18 Canadian Occupational Safety www.cos-mag.com
A
laboratory researcher
at the University of
Wisconsin-Madison
was removing a few
grams of titanium
metal powder from a
bag with a spatula when the powder
suddenly caught fi re. In an effort to
put out the fi re, the researcher doused
the fl ames with water — which caused
the fi re to intensify. He then grabbed
an ABC-rated fi re extinguisher (which
is an improper extinguishing agent in
this situation) and was able to extin-
guish the fi re due to the small amount
of burning metal.
A later investigation concluded the
fi re was likely caused by static charge
or chemical contamination of the
spatula.
Titanium, along with magnesium,
is one of the most common causes of
burning metal, or Class D, fi res. Com-
bustible metals — which also include
aluminum, lithium, potassium, zir-
conium and sodium — are used in
many warehouses and factories, as
well as laboratories. Not fl ammable
in large pieces, these metals can ignite
when a manufacturing process, such as
sanding or grinding, produces "fi nes"
(fi lings or shavings).
In the above case, the researcher,
fortunately, was wearing his personal
protective equipment (PPE) and did
not sustain any injuries. It's impor-
tant employers provide all workers
handling combustible metals with the
appropriate PPE.
John McMahon, safety offi cer with
Nova Scotia Community College in
Halifax, says selection of PPE depends
on the initial hazard assessment, when
materials used, particle sizes and
explosivity (KST test) are identifi ed.
Primarily, PPE must be fl ame resis-
tant and provide insulation against
the fl ash of the fi re.
Basic body protection consists of
coveralls, trousers and shirts, often
made of cotton treated with a fl ame-
resistant chemical, McMahon says.
With other materials, such as Nomex,
the fi re-resistance property is inherent
in the fi bre.
Above all, he adds, synthetic mate-
rials should be avoided because they
ignite easily, may melt into the skin
and tend to accumulate static electric-
ity so can become an ignition source.
Clothing should be designed not
Working with
combustible metal
requires PPE that is
resistant to fi re,
dust, static
NOT
SO
PRECIOUS
METALS
By Linda Johnson
