Skip to content

Fire in welding fumes extraction system

What happened?

In a shore-based workshop facility, the filters inside a welding fume extraction unit ignited whilst in operation.

On investigating an initial smell of burning, smoke was seen escaping from the welding fume extraction system at the rear of the workshop.  Smoke ingress into the workshop activated the smoke alarm and the workshop was safely evacuated.  The system was shut down and initial attempts using portable C02 extinguishers at the base of the unit was unsuccessful, as the fire progressed upwards through the filter banks.  On arrival the emergency services extinguished the fire through direct water application and cooling.

What were the causes? What went wrong?

Following initial investigation and discussions with the supplier it was found that the filters were blocked which allowed metal particles to build up, oxidize on the filter surfaces, heat up and eventually lead to a fire.

  • The unit was well within its annual inspection period and nothing related to filter replacement was highlighted at the previous inspection;
  • The supplier advised that blocked filters are indicated by a reading of 2.0 or above on the unit’s display (2000 Pascals). As an example, the display from an operational unit is shown here. This indicates 0.28 (280 Pascals) showing it is nearly new and well within the limit.


Where similar systems are used, check the display for high or excessive pressure readings as outlined in the manufacturer’s instructions and ensure that this check is included in regular operational and maintenance checks.

Members may wish to refer to

Safety Event

Published: 25 August 2020
Download: IMCA SF 25/20

Relevant life-saving rules:
IMCA Safety Flashes
Submit a Report

IMCA Safety Flashes summarise key safety matters and incidents, allowing lessons to be more easily learnt for the benefit of all. The effectiveness of the IMCA Safety Flash system depends on Members sharing information and so avoiding repeat incidents. Please consider adding [email protected] to your internal distribution list for safety alerts or manually submitting information on incidents you consider may be relevant. All information is anonymised or sanitised, as appropriate.

IMCA’s store terms and conditions ( apply to all downloads from IMCA’s website, including this document.

IMCA makes every effort to ensure the accuracy and reliability of the data contained in the documents it publishes, but IMCA shall not be liable for any guidance and/or recommendation and/or statement herein contained. The information contained in this document does not fulfil or replace any individual’s or Member's legal, regulatory or other duties or obligations in respect of their operations. Individuals and Members remain solely responsible for the safe, lawful and proper conduct of their operations.