Wt4603 unit8 week9

WT4603 Wood Processing Safety & Practice

Lecture Unit 0

WOOD DUST & RISK ASSESSMENT Lecturer: Mr. Joseph Lyster [email protected] Notes prepared by: Mr. Michael Brennan and Mr. Joseph Lyster Notes available on www.slideshare.net/WT4603

mailto:[email protected]

http://www.slideshare.net/WT4603

Department of Manufacturing & Operations Engineering

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• A hazard is anything which has the potential to cause harm to life, health, property or the environment

• Generally speaking, untreated timber in bulk is not classified as a hazard

• However, when worked and processed some of the wood is broken down into tiny dust particles which can cause severe health problems

• Traditionally, wood dust was seen as an inconvenience in the workplace. However, in recent years research has highlighted the dangers of wood dust

Wood Dust


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• Research , such as that of Greenberg (2003) found that “workers exposed to dust in occupations such as furniture making, sanding and wood machining may have an increased risk of nasal and paranasal sinus cancer. Thus in 1994 the International Agency for Research on Cancer designated wood dust as a known carcinogen”

• Hardwood and M.D.F. have been classified by the I.A.R.C. as a class 1 carcinogen

Hard wood dust air sampling

Wood dust and Cancer


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• Asthma is a chronic (long term) lung disease• Asthma affects the airways• A persons airway is made up by a system of small tubes which carries air in

and out of the lungs• Asthma causes the airways to become extremely sensitive• This sensitivity causes the airways to react to things which would not

normally cause a problem, for example, cold air and wood dust• As the airways react to these stimuli, the muscular walls of the airways

contract, making breathing difficult. The lining of the airways also gets swollen, which promotes the production of mucus. This mucus clogs up the airways, hence adding to the difficulty breathing

Occupational Asthma


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• Tightening of the muscles around the airways (an asthma attack) can happen very quickly and is the most likely cause of mild asthma

• Such an attack can be relived quickly using the correct inhaler. Swelling of the mucus however takes much longer to treat and is particular dangerous in a bad asthma attack

• The main symptoms of asthma include shortness of breath, tightening of the chest dyspnoea wheezing coughing.

• These symptoms may develop at any time in ones life and may be episodic or persistent

Occupational Asthma


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•In accordance with the 1995 London Hazard Centre Fact Sheet on Wood Based Boards, manufactured boards can be divided into three sub groups:

Laminated BoardsParticle BoardsFibre Boards

•These boards consist of wood particles which may be glued or bonded together by formaldehyde resin•Formaldehyde is a strong irritant and sensitizer to humans and animals. The two main routes of exposure are inhalation and dermal contact

Formaldehyde


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•The short term health effects of formaldehyde exposure include“When formaldehyde is present in the air at levels exceeding 0.1 ppm, some individuals may experience health effects such as watery eyes; burning sensations of the eyes, nose, and throat; coughing; wheezing; nausea; and skin irritation. Some people are very sensitive to formaldehyde, while others have no reaction to the same level of exposure.” (www.cancer.gov)

•Although there is a lot of research and evidence on the short term health effects of formaldehyde exposure, very little is known about the long term health effects. •Many carcinogenicity studies have been carried out, the most relevant being the IARCs (International Agency for Research on Cancer) 2004 reclassification of formaldehyde as a known human carcinogen.

Formaldehyde

http://www.cancer.gov/

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•Isocyanates are chemical compounds. When they react with compounds containing alcohol (Hydroxyl) they produce polyurethane polymers, which are the basis of all polyurethane products, for example, polyurethane paint and glue

•In the woodwork room, Isocyanates are used as binders in manufactured boards such as Orientated Strad Board (O.S.B.), Medium Density Fibre Board (M.D.F.) and Particle Board

•Isocyanates are very suited for this role as being a urethane adhesive they have very good bonding properties.

Isocyantes

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•Although very useful, Isocyantes can have ill effects on human health.

“Acute or chronic exposure to high concentrations of isocyanates can result in respiroratry health effects through a direct irritant action” (Davies, 1984)

•Isocyanates have been shown to cause occupational asthma through a sensitising mechanism

•Subsequently, Isocyanates are now deemed to be the number one cause of occupational asthma (Chun-Yeung and Malo, 1994)

Isocyantes

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•As with all occupational asthma triggers, asthma symptoms vary in development “Extended exposure to isocyanate vapour at barely measureable levels can cause asthma or asthma like conditions in some individuals. Alternatively, a single event involving a high exposure may have similar effects.”

(Steven et al, 1999)

•Once a person has become sensitised, the individual may develop asthma like conditions after exposure to very low concentrations of isocyantes, even less than the Occupational Exposure Limit (O.E.L.)

•In the Technology room, the main form of isocyanate exposure comes from inhalation of dust from manufactured boards. Another potential route of exposure is the use of polyurethane based paints and varnishes (evaporation and sanding).

Isocyantes

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•Dust explosions are not a new phenomenon. Records such as those of the British coal mines during the nineteenth century highlight the existence of such incidents.What exactly is a dust explosion? “The phenomenon named dust explosion is in fact quite simple and easy to envisage in terms of daily light exposure. Any solid material that can burn in air will do so with a violence and speed that increases with increasing degree of subdivision of the material”

(Eckhoff 2003, p.1)

•This can be simplified as illustrated in fig 1.1. If a combustible material such as wood is ignited in a large solid form it burns slowly, releasing heat and energy over a long period of time. If the same piece of timber is cut up, it burns quicker and releases more energy due to the increased surface area exposed to oxygen in the air.

Wood Dust Explosion

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Wood Dust Explosion

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•The effects of a dust explosion can include death or serious injury to workers, destruction of plant and building, a large fireball, secondary explosions and fire. Dust explosions in wood dust extraction systems can be very catastrophic as :

“When a dust cloud ignites in an enclosed volume it results in a very rapid rise in pressure within the container. Typical peak pressures in laboratory apparatus are in the range 8-10 bar. In normal circumstances the plant or building will not be strong enough to withstand the pressure from the explosion and it will fail in a sudden and uncontrolled manor. Anyone close to exploding plant or inside a room where an explosion occurs is likely to be killed or seriously injured

(Health And Safety Executive 2003)

Wood Dust Explosion

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•Processing wood results in the creation of airborne dust particles. •These particles vary in size•It is commonly acknowledged that there are two particle size ranges which are of concern when studying Local Exhaust Ventilation.

Respirable – Reach the depth of the lungs

Inhalable – Dust that can be breathed in but gets caught in the nose, mouth and upper respiratory tract

Creation of Wood Dust

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•The size of wood dust particles depends on various factors

Creation of Wood Dust

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•Local exhaust ventilation (L.E.V.) is the most common method of removing potential airborne wood particles from a class room

•L.E.V. involves having an extraction unit located in close proximity of a dust source (i.e., a machine), which, in turn, draws the dust away before it becomes airborne

•Although it is almost impossible to have complete dust extraction, extraction systems are of vital importance as they control dust levels to within the occupational exposure limit

•There are two different types of L.E.V. which are used in Irish post primary schools and are specifically highlighted in circular letter M45/01. They are (a) Local system and (b) Centralised system

L.E.V


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•Local system comprises a fan and filter collection unit mounted adjacent to the machine and connected to dust outlets or a fan and filter collection unit that forms part of the machine

L.E.V


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•A centralised system comprises one or more larger fans and filter collection unit that is situated remote to the machine. A system of ductwork is connected to the central unit and the machines.

L.E.V


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• An Occupational Exposure Limits (O.E.L.) is the concentration of a hazardous substance in the workplace air which most people can be exposed to without any negative effects.

• The Occupational Exposure Limit for wood dust is laid down in the Health, Safety and Welfare (Chemical Agents) Regulations, 2001 10mg/m³ for inhalable dust 5mg/m³ for respirable dust

Circular letter M45/01 D.E.S. Incentive for the provision of wood dust extraction

systems in Irish second level schools

Occupational Exposure Limits


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(Reproduced from: Australian Wood Panel Association, 2006)


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Introduction: (Page 1 – side 1)i. Outline the purpose of this bookletii. Outline the sections to be containediii. Outline the machines to be assessed

Risk Assessment


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Nature of Environment: (Page 1 – side 1)i. Outline location (Main work shop SR2-047)ii. Outline who uses the environmentiii. Outline activities carried out in the environment

Risk Assessment


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Health & Safety: (Page 1 – side 2)i. Outline risk assessment as in HSA act 2005ii. Outline risk assessment as in BS4163iii. Both articles are quoted in Unit 1 and Unit 2 lecture notes

Risk Assessment


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Machine Provision: (Page 2 – side 1)i. Simple floor plan sketch of the workshop and the position of each machine to

be assessedii. Note safe paths marked out on workshop flooriii. Also note main power control and isolator positionsiv. Note that machines are CE marked

Risk Assessment


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Hazards, Risks and Risk Control Measures (Page 2 – side 2)i. Define a hazard (Give an example)ii. Define a risk (Give an example)iii. Define a risk control measure (Give an example)

Risk Assessment


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Risk Assessment Procedure (Page 2 – side 2)i. Show HSA cyclical model (Briefly explain each part of model)ii. Risk Assessment (Show a blank risk assessment matrix template – explain

parts)iii. Risk Magnitude (Show a blank risk magnitude matrix template – explain

parts)

Risk Assessment


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Workshop Health & Safety Management (Page 3 – Side 1)i. Note any regulations, conditions of work etc… posted on the walls.ii. Outline the different types of safety signage in the workshop (Show images)

Risk Assessment


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Machine & Power Tool Risk Assessment (Page 3 – 10: Side 1 & 2)

i. Machines to be assessed – Rip Saw, Surface Planer, Thicknesser, Bandsaw, Morticer, Pillar Drill and Router.

Risk Assessment


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i. Machine a. Describe Machine purposeb. Max of 2-3 labelled imagesc. List Existing Hazards/Control Measures (Use a table – 2 columns x

No. of rows)d. Risk Magnitude matrix for each Hazard Identified (Can vary

depending on Machine)e. Complete Risk Assessment matrix table outlining all information

Risk Assessment


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Risk Assessment: HSA Model


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Risk Magnitude


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RISK ASSESSMENTLocation: SR2-047 Date: 24-09-2010 Assessment Carried out by: Mr. Joe Lyster

Assessment of: PILLAR DRILL CE Marking (Machines): Yes □ No □

Page 1 of 1 Assessment Review Date: 24-09-2010

HAZARDRISK MAGNITUDE PERSONS AT RISK EXISTING CONTROLS REQUIRED CONTROLS PERSONS RESPONSIBLE TARGET DATE

Risk Assessment


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RISK ASSESSMENT

Location: SR2-047 Date: 24-09-2010 Assessment Carried out by: Mr. Joe Lyster

Assessment of: PILLAR DRILL CE Marking (Machines): Yes No □□̷�

Page 1 of 1 Assessment Review Date: 24-09-2010

HAZARDRISK MAGNITUDE PERSONS AT RISK EXISTING CONTROLS REQUIRED CONTROLS PERSONS RESPONSIBLE TARGET DATE

1. EntanglementIntolerable User of Machine Securing Clothes/Hair Chuck Guard Teacher/Students 24-09-2010

2. Violent EjectionModerate All in Class Spring Loaded Chuck Chuck Guard Teacher/Students 24-09-2010

3. Piece SpinningModerate All in Vicinity Clamp Correct Clamping Teacher/Students 24-09-2010

4. Electric Shock Hazards Moderate User of Machine Inspection of

EquipmentRegular Inspection of electrical components

Teacher/Students 24-09-2010

5. Cuts

Moderate User of Machine TrainingExclusion zones

marked clearly in relation to work area


6. Inadvertent Starting

Moderate All in Vicinity Lockable Isolator Switch

Lock isolator in the off position when not in

useTeacher/Students 24-09-2010

7. Space around Machine

Substantial User of Machine NothingSafe work area

exclusion zone marked around machine


8. Tripping/SlippingModerate User of Machine Nothing Sign posts Teacher/Students 24-09-2010

9. Pinch PointSubstantial User of Machine Nothing Chuck Guard Teacher/Students 24-09-2010

10. Falling TableModerate User of Machine Pillar Post Lock

Handle Correct Locking/Clamp Teacher/Students 24-09-2010

11. Noise LevelsTrivial All in Class Nothing PPE & Sign posts Teacher/Students 24-09-2010

12. CrushingIntolerable All in Vicinity Nothing Secure Fixing Teacher/Students 24-09-2010


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More information can be found byconsulting manufacturer’s manual


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Health & Safety at Work Act 2005

Pg. 30 of Health & Safety at Work Act

2005


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Revised Drawer Detail


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End of Semester ExamINSTRUCTIONS TO CANDIDATES:

Students MUST answer TWO questions from SECTION A (2 x 25 Marks)

AND

Students MUST answer ANY 10 questions from SECTION B (10 x 5 Marks)

NOTE FOR SECTION A:

LM094 – (Materials & Architectural Technology) must answer question 1 in Section A and may not answer question 2

LM067 – (Wood Science & Technology) must answer question 2 in Section A and may not answer question 1


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Next Week: The Lathe

Wt4603 unit8 week9

Education

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