TOOL TYPE SAFETY TALK
GEOGRAPHY US
LAST REVIEWED 08/9/12
SOURCE: SSOL
CONFINED SPACES TRAINING:
SAFETY TALK 3: CONFINED SPACES &
FLAMMABLES
P ROBLEM
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.
H OW THE T OOL H ELPS S OLVE THE P ROBLEM
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.