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Working safely with solvents鈥�
Exposure to solvents can affect your health in many ways. In some circumstances, the effect can be very serious, therefore you must control the risks from exposure to potentially harmful solvents.
Within 最准的六合彩论坛 there is聽a large range of solvents used as standard聽and even more chemicals that are used as experimental solvents.
Types of solvents
- Organic solvents聽(containing carbon)聽
- Hydrocarbon solvents聽are aliphatic and aromatic, such as benzene or petrol
- Oxygenated solvents聽such as alcohols, ketones鈥�, aldehydes, esters, glycol etheres, etc
- Halogenated solvents聽such as dichloromethane聽鈥�(Chlorinated and brominated hydrocarbons)
- 鈥婭norganic non-aqueous solvents聽
These are聽solvents other than water, that are聽not organic compounds. Common聽examples are liquid ammonia, liquid sulphur dioxide, phosphoryl chloride and pure sulphuric聽acid. Water聽is聽classed as an inorganic solvent as its chemical structure does not contain carbon.鈥�
Hazards relating to solvents
No matter what the solvent is, it is important to remember to assess the hazards associated with the chosen solvent, as well as those associated with the other chemicals involved in the experiment.
- Health risks from solvents
Solvents may enter the body through inhalation or through the skin.聽 Due to their low聽vapour pressure, the health risks they pose can be realised easily.
Use the solvent Safety Data Sheet as guidance for聽hazards, storage, use and waste.鈥�
- Physical risks
Although these chemicals are used for their properties as solvents, it must not be forgotten聽that they are hazardous chemical in their own right and can react violently when mixed with other聽chemicals聽including other solvents.
Due to this聽solvent waste must be separated from other waste聽and in separate聽solvent waste streams, for example, Chlorinated and Non-chlorinated waste.
- Examples of hazards
- Flammable -聽Most organic solvents鈥�
- Explosive -聽Nitromethane, ether residue (peroxide formation)鈥�
- Narcotic -聽Ether, chloroform鈥�
- Carcinogenic -聽Dichloromethane, benzene鈥�
- Mutagenic -聽teratogenic Toluene, ethanol鈥�
- Toxic -聽Methanol, carbon聽disulfide鈥�
- Chronic conditions -聽such as contact dermatitis and workplace asthma鈥�
- Acute conditions -聽such as irritation of the skin, eyes and lungs, headaches, nausea and dizziness.鈥�
Exposure limits
A major risk of solvent use is its volatility (low boiling point) causing flammable or toxic vapour.鈥�
Some general information on solvent properties聽demonstrates that possibility.鈥�
鈥婽he exposure limits are the maximum amount you may legallly be exposed to in an聽8 hour period (long-term聽limit), or in a 15-minute聽period (short-term limit).鈥�
The explosive limit is the percentage of vapour that will generate a flammable mixture with air. When聽working with small small volumes and in a fume cupboard or with an LEV this is not relevant. Outside聽an聽LEV/fume cupboard or on a large scale聽a Dangerous Substance and Explosive Atmosphere Regulations (DSEAR) risk assessment may be required.鈥�
- View common solvent chemical聽limits
Solvent Melting point oC Boiling Point oC Flash Point oC Explosive limits %GHS label Exposure limits short term/long term鈥� Acetone聽 -94.7 56.1 -20.7 2.6-12.8 Flammable Irritant 500 ppm/ 1500 ppm鈥� Acetic acid 16 118 40 Apr-16 Flammable Corrosive Acetic anhydride -73.1 139.8 49 2.7-10.3 Flammable Irritant Corrosive Acetonitrile -46 81 2 4.4-16.0 Flammable Irritant Butanol -89.8 117.7 35 1.45-11.25 Flammable Corrosive Irritant t-Butanol 25 82 11 2.4-8.0 Flammable Irritant Benzene 5.5 80.1 -11.6 1.2-7.8 Flammable Irritant Health Hazard 1 ppm/ Carcinogenic鈥� Chloroform -63.5 61.2 non-flammable Irritant Health Hazard 2 ppm/ Absorbed through skin鈥� Cyclohexane 6.5 80.7 -20 1.3-8 Flamm. Irritant Environ. Hazard Dichloromethane -96.7 39.6 above 100 Irritant Health Hazard 100 ppm/ unknown鈥� Diethyl ether -116.3 34.6 -45 1.9-48.0 Flammable Irritant DMF -60.5 152 58 2.2-15.2 Flammable Irritant Health Hazard DMSO 19 189 89 2.6-42 Flammable Irritant Health Hazard Ethyl acetate -83.6 77.1 -4 2.0-11.5 Flammable Irritant Ethanol -114.1 78.2 16.6 3.3-19 Flammable Irritant Hexane -96 68.5 -26 1.2-7.4 Flamm. Irritant Health/Environ. Hazard20 ppm/ not reported鈥� Isopropanol -89 82.6 11.7 2.2- % Flammable Irritant Methanol -97.6 64.7 11 6.7-36.0 Flammable Health Hazard Toxic Pentane -130.5 35.9 -49 1.4-7.8 Flamm. Irritant Health/Environ. Hazard600 ppm/ not reported鈥� THF -108.4 66 -14 2.0- Flammable Irritant Health Hazard Toluene -95 111 6 1.2-7.1 Flammable Irritant Health Hazard Xylene -47.4 138.5 30 1.1-6.6 Flammable Irritant Health Hazard
鈥婫ood Practice鈥�
- Eliminate聽 -聽Substitute hazardous solvents with less toxic or hazardous solvents Carry out a risk assessment聽before using any solvent for the first time and show why that solvent is the best to use both for safety and for聽the experiment.聽鈥�
- Minimise -聽Solvents evaporate quickly, so lids should be properly replaced聽on storage vessels / Winchesters immediately after use.聽 Do not decant in open-top vessels, and when designing聽the experiment, minimise the risk of evaporation of the solvent as far as聽reasonably聽practicable. This includes solvent-based products, including paints, and cleaning substances.鈥�
- Always have good ventilation -聽For some聽substances, the odour threshold exceeds legal exposure limits.聽Therefore, if you can smell chloroform, benzene, carbon tetrachloride and dichloromethane, you may be聽overexposed. Always check to see if the solvent has defined workplace exposure limits (WELs). When聽working with solvents, know whether the solvent readily forms a hazardous vapour. The risks may require that聽there is good ventilation or a requirement for forced ventilation.鈥�
- PPE - This is only to be used in addition to all the other control measures. If reusable PPE is chosen such as聽RPE with filters, a documented procedure on how RPE is stored and needs to be available and followed鈥�.聽
Waste solvents鈥�
鈥婭t is necessary for solvent waste to be classified either according to their own properties or by聽the chemical that they have been used in conjunction with.鈥�
Each work area needs to plan for the removal of waste before generating it, and reassess the requirements聽when a new project is started in the work area.
The most common聽solvent is water, but as with most solvents, after it has been used in an experiment it will be contaminated with the reactants / products from the experiment and will聽need to be either 鈥渃leaned鈥� or sent to the correct waste stream.
All labs / departments should have a waste management plan which will require a section for solvents.
The following information is required:聽
- The types of solvents used in the laboratory that may produce聽waste鈥�
- The processes and operations that may produce waste聽solvents.鈥�
- The types of waste solvents produced (e.g. contamination).鈥�
- Any specific hazards associated with waste聽solvents.鈥�
- The quantities of waste solvents generated.
It should be noted that if a laboratory produces or聽holds 500 kilograms or more of hazardous waste in any 12-month period, it must register the聽laboratory with the .鈥�
- 鈥婻isk groups when dealing with waste solvents
When dealing with waste solvents, as well as the risk to the users and others in the work聽area, the following risk groups聽have to聽be taken into account.鈥�
- The聽environment - staff聽(porters / contractors) involved in the removal of waste from the work area鈥�
- The waste carrier聽鈥嬧��
- Management of waste solvents
Once the manager for the work area has the above information, a聽waste聽management plan for the solvents聽can be written.
This will depend on the information from the first section聽but will cover;鈥�
- Waste Segregation聽- Is waste separated聽into appropriate categories? Are staff members made聽aware of segregation requirements and arrangements?鈥�
- 颁辞苍迟补颈苍别谤蝉听-聽Are appropriate receptacles used for the storage? Are the containers sensibly聽located and suitably labelled?鈥�
- Waste Handling聽-聽Are hazardous waste solvents handled in a safe manner with due attention to聽any associated hazard? Are contractors handling waste informed of the dangers?鈥�
- Storage Areas聽-聽How and where are the waste solvents stored? How long are solvents stored聽prior to transport and disposal?鈥�
- 笔谤辞肠别诲耻谤别蝉听- 聽How do we meet our duty of care under environmental legislation? What聽emergency procedures are in place in the event of an unwanted incident?鈥�
- 厂补蹿别迟测听- Are employees made aware of the hazards of the waste solvents? Are adequate safety聽equipment and systems provided?鈥�
Last updated: Tuesday, May 11, 2021
