Transcript Document

Health
Healthand
andSafety
Safety
Executive
Executive
Silica Dust & the
Cutting of Roof Tiles
Marjory Mitchell
HM Health and Safety Inspector
(Occupational Hygiene)
Duncan Smith
HM Health and Safety Inspector
(Occupational Hygiene)
How did we get here?
• Construction Supply Chain Projects
– kerb, paving and block cutting
• Led to numerous queries about dust
suppression in relation to roof tile cutting
• Construction industry engagement on
issue and solution:
– Improve knowledge of health risks
– Improve use of controls
What is the problem?
Dust in general and Silica in particular
Silica is one of the most abundant materials on earth
Found in many materials used in construction:
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•
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Sandstone (>70%)
Brick and tiles (up to 30%)
Cement, mortar, concrete (25 to 70%)
Sand, gravel, flint (up to 70%)
Poor industry appreciation
“It’s only dust you know!”
Industry appreciation of the risk is poor:
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•
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People not aware of health risks
Underestimation of exposure levels
Require convincing that control measures work
Why is it a problem?
Main concerns are:
– Silicosis
– Lung Cancer
– Chronic lung diseases, emphysema,
bronchitis, COPD.
These diseases;
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•
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Cause reduced lung function
Continue to develop after exposure stops
Can cause death
Why is silica a problem?
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Issue is Respirable Crystalline
Silica or RCS
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Respirable particles can
penetrate to deep lung
•
Often invisible under normal
conditions
The size of the problem?
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Over 500 lung cancer deaths in 2004 related to
past silica exposure in construction
– Over 10 a week
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Research suggests silica is the second most
important cause of occupational lung cancer
after asbestos
UK accident v ill health deaths
Other non-malignant
Respiratory Disease
Respiratory
Disease
Fatal Injury
2% 2% 2% 1%
COPD
37%
Asbestosis
Cancer
56%
Roof tiles
Many of the issues discussed are relevant to the
cutting of roof tiles:
•Cutting tiles produces
silica dust
•Roofers will breathe this
in and are therefore at
risk
•Control measures are
required to protect their
health
Why do we need to tackle this?
• To protect people from suffering ill-health
• Ensure consistency of approach by
industry and the regulator
• Improve industry image – considered dusty
• Legal duty under COSHH to adequately
control exposure
How much is a problem?
COSHH sets Workplace Exposure Limits for
dust:
General Dust
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•
10 mg.m-3 (inhalable)
4 mg.m-3 (respirable)
Respirable Silica
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0.1 mg.m-3 (8-hour TWA)
Tile cutting tasks
Cutting or grinding
•
High energy processes that generate high
dust levels
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When working on tiles the dust contains
high level of RCS
Management controls
Arrangements:
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An assessment(s) of the risk
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Arrangements for the maintenance, examination
and testing of control measures
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Effective supervision, monitoring and review
They have given appropriate information,
instruction and training.
Slips, trips and working at height
Controls
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On-tool extraction
OR
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Water suppression
RPE/PPE
Training
OR
Tile cutting interim control solutions
Wet Cutting =
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–
–
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Dedicated cutting area
Adequate supply of water
Scaffold board protection
Additional use of RPE
Interim arrangements for setting out
the roof
Plan the work area on the top lift of the scaffold
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Locate away from the side of the building e.g. on a loading
bay area
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Use sheeting to control slurry runoff
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Move controls (on-tool extraction or water suppression and
RPE) onto the scaffold by mechanical lifting aids
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Additional measures may be needed to prevent slips, trips
and falls e.g. brick guards
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Ensure that there are no other trades working in the vicinity
Place sacrifical material between the tile and the scaffold
board
Interim control solutions
Verge and Ridge Tiles
– Cut with water suppression on scaffolding
Hip Tiles
– Rough cut in situ or with water suppression
on scaffolding
Interim position
Valley Tiles
– Cut in-situ using Protection Factor 20 RPE
Agreement on control solutions
• Made explicit that any such agreement is
only interim in nature.
• Operational Guidance – SIM 02/2010/01
Control solutions
Water Suppression
Control solutions
Water Sources
Control solutions
Water Suppression has other
advantages:
• Extends the life of
expensive diamond blades
• Helps prevent build up of
dust in the machine workings
Control solutions
Issues associated with water suppression use:
• Marking the cut line
• Slurry generation
• Wet legs
Control solutions
On-Tool LEV is
also an option.
Looking into the crystal ball
New innovations and new roofing
systems
What about RPE?
Powered Respirator with Hood
Half Mask (with P3 Filter)
PF = 20
Respiratory protective equipment
Disposable
FFP3
Protection Factor = 20
Correct Mask Type: FFP3
Manufacturer product no.
European
Standard
Class of
Respirator:
FFP3
Conformity mark & Notified Body
Make sure it will work
Must fit correctly
– ‘Fit testing’
Be worn correctly
What other PPE?
• Waterproofs
• Coveralls
HSE’s enforcement expectations
Exposure to RCS is considered to
constitute a:
‘serious health effect’
No control = ENFORCEMENT
Initial enforcement expectation
Control failure
Serious health effect
likelihood
Consider
PN
Consider
IN
No control measures (i.e.
no water suppression,
LEV or RPE)
Probable
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√
Ineffective control
measures (i.e. water
suppression weak/no
flow and RPE badly
worn/damaged/incorr
ect APF/no face fit)
Probable
√
√
No or ineffective water
suppression or LEV
but effective and
suitable RPE
Possible
√*
√*
Effective water
suppression/LEV but
no suitable and
effective RPE
Possible
√*
√*
* = Task Specific
Consider
Letter Advice
More information
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Operational Instructions on tile cutting
http://www.hse.gov.uk/foi/internalops/sectors/construction/021001.htm
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Time to Clear the air – free leaflet
http://www.hse.gov.uk/pubns/misc830.pdf
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Time to clear the air! Using cut-off saws for cutting kerbs
and flag paving – DVD
http://www.hse.gov.uk/construction/cleartheair/index.htm
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RPE and Fit Testing
http://www.hse.gov.uk/news/2009/fit-testing-poster.pdf
http://www.hse.gov.uk/pubns/fittesting.pdf
Thank You
Any Questions?