FLAMMABLE LABORATORY MATERIALS AND ITS HANDLING

¨     Chemicals and hazardous substances that can easily ignite and burn rapidly

¨     It may be in any form – solids, gases and liquids.

¨     Liquids and gases acts as combustible materials.

¨     Solids may catch fire when it is nearby with heat, heat acts as an ignition sources.

¨     Oxygen is an important requisite to ignite flame

¨     Flammable gases such as carbon monoxide and hydrogen sulphide are toxic at very low concentrations.

¨     Most vapours from flammable liquids are heavier than air and will accumulate near the ground. They can displace the air. When there is not enough air or oxygen, there is a hazard of asphyxiation (suffocation).

¨     Autoignition temperature – the flammable material which ignite on its own at a lowest temperature.

¨     Flashpoint — The lowest temperature at which a flammable or combustible liquid gives off enough vapour to form an ignitable mixture with air, since it is the vapour, not the liquid, which burns.

o   The lower the value, the more easily the material will burn.

o   Hot combustible liquids can generate as much flammable vapour as cold flammable liquids

¨      

Solids – plastics, cotton, papers, coal, potassium, sodium, phosphorous, gun powders and especially match sticks.

Gases - methane, propane, butane, acetylene, carbon monoxide, hydrogen sulphide. Flammable gases are usually gases with a lower explosive limit of less than 13 percent in air, or have a flammable range in air of at least 12 percent.

Liquids - acetone, alcohols and toluene, paints and paint thinners, adhesives, degreasers, cleaners, waxes and polishes.

 

Handling and work procedures

Key factors for working with flammable materials include

storage

·       dispensing

·       spill clean up

·       incompatible materials

·       use and maintenance of engineering controls used in the workplace (such as ventilation)

·       required personal protective equipment for handling flammable products

·       fire protection and prevention

·       special circumstances (e.g. confined spaces, hot work) which may require additional precautions and training.

Storage of flammable products

¨     It should never be stored near - exits, electrical equipment or heating equipment

¨     Storage must be separate, well-ventilated storage area, away from potential sources of ignition.

¨     Storage containers must be - made of metal or plastic, are vapour-proof and have:

o   welded seams,

o   spark or flame arrestors,

o   pressure release valves or spring closing lids with spout covers.

¨     Containers must be labelled with contents, flammable, away from ignition sources, kept closed in unusable conditions, date of manufacturing and expiry.

¨     Do not store compressed gases beside flammable material containers.

¨     Bulk storage areas should be equipped with spill protection.

¨     Bulk storage areas and rooms must have appropriate signage or placarding with proper ventilation.

¨     Smoking should never be allowed near flammable material storage areas.

¨     Flammable gases stored in cylinders must be stored separately in a well ventilated room.

¨     Storing oxygen cylinders near flammable gas cylinders must be avoided.

Handling of flammable materials

To prevent fires, flammable materials must be properly managed in the workplace. There are three main ways to prevent fires:

(1)  Limit the amounts of flammable and combustible materials, keep only what you need on-site, do not let hazardous wastes accumulate at the work site, Store products, including wastes, used at the work site in proper containers and keep flammable materials separate from other processes and storage areas.

(2)  Provide proper ventilation to ensure flammable vapours do not accumulate, ensure that processes that use or make flammable materials do not exhaust back in the work site.

(3)  Control ignition sources - Ground and bond all work and ignition-proof equipment, no smoking in work areas, never store flammable materials near hot equipment or open flames and use intrinsically safe and non-sparking tools. Also create an Inert atmosphere to prevent firing.

Use personnel protective equipment