Flammable substances, working

Use of, or work with, highly flammable substances Working directly overhead building occupants Maintenance of live electrical systems... 

Bunsen burners. These are of very limited use, as most reactions require flammable substances. Their purpose is mainly for gkss work, generating and super heating steam (see work bench diagram for safe usage). 

Perform all work with substances that are poisonous or have an unpleasant odour, and also the evaporation of acids and acidic solutions only in a fume cupboard work far from a flame with flammable substances. 

Flammable substances used and stored in the laboratory are also subject to further risk assessment and control in UK law under the the Health and Safety at Work Act 1974, the Management of Health and Safety at Work Regulations 1999, the COSHH Regulations 2002, the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR), and the Regulatory Reform (Fire Safety) Order 2005. 

Extinguish all naked flames when working with flammable substances. 

The hood offers a number of advantages for work with toxic and flammable substances. Not only does it draw off the toxic and flammable fumes, it also affords an excellent physical barrier on all four sides of a reacting system when the sash is pulled down. And should a chemical spill occur, it is nicely contained within the hood. 

It should be noted, however, that tabulations of properties of flammable substances are based on standard test methods, which may have very different conditions from those encountered in practical laboratory use. Large safety factors should be applied. For example, the published flammability limits of vapors are for uniform mixtures with air. In a real situation, local concentrations that are much higher than the average may exist. Thus, it is good practice to set the maximum allowable concentration for safe working conditions at some fraction of the tabulated LEL 20% is a commonly accepted value. 

Handle flammable substances only in areas Ifee of ignition sources. Besides open flames, ignition sources include electrical equipment (especially motors), static electricity, and, for some materials (e.g., carbon disulfide), even hot surfaces. Check the work area for flames or ignition sources before using a flammable substance. Before igniting a flame, check for the presence of a flammable substance. 

Commercial acrolein contains an inhibitor such as hydroquinone samples from which the inhibitor has been removed (e.g., by distillation) are extremely hazardous. Because of its corrosivity, flammability, and high acute toxicity, acrolein should be handled using the "basic prudent practices" of (Chapter 5.C, supplemented by the additional precautions for work with compounds of high toxicity (Chapter 5.D) and extremely flammable substances (Chapter 5.F). In particular, work with acrolein should be conducted in a fume hood to prevent exposure by inhalation, and splash goggles and butyl rubber gloves should be worn at all times to prevent eye and skin contact. Acrolein should be used only in areas free of ignition sources. Containers of acrolein should be stored in secondary containers in areas separate from amines, oxidizers, acids, and bases. 

Storage and Handling ferf-Butyl hydroperoxide should be handled in the laboratory using the "basic prudent practices" described in Chapter 5.C supplemented by the additional precautions for work with reactive and explosive substances (Chapter 5.G). In particular, terf-butyl hydroperoxide should be stored in the dark at room temperature (do not refrigerate) separately from oxidizable compounds, flammable substances, and acids. Reactions involving this substance should be carried out behind a safety shield. 

A first aider is someone who has undergone a training course to administer first aid at work and holds a current first aid certificate. The lowest temperature at which sufficient vapour is given off from a flammable substance to form an explosive gas-air mixture is called the flashpoint. 

Many highly flammable substances are used at work and in spite of their flammable nature can be used quite safely if certain precautions are taken. 

Many tools generate hot surfaces in their use, others use heat for their operation and some give off incandescent particles in their operation. In circumstances where a flammable substance may be present, the use of such tools must be controlled. For burning, welding and grinding, the area in which the work has to be done should be clearly defined and surrounded by a non-flammable curtain, all flammable debris should be removed and standby firemen should be at the ready. When soldering irons are used insulated rests should be available and used. 

If demolition or refurbishment is to be undertaken, then hazards associated with structural collapse, fire, working at height, lifting and carrying and electricity must be considered together with health hazards from lead, asbestos, vermin and insects. As mentioned in Chapter 10, a structural survey before work commenced should reduce the risk of unintentional structural collapse. The issue of hot work permits, provision of fire-fighting equipment and suitable storage facilities for flammable substances should control the fire risk. Health risks can be controlled, for example, by the use of licensed contractors for the removal of asbestos, specialist contractors to eradicate vermin and the provision of suitable personal protective equipment. 

The monitoring and management of contractors is aiso required at a high ievei particuiariy when works invoke high risk processes such as the use of flammable substances or where works are undertaken on access and egress routes. 

While the industry is attempting to reduce the use of flammable substances as a matter of overall risk management many proprietary substances used in the work cannot be substituted. 

Various techniques can be employed to ensure that flammable substances are managed effectively including purging or inerting the system prior to undertaking operations. Ensuring that residues are removed and that any supply system has been isolated from both power sources and process materials must also be undertaken as part of the systems of work and the PTW. 

Heat flammable substances in steam, water, oil, hot air baths, or heating mantle. Restrict the amount of stored flammables, and minimize the amount of flammables present in a work area. 

---