do we know whether these active fall arrest
systems will actually protect the workers before we approve the permit?
I would like to share six pointers to help you decide.
Recently, I was involved in a research project under the Institution of Engineers Singapore,
IES and with Dr Goh Yang Miang from the National University of Singapore, NUS.
We found that 55.8% of the fall arrest systems used in the workplace were endorsed by Professional
Engineers. That's good news isn't it? For the PEs here, it means that there's another
44.2% more business for you!
But...
0% calculated for the Maximum Arrest Force.
Remember... it is not the fall that kills but the sudden stop at the end.
That is the Maximum Arrest Force.
That decides whether I will get killed from internal injuries.
The Maximum Arrest Force was not calculated.
So what did we calculate?
The PEs have calculated for the shear-force on the anchor, whether the thickness of the
post is sufficient, the load on the structure.. everything that is non-living...
... except for the live human being, hanging at the end of the lifeline.
So when the worker falls, the beam won't fall off, the anchor post won't bend, the lifeline
won't break, but the worker is hanging there... blood coming out from his nose, eyes and mouth.
We have forgotten that it is the worker whom we are trying to save... not the building
or the structure. And the best way not to forget that...
... is to put ourselves in the worker's shoes.
In this case, think of ourselves in the harness:
Do I myself dare to fall on this system that I'm approving?
The energy absorber in our lanyard is certified to EN355. It is designed to reduce the Maximum
Arrest Force to 6kN. This is considered the safe limit for a live human being.
This is also equivalent to six of these big beefy football players jumping on me at the
same time.
Ouch! But I will survive the fall.
What if the Maximum Arrest Force is more?
This is a photo of simulated fall using a dummy. His lanyard was anchored to the guardrail.
See how the impact force had bent it.
Now imagine if I am the one in the harness. If the impact force can bend the guardrail,
what will it do to my family jewels, down at the groin area, where the harness leg loops
wraps around?
This one no need PE to endorse, my “baya” or Bangladeshi worker can also chop, sign
and confirm...
… no more Father's Day!
This is not a good excuse to the Singapore government that I cannot have more babies!
So do I dare to fall on this system?
The Maximum Arrest Force can also be as high as 22kN. This is like being run over by 2-ton
vehicle in this photo.
How many of us can survive this?
Unless you tell me your secret identity is Superman and you wear your underwear on the
outside.
So, the first pointer is: make sure that the Maximum Arrest Force is evaluated before you
approve the fall arrest system for use. Excessive Maximum Arrest Force can not only kill but
also seriously injure a worker.
Next, will the anchor break when I fall?
If we look at the equipment standards and instruction manuals for our harnesses and
lanyards, it is stated clearly that the anchors used should be able to take 10kN for the European
standards and (point) 22kN for the American standards... per worker!
Now this 10kN or 1-ton is about the weight of a small car. So look at the anchor and
ask “Can it “tahan” or hold a car?”
Newton's third law says that for every action, there is an equal and opposite reaction. This
is like a tug of war.
So on one end of the lifeline, we have Maximum Arrest Force of up to 22kN (or even more),
and on the other end, we have the design load of the anchors.
What we are seeing is engineers taking the weight of a worker and multiplying it by a
safety factor to get the load on anchors. The worker's weight used ranged from 75Kg
to 100Kg.
Using 75Kg may be still acceptable for workers but if your boss or the owner wants to go
up, then maybe... I think we need cater for a little bit more weight... well, the Americans
use 140Kg for their design mass.
The safety factor used ranged from 1.5 to 3. So we have the anchor design load of only
1.125kN to 3kN per worker on this side versus the Maximum Arrest Force on the other side.
Which side will lose the tug of war?
We were just talking about this over the networking dinner last night, and Mr Chan Yew Kwong,
Director from the Workplace Safety and Health Council said,
“This anchor is not designed to save lives.
This anchor is designed for hanging a dead man!”
So the second pointer is: check that the design load of the anchors is at least 2 times of
the maximum arrest force calculated or that it complies with the equipment standards of
10kN or 22kN.
Third, the capacity of the system.
How many workers should the system support and how many workers can the system support?
We all know that we should not work alone at heights, so the system should support at
least 2. We also know that there should be a rescuer. So count him in as well and the
system should support at least 3.
Then, consider how many workers are required to do the job. We do not want to see 10 workers
hooked on a horizontal lifeline designed for only 3 workers and overload the system like
this pick-up truck.
In Singapore, our taxis display their capacity: excluding the driver, 4 adult passengers and
honestly, I didn't know that we can put 6 children into a taxi. I mean... a taxi driver
driving, and 6 monkeys... sounds like a recipe for an accident to me.
Anyway, for cranes, we also have the Safe Working Load and the Maximum Loads displayed.
What about fall arrest systems?
The capacity of the systems should be displayed and it should match the number of users required
to carry out the job.
Here, it shows the capacity for a maximum of 3 workers, including the rescuer and each
worker should not exceed 100kG, which is also the weight limit in the European equipment
standards.
Now, for the fourth pointer.
Lesson learnt: even if we are not superman, make sure to wear nice underwear, in case
we fall.
Simply put, fall clearance or clearance height is whether I will hit the ground or an obstacle
such as a ledge in a fall. This includes the vertical deflection in a horizontal lifeline
or the extension of an energy absorber when it tears out.
Only 4% of the users are guaranteed not to hit the ground in a fall.
The other 96% do not know the answer to that question...
until they fall.
I think we can do better.
Now let's take a look at an example.
This is a screen capture taken off a TV show featuring a construction site in Singapore.
The TV host was going up with some workers in a gondola and this was the active fall
arrest system used.
I have drawn a diagram to make it more clear.
We have a vertical lifeline. Attached to it is a mobile fall arrester. A short lanyard
here and an energy absorber. This is the original set-up intended by the manufacturer.
Then somebody added an additional twin lanyard with energy absorber.
For our friends from overseas, this is a uniquely Singapore practice, known in the construction
industry as “ali-baba”.
So now we have two energy absorbers and two lanyards, if one breaks, we have another...
"double" safety.
The question is, does more equals to safer?
We compared the actual set-up with the original intended set-up.
We found that the linkage length was increased by up to 400%. This means that in a fall,
there is a much higher chance of the longer lanyard getting entangled in the worker's
arms or legs and causing injury.
The fall clearance required was also doubled, meaning a greater height required to stop
a fall and a higher chance of collision with the ground or an obstacle in the fall path.
This “ali-baba”, “lili-baba” or “baba-ali” system, whatever you want to call it... has
failed the fundamental purpose of a fall arrest system - that is to minimize injury to a worker
in a fall.
And it has also failed to comply with the relevant standards and regulations.
So who approved this setup and signed on the permit-to-work?
Has he signed the death warrant for the workers?
Has he unknowingly guaranteed that they will get killed from internal injuries or from
hitting the ground in a fall?
Second last pointer, consider the Swing Drop Distance.
Often, the fall arrest anchor is not directly above our work area and we have this situation
of a swing fall.
So we need to calculate the swing drop distance.
Will it increase my fall clearance required. And will I crash into a wall?
You will also realize that this means that we have to know the location where the active
fall arrest system is to be used and the specific location where the job is to be carried out.
OK, the last pointer. Just a quick show of hands, who will NOT let our dentist do this
to us?
Well, I definitely would not pay him!!
Yes, he will still manage to get my tooth out, if I let him touch me, but is he using
the right equipment?
There are many different brands of equipment components that can be assembled into a fall
arrest system.
They are also certified to different equipment standards, conforming to different performance
criteria.
To work together as a system, the components need to be compatible.
In one project, we were using rope grabs or guided type fall arresters attached to a vertical
lifeline.
When we went for our lunch break, another contractors' workers came to our work area
and used the vertical lifelines that we had left hanging there.
But the fall arresters that they were using required a 16mm diameter lifeline while our
lifeline was a smaller 12mm diameter.
Their fall arrester would not have worked properly on our smaller diameter lifeline
to stop their fall.
Fortunately, they were discovered and stopped in time.
So the last pointer is: check that the compatible components to be used in the fall arrest systems
are specified.
In summary, when evaluating active fall arrest systems, imagine ourselves in the harness
and decide if we ourselves dare to fall on the system.
Reject it if the Maximum Arrest Force is not considered and we are not convinced that we
will not suffer internal injuries in a fall.
Reject it if we are not convinced that the anchor can take the load.
Reject it if the Fall Clearance is not calculated and we are not convinced that we will not
hit the ground in a fall.
Reject it if the number of users permitted is not specified or if the rescuer is not
considered in the system capacity.
Reject it if the swing drop distance is not considered when the position of the anchor
is not directly above the work area and we are not convinced that we will not crash into
some obstacle in a fall.
Reject it if the system components are not specified and we do not know what are the
compatible equipment to use.
These are some of the pointers when evaluating active fall arrest systems.
Look out for them in the safe work procedures and the fall prevention plan.
Demand these from your contractors, safety professionals and engineers.
For more guidance, do refer to the Canadian standards Z259.16 and the American standards
Z359.6.
I will close with a quote from Albert Einstein.
He said,
“The world is a dangerous place, not because of those who do evil,
but because of those who look on
and do nothing.”
The UK change to their Health and Safety at Work Act in 1974.
Singapore also changed from the Factories Act to Workplace Safety and Health Act in
2006.
That's 32 years after the UK.
The UK Work at Height Regulations was enacted in 2005 and I have heard that Ministry of
Manpower in Singapore is legislating work-at-height in 2013.
That's 8 years after UK.
Canada has design codes for Active Fall Protection Systems since 2004... that's 8 years ago.
The US also developed theirs in 2009, that's 3 years ago.
Singapore? We do not yet have such standards or guidance for the industry.
I do not know when we will catch up..
another 32 years? 8 years? 3 years? I don't know.
But our workers cannot wait.
Their families cannot wait.
Their lives.. are already on the line.
It is completely within your power to do something now, with or without local legislation or
standards.
Whether you work in a big company with abundant resources or a small company with limited
resources, you can do more by demanding more.
In Singapore, I would say “use your mouth power” to demand that active fall arrest
systems are evaluated properly.
Demand this from your subcontractors,
Demand it from your safety officers,
Demand it from your Professional Engineers.
And engineers, I leave it to you to demand more fees from your clients.
Former US president, John F Kennedy once said,
”There are risks and costs to action. But they are far less than the long range risks
of comfortable inaction.”
You may become unpopular for doing more and demanding more. People may call you names.
But these are far less than the cost of a life.
Fall Arrest Systems are the last line of defence in the hierarchy of control measures.
Do not take this away from our workers.
Do not approve the fall arrest systems and the permit-to-work at height blindly.
The price may be too high to pay.
Let us do more and demand more now.
Thank you.