Biological & Environmental     Sciences, Faculty of Natural       Sciences 

Good Laboratory Practice (GLP) Good laboratory practice is safe laboratory practice and should come as second nature to all laboratory workers. It should not be viewed as extra to normal procedures, an additional and arduous planning task, or merely a paper exercise. Good and safe laboratory practice should be the norm where the health and safety of staff and students is not compromised, or the integrity of the University infrastructure threatened by unsafe acts.

The object of this Code of Practice is to provide a standard for good laboratory practice when working with chemicals rather than being specific regarding either substances or procedures. There are many thousands of chemicals that may be encountered by laboratory workers, some will have known and well documented health hazards, others will be a byproduct of work, and sometimes new substances will be generated with unknown health hazards. It is therefore extremely important that laboratory workers undertake their work and conduct themselves in a manner that ensures that exposure to hazardous chemicals is minimised and that where this occurs both exposure, by all available routes, and physical hazard, is adequately controlled so as to prevent risk to health or safety.

1.1 Principles of Good Practice There are four basic principles that underpin good practice in all laboratory work.

Forward planning Any potential hazards associated with laboratory work, including, the hazards posed by chemicals used, or produced, should be determined well before the commencement of the project. To do this you will have to consult literature, this could be: Material Safety Data Sheets (MSDS) supplied by the manufacturer, data bases of generic MSDS, textbooks, toxicity reviews and the BES Chemical Database. If it is possible to carry out a project without hazardous chemicals then this must be the approach adopted. If this is

 

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not possible can the chemical be substituted for one which is less hazardous.

Risk assess, minimise risk and control exposure to chemicals You must undertake a risk assessment of the entire laboratory work project including; equipment and any chemicals you use, or produce, during the work. The aim of the risk assessment is to minimise the risk to persons health or safety from physical hazards (glass, fire, explosion, etc.), and from health hazards (chemical vapours, fume, dusts, toxic powders, corrosives, etc.) by implementing risk control measures such as safe equipment, use of fume cupboards, suitable protective clothing and equipment, etc. Importantly the risk assessment process must result in the development of a Safe System of Work (SSW), sometimes known as Safe Operating Procedures (SOP), essentially a set of rules, that is conveyed to the persons involved in the work project, that they must follow in order to ensure, so far as is reasonably practicable, the health and safety of not only themselves but that of others who may be affected by what they do.

If you follow good laboratory practice you will go some way to satisfying health and safety legislation such as the Control of Substances Hazardous to Health Regulations (COSHH) which requires the following of good practice by the introduction of eight principles. Employers who do not follow these eight principles will, by implication, not be properly protecting their employees.

The principles are ● Design and operate processes and activities to minimise emission, release and

spread of substances hazardous to health. ● Take into account all relevant routes of exposure - inhalation, skin absorption and

ingestion - when developing control measures. ● Control exposure by measures that are proportionate to the health risk. ● Choose the most effective and reliable control options, which minimise the

escape and spread of substances hazardous to health. ● Where adequate control of exposure cannot be achieved by other means,

provide, in combination with other control measures, suitable personal protective equipment.

● Check and review regularly all elements of control measures for their continuing effectiveness.

● Inform and train all employees on the hazards and risks from the substances with which they work and the use of control measures developed to minimise the risks.

 

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● Ensure that the introduction of control measures does not increase the overall risk to health and safety

Do not underestimate the risk It is sensible to assume that where more than one chemical is used in an activity that the resultant mixture will be more toxic than its most toxic component. Do not assume that a fume cupboard will prevent the build up of explosive atmospheres, especially when working with very volatile chemicals that have a low flashpoint e.g. ethers. If a substance or preparation is classified as explosive, oxidising, extremely flammable, highly flammable or flammable then it is a dangerous substance and you are required by law to undertake a risk assessment in compliance with the Dangerous Substances and Explosive Atmospheres Regulations (DSEAR), as well as the risk assessment you undertake to satisfy the requirements of COSHH.

Be prepared for emergency situations All laboratory workers should be aware of the action to take should an accident occur, such as a chemical spill, or unintentional release of gas or vapour. Certain chemicals may require a specific action to be taken e.g. hydrofluoric acid, therefore you must ensure that all laboratory workers are informed of your activities so they can respond appropriately. All laboratory workers must be familiar with the local emergency procedures; they should know the location of: the nearest fire alarm point, fire extinguishers, chemical spill kits, the nearest telephone and the emergency telephone numbers that are to be used (2222). They should know how to call out area spill response teams, where applicable, and how to summon local first aiders. They should know the health effects of the chemicals being used in order that basic first aid can be administered and the MSDS should be readily available, so that a copy can be sent to the hospital with the casualty.

1.2. Behaviour in the Laboratory  The highest standards of professional personal behaviour are expected of all workers in the laboratory:

● Always wear laboratory coats of a type suited to the hazard (long sleeved coat, high necked Howie type coat, coverall, etc.) and always wear them properly fastened. The wearing of normal everyday clothing alone can never be justified in a laboratory and is indicative of sloppy practice and poor risk assessment.

● Laboratory coats, or coveralls, must not be worn outwith laboratories e.g.

 

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common rooms, dining rooms, libraries, computer labs, etc ● In order to prevent cross contamination chemical resistant gloves must not be

worn outwith the laboratory, or in designated write up areas, where telephones, door handles, pens, etc. may subsequently be touched by persons not wearing protective gloves.

● Long hair must be secured behind the head when working in a laboratory to reduce the risk of it dipping in chemicals or catching fire.

● Open-toed shoes or sandals should never be worn in a laboratory where chemicals are used and trousers are to be preferred to shorts or skirts.

● Do not indulge in horseplay or practical jokes in the laboratory. ● Never run in a laboratory, or hurry through doorways. ● Do not allow visitors into laboratories unless authorised by the lab supervisor and

provided with suitable personal protective equipment. This is particularly important in the case of young persons on school educational visits, etc.

● All work in laboratories by contractors/University maintenance personnel is subject to a Permit to Work Scheme, issued by the lab supervisor or Technical Manager and must be adhered to.

● Make sure equipment is used only for its designated purpose. ● Never alter the design, or construction, of any purchased equipment. ● Make sure all equipment is serviceable and suitable for the intended use. ● If photography, or video filming, is to be undertaken for publicity or teaching

purposes make sure that all of those shown are wearing appropriate personal protective equipment e.g. laboratory coats, chemical safety spectacles, chemical resistant gloves, etc.

1.3 Safe Systems of Work  A safe system of work, or safe operating procedure, will generally arise naturally out of the COSHH risk assessment. However, it should be noted that all chemical substances are hazardous in some way or another and thus must be regarded as potentially dangerous materials. When planning new research work, all possible sources of danger must be considered and specialist advice must be sought before commencing experimental work with unknown risks. Literature on reactive chemical hazards should be searched before designing experiments.

"First time experiments" involving novel combinations of chemical reagents should always be carried out on a small scale; an experienced chemist should be consulted prior to scaling-up the size of any preparative reactions. In general, the danger periods of a chemical reaction are during the initial heating, when the reflux or reaction temperature is reached, and when further reactants or catalysts are added. Provision

 

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should always be made for the rapid removal of any heating source.

Never attempt to carry out experimental work with hazardous materials when alone, or when tired or unwell.

Safe Systems of Work that have developed from the risk assessment process must be conveyed in writing to the operatives and a signature obtained to confirm that they have both read and understood the SSW. Risk assessments should be available in every laboratory.

1.4 Exposure Routes and Minimising Risk 

Ingestion ● Eating, drinking, chewing gum, applying cosmetics in the laboratory is strictly

prohibited. ● Smoking is prohibited in all University buildings. ● Food, and drinking or eating utensils must not be stored within laboratories. ● Laboratory refrigerators, freezers, ovens, etc. must never be used for food

storage or preparation. ● Water supply points within a laboratory should never be used for drinking

purposes, with the exception of dedicated drinking fountains. ● Laboratory glassware must never be used for food purposes. ● Mouth pipetting is prohibited. Automatic pipettes, bulbs, or aspirators should be

used to pipette chemicals or start a siphon. ● Gloves should be washed before being removed and hands washed following

work with any laboratory chemicals.

Inhalation ● Chemicals, or chemical by-products, that are very toxic, or toxic by inhalation,

must be worked with only in a glove box, or fume cupboard, the appropriate mechanical control having been chosen as a result of thorough and documented risk assessment.

● Chemicals that are classed as harmful, or irritant, by inhalation should be used whenever possible within a fume cupboard. They should only be worked with on the bench top when risk assessment concludes that it is safe to do so and with any required combination of risk control measure (e.g. Local Exhaust Ventilation (LEV), Personal Protective Equipment (PPE)) in place and operating.

● Use only fume cupboards that have been tested for adequate face velocity and containment within the last 14 months and have visible evidence of such testing

 

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posted on the sash screen. ● You should keep hazardous chemicals and any reactions at least 15 cm behind

the plane of the sash. ● You should never insert your head inside a fume cupboard to check a procedure,

remember the barrier between clean and contaminated air is the plane of the sash.

● Always work with the sash in the lowest practicable position and always close the sash when leaving the fume cupboard unattended.

● If Hydrofluoric Acid (HF) is being used this must only be done in fume cupboard fitted with a suitable scrubber unit and Calcium Gluconate antidote must be available. If the process is to be left unattended, always close the sash window and ensure that a notice informing that HF is being used is attached to the sash window.

● Do not clutter fume cupboards with unnecessary equipment, or store bottles of chemicals within them as this may restrict the airflow and affect containment. Where possible raise equipment that is to remain in the fume cupboard on racks, etc, so that air can flow freely underneath it.

● Always ensure that the space below the fume cupboard sill is kept clear of obstruction so as to ensure optimum airflow and thus containment.

● Never use a fume cupboard that is suspected to be malfunctioning, or override a warning indicator and always report any malfunction immediately to Property Management fault line (x2444)

● Maintenance of recirculating fume cupboards is the responsibility the Faculty. Ensure that a maintenance agreement with a competent engineering company is in place, that includes 14 monthly inspection and test, and that this test includes a filter integrity test.

● If PPE in the form of Respiratory Protective Equipment (RPE), commonly referred to as masks, is to be worn as a control measure then care must be taken that the correct respirator and appropriate filters is chosen. Importantly: in compliance with the COSHH Regulations wearers of respirators that rely on a tight fit to the face to protect the worker are required to be individually face-fit tested to a particular make and size of respirator and a certificate of successful fit- test obtained.

Dermal Contact  Dermal hazards are varied; excesses of heat or cold, corrosives, toxic chemicals that can be absorbed through the skin, skin irritants, etc. and the exposure route is not confined to the hands, but may also include the forearms, face, and any other area of

 

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exposed skin. Gloves of a type suitable to protect against a particular hazard should be worn; the following is general good practice that applies to the selection and use of gloves. More specific and detailed guidance can be found at:

Personal Protective Equipment ● Only wear gloves that you know to be suitably resistant to the chemical in use

and for the type and duration of use e.g. splash contact or immersion contact. Do not assume that, general nitrile disposable laboratory glove, will protect against the particular chemicals in use, it may not, different chemicals permeate through differing glove materials at different rates. Wearing gloves of the wrong material can be more hazardous than not wearing gloves at all, as a chemical could become trapped in contact with the skin for a prolonged period.

● You should always inspect gloves as you put them on for any holes or tears. ● Reusable gloves should be washed as appropriate before removal to prevent

prolonged chemical residue contact and premature degradation. Disposable gloves should be rinsed before removal as this helps to prevent contamination transfer to the hands on removal. However, bear in mind that some glove material is water permeable e.g. polyvinyl alcohol (PVA), leather, etc.

● Reusable gloves should be subject to regular inspection and replaced periodically dependent on their permeation and degradation features in respect of the chemical in use.

● In order to prevent the unintentional contamination of surfaces that may subsequently be touched by other persons not wearing gloves, gloves must be removed before leaving the laboratory, touching door handles, telephones, pens, books, computer keyboards, etc.

● Always wear your laboratory coat sleeves rolled down in case of accidental splashing and always wear close fitting chemical resistant safety spectacles. In the case of work with corrosive liquids a chemical resistant face shield should be worn.

● When transferring cryogenic materials always wear suitable cryogenic temperature resistant gloves and a full face shield.

Eye protection ● Close fitting chemical resistant safety spectacles, or goggles, should always be

worn when working with chemicals. When working with corrosive chemicals, or chemicals which toxicity can be absorbed through skin, a chemical resistant full face shield should be worn.

 

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Minimizing injection hazards There may be instances where solutions of chemicals are transferred in syringes and in some cases these may be fitted with hypodermic needles. In such instances extreme care is required as the risk of inadvertent injection is significant.

● Never walk about with an unsheathed hypodermic syringe in your hand, always secure in a secondary containment for transfer.

● Never re-sheath a hypodermic needle. ● Dispose of needles only in properly designed and designated sharps boxes.

1.5 Training and Supervision All persons studying or working in laboratories must receive information, training and supervision appropriate for the work undertaken, so that risks to the health and safety of all persons involved are controlled.

Staff who supervise experimental work carried out by technical staff, postgraduate students, research assistants or undergraduate students are required to give careful attention to the health and safety of those under their supervision. This applies not only to work on University premises but also to University work carried out elsewhere either in the UK or abroad. To fulfil its function, the degree of supervision must have reasonable regard for the level of training and expertise of the staff or students being supervised.

The University has a duty to ensure that postgraduate students do not create unsafe conditions by unauthorised initiatives and supervision must be adequate to meet this requirement. Accordingly, prior to the commencement of any hazardous work or activity, the Principal Investigator (PI) or supervisor should provide, obtain or agree to appropriate procedures which would minimise foreseeable risks and thereafter should keep in regular touch with the student's work. During any prolonged absence of the PI or supervisor, a second designated supervisor should be available to ensure that established health and safety procedures are maintained.

1.6 General Housekeeping  There is a direct correlation between order and safety; in general an untidy and disorderly laboratory is one where safety is given low priority and sloppy work practice prevails. The following general points must be adhered to in all laboratories:

● The laboratory floor and in particular traffic areas should be kept free of obstructions, items such as chemical containers, boxes, apparatus, etc, should

 

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not be stored on the floor. ● Access to emergency exits, emergency showering facilities, or emergency

equipment such as fire extinguishers and first aid boxes must never be obstructed.

● Benches should be clean and tidy and free from clutter by chemicals or apparatus that is not in use.

● Floors should be cleaned regularly and spills dealt with immediately, in the appropriate manner, by persons who are able to take due account of the nature of the materials spilled. In certain departments there may be a dedicated ‘Spill Team’ or Trained ‘Breathing Apparatus Team’ available to deal with toxic or highly volatile materials.

● All compressed gas cylinders must be securely fastened in an upright position to proper cylinder cradle which are in turn secured to benches or walls.

● Do not write, hang, or secure, non-hazard warning notices to fume cupboard sash panes as this can restrict proper view of apparatus and experiments and result in accident.

● Correctly label all containers containing chemicals with detail of the content; this is particularly important in the case of materials that have been decanted from a larger container, or where solutions have been made from two or more substances. In the case where the master container displays hazard warning symbols in compliance with the CLP Regulations identical labels should be affixed to the new container. (These labels are readily available, in differing sizes to suit container size, from your laboratory consumables supplier.) In addition when a chemical is transferred from the container in which it was supplied to another container, as much as possible of the information given on the label of the original container should appear on the label of the repackaged material.

1.7 Closing of Laboratories and Overnight Experiments  The last person to leave a laboratory at the end of the day should check that any gas, water and electricity supplies not in use have been turned off, and that all stocks of flammable reagents and solvents have been returned to their fire-resistant cupboards, cabinets or bins.

Apparatus left running overnight must be clearly marked with a notice giving the name and telephone number of the person to contact in any emergency. The notice should also be duplicated on the external of the laboratory door. All experiments involving toxic and/or flammable substances must be checked and authorised by an experienced person prior to being left running overnight.

 

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Water connections to experiments left running overnight must be made secure by a screw clip, or similar device and a water failure cut-out switch should be fitted, where appropriate. It is recommended that the apparatus and/or experiment should be operated attended for at least one hour under the conditions it will run unattended overnight.

Any hot work that has been taking place during normal hours should be completed at least 30mins before close of the laboratory for the night and all apparatus and materials checked to ensure that they are cool before being left unattended.

1.8 Toxic Substances  All experiments involving toxic reagents, their products and by-products, particularly when these are gaseous or volatile, should be carried out only in an efficient fume cupboard, or glove box so as not to endanger other nearby workers. If an efficient fume cupboard is not available, the experiment should not be carried out. Where work with very toxic chemicals, mutagens or teratogens is being planned, it is a requirement that the BES Safety Officer is informed and other workers in the same laboratory notified of the dangers.

1.9 Mercury Mercury vapour, and most compounds of mercury, are toxic to the human nervous system and act as cumulative poisons. The developing brains of foetuses and infants are especially sensitive to mercury’s toxic effects. Because mercury vapours are readily absorbed through the lungs into the bloodstream, they are particularly hazardous. Exposure to mercury vapours can occur when mercury containing products (such as thermometers, sphygmomanometers and fluorescent lamps) are broken. Whilst spills such as that from a broken thermometer do not pose a high risk, the area of the spill should be cordoned off and the spill cleaned up immediately to prevent spread and secondary exposures. Mercury vapours are heavier than air and may linger in higher concentrations at the site of the spill.

Where mercury is used, the following precautions should be observed:

● Keep mercury surfaces covered to prevent evaporation. ● Ensure good ventilation of the working area. ● Carry out manipulations of mercury over a tray which will contain spills. The

surface of the tray should be smooth and impervious. ● Clean up spilled mercury, at once. ● If a mercury hazard is suspected, arrange with the BES Safety Officer for

 

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airborne concentrations of mercury vapour to be measured. ● Alcohol thermometers must be used in preference to mercury thermometers

wherever practical, especially when a thermometer is to be left in a heating block.

1.10 Flammable Reagents and Solvents For persons experienced in the laboratory techniques of distillation, solvent extraction and solvent evaporation, a limited batch size of 2.5 litres of flammable solvents is suggested; less experienced workers are recommended to use appreciably smaller batches. Precautions must be taken to minimise the concentration of flammable vapour in the working area and to eliminate all sources of ignition, such as sparking thermostat controllers, etc. Thought must be given, before starting a process, as to the action required should there be an accident with flammable solvents leading to a fire.

Dialkyl ethers and tetrahydrofuran form peroxides in contact with air or exposure to sunlight; the distillation to near dryness of a peroxidised solvent can lead to an explosion. Any peroxides present must always be removed prior to distillation.

Solvent residues and other combustible materials must not be allowed to accumulate in laboratories. Flammable reagents and solvents must never be poured down drains, but must be collected and arrangements made for their safe disposal via the BES stores waste disposal system. Waste acetone and chloroform must not be mixed, as this can lead to an exothermic reaction.

1.11 Highly Reactive Chemicals and Explosive Reactions  Certain highly reactive chemicals, such as acetylides, azides, diazoalkanes, nitrogen halides, perchlorates, peroxides and polynitro-compounds often behave unpredictably and are prone to decompose explosively. Reactions involving these, and other like materials must therefore only be undertaken by, or under the close supervision of, experienced and cautious investigators who are fully conversant with the relevant literature. A careful appraisal must always be made of the proposed operating conditions and techniques and the batch size must be strictly limited.

Wherever there is the possibility of an explosive atmosphere being generated the requirements of the Dangerous Substances and Explosive Atmospheres Regulations (DSEAR) must be addressed before commencement of the activity.

Protection must be provided against the hazards of explosion, rupture of apparatus from overpressure, sprays or emission of toxic or corrosive materials and flash ignition of vented vapours or gases. Apparatus must be placed so that no-one can be injured if an explosion occurs. Operation within an appropriate fume cupboard is always

 

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recommended with the additional protection of a safety screen, which is either fixed or weighted so that it does not become a missile itself during an explosion. If a safety screen is used to protect against an explosion risk during work on the open bench, place the apparatus and the screen so that no-one in the area is at risk from flying debris.

1.12 Storage of Chemicals  The Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) require risks from the indoor storage of dangerous substances to be controlled by elimination or by reducing the quantities of such substances in the workplace to a minimum and providing mitigation to protect against foreseeable incidents.

It is recognised that for practical purposes where flammable liquids are used, there is likely to be a need for a limited quantity to be stored in the workroom/working area. It is the responsibility of the employer / dutyholder when carrying out their risk assessment required under DSEAR Regulation 5, to justify the need to store any particular quantity of flammable liquid within a workroom/working area.

The reception, storage and distribution of chemicals must be the responsibility of authorised persons only. Only the minimum amount of chemicals should be purchased for each work project thus preventing unnecessary accumulation of chemicals. Where there remains an excess of a chemical on the completion of a project, unless that chemical is a common reagent that is likely to be used without delay by a colleague, it should be properly disposed of via the BES Stores waste disposal system.

It is important to prevent situations arising in which potentially hazardous materials, of either unknown or known composition, accumulate to form a growing residue for disposal. Disposal procedures must be planned to prevent, for example, research groups moving on, and leaving such residues behind for others to deal with.

● In order to minimise the risk of a serious laboratory fire, the maximum amount of flammable reagents and solvents etc., stored in any one laboratory must not exceed 50 L.

● Reasonable quantities of flammable reagents and solvents may be kept in the open laboratory in suitable closed vessels of volume not greater than 500 cm3; these small quantities are excluded from the 50 L storage limit suggested for each room.

● All chemicals, other than those small amounts in use, must be stored in proper fire resistant chemical storage cupboards on drip trays and the external of the cupboard appropriately signed with a hazard warning signs relevant to the hazardous properties of the stored chemicals. Storage cupboards or bins must

 

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be constructed of materials that ensure that the sides, top, bottom, doors and lid are capable of providing 30 minutes fire resistance. These storage cupboards must not be sited adjacent to doors or other means of escape from the laboratory.

● When new cabinets are being purchased either as replacements for old cabinets, or in cases of fitting out a laboratory after refurbishment or new build, all cabinets or bins used for the storage of flammable liquids must conform in construction to the more demanding BS EN 14470- 1:2004 ‘Fire safety storage cabinets – Part1: Safety storage cabinets for flammable liquids; Factory Mutual, Underwriters Laboratories and ANSI/NFPA 30 standards.

● Individual workers should not retain chemicals superfluous to current needs and should return these to the storage cupboard, cabinet, or bin, as soon as possible after use or, if the materials cannot be used again, make arrangements for their safe disposal.

● Certain chemical compounds, e.g. ethers as peroxide formers, should have the date of opening, test history and date of discard written on the label

● If flammable chemicals are to be stored in refrigerators these must be intrinsically safe (spark proof), ordinary domestic fridges, as supplied, are not suitable for this purpose.

● Chemicals in liquid form should not be stored above head height. ● Great care must be taken to ensure that incompatible chemicals are stored

separately (e.g. mineral acids and organic solvents, oxidisers and flammables) to prevent violent reaction in case of spillage or leakage.

● Regulations governing the storage and labelling of toxic and other hazardous materials must always be observed. Schedule 1 Poisons (e.g. arsenic compounds, mercury compounds, sodium and potassium cyanide) Highly or Very Toxic substances and Cytotoxic substances must always be kept in secure storage, access to which is available only to nominated key holders. Accurate records of chemicals issued from a secure store must be kept by a nominated person. Lists of chemical substances within the above categories can be found on the BES Chemical Database.

The storage quantities quoted above are intended to be viewed as recommended maxima representing good industry safe practice, rather than be taken as absolute limits. There is intended to be some flexibility with these limits, where it is recognised that the design of modern day buildings and the pattern of work can sometimes make adherence to these quantities difficult to achieve; for example, in large or open-plan workrooms / working areas. However, where the employer/dutyholder does identify a need to store quantities in excess of the recommended maxima, a robust demonstration

 

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of this requirement would need to be made and in particular the risk assessment, under DSEAR Regulation 5, must take into account:

● The properties of the materials to be stored or handled in the workroom / working area. For mixed storage the worst case situation should be applied, i.e. all materials in the storage cupboard or bin should be considered as being the same material as the one that has the lowest flashpoint.

● The size of the workroom / working area and the number of people working in it. ● The amount of flammable liquids being handled in the workroom / working area

and the quantities of liquid that may be accidentally released or spilled. ● Ignition sources in the workroom / working area and potential fire spread in the

event of an ignition. ● Exhaust ventilation provision to the workroom / working area and / or the storage

cupboard or bin. ● The fire performance of the storage cupboard or bin. ● The arrangements for closing the cupboard or bin doors/lid in the event of a fire. ● Means of escape from the workroom / working area.

The particular objective, in the event of an incident, is to ensure that people can safely escape from the workroom / working area. In this context, the purpose of storing dangerous substances in cupboards and bins of appropriate construction and design is to provide a physical barrier to delay the involvement of these materials in a fire, for sufficient time for people’s safe evacuation and the dutyholder’s immediate emergency procedures supporting this to be implemented.

Where quantities in excess of the recommended maxima are to be stored employers/dutyholders will find cabinets with enhanced fire performance i.e. to BS EN 14470-1:2004 standard a help in making their risk assessment demonstration. In cases where the recommended maxima are to be stored all cabinets within the area must be to 60 minute fire resistant standard.

1.13 Disposal of Waste Chemicals  The disposal of waste is controlled by legislation, and there are very few chemicals that can be legally discharged into the public sewage system. Chemicals must not be ordered, stored, or used in any activity until thought has been given to the proper disposal of any waste material. It falls to individual users to ensure that their chemicals are disposed of in accordance with the "Duty of Care", outlined by the Environmental Protection Act. Advice should be taken from Principal Investigators, Supervisors, or the BES Safety Officer, as appropriate, on waste disposal procedures.

 

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1.14 Pressurised Gas Cylinders Where cylinders are presently and unavoidably sited within buildings only the minimum number of cylinders in actual use should be kept within each laboratory and all the cylinders must be firmly supported in a vertical manner by restraining chains, bench clamps or similar devices specifically designed for that purpose.

Storage ● Gas cylinders must be stored in a properly constructed well ventilated store,

preferably in the open air, where full and empty cylinders should be separated, and where the use of naked flames is prohibited. Where it is not reasonably practicable to store cylinders external to a building they must be stored in an adequately ventilated part of the building specifically designed for this purpose.

● Storage areas must be secure and lockable. ● Ensure the external of the entrance to the store is designated by proper and

appropriate hazard warning signage in compliance with both the COSHH and DSEAR Regulations and any appropriate mandatory signage (e.g. NO NAKED FLAMES)

● Cylinders of oxidising gases must be kept separate from cylinders of flammable gases, and toxic and/or corrosive gases should always be stored separately, as should LPG.

● All cylinders must be secured upright away from heat sources, flammable or corrosive materials and oils. Cylinders must not be stored in standing water.

● Rotate stock on a first in, first out basis – this ensures that cylinders are returned to the supplier for regular legally required safety checks.

Handling gas cylinders  Gas cylinders are generally unstable due to their diameter to height ratio and are easily toppled and are also heavy with large cylinders weighing over 100kg when full. The potential for injury when handling cylinders is therefore high, this being the case the law requires that a formal manual handling risk assessment be undertaken and any significant findings recorded.

● In many cases a generic risk assessment will suffice for multiple laboratories or stores areas in a building, but remember that there may be specific areas of building design within your work area that present additional hazard e.g. rough ground, steps, low headroom, etc. this has to be taken into consideration in your steps to mitigate risk.

 

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● Similarly the personal capability of the employee expected to carry out the manual handling of cylinders must be taken into account; factors such as physical build, gender, health, etc need to be explored.

● Specialist training in the moving of cylinders will be required e.g. in the technique of ‘churning’, this can be effectively carried out in-house by experienced members of staff, but all training must be recorded.

● Ensure that the Safety Data Sheets for the gases being handled are available. ● Do not drop, roll or drag gas cylinders. ● If moving cylinders more than a few feet a properly constructed cylinder trolley

must be used. ● Always use appropriate protective equipment. Eyes, hands and feet should be

protected when handling or using cylinders. Many injuries to the foot affect the metatarsal (instep) bone. Safety footwear must be provided and worn - footwear with metatarsal protection is recommended.

● Never attempt to catch a falling cylinder but rather get out of the way. ● Cylinders transported in lifts should not be accompanied by personnel and steps

must be taken to ensure that persons cannot enter the lift at intermediate floor stops.

General guidelines for gas cylinder storage are published by the British Compressed Gases Association. This site is also the source of many helpful Guidance Notes, Technical Information Sheets and Codes of Practice.

Gas company emergency contact numbers:

● Air Liquide 01675 462695 ● Air Products 0500 02 02 02 ● BOC 0800 111 333 ● Energas 01482 329 333

1.15 Cryogenic material and equipment

Cryogenic materials Liquid oxygen and liquid air are dangerous because substances not normally regarded as easily combustible become highly flammable in their presence. Containers of either must be clearly labelled and not used for any other purpose. Liquid nitrogen or solid carbon dioxide should be used as coolants.

Liquid Nitrogen (LN2) is normally employed for the cooling instrument detectors such as in the Environmental Radioactivity Lab.

 

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Properties ● LN2 is extremely cold (-196oC) at atmospheric pressure. This can cause severe

frostbite. ● On vapourising LN2 expands by a factor of 700, therefore one litre of LN2

becomes 700 litres of nitrogen gas. ● Nitrogen gas is colourless and odourless, thus there are no sensory warnings of

its presence. ● Liquid Nitrogen evaporates very quickly at room temperature thus increasing the

concentration of nitrogen gas in the atmosphere and a decrease in oxygen concentration which can cause drowsiness, disorientation and potentially suffocation.

● The colder nitrogen gas will tend to collect in higher concentration at low level, thus if a human collapses, due to oxygen depletion within a room, they are likely to fall into even higher concentrations of nitrogen gas.

Precautions when working with LN2 ● Always use a ‘buddy’ system when entering a LN2 storage facility, even if the

store is fitted with three-stage ventilation. ● Never enter an LN2 storage facility alone out of hours. ● Should a colleague collapse within an LN2 storage facility call the Fire & Rescue

Service immediately via the University’s emergency number (2222). Do not attempt to rescue the casualty until the oxygen level has returned to at least 19.5% (normal oxygen content of air 21%)

● Do not allow LN2 to be trapped in clothing near the skin. Always wear a fastened laboratory coat when handling.

● Cryogenic gloves must be worn, these should be loose fitting close cuff in order that they can be quickly and easily discarded and to avoid liquid pour inside them.

● A full Face Visor must be worn when decanting LN2. ● Use only containers designed and approved for LN2 use, never use domestic

thermos flasks. ● Always wear suitable closed footwear when handling LN2, sandals or open toed

shoes are not acceptable. ● Great care must be taken to ensure that ingress of air into vessels containing

liquid nitrogen does not lead to condensation of oxygen. ● Steps must be taken to ensure that evaporation of liquid nitrogen or the

sublimation of solid carbon dioxide does not occur in a poorly ventilated room as

 

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this can lower the oxygen concentration to such an extent that a person entering the room can lose consciousness and die.

1.16 Glass Apparatus Many serious accidents are caused by careless handling of glass apparatus including glass tubing, rods and thermometers. A protective cloth should always be used when cutting glass tubing, particularly large diameter, or when inserting tubing or thermometers into rubber bungs; a lubricant should be used where appropriate. Cut ends of glass rods and tubing should be fire- polished before use.

All glassware should be examined closely before use and any damaged pieces disposed of. Never return damaged glassware to storage. Always clear up broken glass apparatus immediately. Broken glass must always be placed in a separate bin for disposal. Never allow broken glass into the general waste, someone may be cut very badly through such thoughtlessness.

Eye protection is mandatory when operating glass apparatus under vacuum. Thin walled glass vessels that are to be evacuated should be protected by binding with adhesive tape (half inch wide) leaving gaps of no more than one inch, a metal mesh cover will provide the same protection. The use of plastic mesh covers is not recommended. Evacuated glass desiccators should be protected with a metal mesh cage and must not be transported whilst evacuated. Air should be admitted gradually when a vacuum within glass apparatus is to be released. Never evacuate a badly scratched flask or one with a star crack, apparatus damaged in this way will often fail under vacuum.

All large glass flasks should be supported adequately, it is dangerous to clamp such a vessel only at the neck. Avoid handling glassware with wet hands. Winchester bottles must never be carried by the neck but must always be transported in properly designed bottle carriers.

Care should be exercised when freeing stoppers from flasks or bottles, particularly if the contents are hazardous. If a bottle of chemical has been heated by sunlight or as a result of being stored near a burner, hotplate or radiator, the contents should be cooled prior to releasing the stopper, this is particularly important in the case of strong ammonia solutions. Bottles containing strong acids, particularly perchloric acid, or strong alkalis, must not be placed directly on wooden shelving or bench tops, porcelain or plastic dishes or trays should always be used.

 

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Glass vacuum lines  A visual inspection of glassware to check for cracks and scratches and that all stopcocks are free to open and close should be undertaken before operating vacuum pumps. Glassware that is regularly subjected to extremes of temperature or which is liable to experience mechanical stress during use, or in cleaning operations, should be checked regularly and replaced when required.

Glass Dewar vessels should be contained within metal or plastic secondary containment vessels.

Glass bulbs with a volume greater than 100 cm3 should be taped or encased in a metal mesh cover.

Any vessel that has been cooled in liquid nitrogen should not be allowed to warm up without first being evacuated to a pressure less than 1 mm Hg (133.322 Pascal) in order to ensure that no liquid air has been condensed.

Pipetting Pipetting by mouth is strictly prohibited. Electronic pipettes, bulbs, Pi-pumps or aspirators should be used to pipette chemicals or start a siphon. Fitting pipette pumps or other pipetting aids incorrectly is the cause of many glass cut injuries, which are often serious. Pipetting aids should be fitted with great care, utilising suitable lubrication where necessary, and employing a protective cloth, in case the pipette should fracture. Laboratory workers should receive suitable instruction in the correct use of teats and mechanical pipetting devices from their supervisors or PI’s.

1.17 Pressure Vessels  If pressure equipment fails in use it can seriously injure or kill people nearby and cause serious damage to property. It is therefore paramount that pressure equipment is both maintained and used in a safe manner. The main regulations that cover pressure equipment and pressure vessels are the Pressure Equipment Regulations 1999 and the Pressure Systems Safety Regulations 2000.

One of the main requirements of the Regulations is that a ‘Written Scheme of Examination’ is drawn up by a ‘Competent Person’ for any pressure system and that that system then be examined annually and maintained in accordance with the Written Scheme of Examination. In order to ensure that a Written Scheme of Examination is drawn up for any pressure system that a Department may have, details must be passed to the Insurance Office by the competent person.

 

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Details required are;

● Name of Department and Faculty ● Contact name/telephone number ● Description of equipment (e.g. air receiver) ● Manufacturers name ● Serial number of item (usually found on a plate affixed to the equipment) ● Exact location of equipment

Guidance on pressure systems A ‘Pressure System’ is a system comprising one or more pressure vessels of rigid construction, any associated pipework and protective and measuring devices, or the pipework with its protective devices to which a transportable pressure receptacle is, or is intended to be, connected and which contains or is liable to contain a relevant fluid, but does not include a transportable pressure receptacle (gas cylinder). ‘Pipework’ means a pipe or system of pipes together with associated valves, pumps, compressors and other pressure containing components and includes a hose or bellows but does not include a pipeline or any protective devices.

A ‘relevant fluid’ means –

1. steam (at any pressure); 2. any fluid or mixture of fluids which is at a pressure greater than 0.5 bar (7.25 psi)

above atmospheric pressure, and which fluid or mixture of fluids is- a. a gas, or b. a liquid which would have a vapour pressure greater than 0.5 bar above

atmospheric pressure when in equilibrium with its vapour at either the actual temperature of the liquid or 17.5oC; or

c. a gas dissolved under pressure in a solvent contained in a porous substance at ambient temperature and which could be released from the solvent without the application of heat. ‘Pipeline’ means a pipe or system of pipes used for the conveyance of relevant fluid across the boundaries of premises, together with any apparatus for inducing or facilitating the flow of relevant fluid through, or through a part of, the pipe or system, and any valves, valve chambers, pumps, compressors and similar works which are annexed to, or incorporated in the course of, the pipe or system.

The following pressurised systems are likely to require a written Scheme of Examination:

● A compressed air receiver and the associated pipework, where the product of the pressure in bars multiplied by the internal capacity in litres of the receiver is equal

 

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to or greater than 250 bar litres; ● A steam sterilising autoclave and associated pipework and protective devices ● A steam boiler and associated pipework and protective devices; ● A pressure cooker ● A gas loaded hydraulic accumulator ● A vapour compression refrigeration system where the installed power exceeds

25 kW ● The components of self-contained breathing apparatus (BA) but excluding the

gas cylinder ● A fixed LPG storage, system supplying heating for the workplace

The following systems are unlikely to require a Written Scheme of Examination;

● An office hot water urn ● A machine tool hydraulic system ● A pneumatic cylinder in a compressed air system ● A portable compressed air system and associated pipework where the product of

the pressure in bars multiplied by the internal capacity of the receiver is less than 250 bar litres

● Any ‘pipeline’ and its protective devices in which the pressure does not exceed 2 bar above atmospheric pressure

● A portable fire extinguisher with a working pressure below 25 bar at 60oC and having a total mass not exceeding 23 Kg

● A portable LPG cylinder ● A tyre used on a vehicle

If you are unsure as to whether a particular system requires a Written Scheme of Examination report the details to the Insurance Office who will pass the details to the Competent Person to make that decision.

 

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1.18 Chemical Hazard Symbols 

 

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