Welding activities: guide to reporting

This page outlines the steps that facilities with welding activities should follow to report to the National Pollutant Release Inventory (NPRI).

Background information

The main NPRI substances used in the welding process are Part 1A metals (for example, Cr3+, Co, Mn, Ni) and Part 1B metals (for example, hexavalent chromium (Cr6+), lead). Part 4 substances – Criteria Air Contaminants (CACs) – are also released during the welding process. The main CACs of concern are total particulate matter (TPM), particulate matter less than or equal to 10 microns in diameter (PM10), and particulate matter less than or equal to 2.5 microns in diameter (PM2.5).  

You need to consider the NPRI substances associated with welding activities occurring at your facility when you perform threshold calculations.

In order to correctly perform threshold calculations for welding activities, you need to understand the term "article".

  • An "article" is defined as a manufactured item that does not release an NPRI substance when it undergoes processing or other use. When an article is processed and there are no releases, or the releases are recycled 100% with due care, the NPRI substances in that article need not be included in the threshold calculation.

Categories of welding processes in Canada

One of the categories of welding processes found in Canada is consumable electrode welding processes. The most common example of this type of process is shielded metal arc welding (SMAW). Other examples include flux cored arc welding (FCAW), gas-metal arc welding (GMAW) and submerged arc welding (SAW). Welding rods and wire are similar and are considered consumable electrodes.

The other category of welding processes in Canada is non-consumable electrode welding processes. This includes gas-tungsten arc welding (GTAW), plasma arc welding (PAW) and fusion welding.

This document does not contain information on non-consumable electrode processes as little information is currently available on this type of welding. Despite this, estimates are still required if you have that information available and provided that the applicable substance threshold is satisfied.

The remainder of this guidance document will be focused on the reporting requirements related to consumable electrode welding processes.

Please note that soldering activities are not considered to be a welding operation, although NPRI reporting still applies to them.

Reporting on consumable electrode welding processes

Parts 1 A and B metals

You can use these points to determine which sources of NPRI substances need to be considered in your threshold calculations:

  • The weight of the NPRI-listed substances found in the consumable welding electrodes must be calculated. The safety data sheet (SDS) can be used to determine the composition of the welding electrode. This, combined with the mass of the specific electrode used, can determine the amount of the NPRI substance(s) manufactured, processed or otherwise used (MPO).
  • For Part 1A metals, you need to determine if your facility MPO greater than or equal to 10 tonnes of each substance based on the amount and composition of the consumable welding electrodes. If these substances are MPO in other processes at your facility, these sources must also be considered in your threshold calculations.
  • For Part 1B metals, you will need to determine if your facility MPO greater than or equal to the mass threshold of each substance based on the amount and composition of the consumable materials. The mass threshold can be found in the Guide for Reporting to the National Pollutant Release Inventory. If these substances are MPO in other processes at your facility, these sources must also be considered in your threshold calculations.
  • The base metal being welded retains article status. As such, all NPRI-listed substances found in the base metal need not be considered in your threshold calculation.

After you have completed your threshold calculations and compared the total amounts MPO to the reporting threshold, you must then calculate the released, recycled and disposed values for those substances that meet or exceed the reporting threshold.

The electric arc welding calculator considers four different types of consumable electrode welding processes and various welding electrode or rod/wire types. If the specific consumable electrode welding process and standard welding rods/wire used is not available in the spreadsheet, and no other site-specific estimation method is available for your facility activities, please contact the NPRI help desk for direction.

The table below lists the types of welding rods/wire included in the spreadsheet calculations. The spreadsheet is the preferred method of calculation.

Welding processes and electrode types included in the electric arc welding calculator

Welding process - SMAW(SCC 309051xx)
Electrode type Last 2 digits of SCC
14Mn-4Cr (-04)
E11018 (includes E11018-M) (-08)
E308 (includes E308-16 and E308L-15) (-12)
E310 (includes E310-16) (-16)
E316 (includes E316-15, E316-16, and E316L-16) (-20)
E410 (includes E410-16) (-24)
E6010 (-28)
E6011 (-32)
E6012 (-36)
E6013 (-40)
E7018 (-44)
E7024 (-48)
E7028 (-52)
E8018 (includes E8018C3) (-56)
E9015 (includes E9015B3) (-60)
E9018 (includes E9018B3 and E9018G) (-64)
ECoCr (includes ECoCr-A) (-68)
ENi-Cl (-72)
ENiCrMo (includes ENiCrMo-4) (-76)
ENi-Cu (includes ENi-Cu-2) (-80)
Welding process - GMAW(SCC 309052xx)
Electrode type Last 2 digits of SCC
E308L (includes E308LSi) (-12)
E70S (includes E70S-3, E70S-5, and E70S-6) (-54)
ER1260 (-10)
ER5154 (-26)
ER316 (includes ER316I-Si and ER316L-Si) (-20)
ERNiCrMo (includes ENiCrMo-3 and ENi-CrMo-4) (-76)
ERNiCu (includes ERNiCu-7) (-80)
Welding process - FCAW(SCC 309053xx)
Electrode type Last 2 digits of SCC
E110 (includes E110TS-K3) (-06)
E11018 (-08)
E308LT (includes E308LT-3) (-12)
E316LT (includes E316LT-3) (-20)
E70T (includes E70T-1, E70T-2, E70T-4, E70T-5, E70T-7, and E70T-G) (-54)
E71T (includes E71T-1 and E71T-11) (-55)
Welding process - SAW(SCC 309054xx)
Electrode type Last 2 digits of SCC
EM12K (includes EM12K1 and F72-EM12K2) (-10)

Calculation example

Let’s assume the following for our example:

  • Process: SMAW
  • Amount of base metal welded: 14,000 tonnes during the reporting year
  • Amount of welding wire used: 1,000 tonnes of E310-15 welding wire during the reporting year. The wire contains 1.3% manganese by weight, obtained from the SDS.

Step One:

Determine the amount of manganese (a Part 1A substance) manufactured, processed or otherwise used (MPO) and compare it to the 10-tonne reporting threshold. If it is greater than the 10-tonne threshold, calculate the amount of manganese released due to the welding process.

Remember: When using a consumable electrode welding process, the base metal being welded retains its article status. Therefore, it does not need to be considered in either the threshold or release calculations.

The amount of MPO can be calculated using the following equation:

Amount of manganese = Amount of welding rod used [tonnes] x (weight percent manganese in welding/100%)
= 1 000 tonnes x (1.3%/100%)
= 13 tonnes of manganese

Since the amount of manganese is greater than the 10-tonne reporting threshold, your facility must submit a manganese substance report. In this example, we assumed that no manganese is recycled or disposed, but that some manganese is released as a result of the welding activity. As a result, the release estimate must be completed.

The electric arc welding calculator will automatically calculate the releases for all relevant substances once you enter the rod usage amount.

The amount of manganese released can be calculated using the following equation:

Manganese released [tonnes] = Amount of welding rod used [kg] x emission factor [kg Mn released/kg welding rod used] x [1 tonne/1 000 kg]
= 1000 [tonnes] welding rod used x 1000 [kg/tonne] x 0.0022 [kg Mn released/kg welding rod used] x 0.001 [tonnes/kg]
= 2.2 tonnes manganese released

Based on the above, 2.2 tonnes of manganese would be reported to the NPRI for the reporting year as a result of the welding activities occurring onsite. In this case, it would be reported as a release to air. Note that since the reporting threshold was satisfied for manganese, the facility must now report for all manganese that was released, recycled or disposed.

Step Two:

Determine the amount of PM10 released from the welding process.

As mentioned above, the electric arc welding calculator will automatically calculate the releases for all applicable substance once you enter the rod usage amount.

The amount of PM10 released can be calculated using the following equation.

PM10 released [tonnes] = Amount of welding rod used [kg] x emission factor [kg PM10 released/kg welding rod used] x 0.001 [tonne/kg]
= 1 000 [tonnes] welding rod used x 1000 [kg/tonne] x 0.0151 [kg PM10 released/kg welding rod used] x 0.001 [tonne/kg]
= 15.1 tonnes PM10 released

The reporting threshold for PM10 is 0.5 tonnes released to air. Since the release value for this example is 15.1 tonnes, a substance report is required for PM10. As well, you must add all other PM10 releases at the facility to the 15.1 tonnes. You must report the resulting value to the NPRI.

References

US Environmental Protection Agency (US EPA), 1998. "Section 313 of the Emergency planning and community right-to-know act - EPCRA section 313 questions and answers," Office of Pollution Prevention and Toxics, revised 1998 version, EPA 745-B-98-004, December 1998.

US Environmental Protection Agency (US EPA), 1994. "Development of particulate and hazardous emission factors for electric arc welding," revised final report, EPA contract no. 68-D2-0159, MRI project no. 4601-02, May 20, 1994.

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