CONCRETE SAWING AND DRILLING
Take control of dust
Above: Cutting concrete
slabs is one of the main
tasks that generates large
amounts of construction
dust.
Top right: An internal
building room showing
breaking, sanding and
cutting without dust
extraction. The image was
taken after only six seconds
of power tool usage.
With the right steps – and more importantly
with the right equipment – employees, tools
and the working environment can all be
protected from construction-related dust and
productivity can be increased. Nazia Uddin of
Hilti reports.
t is the very fact that dust is so ubiquitous on
construction sites – occurring during drilling,
sawing, breaking, grinding and transportation
– that has led health and safety experts to warn that it
could be ‘the next asbestos’ for the industry if not tackled
head-on, because workers simply do not realise that the
dust arising from concrete, tile, brick and mortar is so
hazardous to health.”
These words are lifted directly from a recent
Construction News supplement entitled ‘Take control of
dust’(1).
At first the statement may seem a little shocking, but
when one considers that a new Health & Safety Executive
(HSE) cross-industry initiative, named the Construction
Dust Partnership, was launched last year and that a new
European law is to be introduced in 2015 for measuring
dust created by power tools in a ‘real world’ situation,
then it’s clear to see the calls to address this critical
occupational health hazard are gathering momentum.
But the current situation should not be perceived
as a burden, more an opportunity. It is a fact that dust
hurts jobsite productivity, it impairs working comfort
and it can damage existing fixtures and fittings. Less
noticeably, dust clogs up tools and inserts, reducing
their productivity, resulting in more downtime and
shortening their lifespan.
“I
500 deaths every single year from silica-related lung
cancer and 4000 deaths from chronic obstructive
pulmonary disease related to dusts, vapours and fumes.
Although these aren’t all related to construction, it is
clear that a significant number of them will be, because
the silica that causes the worst problems is found in
concrete, mortar and sandstone, as well as bricks and
tiles (see Table 1).
Every time silica is drilled into, sawn, ground,
smoothed, chased, sanded or broken up, it creates the
potentially damaging fine dust, termed RCS (respirable
crystalline silica), which can travel deep into the lungs.
There is urgency to the message because in addition to
the most serious disease, there are other problems that
the dust can cause, namely silicosis, in which lungs are
scarred.
HSE has formed a cross-industry group called
the Construction Dust Partnership (CDP) – with
representatives from contractors, hire companies and
tool and safety gear manufacturers – in a bid to raise
awareness of the problem and to help the industry find
ways to avoid it.
Table 1 – Approximate crystalline silica
content of materials
Sandstone
70–90%
Concrete, mortar
25–70%
Tile
30–45%
Granite
20–45 (typically 30%)
Slate
20–40%
Brick
Up to 30%
Limestone
2%
Marble
2%
Tackle dust at source
Dust is an occupational hazard of site life. Almost every
job on-site creates dust: drilling, breaking, grinding,
sawing, etc. But the message coming through loud and
clear is that the construction industry needs to wake
up to the problem of dust exposure, because it isn’t
something that just makes you sneeze or cough – it is
something that could ultimately kill if preventative steps
are not taken.
HSE also has some pretty compelling evidence: its
latest statistics bulletin(2) shows that there are almost
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concrete
MARCH 2015 • Evolving Concrete 6–7 May 2015 www.evolving-concrete.org
Table 2 – COSHH dust limits
Dust type
Inhalable
Respirable
RCS
N/A
0.1mg/m3
Wood
5mg/m3
N/A
CONCRETE SAWING AND DRILLING
Dust: the legislative landscape
Straight to the TOP
The key piece of legislation on-site governing dust
exposure is COSHH, which sets out maximum
workplace exposure limits (WEL) for dust, whether
inhalable – referring to the entire inhalable portion
of the dust through mouth and nose – or respirable,
relating to the portion of the respirable dust that can
reach the pulmonary alveoli due to its small particle size.
As can be seen from Table 2, the amounts described
are miniscule. If you imagine a kilogram bag of sugar is 1
million mg, it soon becomes clear that 5mg is an amount
of dust that will be virtually impossible for the average
site worker to physically see, let alone measure, and the
RCS respirable limit is one-fiftieth of that, at 0.1mg.
Thus it is clear that the law puts the emphasis on
workers to prevent the dust occurring in the first place.
The important thing will be to ensure that they are:
• using the best possible methods to reduce dust
• properly protected.
The importance of tackling dust was recognised early
on by Hilti, which established its own dust research
department six years ago at its facility in Kaufering,
Germany.
Dust-related activities are led by Andras Biczo,
who was engaged to tackle the issues, after six years
researching the subject at university.
Along with running the test programmes for
Hilti’s equipment, one of Biczo’s key roles has been to
collaborate with other tool manufacturers in the writing
of EN 50632. As a result of all this, he is one of the
world’s top authorities on construction dust and tools.
Biczo also offers a handy aide-mémoire for dealing
with dust – ‘Go for the TOP’:
• Technical solution, ie, using equipment methods.
• Organisational solution, such as job rotation or
halving the work time, to ensure that the workers
stay under exposure limits.
• Personal protective equipment, as the final line of
defence only.
However, for those tasked with ensuring health
and safety on-site, the exposure levels will be crucial.
Summarised in Table 2 are the WELs for different types
of dust, based on an eight-hour day, expressed as a
concentration of dust particles in a volume of air.
The CDP stresses in its toolbox talk that the WEL
shouldn’t be looked at as a legal minimum that can
be used in isolation. It says: “Instead it is a maximum
concentration of a substance that should be found
in the air, averaged over the reference period, after
good control principles have been applied.” It is about
recognising the hazards and creating less dust by
whatever means possible. Now is the time to take action.
Tool standards
The other key piece of legislation is a new European
Standard, EN 50632(3), which has been created
specifically for measuring dust created by power tools in
a real-world situation and the effect of their on-tool dust
extraction, where appropriate. This Standard, due to
come into force in 2015, is expected to become a crucial
part of the landscape.
John Saunders, Health & Safety Laboratory (HSL)
principal scientist for its chemical and biological risks
unit, says the Standard is welcome, “There can be just as
many problems from using the wrong tool or the wrong
extraction. There has previously been no measurement
for extraction, so a lot of the systems haven’t been tested.
Extraction systems mustn’t be designed in isolation and
they must be designed for continual use.
“The Standard will allow people to compare like with
like and it will enable manufacturers to compare the
effectiveness of on-tool extraction and to design their
tools accordingly.”
Clearly within this protocol, it is finding the best
equipment solutions that will hold the key to reduced
exposure.
System harmony
Safety bodies agree on the importance of a ‘system
approach’. German safety body BAU said: “The essence
in future will be to prompt firms only to use tool systems
recommended and harmonised by the manufacturer.”
But Andras Biczo is firmly of the belief that when
it comes to dust exposure, not all systems are created
equal. Whereas the full range of Hilti systems – meaning
an integrated system of tool plus extraction device
plus vacuum cleaner – all meet the eight-hour WEL,
measured to the standards of EN 50632, he says such a
description cannot be applied to every manufacturer’s
equipment.
Above: Integrated systems
have the advantage of
being powered by the rotary
hammer’s own motor, so no
separate vacuum cleaner
is required. Available for
cordless rotary hammers
such as the Hilti TE 6-A36AVR, it removes dust directly
from the point of impact.
Bottom left: A DCG 230-D
angle grinder slitting into
brickwork with a Hilti DC-EX
230/9" dust extraction
hood, attached to a Hilti
M-class vacuum cleaner.
Below: The Hilti TE 80-ATC
combi-hammer with a TE
DRS-Y dust extraction
adaptor, which come in
a variety of shapes and
sizes to match the range
of drill bits and chisels. A
tube adaptor ensures the
optimum amount of dust
is collected by the Hilti
vacuum cleaner.
www.concrete.org.uk MARCH 2015
concrete
37
CONCRETE SAWING AND DRILLING
‘Clear the air’ talks
Above: For breakers, the
TE DRS-B adapter is equally
effective in removing dust
from the point of impact by
the chisel, as shown with
the TE 1000-AVR breaker.
The result of six years’ research and the dedicated R&D
facilities is a range of dust removal systems – over
70 solutions covering 95% of the applicable range –
perfectly matched to the tool to maximise the amount of
dust removed at source and collected efficiently by the
vacuum.
The Hilti range of dust removal systems (DRS), for use
with concrete, includes integrated solutions for cordless
drilling, accessories for combi-hammers and breakers,
as well as hollow drill bits for drilling and hole cleaning
in one step.
Integrated systems have the advantage of being
powered by the rotary hammer’s own motor, so no
separate vacuum cleaner is required. Available for
cordless rotary hammers such as the Hilti TE 6-A36AVR, it removes dust directly from the point of impact.
Hilti also provides a range of TE DRS-Y accessories
for combi-hammers, which come in a variety of shapes
and sizes to match the range of drill bits and chisels. A
tube adaptor ensures that the optimum amount of dust
is collected by the vacuum cleaner. For breakers, the TE
DRS-B adapter is equally effective in removing dust from
the point of impact by the chisel.
Alternatively, the TE-CD/TE-YD hollow drill bit
drills and cleans the hole in one step. Compatible with
a variety of combi-hammers and vacuum cleaners it
allows the operator to enjoy a safe, virtually dust-free
working environment.
For drilling and chiselling applications there are
additional advantages to an efficient dust extraction
system beyond health. Using dust removal systems
mean less dust clogging up the tools and consumables,
ultimately meaning tools used with DRS have up to a
60% longer working lifetime.
Removing dust at the point of impact has productivity
advantages too, from the ability to drill and chisel
quicker, unimpeded by debris, to being able to work
longer due to improved working comfort, to avoiding
the need for time spent preparing beforehand or
cleaning up afterwards.
Clear skies
The upshot is that implementing an overall dust
extraction policy is not an onerous task. The range
of benefits that can be achieved through improved
health and safety, longer working lifetime of tools
and consumables and higher productivity, ultimately
resulting in higher profits, is a reality and not a pipe
dream.
The key is in selecting product systems –
incorporating the tool, insert and vacuum – that are
perfectly matched for maximum dust removal.
If this step is followed, we can prepare for cleaner,
more productive sites and clear skies ahead. ●
References
1. CONSTRUCTION NEWS. Take control of dust. EMAP Publishing,
Northampton, December 2014.
2. HEALTH AND SAFETY EXECUTIVE. Cancer and Construction:
Silica. Available at: www.hse.gov.uk/construction/healthrisks/
cancer-and-construction/silica-dust.htm.
3. BRITISH STANDARDS INSTITUTION, BS EN 50632. Electric
motor-operated tools. Dust measurement Procedure. Part 1 –
General requirement. BSI, London, 2014, draft.
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