Geography / US / Source: SSOL
CONFINED SPACES TRAINING:
SAFETY TALK 3: CONFINED SPACES & FLAMMABLES
Problem
The OSHA Permit Required Confined Spaces Standard requires employers to provide training to personnel involved in permit space entries, including “authorized entrants,” i.e., workers with authority to enter permit spaces.
How the Tool Helps Solve the Problem
Here’s a Safety Talk that explains one of the biggest dangers of confined space work—flammables inside confined spaces—that you can use as part of your confined spaces safety training for authorized entrants.
Confined Spaces and Flammables
Fire and explosion are among the serious hazards associated with confined spaces. When the atmosphere inside the confined space contains flammable gas, flammable liquid vapor or even dust in certain quantities, heat or a spark can set off a massive explosion.
A confined space may be defined as a place where the means of entry or exit are restricted because of location, design, construction or contents. Confined spaces are not designed for continuous human occupancy.
Flammable substances may be present in the confined space because they are being stored there. Or a tank can appear to be empty but a flammable residue may remain. Flammable substances such as gasoline can leak into confined spaces such as underground vaults or sewage tunnels. Flammable gases can even be created from processes within or near the confined space. Methane, for instance, is created from rotting organic material. Carbon monoxide can come from fuel burning engines. Flammable dusts can be organic or mineral, ranging from cornstarch to iron.
Examples of ignition sources include matches, lighters, hot work such as welding, grinding, brazing, drilling or cutting. Less obvious ignition sources are sparks from electrical equipment - including light switches. Use of ordinary power tools and flashlights in the confined space can set off a fatal fire. Even a spark created by static electricity can ignite an explosion.
Preparation for confined space entry includes testing for atmospheric hazards - by a qualified person using the right testing and monitoring equipment. Testing must take into consideration the fact that conditions can be different in various parts of the confined space as gases or vapors accumulate in recessed areas or the upper or lower regions. Conditions can also change over time.
Fires and explosions can happen in confined spaces which have an atmosphere within the explosive or flammable limits. These limits are the minimum or maximum concentrations of flammable gas or vapors between which ignition can occur. Concentrations below the lower explosive limit (LEL) or above the upper explosive limit (UEL) will not burn.
Dust particles have a lower explosive limit but almost no upper explosion limit.
When a flammable atmosphere is a concern, workers must follow proper grounding procedures to dissipate any static charge.
All sources of ignition must be avoided. Explosion-proof tools and lighting systems are available, but never rely on these to prevent an explosion: All other precautions should be taken. The area may need to be ventilated or cleaned with steam or detergent. Filling the confined space with an inert gas (which will not explode or burn) may also be carried out in certain cases. Water spray may be used to settle dust particles.
Flammable atmosphere and a confined space is a deadly combination. Only highly trained workers who are properly equipped should approach such a situation, and they should follow all possible safeguards.