Local Exhaust Ventilation (LEV)

Transcription

1 Local Exhaust Ventilation (LEV) Good practice advice and new (-ish( ish) HSE guidance N&D Safety Group nd December nd

2 Acknowledgement Some of the slides and video clips in this presentation are taken from HSE material provided in their LEV Trainer Adviser Briefing Days

3 Contents Introduction why new guidance? Principles of LEV for effective airborne contaminant control Examples What the law says about LEV HSG258 what you should do to comply

4 A brief introduction to BOHS A multidisciplinary, learned and professional society established since 1953 The voice of the occupational hygiene community in the UK An unrivalled source of information and expertise for members and non-members alike An examining board, through the Faculty of Occupational Hygiene, awarding qualifications in occupational hygiene and allied subjects For anyone with an interest in occupational hygiene, or a need for our services

5 The BOHS The Society s aim is simple: To help to reduce work-related related ill-health The result is dramatic: A healthy worker in a healthy working environment

6 BOHS in East Anglia Organises meetings, network events Previous meetings have covered COSHH, Noise at Work, REACH, LEV March 18 th 2010 Asbestos, new guidance Links with fellow H&S groups (e.g. N&DSG, IOSH, FISHnet, OHPAG) Small steering team Regional Organiser Andy Marshall (Bayer Crop Science, Norwich)

7 LEV Guidance Why? 1000s of workers contract occupational disease each year Occupational asthma per year Pneumoconiosis hundreds per year Chronic obstructive pulmonary disease (COPD) tens of thousands per year Cancers?? Other?? 175,000 self reported breathing or lung problems 2006/2007

8 Exposure Routes Ingestion Eye Inhalation Skin

9 Why New Guidance? Work-related disease is unnecessary and is often caused by Poor control of dust, fume, gases etc In particular, ineffective LEV leading to excessive exposures

10 The human story Phil the welder

11 New LEV guidance for suppliers HSG 258 Controlling airborne contaminants at work: A guide to local exhaust ventilation Priced Publication ( 12.50). (replaces HSGs 37 and 54)

12 New LEV guidance for employers and employees INDG 408 Clearing the air: A simple guide to buying and using local exhaust ventilation Leaflet available on: INDG 409 Time to clear the air! A pocket guide to local exhaust ventilation (LEV) Leaflet available on:

13 Principles of LEV Elements of effective LEV Properties of airborne contaminants (dusts and gases/ vapours) LEV hoods

14 Effective LEV - the four overlapping elements Contaminant cloud size, speed and direction Effective control Work process requirements LEV hood type, size and airflow Operator requirements and needs

15 0.01 µm to 100 µm+ particle size Inhalable dust (all particles which enter the nose and mouth) Respirable dust (fine particles which enter the gas exchange region of the lungs; generally <10 µm) Dust

16 Movement of particles in air particles in contaminant clouds move with the air in which they are suspended. HSG 258 Particles>100um travel some distance if ejected at speed but settle out quickly Particles ~100um settle out of air near process that generated them Smaller particles float and remain suspended in air (minutes) & move with air currents Source: HSE

17 Settling velocities and stop distances Particle size (not to scale) Settling velocity Stop distance* 2000 µm Grain of salt 6.9 m/s 12.8 m 100µm 250mm/s 127mm 1µm 0.035mm/s 0.004mm Source: HSE

18 Dustiness Dustiness is the tendency of a material to generate airborne dust during its handling Moist, sticky materials Fine, light powders give off more dust Milled, micronised products may be the most dusty Free-flowing materials

19 Visibility of particle clouds What you see is not necessarily what s there When contaminant clouds contain nearly all respirable particles they are practically invisible to the naked eye When contaminant clouds contain inhalable particles they are partially visible

20 Sunbeams in a foundry

21 Fine ( respirable ), airborne particles are invisible. Particle clouds can be made visible by Tyndall illumination Now you see it Now you don t

22 Sanding with & without illumination 4C- sanding without illumination.mpg 1C- Sanding with illumination.mpg

23 Controlling dust Must identify all sources of dust emission Apply controls to all significant sources Apply control at the point of generation of dust (once in the general air it is much more difficult to control)

24 Capture and working zones 24 capture and working zones Best.mpg

25 Dust sources Primary activity (e.g. emptying bag) Ancillary activities (e.g. bag disposal) Secondary sources (e.g. resuspension of settled dust from surfaces or clothing) Non-routine activities (e.g. cleaning, filter changing, maintenance)

26 Sack emptying, with LEV control Source: HSE

27 Sack disposal with no LEV control Source: HSE

28 But no control for sack stacking Source: HSE

29 Properties of airborne vapours Important to consider: Vapours & gases move with air Vapours & gases capable of penetrating deep into lungs Density.. [to an extent]

30 Is this how vapour flows out of a mixer?

31 Is this how vapour flows out of a mixer and is sucked away by the LEV slot?

32 How hexane-air air mixture really flows

33 Small mouldings workshop

34 Small mouldings workshop

35 The three basic types of LEV hood Enclosure (Contain and separate) Receptor (Receive, contain & empty) Capture (Capture)

36 LEV control effectiveness Increasing exposure 10,000 1, Full enclosures Almost full enclosures Down flow walk-in booths Large and small booths + Receiving hoods Capturing hoods LEV effectiveness

37 Four methods of eliminating or reducing wake effect Barrier Side-draught Move source True down-draught

38 Examples of processes Rotating tools and parts Hot (and cold) processes Free falling materials Spraying and blasting Impact and vibration Handling Machining Abrasion Sweeping HSG258: examples are listed, creation mechanism(s) described, sources described, possible control options

39 Dropping powder into vessel Dropping powderinto vessel.mpg

40 Disc cutter and moveable capture LEV 39 disc cutter & movable capture LEV ON.mpg

41 Spraygun smoke Spraygun smoke.mpg

42 Bag disposal DO s Ensure bag is fully emptied before disposal Fold bag away from your breathing zone Use LEV Have waste bin close to equipment DON Ts Fold bag against your body Scrunch bag with open end facing your breathing zone Stuff bag into open waste bin

43 Emptying containers DO s Use mechanical aids where provided Smooth flow of powder not too fast Use LEV if possible Ensure container and receiving vessel are lined up accurately DON Ts Manually tip instead of using mechanical aids to save time Forget about how you will dispose of empty liners Use hands to pull powder out of container

44 Hand scooping and weighing DO s Work at same height Use LEV properly hood close to source Work steadily don t rush Place powder into container don t drop DON Ts Overload the scoop with too much powder Let powder drop from height Move scoop over large distances

45 PPE Check SOP and WI for appropriate PPE for the job Keep powders off the skin Do not contact powders directly Wear gloves and cover exposed parts of skin Don and remove overalls carefully Do not clean dust off overalls using compressed air line RPE is the last line of defence ; don t rely on RPE alone to protect you!

46 Legal aspects COSHH (1988) 2004 MHWR (1992) 1999 HSW Act 1974 SMSR (1992) 2005

47

48 Regulation 7.7 control of that exposure shall only be treated as adequate if (a)the principles of good (control) practice are applied (b)any workplace exposure limit...is not exceeded (c ). Asthmagens and carcinogens = AFAIRP (R42 or R42/R43 R45, R46 or R49)

49 Principles of good practice checklist 1. Processes designed and run to minimise emission and spread of contaminant 2. Think about all routes of exposure - by breathing, on skin or swallowing 3. Choose measures that will control the risk 4. Make sure that controls are effective, easy to use and reliable 5. Is supplementary protective equipment needed? Gloves? A respirator? 6. Regularly check controls work and keep simple records 7. Tell workers about the dangers, how controls work and how to use them properly 8. Don t increase other health and safety risks

50 Regulation 9(1) Wording now covers all aspects of control measures Every employer who provides any control measure to meet the requirements of Regulation 7 shall ensure that (a) In the case of plant and equipment, including engineering controls and personal protective equipment, it is maintained in an efficient state, in efficient working order, in good repair and in a clean condition; (b) In the case of the provision of systems of work and supervision and of any other measures, it is reviewed at suitable intervals and revised if necessary

51 Extract from Regulation 9 ACoP/Guidance The objective...is to ensure that every element of a control measure performs as originally intended, and continues to adequately control the exposure of employees... (160) Anyone who checks the effectiveness of any element of a control measure should have the competence to do so (162) Employers must ensure that whoever carries out maintenance, examination and tests is competent... (167) Para 176 "A suitable record...should contain at least the following details: A non-inclusive list...see paragraph 176 HSG 258 guidance overlaps with paragraph 176

52 LEV User Manual Simple description (inc a diagram) Performance information (design and commissioning) Checking and maintenance schedule Replacement parts (inc part numbers) Common signs of wear and control failure Instructions on how best to use the LEV Detailed description of through examination and test

53 LEV Log Book Hoods, filter etc static pressures (and velocities) Physical condition of LEV system Maintenance done and parts replaced Operator use of LEV in-line with agreed working methods Exposure control effectiveness

54 Suppliers have legal responsibilities Health and Safety at Work etc Act 1974 Section 6 applies to the safety of supplied goods this includes LEV Section 3 Duty to employees (not necessarily yours). Applies to self-employed. Section 36.1 says (1) Where the commission by any person of an offence under any of the relevant statutory provisions is due to the act or default of some other person, that other person shall be guilty of the offence, and a person may be charged with and convicted of the offence by virtue of this subsection whether or not proceedings are taken against the first-mentioned person

55 Suppliers have legal responsibilities Supply of Machinery Regulations (SMSR 1992) and relevant standards, enable the Machinery Directive The Regulations apply where machines emit airborne contaminants while carrying out their normal function. Essential Health and Safety Requirements (EHSR) requirements include: Where a hazard exists, the machinery must be so equipped that the said substances can be contained and/or evacuated. Annex 4 of the Directive stipulates EN A and B standards, with C standards for specified machines. The machine designer may specify an extraction rate. The provision of sufficient extract air is the responsibility of the installation contractor or machine owner. See HSG 258 Appendix 1 Table Equipment supplier s legislative framework

56 HSG 258 what you should do to comply HSE Inspection programme Issues and enforcement Getting ready

57 The control problem in a nutshell LEV design often the LEV hood is not matched to the process and source(s) causing exposure LEV commissioning this is rarely done thoroughly, often done mechanically, and control effectiveness, matched to need, is usually missed out LEV checking and maintenance suppliers provide little guidance and employers don't do it frequently or systematically enough LEV thorough examination and test is often not done and when it is, it is often incomplete and uncritical (it's not "thorough")

58 HSE inspection programme Training of 400 Inspectors.. LEV is now an inspection initiative and anyone using LEV needs to get up to speed! New Guidance will have a huge impact on anyone supplying, using, testing LEV All need to review current position HSE enforcement imminent: Post code lottery Many legal requirements are not new

59 What will inspectors do? Provide information on employer s responsibilities (INDG 408) and employees role (INDG 409) More searching investigation of employer s management of LEV checking, maintenance and examination More in depth assessment of LEV hoods and systems using new equipment where necessary More enforcement on duty holders (where control is poor) More focus on supply-side stakeholders More influencing of suppliers (letters, central approaches, enforcement?) More targeted involvement of Specialist OH Inspectors Further information: see LEV Topic Pack on HSE website

60 HSE website

61 Employer: Enforcement Actions No responsible person and/or person is incompetent (Letter) No system of checking and maintenance (letter/in) Remedial work not carried out (letter/in) No LEV TEAT (IN) No action taken on receipt of TEAT report (letter/in) No use of TEAT as audit tool (letter) No, or poor, specification of new (altered) LEV (letter)

62 LEV suppliers: issues and enforcement Supplier s quotation matches needs in occupier s (clients) specification/requirements (Letter) LEV system must match and cope with the process(es) Supplier competence? (letter/in?) User Manual and Log Book supplied (letter) LEV system instrumented, especially hoods (letter) System must be commissioned properly and work effectively. Supplier competence? (letter/in/pr if significant risk)

63 Getting ready Need to review position with respect to: Existing LEV systems Effective or not Simple remedy or major redesign needed? Maintenance regime and records Do they comply with old and new guidance? New systems Competent Design (get it right first time!) Spec, user manual, log book Commissioning Maintenance schedule Competence (own staff, contractors) Training

64 Summary Existing situation is unacceptable Poor LEV design + Poor LEV maintenance = ill health HSE have done comprehensive update on guidance for suppliers, employers, users The messages will be cascaded via training packages HSE inspectors already trained Employers must ensure LEV systems are effective and properly maintained