STORAGE OF HAZARDOUS CHEMICAL AGENTS (HCA)

Transcription

1 Safety Guideline SG-C STORAGE OF HAZARDOUS CHEMICAL AGENTS (HCA) Abstract In accordance with General Safety Instruction GSI-C-1, Prevention and protection measures [1], this Safety Guideline is intended to give directives concerning the storage of hazardous chemical agents. Chemical agents must be stored either in a central storage area or in the chemical laboratory or workshop. Workbenches or fume cupboards must not be used for the storage of chemical agents, but rather for placing chemical agents which are in use. At the end of the working day chemical agents must be returned to storage, either to a cabinet in the laboratory or else to the central storage area. Reference documents: DOCUMENTATION [1] General Safety Instruction GSI-C-1, Prevention and protection measures (EDMS ). Further reading: - Regulation (EC) 1272/2008 of the European Parliament and of the Council of 16 December 2008 on classification, labelling and packaging of substances and mixtures, amending and repealing Directives 67/548/EEC and 1999/45/EC, and amending Regulation (EC) 1907/ EN , Fire safety storage cabinets - Part 1: Safety storage cabinets for flammable liquids. - EN , Fire safety storage cabinets Part 2: Safety cabinets for pressurised gas cylinders. - Safety data sheets from chemical suppliers. TRACEABILITY Reference.: Safety Guideline SG-C EDMS.: ver. 6 Prepared by: J. Gulley, HSE/SEE Date: 18/01/2017 Verified by: C. Laverriere, F. Angerand, U. Tihinen HSE/SEE Date: 29/05/2017 Approved by: E. Cennini, HSE/SEE Date: 30/05/2017 Distribution: Public document published in the Safety Rules web site. Rev.. Date Description of Changes /09/ (addition matrix), 4.1 & 4.2 (texts added) and text below Fig /12/2011 End of 4 (text added). This follows a communication and discussions with CERN s Dangerous Goods Safety Advisor employed by GS. Change to take effect on 1 st January /2/2013 Text added (chapters 5 and 5.1) to give the recommendations and explain best practice with respect to the ventilation of chemical storage cabinets /05/2017 Update of regulations and standards. Page 1 of 10 EDMS v.6

2 1 INTRODUCTION In accordance with General Safety Instruction GSI-C-1, Prevention and protection measures [1], this Safety Guideline is intended to give directives concerning the storage of hazardous chemical agents. Chemical agents must be stored either in a central storage area or in the chemical laboratory or workshop. Workbenches or fume cupboards must not be used for the storage of chemical agents, but rather for placing chemical agents which are in use. At the end of the working day chemical agents must be returned to storage, either to a cabinet in the laboratory or else to the central storage area. 2 DIFFERENT STORAGE AREAS 2.1 Central storage area Central storage areas are for the storage of those chemical agents required for use in the medium to long-term. Ideally the storage area should be isolated from the rest of the building, but not too far from the laboratory or place of use. In case this is not possible, the central storage area may be located inside the building (on the same floor as the laboratory or place of use) but storage in the basement of a building should be avoided. Such storage areas must be equipped with mechanical ventilation. An air exchange rate of 4-6 times the volume of the room per hour is recommended. 2.2 Storage in the chemical laboratory Cabinets reserved for the storage of chemical agents must only be used to store those quantities of chemical agents required for use in the short or, in certain cases, medium-term (< 3 months). The quantities stored should be kept to a practical minimum, acting as a buffer volume to the larger quantities stored in the central storage area. 3 SEPARATION OF INCOMPATIBLE CHEMICAL AGENTS Incompatible chemical agents must be stored separately to prevent them from coming into contact with one another and causing an explosion, fire, liquid projection or the release of a toxic or harmful gas. In order to achieve this, the safety data sheet for each chemical agent should be carefully consulted, in particular part 10, Stability and Reactivity and the hazard classification, given in part 15. The procedure for the choice of storage, shown below in Figure 1, should be followed taking into account the hazard of the chemical agent. Further separation within each storage group (e.g. separation of liquids and solids) may be required. Page 2 of 10 EDMS v.6

3 Is the HCA water reactive? Store with water reactives (take steps to remove risk of contact with water) Is the HCA flammable (liquid/solid)? Store with flammables (keep liquids and solids separate. Ventilated cupboard for flammable liquids) Is the HCA an oxidizing agent? Store with Oxidizing agents (kept separate from combustible materials, in particular flammable materials) Is the HCA toxic/cmr/harmful/a sensitizing agent/an aspiration hazard? Store with Toxics (locked cupboard) Mechanical ventilation for toxic/harmful/cmr/ sensitizing agents which are volatile and toxic/ harmful by inhalation Is the HCA corrosive? Is it acidic? Is it basic? The remaining chemicals, which do not exhibit any of the hazards above, can be stored together (for chemicals which are classified as Explosive see with HSE Unit) Store with Corrosives - acids May be stored in the same cupboard but in separate retention volumes. Store with Corrosives - bases Figure 1 Procedure for the choice of storage (HCA) When a chemical agent has two or more hazards the storage place must be chosen based on the property that is considered the most hazardous for the laboratory, taking into account the chemical agent s reactivity with other chemical agents. Further separation within each storage group (e.g. separation of oxidizing acids from mineral acids) may be required. Page 3 of 10 EDMS v.6

4 The matrix below shows combinations of chemicals which may be stored together (+) or not (-). It is valid for storage rooms with a total capacity of stored chemicals of less than 1 ton or for the segregation of small quantities of chemicals stored in safety cupboards. It does not apply to explosive substances, gases, organic peroxides, self-reactive substances and radioactive substances. Copyright: Merck 3.1 Classifying mixtures Mixtures or solutions composed of two or more substances are often made-up at CERN. In this case the user must apply bridging principles, if applicable, or estimate the hazard of the mixture based on the known constituents. For more information contact HSE Unit (Jonathan.Gulley@cern.ch). Page 4 of 10 EDMS v.6

5 4 STORAGE OF FLAMMABLE AND COMBUSTIBLE LIQUIDS 4.1 Safety cabinets (internal volume less than or equal to 1 m 3 ) For storage in a chemical laboratory, or where required by the risk assessment, a special fire resistant cabinet is necessary (according to European Standard EN , 2004; see examples below). The cabinet is designed and constructed to ensure that in the event of fire, the contents of the cabinet do not contribute any additional risks or spread the fire for at least 15 minutes. Increased fire resistance is possible if required by the risk assessment with fire ratings of 30/60/90 minutes also available. When determining the appropriate cabinet fire rating for the storage of flammables having autoignition temperatures below 200 C and/or having high vapour pressures at room temperature, expert advice should be sought. The maximum quantities of flammable liquids stored in a fire resistant cabinet will depend on the outcome of the risk assessment. In general, the quantities given in Table 1 should be respected. Table 1 Recommended maxima for flammable liquid storage Classification (according to Regulation (EC) 1272/2008) Extremely flammable liquid and vapour (Flash Point < 23 C and initial boiling point 35 C) Highly flammable liquid and vapour (Flash Point < 23 C and initial boiling point > 35 C) Flammable liquid and vapour (Flash Point > 23 C and 60 C) Maximum quantities for storage in cabinet (litres) Page 5 of 10 EDMS v.6

6 The above mentioned quantities are recommended maxima representing good safe practice. Where a need to store quantities in excess of these maxima is identified, a justification of this need must be made and in particular the risk assessment should take into account: the properties of all the flammable liquids stored; the fire resistance of the storage cupboard; the ignition sources and potential fire spread in the event of an ignition; the general or local exhaust ventilation in the area; the size of the workplace and the number of people working in it; the means of escape. The maximum stored quantities of flammable and combustible liquids should not exceed those given in Table 2, below. 4.2 Metal cabinets For storage in a large hall or workshop, a special fire resistant cabinet may not be required, instead simply a cabinet or compartment constructed from a material that is non-combustible (e.g. metal). The same recommended maxima given in Table 1 above still apply. Where a need to store quantities in excess of these maxima is identified, the maximum stored quantities of flammable and combustible liquids should not exceed those given in Table 2, below. Table 2 Maxima for flammable and combustible liquid storage Classification (according to Regulation (EC) 1272/2008) Extremely flammable liquid & vapour (Flash Point <23 C and initial boiling point 35 C) Highly flammable liquid and vapour (Flash Point < 23 C and initial boiling point > 35 C) Flammable liquid and vapour (Flash Point > 23 C and 60 C) Combustible liquid (Flash Point > 60 C and 93 C) Maximum quantities for storage in cabinet (litres) Flammable liquids for use in workshops must be stored in an appropriate safety can. The old red safety cans in use at CERN may still be used provided that there is no significant damage to the can itself, or to the self-closing lid. These cans should be equipped with: a self-closing, leakproof lid; a flame arrester; pressure relief mechanism. Page 6 of 10 EDMS v.6

7 If the cans have significant damage, or are in bad condition (e.g. rusting) or if the safety devices listed above are not present or not functioning then the safety cans must be replaced with new ones (e.g. those available in the CERN stores) (SCEM : & A). The red safety cans are not authorized for the transport of flammable liquids by road. 5 VENTILATION OF CHEMICAL STORAGE CABINETS Where, because the general ventilation of an area is inadequate or due to the nature of the chemicals stored (e.g. volatile toxic, harmful or corrosive chemicals or chemicals having an unpleasant odour) a cabinet should be equipped with mechanical ventilation. The ventilation systems for different storage cabinets should be segregated (not manifolded) and should be either vented directly to the outdoors or equipped with special filters (e.g. for toxic, harmful or corrosive vapours). Alternatively the storage cabinet may be vented through an adjacent fume cupboard by direct connection to its exhaust system. Design and supply of special extraction components (e.g. filters, ATEX electrical motors) are usually available from the supplier. Some cabinets are available with a built-in fan and motor. 5.1 Ventilation of Flammable Liquid Storage Cabinets A cabinet used for the storage of flammable liquids is not required to be vented for fire protection purposes. If, for health protection purposes it is decided that the cabinet should be vented, the following measures need to be taken into account: Thermally actuated dampers, or intumescent louvers, should be fitted on the vent openings; they should be fitted with boxing and insulating materials of the same level of fire resistance as the cabinet; If venting to the outdoors, the pipework must be composed of (or boxed with) materials having the same degree of fire-resistance as the cabinet; Flame arrestors must be fitted on the air inlet and the exhaust outlet; An air exchange rate of at least 10 times the volumetric capacity of the cabinet per hour shall take place, with a pressure drop not exceeding 150 Pa. (An exchange rate of > 10 may be necessary for the reduction of smell). 6 STORAGE OF GASES Gas bottles should be stored outside. This is particularly true for bottles containing flammable or toxic gas. Nevertheless in some circumstances storage inside or at the point of use may be necessary. 6.1 Safety cabinets (internal volume not exceeding 220 l) Where required by the risk assessment safety cabinets are available for the storage of gas bottles inside a building. The cabinet is designed and constructed to ensure that in the event of fire, the contents of the cabinet do not contribute any additional risks or spread the fire for at least 15 minutes. Increased fire resistance is possible if required by the risk assessment with fire ratings of 30/60/90 minutes also available (according to European Standard EN , 2006). Page 7 of 10 EDMS v.6

8 Where, because of the nature of the gases stored, the cabinet must be equipped with mechanical ventilation, for bottles containing flammable and fire supporting gas, at least 10 air changes of the cabinet's volume per hour are required; when using toxic gas, at least 120 air changes of the cabinet's volume per hour. 6.2 Separation of incompatible gases For the particular case of gases, the procedure for the choice of storage, shown below in Figure 2, should be followed. In order to achieve this, the safety data sheet for each gas must be carefully consulted, in particular part 10, Stability and Reactivity and the hazard classification, given in part 15. Is the gas flammable? Store with flammable gases Is the gas oxidising? Store with Oxidising gases Is the gas toxic/ harmful? Store with Toxic gases Is the gas corrosive? Store with Corrosive gases Is the gas inert/gas under pressure? Store with inerts/ gases under pressure Figure 2 Procedure for the choice of storage (gases) Page 8 of 10 EDMS v.6

9 When a gas has two or more hazards the storage place must be chosen based on the property that is considered the most hazardous, taking into account the reactivity of the gas. Cylinders containing oxygen or oxidising gases should be separated from those containing flammable gases, by a minimum of six metres distance or a fire resistant partition (minimum 30 minutes flame resistance), of a height of 1.5 metres. 7 STORAGE OF FLAMMABLE AEROSOLS Aerosols must be stored separate from other chemical agents in a cool, dry, well ventilated area, sheltered from sunlight and sources of heat. 8 STORAGE OF EXPLOSIVES, SELF-REACTIVE SUBSTANCES AND MIXTURES, PYROPHORIC LIQUIDS AND SOLIDS, SELF-HEATING SUBSTANCES AND MIXTURES AND SUBSTANCES CORROSIVE TO METALS For all the above mentioned substances the chosen storage place must be given particular attention to ensure adequate segregation from incompatible chemical agents and materials. For more information contact HSE Unit (Jonathan.Gulley@cern.ch). 9 STORAGE OF LIQUIDS (RETENTION VOLUMES) Liquid chemical agents must be placed in a retention volume (e.g. SCEM : ) made of a suitable material. The retention volume requirements are given in Table 3, for indoor and outdoor storage, based on the volume of the chemical agent container. Situation Indoor storage/covered outdoor storage Table 3 Retention volume requirements Volume of chemical Retention volume required container < 250 l 100% of the largest volume. Special case for flammable liquids stored in a fire resistant cabinet: a spill containment sump shall be installed underneath the lowest storage level in the cabinet. The sump shall be designed such that liquids spilled from higher shelves are collected in the sump. The sump shall have a minimum capacity of 10% of the volume of all the containers stored in the cabinet, or at least 110% of the volume of the largest container. Page 9 of 10 EDMS v.6

10 >250 l If only one container: 100% of the volume. If several containers: 100% of the largest volume or 50% of the total volume, whichever is the greatest. Outdoor storage (uncovered) < 250 l 110% of the largest volume. >250 l If only one container: 110% of the volume. If several containers: 110% of the largest volume or 60% of the total volume, whichever is the greatest. Page 10 of 10 EDMS v.6