100-00-16
General Information
100-00-16
DESCRIPTION AND OPERATION (
CONTINUED
)
E850 EN
02/2001 2002 Bantam
Viton is a fluoroelastomer that is a synthetic rubber
type, which contains Fluorine. It is commonly used for
O-rings, gaskets and seals of all types. Although Viton
is the most well known fluoroelastomer, there are
others, including Fluorel and Tecmoflon.
When used under design conditions fluoroelastomers
are perfectly safe. If, however, they are exposed to
temperatures in excess of 400°C, the material will not
burn, but will decompose, and one of the products
formed is hydrofluoric acid.
This acid is extremely corrosive and may be absorbed
directly, through contact, into the general body
system.
O-rings, seals or gaskets which have been exposed to
very high temperatures will appear charred or as a
black sticky substance.
DO NOT; under any circumstances touch them or the
attached components.
Enquiries should be made to determine whether Viton
or any other fluoroelastomer has been used in the
affected O-ring, seal or gasket. If they are of natural
rubber or nitrile there is no hazard. If in doubt, be
cautious, as the material may be Viton or any
fluoroelastomer.
If Viton or any other fluoroelastomers have been used,
the affected area should be decontaminated before
the commencement of work.
Disposable heavy duty plastic gloves should be worn
at all times, and the affected area washed down using
wire wool and a limewater (calcium hydroxide) solution
to neutralise the acid before disposing of the
decomposed Viton residue and final cleaning of the
area. After use, the plastic gloves should be discarded
carefully and safely.
Welding
See also Fire, Electric Shock, Gas Cylinders.
Welding processes include Resistance Welding (Spot
Welding), Arc Welding and Gas Welding.
Resistance Welding
This process may cause particles of molten metal to
be emitted at a high velocity, and the eyes and skin
must be protected.
Arc Welding
This process emits a high level of ultra-violet radiation,
which may cause arc-eye, and skin burns to the
operator and to other persons nearby. Gas-shielded
welding processes are particularly hazardous in this
respect. Personal protection must be worn, and
screens used to shield other people.
CONTACT LENS WEARERS ARE ADVISED TO
REVERT TO ORDINARY SPECTACLES WHEN ARC
WELDING as the arc spectrum is believed to emit
microwaves which dry out the fluid between the lens
and the eye. This may result in blindness when the
lens is removed from the eye.
Metal spatter will also occur, and appropriate eye and
skin protection is necessary.
The heat of the welding arc will produce fumes and
gases from the metals being welded, the rods and
from any applied coatings or contamination on the
surfaces being worked on. These gases and fumes
may be toxic and inhalation of these should be
avoided. The use of extraction ventilation to remove
the fumes from the working area may be necessary
particularly in cases where the general ventilation is
poor, or where considerable welding work is
anticipated. In extreme cases or confined spaces
where adequate ventilation cannot be provided, air-fed
respirators may be necessary.
Gas Welding (and Cutting)
Oxy-acetylene torches may be used for welding and
cutting, and special care must be taken to prevent
leakage of these gases, with consequent risk of fire
and explosion.
The process will produce metal spatter and eye and
skin protection is necessary.
The flame is bright, and eye protection should be
used, but the ultra-violet emission is much less than
that from arc welding, and lighter filters may be used.
The process itself produces few toxic fumes, but such
fumes and gases may be produced from coatings on
the work, particularly during cutting away of damaged
body parts, and inhalation of the fumes should be
avoided.
In brazing, toxic fumes may be produced from the
metals in the brazing rod, and a severe hazard may
arise if brazing rods containing cadmium are used. In
this event particular care must be taken to avoid
inhalation of fumes and expert advice may be
required.
SPECIAL PRECAUTIONS MUST BE TAKEN
BEFORE ANY WELDING OR CUTTING TAKES
PLACE ON VESSELS, WHICH HAVE CONTAINED
COMBUSTIBLE MATERIALS, FOR EXAMPLE
BOILING OR STEAMING OUT OF FUEL TANKS.
