Explosive Atmospheres Regulations

The dangerous substances and Explosive Atmospheres Regulations 2002 (DSEAR) require risks from the indoor storage of dangerous substances to be controlled by elimination or by reducing the quantities of such substances in the workplace to a minimum and providing mitigation to protect against foreseeable incidents. Because the vapors of flammable liquids ignite and burn easily, strict storage requirements are essential.

There are two primary hazards associated with flammable and combustible liquids: explosion and fire. In order to prevent these hazards, this standard addresses the primary concerns of: design and construction, ventilation, ignition sources, and storage.

It is recognized that for practical purposes where flammable liquids are used, there is likely to be a need for a limited quantity to be stored in the workroom/working area. It is the responsibility of the employer / duty holder when carrying out their risk assessment required under DSEAR Regulation 5, to justify the need to store any particular quantity of flammable liquid within a workroom/working area. However, the guiding principle is that only the minimum quantity needed for frequently occurring activities or that required for use during half a day or one shift should be present in the workroom/working area. Clearly actual quantities will depend on the work activity and also the organizational

arrangements for controlling the fire risks in the workroom/working area

When surveying a workplace and storage options it is important to document and label the containers of flammable or combustible materials on shelves, on countertops, and on top of flammable and combustible material storage cabinets.

Ensure to the storage cabinets is to standard and in good condition, ensure the cabinets need repainted if needed, and have items secured to the cabinet doors through the metal. While these situations appear quite frequently in the workplace, these hazardous practices should be discontinued immediately to prevent employees from being exposed to greater

danger.

According to OSHA/VOSH 29 CFR 1910.106, flammable and combustible liquids are to be stored in approved containers. Additionally, the flammable and combustible storage containers should be constructed according to specifications outlined by OSHA/VOSH, DOT, and National Fire Protection Agency (NFPA), or American National Standards Institute (ANSI). All storage containers, cabinets, and rooms should have warning labels identifying the flammability hazard and should identify the area as a “NO SMOKING” area. Work activities that could potentially create sparks should also be prohibited in these storage areas.

Flammable liquids are identified as liquids that have a flashpoint (minimum temperature needed for the liquid to produce a vapor with enough of a concentration to ignite) below 100 degrees Fahrenheit (F). There is an exception to this definition. If any of the components of the mixture have flashpoints of 100 deg. F or higher, then the material is classified as combustible rather than flammable. Another way to identify flammable liquids is by class. It is important to remember that with flammable liquids that it is the vapor coming off of the liquid that will ignite and burn, not necessarily the liquid itself.

Class IA liquids have flashpoints below 73 degrees F and boiling points below 100 degrees F,
Class IB liquids have flashpoints below 73 degrees F and boiling points at or above 100 degrees F, and Class IC liquids have flashpoints at or above 73 degrees F and below 100 degrees F. Examples include alcohols, acetone, gasoline, solvents, paint thinners, wood stains and spray paints.

It should be mentioned that flash point was selected as the basis for classification of flammable and combustible liquids because it is directly related to a liquid's ability to generate vapor, i.e., its volatility. Since it is the vapor of the liquid, not the liquid itself that burns, vapor generation becomes the primary factor in determining the fire hazard. The expression "low flash/high hazard" applies. Liquids having flash points below ambient storage temperatures generally display a rapid rate of flame spread over the surface of the liquid, since it is not necessary for the heat of the fire to expend its energy in heating the liquid to generate more vapor.