b) The injurious effects suffered during electric shock depend upon the path of the
current through the body. The current path will take the most direct route through the body from
the two points of contact. For this reason, any current path which involves the heart or the brain
is particularly dangerous. Therefore, keeping one hand clear of the equipment will eliminate the
possibility of a current path from arm-to-arm.
a) Soldering can be a safe process if the hazards are recognized and normal safety
precautions are observed. The hazards include heat, fire, shock, fumes, and chemicals.
(1) Heat. Since soldering is a process which requires heat, the danger of burns is
always present. Burns can be received from the primary source of heat (the torch or soldering
iron), from explosions caused by open flames, and from handling soldered metals before they
have cooled sufficiently.
(2) Fire. Closely associated with the danger of heat is the danger of fire. The
torch frequently used for general-purpose soldering presents a definite fire hazard. Fires can
result from the careless handling of flame-heated devices or their use near of flammable fumes or
(3) Fumes. Volatile fumes are an invisible hazard that may damage both
personnel and property. During the soldering operation, the danger may be decreased by
providing adequate ventilation. Combustible gases, such as acetylene or fumes from gasoline or
alcohol, present an explosion hazard. Fumes are dangerous to breathe; fumes from heated fluxes
and degreasing liquids can cause lung and skin irritations.
(4) Shock. Since electrical soldering equipment is commonly used, the possibility
of an electrical shock is present. Electrical defects in soldering equipment and associated supply
circuits may expose the technician to dangerous voltages. This hazard can be minimized by the
use of equipment in good condition.
(5) Chemicals. Chemicals which may present a health hazard are used extensively
in soldering fluxes and degreasing solutions. Non-corrosive fluxes present little problem, but the
alkalis and acids used in corrosive fluxes may cause skin irritations and burns. Danger to the
eyes also exists since many of the chemicals are in liquid solutions, and splashing or spattering
may occur. The hazard presented by chemicals is slight if proper safety precautions are
b) Many precautions are common to all types of soldering and should be observed to
prevent injury or damage to property.
(1) Do not solder electrical equipment unless it is disconnected from the power
supply. Death can result from contact with the high-voltage source being worked on.
(2) Ground all equipment to lessen the danger of electrical shock.