Apartats
Handling of corrosive or irritating liquids
Particularly important in this case is the action on the tissues (chemical burns), and, in certain circumstances, the production and action of vapors.
Containers and transfers
Containers of corrosive liquids should not be larger than 2 liters, or have protection for the container, in the case of glass.- Small bottles should be transported with a bucket, pail or special basket, instead of holding them by the neck or hugging them. On the market there are also some glass bottles of chemical products with a handle; this handle is used to facilitate the transfer, not to be used for the transport of the bottle. When bottles or containers exceed a capacity of 5 liters, they must be transported in carts, never by hand.
Particularly hazardous products must be placed in metal containers filled with untreatable absorbent materials and of a size that can retain all the liquid in the event of breakage of the container.- In the case of transfers, special attention must be paid to the protection of hands and face, since small quantities of some corrosive products are sufficient to cause burns to the teeth and very painful effects if they come into contact with small wounds or cuts. Likewise, even the smallest projection on the eyes is enough to produce effects that may be irreversible. On the other hand, the instinctive reaction that provokes these types of accidents will cause the fall of recipients, multiplying the aggressive effect on the tissues. Therefore, even in the case of small amounts of water being transferred, the use of safety gloves and goggles is essential. If the quantities are larger, additional protection, such as face shields, special aprons or boots, must be used.
- Containers with a capacity of 10 to 20 liters from which transfers must be made must be accompanied by systems that facilitate tilting. If portable pumps are required, care should be taken to ensure that their construction materials are unassailable.
Manipulation in laboratory techniques
Tècniques habituals de laboratori:
- Protection against possible contact and projections: Use of gloves and safety glasses against splashes and projections.
- Manipulació sota campana de gasos sempre que sigui possible. Inescapable when the reagent emits vapors or when vapors may be given off in reactions, heating, etc.
- Cleaning of glass material:
- These tasks must be carried out under a hood due to the possible release of toxic fumes.
- The containers containing chromic mixture must be permanently in the extraction cabinet and conveniently closed, not only because of the possible release of vapors, but also because of the risk of keeping them continuously on the work surfaces or near the washing piles.
- Handling of very aggressive agents, such as perchloric acid or thionyl chloride:
Handling of these types of products must be carried out with the appropriate personal protective equipment, including face shield, retention buckets and always under a fume cabinet. It should be known that instantaneous exposure to agents such as thionyl chloride is sufficient to cause severe irritation of the upper respiratory tract. - Spill collection:
Any spill must be collected with absorbent products, and for acids or bases with specific neutralizing products if available.
Other hazardous liquid products
Such as perchloric acid at 50%, sulfonitric mixture or hydrogen peroxide.
In these cases, instability, combustibility and incompatibilities require specific preventive measures to prevent risks during handling.
Handling of toxic liquids
Whenever possible, and, inevitably, whenever vapors can be generated, either by the vapor pressure of the substances or by the processes to which they are subjected, work must be carried out under fume hoods.
- Some of the chemical products classified as toxic can penetrate the organism through the skin, so that handling should always be carried out with suitable gloves (according to the resistance of the gloves to each type of chemical product).
- The use of safety glasses to avoid possible projections is also mandatory.
- It is essential to have the safety data sheets of all the products present in the laboratory, but it is especially important in this case, in order to be informed about the procedures to be followed in case of accidental ingestion or contact.
Specific case of mercury
According to some studies, laboratories where mercury is handled and where there is no demanding work procedure, present contamination levels that generally are above acceptable environmental hygiene levels. The operations usually carried out with this metal are weighing, transferring, distillation and washing processes, not to mention the accidental breakage of thermometers and pressure gauges. These manipulations involve, in addition to the emission of mercury vapors into the environment, the loss through spillage of quantities of metal that, although discrete, have the capacity to contaminate the environment through the formation of droplets that remain in joints, holes, etc.
- The control of mercury vapors will be carried out by performing all manipulations always under extraction hoods.
- Spill control will be carried out by handling the metal always on plastic trays.
- The collection of spills must be carried out with the appropriate products.
- It is advisable to replace the classic mercury thermometers with digital thermometers. (This preventive measure is especially important in training laboratories).
Handling of flammable liquids
- The handling of flammable chemical products must always be carried out in an extraction cabin, specially designed for working with flammables, or the work must be carried out in a laboratory specially designed for this type of handling.
- It is especially important that the work area is ventilated to avoid exposure to fumes and the possibility of accidentally generating a flammable or explosive atmosphere.
- If the quantities of products to be handled are discrete, it will work under glass, which, in addition to the general characteristics, it is advisable that it meets the following conditions:
- Increased security electrical installation
- Conduction made with materials resistant to fire and with an equally resistant structure.
- Explosion-proof assembled extractor motor located outside the extraction duct
- Inside the display case, as it is logical, there can be no devices that could constitute a focus of ignition.
- It is also recommended that the booth be equipped with automatic sprinklers, to effectively cut off a possible fire, or have a suitable extinguisher close to the handling area.
Containers and transfers
Safety containers for containing flammable liquids must be made of metal and designed in such a way that a possible fire generated on the outside cannot be transmitted to the inside of the container.- Small bottles should be transported with a bucket, pail or special basket, instead of holding them by the neck or hugging them. On the market there are also some glass bottles of chemical products with a handle; this handle is used to facilitate the transfer, not to be used for the transport of the bottle. When bottles or containers exceed a capacity of 5 liters, they must be transported in carts, never by hand.
- The tasks of transferring flammables require special conditions to avoid the risk of fire. If the quantities to be transferred are discrete, the vitrine is the ideal place to carry out the task. If the quantities to be transferred are large, a specific location must be provided, which must have adequate ventilation and, preferably, extraction located in the operating area.
- If pumps are required, manual pneumatic pumps are preferable to electric pumps. In any case, the electric pumps should be explosion-proof.
- In order to avoid electrostatic discharges, a perfect equipotential bonding is required between the emptying recipient and the receiving recipient, and also between the receiving recipient and the metallic elements of the pumping equipment if it is used.
Spill collection
- Any spill of flammable liquid must be collected, either with inert materials such as sand or vermiculite, or with a universal absorbent, always bearing in mind that the solid waste will be highly flammable.
- In the event of a major spill, the action plan must include the elimination of possible ignition sources. The interruption of the electrical systems is the quickest procedure, as well as turning off the possible flames of the laboratory igniter, and cutting off the gas supply.
- It should be borne in mind that flammable solvent vapors, at ambient temperature, are denser than air and can travel relatively long distances and even to lower levels.