Safety in Welding, Cutting, and Allied Processes

ANSI Z49.1:1999
space operations, local exhaust mechanical ventilation and,
when required, respiratory protection shall be used (see
also Section 7).
5.5.1.2 Adjacent Persons. All persons in the immediate
vicinity of welding or cutting operations involving
the materials listed in 5.5.1, shall be similarly protected.
5.5.2 Fluorine Compounds. In confined spaces, when
welding or cutting operations involve fluxes, coatings, or
other materials that contain fluorine compounds, local
exhaust mechanical ventilation or respiratory protection
shall be provided.
5.5.3 Zinc or Copper. Welding or cutting operations
involving consumables, base metals, or coatings containing
zinc or copper shall be done as described in 5.5.2 for
fluorine compounds.
E5.5.2 Fumes and gases from fluorine compounds can
be dangerous to health and can burn eyes and skin on contact.
See 9.6 for labeling of brazing and gas welding fluxes
containing fluorides.
In open spaces, when welding or cutting involves
materials containing fluorine compounds, the need for local
exhaust ventilation or respiratory protection will depend
upon the individual circumstances. However, experience
has shown that such protection is desirable for fixed
location production welding and for all production welding
on stainless steels. Such protection is not necessary
when air samples taken in breathing zones indicate that
the fluorides liberated are below allowable limits.
E5.5.3 Fumes containing zinc or copper compounds
may produce symptoms of nausea, dizziness, or fever,
sometimes called metal fume fever.
5.5.4 Cleaning Compounds. When using cleaning
compounds prior to welding, manufacturers instructions
shall be followed.
5.5.4.1 Chlorinated Hydrocarbons. Degreasing or
cleaning operations involving chlorinated hydrocarbons
shall be so located that vapors from these operations will
not reach or be drawn into the atmosphere surrounding
molten weld metal or the arc.
In addition, these materials shall be kept out of atmospheres
penetrated by the ultraviolet radiation of arc welding
operations.
5.5.5 Arc and Gas Cutting. Oxygen cutting using
either a chemical flux or iron powder, gas-shielded arc
cutting, or plasma cutting shall be done using local mechanical
ventilation or other means adequate to remove
the fumes generated.
5.5.6 Brazing Furnaces. In all cases, adequate mechanical
ventilation shall be provided to remove all explosive
or toxic gases which may emanate from furnace
purging and brazing operations.
5.5.7 Asbestos. Where welding or cutting is to be done
on surfaces that are covered by asbestos insulation, the
regulations of the authority having jurisdiction shall be
consulted before beginning the work.
E5.5.4.1 A reaction product having a characteristic
objectionable, irritating odor, and including highly toxic
phosgene gas is produced when such vapors enter the atmosphere
of arc welding operations. Low levels of exposure
can produce feeling of nausea, dizziness, and malaise.
Heavy exposures may produce serious health impairments.
E5.5.5 Use of water tables, water curtains, underwater
cutting, ventilation or combination of these will depend
upon the individual circumstances. Experience has shown
that such protection is desirable for fixed location production
welding and for all production welding on stainless
steels. Such protection is not necessary when air samples
taken in breathing zones indicate that the materials liberated
are below allowable limits.
E5.5.6 Where complete combustion takes place in or
at the furnace during the heating cycle, the ventilation requirement
may diminish.
E5.5.7 Protection of the employees in the area may require
training, respiratory protection, wetting down the
asbestos, and use of special protective clothing in addition
to special ventilation. See also OSHA asbestos standards.
13