Welding Operations
Metal welding is a fabrication process whereby two or more parts are fused together by means of heat forming a joint as the parts cool. Multiple industrial and manufacturing facilities regularly use a variety of welding processes and materials. Welding operations can create emissions of highly toxic heavy metals including lead, hexavalent chromium, copper, nickel and cadmium. These toxic pollutants can cause adverse health effects, including cancer.
APCD Rule 11, which lists exemptions from permitting requirements, has an exemption for welding operations that do not create elevated health risks. Due to the potential health risks created by welding operations, the APCD established a process to evaluate welding operations in San Diego County.
Public Meeting
The District held a public meeting on April 20, 2022 to discuss potential health risks from welding operations, methodologies to calculate emissions and health risks, and existing permitting requirements.
Welding Operations Map
The map below shows locations of facilities where welding operations are conducted. (Full Screen Map) (download map data)
Compliance Advisory, Methodologies, and Tools
Welding Operations-APCD Information Request & Advisory (Word Doc)
Emissions Calculation Procedures
Welding
Permit Screening Tool (open tool in Microsoft Excel or Google
Sheets for proper functionality)
MIG – GAS METAL ARC WELDING (GMAW)
MIG welding is used in the automotive industry for repairing
vehicle exhausts and in creating homes and buildings. It is one of the
most common types of welding. This is a type of arc welding that uses
a continuous wire called an electrode. This operation utilizes a
shielding gas that travels through the welding gun and protects
against contamination.
TIG – GAS TUNGSTEN ARC WELDING (GTAW)
TIG welding also uses electric arc like MIG. TIG welding uses
an electrode made of tungsten. Tungsten is one of the toughest metal
materials and it will not dissolve or burn off. Welding can be done
through a process known as fusion which might use a filler metal. TIG
also uses an external gas supply, such as argon or helium. Aerospace
and automotive operations also use TIG welding as well as other
industrial operations.
STICK – SHIELDED METAL ARC WELDING (SMAW)
Stick welding can be portable. Stick welding is used in
construction, maintenance and repair, underwater pipelines, and
industrial fabrication. For this type of welding a shielded metal arc
welding (or more commonly known as stick welding) is used. A
consumable and protected electrode, or stick is also used. The stick
softens and combines metals by heating with an arc between a covered
metal electrode and the base metal workpiece. As the stick melts, its
protective cover also melts and shields the weld area from oxygen and
other gases that may be in the air.
FLUX-CORED – FLUX-CORED ARC WELDING (FCAW)
Flux-cored arc welding is similar to MIG welding because both
use continuous wire and power supplies. A continuous electrode is
combined with a base metal. The electrode is a hollow tube filled with
flux that is fed through the weld gun and into the weld pool. When
welding outdoors, a flux shield offers protection against weather
elements. This type of welding is used for welding thicker metals and
is used in machining industries.