Hazardous Substances UHSP/15/HS/03 Schedule 5/04

Transcription

1 Health and Safety Policy Hazardous Substances UHSP/15/HS/03 Schedule 5/04 Hazardous Substances Policy Identification and Storage Arrangements for Keeping and Storage of Hazardous Substances This document is a schedule from and it should be used in conjunction with University hazardous Substances Policy. The arrangements in this Schedule are intended to ensure compliance with the legal requirements of The Control of Substances Hazardous to Health Regulations and the Dangerous Substances and Explosive Atmospheres Regulations. Revised April 2004 UHSP/15/HS/03 Schedule 5/04

2 CONTENTS Introduction 1 Principal Measures 1 Procedure for the Use of Walk-in Hazardous Substance Bulk Stores 3 Quantity Limits 3 Approved Purpose-Built External Storerooms 3 Approved Bins and Cabinets in Laboratories and Workshops 3 Purchasing Policy 4 Classification and Signage for Storage 4 A Liquids that may produce explosive atmospheres 4 B Reactive Substances 4 C Explosive Substances 5 D Oxidising Substances 5 E Corrosive Substances 5 F Toxic Substances 5 G Gases 6 H Cryogenic liquids 6 Segregation of Incompatible Chemical Sustances 6 Complete Separation of Class 6 Partial Separation within Classes 6 PAGE

3 Hazardous Substances Policy - Identification and Storage Introduction Arrangements for Keeping and Storage of Hazardous Substances The main risks from the keeping and storage of hazardous substances include: personal injury or ill-health caused by exposure to escaping substances; fire and explosion involving flammable or unstable substances in the containers; fire and explosion involving flammable or unstable substances as escaping liquid, gas or vapour. These risks may also arise if incompatible substances are incorrectly stored together and an incident causes them to come into contact (See Classification and Signage for Storage). Other factors that influence risk include: durability of the container (e.g., fragility of glass bottles); the state in which the substance is kept (e.g., high pressure of compressed gases or low temperature of liquefied gases); the temperature of reactive instability. The greater the quantity of hazardous substance, the greater the risk from these hazards. Other agents such as heat and sources of fire and ignition increase risk. By storage is meant the facility at which substances in sealed containers and compressed gas containers are kept but not used within that place. Storage includes tanks, cabinets, bins, open air compounds and walk-in buildings. For most substances, unless the substance is released or used it does not present a risk to health and safety. A well-designed and properly used storage facility, and the segregation and separation of incompatible hazardous substances, should therefore present a very low risk. Gases, vapours, mists and dusts can give rise to explosive atmospheres. Areas where there is the potential for an explosive atmosphere to form must be classified as hazardous places under the DSEAR Regulations. 1 For example, the interior of a highly flammable liquids store or cabinet should be regarded as a zone 2 hazardous place. Small quantities of hazardous substances may be kept within laboratories and other workrooms in suitable cabinets or bins. These amounts must be kept within the specified limits and not be excessive in relation to the rate of useage. The procedures and specifications that follow take into account statutory requirements and guidance from the Health and Safety Executive. Principal Measures 1. Storage must be correctly signed to indicate contents and major hazard. Stores for highly flammable materials must be designated hazardous places and also signed with the explosive atmosphere sign 2. Storage must be kept secure against unauthorised access. 3. Wherever they are kept, substances must be separated and segregated according to their incompatibilities. 1 The Dangerous Substances and Explosive Atmospheres Regulations S5-1

4 4. Each hazardous substances bin, cabinet or store must be designated for and restricted to a particular class of substance. In particular, other substances must not be stored with highly flammable substances 5. No other readily combustible material, including packaging, may be kept in nor within 1metre of a hazardous substances bin, cabinet or store. 6. Ignition sources must be adequately controlled or prohibited in and around storage facilities where potentially explosive atmospheres could form. 7. Bulk storage must be to a standard of construction and equipment and in a location approved by the University Fire Prevention Officer and the Director of the Health and Safety Unit, preferably in purpose-built buildings away from the workplace. 8. The total quantity of hazardous substances kept in a storage facility must not exceed the specified maximum capacity, in the case of liquids usually 90% of the capacity of the bunded area. If a store is used by more than one department, each department will be allocated a proportion of the maximum holding and must ensure that its own holding is kept below its allocation.the quantities of hazardous substances and compressed gases containers kept in laboratories and workshops must be kept to a minimum and not exceed the amounts specified under Quantity Limits. Hazardous substances should be put away in the designated place immediately after use. 9. Containers must be kept securely closed when not in use. 10. Bins, cabinets and cupboards for keeping substances inside laboratories and workshops must be: (a) of 30 minutes fire resisting construction; constructed of non-combustible materials; able to resist collapse for at least 30 minutes; (b) able to retain spillage equivalent to 110% of the contents of the largest container; (c) corrosion-proof (d) ignition-free for flammable substances; (e) appropriately labelled to indicate contents and signed to indicate the nature of the hazard; (f) sited so as to ensure adequate separation of incompatibles, and away from sources of heat, sources of ignition, as necessary, and away from hazardous areas and emergency escape routes. 11. Adequately ventilated storage must be used where the release of vapour is unavoidable and always for the more volatile and for fuming substances. 12. A record of the contents must be maintained at each bin, cabinet, store. 13. A system of stock rotation must be employed so that the oldest containers are removed from store first. 14. If date-marked, substances must be used or disposed of by the "use by" or "disposal date", as appropriate. 15. Containers for hazardous substances must be: (a) suitable for the purpose, (b) able to withstand the rigours of the intended work activity, (c) resistant to contents, (d) resistant to anticipated external sources of corrosion and degradation by light (e) fitted with well-fitting lid or other closure. (f) labelled in accordance with statutory requirements, displaying the proper name of the contents, hazard pictograms and phrases and risk phrases. 16. Empty containers must be kept securely closed and stored as though full until disposed of or emptied of all residue including vapour. 17. Storage facilities must be maintained in a safe condition and subject to an annual check to ensure they remain fit for purpose. S5-2

5 Procedure for The Use of Walk-in Hazardous Substance Bulk Stores Each store is designated for a particular class of substance. No other substance or material, including packaging, may be kept in a store. 1. Access to these stores must be restricted to nominated persons only. 2. The door must be fastened in the open position when a user is inside. 3. The store must be kept securely locked at all times when no one is present. 4. A second person must always be present at the door when a user is inside the store. 5. The total quantity of hazardous substances kept in a store must not exceed its specified capacity. If a store is used by more than one department, each department will be allocated a proportion of the maximum holding and must ensure that its own holding is kept below its allocation. 6. A record of the substances and amounts kept in a store must be maintained at the store and a copy held in the department. 7. All containers must be stored off the floor, clear of passageways and ventilation openings. 8. No source of ignition, including electric lights, electrical equipment, naked lights, fire, flame or smoking, capable of igniting flammable vapour, is permitted inside a store or within 2.5 m of any of its openings. 9. Substances must not be dispensed inside a store. (a) Dispensing, if unavoidable, must take place in the open air within 2 m of a store, in the designated area. (b) No source of ignition including electric light, electrical equipment, naked light, fire, flame or smoking, capable of igniting flammable vapour, is permitted within 2 m above and 4 m to the side of any place where highly flammable substances are dispensed. (c) The contents of large containers, once opened, should be completely dispensed into suitable, appropriately labelled smaller containers which may be put back into the store. (d) Suitable protective clothing, including face shield and protective gloves, should be worn during dispensing operation. A suitable respirator must also be to hand. (e) A suitable fire extinguisher must be to hand when high flammable substances are dispensed. 10. Opened, part-full containers of fuming or potentially unstable hazardous chemicals should not be put back into the store. Unwanted chemicals should be disposed of in accordance with University Policy. Quantity Limits Approved Purpose-Built External Storerooms Suitable containers of up to 25 litres capacity are permitted in approved purpose-built external storerooms. However, The maximum amount of material permitted in a particular storeroom is specified in each case by the University Fire Prevention Officer, usually 90% of the volume enclosed by the bund to the store,. The maximum permitted container size is 25 litres, unless appropriate handling equipment is available. Approved Bins and Cabinets in Laboratories and Workshops Suitable containers of capacity up to 500 g for solids and 2.5 litres for liquids are permitted for the keeping of chemical substances in approved bins or cabinets in laboratories and workshops. Bench reagent bottles should preferably not exceed 1/2 litre, though the smallest practicable container size should be employed for the more hazardous substances. The upper limits for quantities of hazardous chemicals kept in laboratories and workshops are: S5-3

6 Class Flammable Liquids (A1 and A 3) Reactive, Explosive or Oxidising substances (B), (C), (D) Corrosive Liquids (E) Toxic liquids and volatile solids (F2) Compressed Gases (G) Flammable Gases (G1) Toxic and Corrosive Gases (G3) Amount 50 litres total severely restricted to needs 25 litres total 50 litres total nil - gas cylinders may not be stored in laboratories or workshops and should normally be removed when not in use 1 large cylinder or equivalent may be permanently plumbed in to an instrument in regular use nil - must be removed when not in use and at the end of each day, unless contained in an approved enclosure Compressed gas should preferably be piped into laboratories from a suitable manifold enclosure outside, where this is reasonably practicable and it does not lead to further hazards. Purchasing policy Purchasing policy should aim to match the size of container to actual needs. However, where it is desirable on economic grounds and it is otherwise reasonable to purchase particular hazardous substances in containers larger than 2.5 litres, then, when first required, these substances should be completely dispensed at one session into a sufficient number of smaller containers, each of which should then be nominally full with a space left for expansion. This arrangement should reduce the amount of handling of larger containers and of the hazardous substances and should involve fewer people, protected as appropriate. Classification and Signage 2 for Storage A Liquids that may produce explosive atmospheres A1 Highly Flammable Liquids - liquids labelled with a flame symbol and any other liquids which have a flash point of less than 32 C. A3 Flammable Liquids - liquids which have a flash point of C. B Reactive Substances B1 Highly Flammable Solids - substances which may readily catch fire after brief contact with a source of ignition and which continue to burn or to be consumed after removal of the source of ignition, indicated by a flame symbol on the container label. B2 Spontaneously Combustible Substances - substances which may become hot and finally catch fire in contact with air at ambient temperature without any application of energy, may be labelled Spontaneously flammable in air. 2 The Health and Safety (Safety Signs and Signals) Regulations S5-4

7 B3 Certain water sensitive substances - Substances which in contact with water or damp air give off highly flammable or combustible gases, may be labelled Contact with water liberates extremely flammable gases. C Explosive Substances C1 Explosives - substances manufactured and supplied for use as explosives and classified as such for the purposes of the Explosives Acts. C2 Explosive Substances - substances, other than those in 1, which may explode under the effect of flame or which are more sensitive to shocks or friction than dinitrobenzene, indicated by the explosive hazard symbol on the container label. (Substances from class D which exhibit oxidising properties with explosive violence are labelled 'explosive'). D1 Oxidising Substances - substances, other than organic peroxides, which give rise to highly exothermic reaction when in contact with other substances, particularly flammable substances, indicated by the oxidising hazard on the container label. D2 Organic peroxides - as oxidising substances. E Corrosive Substances (liquids and fuming solids) - substances which on contact with living tissues may kill or destroy them, indicated by the corrosive hazard symbol on the container label. E1 Acidic substances E2 Alkaline and related substances. - substances labelled irritant with a cross symbol E3 Irritant Liquids and volatile solids E4 Irritant solids F Toxic Substances - substances which if inhaled, ingested or if they penetrate the skin may involve serious acute or chronic health risks and even death, indicated by skull and crossbones on the container label. F1 solids F2 liquids and volatile solids - substances labelled harmful with a cross symbol S5-5

8 F3 liquids and volatile solids F4 solids G Gases - substances which at normal temperature and pressure are gases and which are compressed into cylinders as permanent gases, liquefied gases or dissolved gases. G1 Flammable gases G2 Oxidizing gases G3 Toxic and corrosive gases G4 Inert gases Note An extra sign is required to indicate additional chemical hazard, as appropriate. H Cryogenic liquids - substances which have been cooled to below their boiling points, but which are gases at normal temperature and pressure. Segregation of Incompatible Chemical Substances The likelihood of incompatible substances coming into accidental contact or of human exposure to substances not actually in use is increased with the increased mobility of volatile solids, liquids and their vapours, and gases. With such materials the original container is insufficient to guard against the accidental release and distribution of the substance through breakage or leakage and, therefore, further provision must be made for containment in the form of an outer spill container or a spill-tight storage enclosure, as appropriate. Complete Separation of Class Substances from different classes usually require separate storage, that is, separate, well ventilated, fire-resistant, corrosion-resistant and spill-tight storerooms, cabinets or bins. Whilst flammable substances, especially, must be kept separate from other hazardous substances, where a flammable substance also presents health risks, the flammable hazard takes precedence for storage purposes. Partial Separation within Classes Within each of classes, B, D and E it is necessary for chemicals in different sub- classes to be stored away from one another, that is, effectively segregated in, for example, separate, sealed outer storage containers or separate storage enclosures so that incompatible substances cannot interact. It will also be necessary between certain substances within sub-classes, e.g., ammonium compounds and strong alkalis, perchloric acid and acetic anhydride. Owing to the exceptional mobility of gases, it is necessary to ensure complete separation of substances in each of the sub-classes G1, G2 and G3. g:\aww7text\uhsp\hs15\hs5idst.doc S5-6