Element 8: Hazardous Substances Flashcards
State physical forms of chemical agents which may exist in work place
• Dust.
• Fibres.
• Fumes.
• Gases.
• Mists.
• Vapours.
• Liquids.
Identify five main health hazard classifications of chemicals.
THINK ITCH C.
•Toxic
• Harmful
• Irritant
• Corrosive
• Carcinogenic
Define the characteristics of mist and fumes, identify a potential source of each in construction activities.
Mists - Small liquid droplets suspended in air. e.g. Paint sprayed.
Fumes - Fine solid particles created by condensation of vapour. e.g. emitted from welding processes.
Distinguish briefly between acute & chronic I’ll health effects.
Acute - where quantity of toxic or harmful substance absorbed into body produces very quick harmful effects. I.e. seconds, minutes or hours.
Chronic - Harmful effects of substance absorbed takes very long time to appear. Months or years.
Identify routes of entry of chemicals into the body.
THINK AIII
• Absorption
• Inhalation
• Ingestion
• Injection
What is difference between inhalable substance and a respirable substance?
Inhalable - Enter mouth, nose & upper respiratory tract.
Respirable - Deeper penetration of lung itself (7-8 microns or less)
What information is generally provided on product label of a substance that is classified dangerously for supply.
• Name, Address & Tel.
• Quantity
• product identifiers (EC, CAS or inventory no.)
• Hazard pictograms.
• Signal word.
• Hazard statements.
• Precautionary statements.
• Supplementary info
What is purpose of safety data sheet?
Provide sufficient info about hazards of substance or prep of them to take appropriate steps to ensure H&S in workplace in all aspects of use. Incl. handling, transport & disposal.
What is difference between passive & active sampling devices?
Passive - air sample passes through device natural air currents, diffuses into chamber absorbent material removed for analysis.
Active - Air forced through instrument by pump.
Give limitations in use of stain tube detectors.
• Provide spot sample one moment rather than average reading.
• Accuracy +/- 25%.
• Correct no of strokes must be used; losing count or too many gives inaccurate results.
• Volume air inaccurate (incorrect assembly/ operation leaks etc)
• Cross sensitivity
• Problems caused by temp & pressure variations.
• Deterioration
• Variation of reagent make up between tubes.
What are smoke tubes used for?
To test effectiveness of ventilation or air conditioning systems & chimneys, to detect leaks in industrial equipment, to assess air pressures & provide info on air movements in a work area.
What is Guidance note EH40?
Sets out workplace exposure limits for substances hazardous to health.
What is workplace exposure limit (WEL)?
Max concentration of airborne substance averaged over period to which employees exposed to inhalation under any circumstances.
What do you understand by the term “time weighted average” in relation to a WEL. Under COSHH regs?
Measurements taken over a particular time period (15 mins short or 8hrs for long term limits) then averaged out.
Concept of time weighted averages allows exposures to exceed limit provided equivalent exposures below compensate.
Give 3 examples of limitations of WEL’s
• Take no account of human sensitivity & susceptibility
• Cannot be applied directly to working periods exceed 8 hrs.
• Designed only to control absorption into body following inhalation.
What two reference periods are commonly used with TWAs? (Time weighted averages)
• 15 mins (STEL’s)
• 8 hrs (LTEL’s)
What principles of control are illustrated by the following measures?
A) Using granulated pottery glazes instead of powder.
B) Vacuum cleaning rather than sweeping with a broom.
C) Job rotation.
D) Using water based adhesives rather than solvent based ones.
(A) Substitution
(B) Works process change
(C) Reducing time exposure
(D) Sunbstitution
What is difference between local exhaust ventilation & dilution ventilation?
LEV control measure removing contaminants generated at source.
Dilution ventilation deals with contamination in general atmosphere of workplace area.
What are dead areas, & why are they a problem for dilution ventilation?
Areas that remain dormant where air is not changed due to air flow pattern from positioning of extractor fans.
List 4 main types of respirator & 3 main types breathing apparatus.
• Filtering Facepiece.
• Half mask/ori nasal.
• Full face.
• Powered visor respirators.
- Fresh air hoses
- Compressed airlines
- Self contained systems
What are key criteria in selection of appropriate respirator to use?
• Concentration of contaminant & its hazardous nature (harmful toxic)
• physical form (vapour, dust)
• Level of protection offered by RPE
• Presence or absence of normal oxygen concentrations.
• Duration worn.
• Compatibility with other PPE
• Shape of users face & influences on fit.
• Facial Hair interferes with effective seal.
• Physical requirements of job. Move freely.
• Physical fitness of wearer.
What is main purpose of routine health surveillance?
To identify as early as possible any variations in health of employees which may be related to working conditions.
Identify 6 chemical & 4 biological agents commonly encountered in construction activities.
1) lead
2) silva
3) cement dust
4) asbestos
5) Carbon dioxide
6) Carbon Monoxide
1) Blood borne viruses
2) Weils disease leptospirosis.
3) legionnaires- legionellosis
4) Hepatitis.
Identify two asphyxiant gases & outline their I’ll health effects.
Carbon dioxide & carbon monoxide.
Do not cause direct injury to respiratory tract but reduce oxygen available to body.
