DSEAR in the Waste Industry

Transcription

1 Dangerous Substances Explosive Atmosphere Regulations th October 2014 Simon Rafferty MSc Dip EP CompEx

2 Section Header

3 DSEAR 2002 The Dangerous Substances and Explosive Atmosphere Regulations 2002 DSEAR is the transposition of two European Directives into UK Legislation the Explosive Atmospheres Directive 99/92/EC (ATEX). the safety aspects of the Chemical Agents Directive 98/24/EC (CAD); and COMPANY CONFIDENTIAL: Use this space for disclaimer if needed. 3

4 ATEX 95 and 137 There are two European Directives concerned with working within explosive atmospheres: European Directive 1999/92/EC commonly known as either the ATEX (workplace) Directive or ATEX 137, which defines the minimum requirements for improving the safety and health protection of workers potentially at risk from explosive atmospheres. This is transposed into UK legislation as the Dangerous Substances and Explosive Atmosphere Regulations 2002 (DSEAR) The second ATEX Directive, commonly known as the ATEX (equipment) Directive or ATEX 95 specifies the standards for equipment and protective systems intended for use in potentially explosive atmospheres This is transposed into UK legislation as The Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 1996 (EPS Regulations) ATEX takes its name from the French for ATEX 95 Appareils destinés à être utilisés en ATmosphères EXplosives 4

5 Chemical Agents Directive (CAD) The risks related to chemical agents at work (The Chemical Agents) Directive 98/24/EC (CAD) The objective of this Directive is to lay down minimum requirements for the protection of workers from risks to their safety and health arising, or likely to arise, from the effects of chemical agents that are present at the workplace or as a result of any work activity involving chemical agents. 5

6 Definitions DSEAR provides definitions for the following: dangerous substance means (a) a substance or preparation which meets the criteria in the approved classification and labelling guide for classification as a substance or preparation which is explosive, oxidising, extremely flammable, highly flammable or flammable, whether or not that substance or preparation is classified under the CHIP Regulations; (b) a substance or preparation which because of its physico-chemical or chemical properties and the way it is used or is present at the workplace creates a risk, not being a substance or preparation falling within subparagraph (a) above; or (c) any dust, whether in the form of solid particles or fibrous materials or otherwise, which can form an explosive mixture with air or an explosive atmosphere, not being a substance or preparation falling within subparagraphs (a) or (b) above; explosive atmosphere means a mixture, under atmospheric conditions, of air and one or more dangerous substances in the form of gases, vapours, mists or dusts in which, after ignition has occurred, combustion spreads to the entire unburned mixture; 6

7 Hazard Symbols CHIP 4 Symbols Explosive Oxidizing Flammable CLP Symbols The CHIP regulations will gradually be replaced by the European Classification Labelling and Packaging of Substances (EC 1272/2008) (CLP) regulations. The CLP regulations came into force in January Substances have been relaeblled from December 2010 and mixtures must be relabelled by June

8 What is the purpose of DSEAR? DSEAR is concerned with the protection of persons (not property or infrastructure) against the risks from fire, explosion and similar events arising from the dangerous substances used or present in the workplace. Persons include contractors, visitors and members of the public Regulation 2 of DSEAR defines workplace as: workplace means any premises or part of premises used for or in connection with work, and includes (a) any place within the premises to which an employee has access while at work; (b) any room, lobby, corridor, staircase, road or other place (i) used as a means of access to or egress from that place of work; or, (ii) where facilities are provided for use in connection with that place of work; 8

9 Employers Duties Under DSEAR Employers have a statutory duty to identify: What Dangerous Substances are in the workplace What the Fire and Explosion Risks are from these Dangerous Substances Classify (Zone) where explosive atmospheres may occur Procedures and plans to deal with accidents, incidents and emergencies Training requirements Identify vessels, pipelines and other containers, process plant and conveying systems that are used for dangerous substances Duty of coordination 9

10 Risk Assessment (Regulation 5) Regulation 5 of DSEAR places a duty on employers to undertake a Risk Assessment when a Dangerous Substance is present or is likely to be present on the premises. The requirements of the risk assessment are very proscriptive: Risk assessment 5. (1) Where a dangerous substance is or is liable to be present at the workplace, the employer shall make a suitable and sufficient assessment of the risks to his employees which arise from that substance. (2) The risk assessment shall include consideration of (a) the hazardous properties of the substance; (b) information on safety provided by the supplier, including information contained in any relevant safety data sheet; (c) the circumstances of the work including (i) the work processes and substances used and their possible interactions; (ii) the amount of the substance involved; (iii) where the work will involve more than one dangerous substance, the risk presented by such substances in combination; and 10

11 Risk Assessment continued (iv) the arrangements for the safe handling, storage and transport of dangerous substances and of waste containing dangerous substances; (d) activities, such as maintenance, where there is the potential for a high level of risk; (e) the effect of measures which have been or will be taken pursuant to these Regulations; (f) the likelihood that an explosive atmosphere will occur and its persistence; (g) the likelihood that ignition sources, including electrostatic discharges, will be present and become active and effective; (h) the scale of the anticipated effects of a fire or an explosion; (i) any places which are or can be connected via openings to places in which explosive atmospheres may occur; and (j) such additional safety information as the employer may need in order to complete therisk assessment. 11

12 Risk Assessment continued (3) The risk assessment shall be reviewed by the employer regularly so as to keep it up to date and particularly if (a) there is reason to suspect that the risk assessment is no longer valid; or (b) there has been a significant change in the matters to which the risk assessment relates including when the workplace, work processes, or organisation of the work undergoes significant changes, extensions or conversions; and where, as a result of the review, changes to the risk assessment are required, those changes shall be made. (4) Where the employer employs five or more employees, the employer shall record the significant findings of the risk assessment as soon as is practicable after that assessment is made, including in particular (a) the measures which have been or will be taken by him pursuant to these Regulations; (b) sufficient information to show that the workplace and work processes are designed, operated and maintained with due regard for safety and that, in accordance with the Provision and Use of Work Equipment Regulations 1998(a), adequate arrangements have been made for the safe use of work equipment; and 12

13 Risk Assessment continued (c) where an explosive atmosphere may occur at the workplace and subject to the transitional provisions in regulation 17(1) to (3), suycient information to show (i) those places which have been classified into zones pursuant to regulation 7(1); (ii) equipment which is required for, or helps to ensure, the safe operation of equipment located in places classified as hazardous pursuant to regulation 7(1); (a) S.I. 1998/2306, amended by S.I. 1999/860 and 1999/2001. (iii) that any verification of overall explosion safety required by regulation 7(4) has been carried out; and (iv) the aim of any co-ordination required by regulation 11 and the measures and procedures for implementing it. (5) No new work activity involving a dangerous substance shall commence unless (a) an assessment has been made; and (b) the measures required by these Regulations have been implemented. 13

14 Elimination or reduction of risks from dangerous substances (Regulation 6) Regulation 6 sets out how to eliminate or reduce risk to people s safety from the presence of dangerous substances by removing or controlling risks, and by providing measures to limit or mitigate the consequences for people, should an incident occur. A hierarchy of control measures is set out in regulation 6(4) and the measures required to reduce the effects of an incident are listed in regulation 6(5). The employer has a duty to provide and to maintain the measures. The initial approach should always be the elimination of the Dangerous Substance where possible. Where elimination is not possible then the control measures set out in Regulation 6(4) should be implemented in order of priority. 14

15 Hierarchy of Control The hierarchy of control (in order of priority), as defined in regulation 6 are: the reduction of the quantity of dangerous substances to a minimum; the avoidance or minimising of the release of a dangerous substance; the control of the release of a dangerous substance at source; the prevention of the formation of an explosive atmosphere, including the application of appropriate ventilation; ensuring that any release of a dangerous substance which may give rise to risk is suitably collected, safely contained, removed to a safe place, or otherwise rendered safe, as appropriate; the avoidance of (i) ignition sources including electrostatic discharges; and (ii) adverse conditions which could cause dangerous substances to give rise to harmful physical effects; and (g) the segregation of incompatible dangerous substances. 15

16 Places where explosive atmospheres may occur (Regulation 7) Regulation 7 contains specific requirements to be applied where an explosive atmosphere may occur (in addition to the requirements in regulations 5 and 6). The regulation requires competent identification of hazardous and non-hazardous zones before new work starts and verification by a competent person. Employers once again have statutory duties under regulation 7 (1) Every employer shall classify places at the workplace where an explosive atmosphere may occur into hazardous or non-hazardous places in accordance with paragraph 1 of Schedule 2 and shall classify those places so classified as hazardous into zones in accordance with paragraph 2 of that Schedule; and that Schedule shall have effect subject to the notes at the end of that Schedule. (2) The employer shall ensure that the requirements specified in Schedule 3 are applied to equipment and protective systems in the places classified as hazardous pursuant to paragraph (1). (3) Where necessary, places classified as hazardous pursuant to paragraph (1) shall be marked by the employer with signs at their points of entry in accordance with Schedule 4. 16

17 Places where explosive atmospheres may occur (Regulation 7) Continued (4) Before a workplace containing places classified as hazardous pursuant to paragraph (1) is used for the first time, the employer shall ensure that its overall explosion safety is verified by a person who is competent in the field of explosion protection as a result of his experience or any professional training or both. (5) The employer shall ensure that appropriate work clothing which does not give rise to electrostatic discharges is provided for use in places classified as hazardous pursuant to paragraph (1). 17

18 Schedule 2 Classification of places where explosive atmospheres may occur Regulation 7(1) (1) Places where explosive atmospheres may occur A place in which an explosive atmosphere may occur in such quantities as to require special precautions to protect the health and safety of the workers concerned is deemed to be hazardous. A place in which an explosive atmosphere is not expected to occur in such quantities as to require special precautions is deemed to be non-hazardous. (2) Classification of hazardous places Hazardous places are classified in terms of zones on the basis of the frequency and duration of the occurrence of an explosive atmosphere. 18

19 Hazardous Places (Zones) Gasses and Vapours Zone 0 A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapour or mist is present continuously or for long periods or frequently. Zone 1 A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapour or mist is likely to occur in normal operation occasionally. Zone 2 A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapour or mist is not likely to occur in normal operation but, if it does occur, will persist for a short period only. 19

20 Hazardous Places (Zones) Continued Dusts Zone 20 A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is present continuously, or for long periods or frequently. Zone 21 A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is likely to occur in normal operation occasionally. Zone 22 A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is not likely to occur in normal operation but, if it does occur, will persist for a short period only. Layers, deposits and heaps of combustible dust must be considered as any other source which can form an explosive atmosphere. Normal operation means the situation when installations are used within their design parameters. 20

21 Hazardous Area Signs (Regulation 7(3) ) Where it has been identified that an explosive atmosphere may occur Regulation 7(3) requires that : (3) Where necessary, places classified as hazardous pursuant to paragraph (1) shall be marked by the employer with signs at their points of entry The sign to designate a place deemed as Hazardous (where a flammable or explosive atmosphere occur) is: 21

22 Fire and explosion What may cause a fire or explosion? Typical substances that may cause fire or explosion are: petrol; liquefied petroleum gas (LPG); propane; paints; varnishes; thinners; solvents; and dusts which when mixed with air could cause an explosive atmosphere, for example, dusts from milling and sanding operations. There are literally thousands more, but these are a few of the more common substances that you may find. 22

23 Fire and explosion (powders and dusts) Powders that have the ability to explode are: flour; sugar powder; powdered substances used in food production wood dust; aluminium powder; fine iron powder; and coal dust. There are literally thousands more, but these are a few of the more common substances that you may find. 23

24 Inert powders Powders that generally do not explode are minerals such as: clays; limestones; silicas; talc; cement; gypsum; and refractories. 24

25 Flammable, combustion and explosion What is Flammable? Flammable is a substance that will burn, combust or ignite. The definition of flammable is identified in Directive 2004/73/EC What is an explosion? An explosion is defined as: The process in which combustion occurs and spreads so rapidly as to create a high pressure, forming a blast wave which travels outwards from the source and with flame and high temperatures. So what is combustion? Combustion is an exothermic reaction (a reaction that creates heat) between a fuel and an oxidant to produce energy in the form of heat (and light). 25

26 Combustion and the Fire Triangle For combustion to take place we need to have 3 elements: Fuel Something that can burn Oxygen either as an atmosphere or chemical that can provide oxygen to the combustion Ignition Source normally heat, but electricity or impulse energy may also cause material to ignite These are represented by the Fire Triangle Fire Triangle Remove any one of the 3 legs of the triangle and combustion cannot take place. 26

27 Explosions There are two types of Explosion: Detonation - a violent explosion whose pressure wave exceeds the speed of sound (330m/s) and has a combined flame front and shock wave travelling (typically) between m/s. In a detonation the reaction is propagated through the shockwave itself. Detonations are what we get with modern explosives Deflagration is an explosion whose pressure wave is less than the speed of sound (330m/ s) and generally the flame front travels behind the pressure wave. In a detonation the reaction is propagated through the combustion of the fuel supply. Lighting a gas cooker when the gas has been turned on too early. 27

28 Dust Explosion For a dust explosion (compared to a chemical explosion of gas or flammable liquid vapour) we need two extra elements, Mixing (dispersion) and confinement. This is often referred to as the Dust Explosion Pentagon: Confinement By confining an explosion (e.g. inside a building, a vessel or ductwork), pressure can rapidly build up and when released (e.g. The building fabric fails due to extreme pressure), the shock wave can increase in pressure and speed, transitioning from a deflagration to a detonation, causing far more damage than the initial explosion. 28

29 Dust Explosions ADM Grain Mill, Kansas 1979 Grain Elevator Explosion 0 Deaths 29

30 Dust Explosions 1998 De Bruce Grain Elevator Explosion 7 Dead 30

31 Dust Explosions 1977 Westwego Grain Elevator Explosion 59 Dead 31

32 Primary and Secondary Dust Explosions The other thing to note here, which is typical of dust explosions these were not one single explosion but multiple explosions. The first primary explosion may be relatively small, but it disturbs more dust (mixing or dispersion), which is then ignited by the flame from the primary explosion, which then also explodes, which disturbs more dust etc..etc This chain reaction will continue until the explosion runs out of fuel. Hence the silos in the above explosions did not all explode at once, many went off like a battery of roman candles, one after another. Whereas if these had been chemical explosions, there would most likely have been single large explosion followed by a huge fire, like at Buncefield. 32

33 Buncefield Fuel Depot Buncefield was the single largest fire and explosion in the UK since WWII. On 11 December 2005 a huge vapour cloud of petroleum vapour, that had formed from a storage tank overflowing, detonated. The resulting unconfined fuel air explosion was measured by the BGS at 2.4 on the richter scale. The shockwave of the initial explosion was felt 28 miles away in Finchampstead. The smoke cloud was 2,900m high. It was estimated that 60,000,000 gallons of fuel were consumed in the fire that burned for 4 days. 33

34 Buncefield 11 December 2005, Buncefield Fuel Storage Depot 34

35 Buncefield Afterwards! Most of the damage has been done through the sheer heat, melting many of the tanks. Buncefield was unique in that it was an unconfined fuel vapour cloud detonated (which the petroleum industry said could never happen!!!) 35

36 How much is too little? We normally use a rule of thumb that anything under 500ml is deminimus for DSEAR but Consider a 500ml can of compressed butane. Butane has a compression ratio of approximately 230:1 so 500ml of liquid butane can produce approximately 115 litre of gaseous butane. Butane has a lower explosion limit of 1.6% in air. That equates to a volume of 7,187 litres of air/butane mix are explosive just over 7 m3!! Granted the explosion would not be huge, but it would be substantial and if confined would do considerable damage (up to 9bar overpressure) also the associated fireball would cause serious burns. Trivial? Now consider the 29Litre cylinder of Propane that powers a forklift truck, Butane and Propane are very similar 36

37 How does it affect the Waste Industry Areas within the waste industry where DSEAR is likely to impact: Organic Dusts including wood, food, paper shredding Metals fine metal powders from bag filters, dross, magnesium Biomass wood chipping and peletising Waste Hydrocarbons, oils, petroleum, solvents, paints Waste batteries hydrogen from wet cells 37

38 Wood Chipping / Biomass One of the largest growth areas over the past 10 years has been the biomass energy business. Mainly taking timber and chipping and pelletizing it to make fuel for biomass plants and for powerstations to burn (such as Tillbury). Wood Chips present a whole host of problems: Dust Handling Storage Moisture Content Spontaneous Ignition Explosion Risk 38

39 Recent Biomass Explosions UK - Egger Hexham chipboard plant in June Their wood burning biomass incinerator caught fire. USA - Buena Vista Biomass power plant, California in May Two people injured one seriously, catastrophic mechanical failure. USA - Koda Energy CHP plant Minnesota exploded April 2013 igniting a fire in 2 of its fuel storage silos that burned for a week. USA - Biomass One Incinerator in Oregon, burst into flames September 15th and 18th in This is supposed to be caused by Spontaneous combustion in the woodchip pile. Denmark - Dong Energy biomass incinerator in Copenhagen experienced a fire in August 2012 that began in its electrical conveyer system and spread on to its wood pellet silos. Denmark - Amager Power station in Copenhagen burns biomass and coal. In May 2012 three people injured from wood dust explosion caused by a cleaning process called bang and clean using small explosions of oxygen and methane to clean boiler but this time used to unblock a plug of wood pellets. Fire returned to the facility also in December

40 Recent Biomass Explosions UK - Avedore Conveyor roller ignites dust to silo. Fire-fighters, Tilbury a technically challenging fire. Again showing just how important biomass safety is. UK - Rwe s Tilbury Power station in Essex had a biomass fire in February 2012 in its converted coal silos probably from smouldering wood pellets on an external source above the silo. UK - On Monday 27 February 2012 at approximately hrs a fire broke out in the bunker house for Units 9 and 10 at Tilbury Power Station. The fire was brought under control by hrs but smouldering of remaining fuel in the bunkers continued for a number of days. The fire developed from smouldering wood pellets in one of the bunkers, that had been initiated by hot dust and embers falling into the bunker. (Saturday 25 February at around hrs) The smouldering had been detected and controlled immediately by capping the affected area with high expansion fire suppressant foam. Further applications of foam and increased monitoring of the area continued throughout the weekend. The plant was out of service during that time and no material was added to or removed from the smouldering bunker. 40

41 Recent Biomass Explosions UK - A huge fire ripped through the wood pellet storage facility in the Port of Tyne in October It is thought to be from spontaneous combustion inside the silo. Germany - Three workers killed in the Brilon Chipboard plant in Germany in February 2010 cause unknown 41

42 Questions Thank You Any Questions? 42