ISO 15011-2:2009 defines laboratory methods for measuring the emission rates of carbon monoxide (CO), carbon dioxide (CO2), nitrogen monoxide (NO) and nitrogen dioxide (NO2) generated during arc welding, cutting and gouging, using a hood technique. The methodology is suitable for use with all open arc welding processes, cutting and gouging, but different designs of hood are used depending on the process and whether or not it can be conducted automatically.