Reported deterioration of particulate filters update

Background

The original Alert identified a potential risk to users of particulate filters that may have deteriorated after being exposed to water. Deteriorated filters pose dangers to workers exposed to asbestos and other airborne hazardous substances.

Wet decontamination in the asbestos removal and lead industries requires workers to wear respirators while showering, and this causes the respirator and filter to get wet. The concern raised with WorkSafe was in relation to possible deterioration of Sundstrom SR510 P3 particulate filters when they were re-used after becoming wet. In response to this concern, WorkSafe issued the original Alert and investigated the matter.

This Alert provides the findings of the investigation and outlines responsibilities for ensuring the appropriate use and maintenance of respirators/filters after they become wet as a result of going through a decontamination / shower.

Outcome of the Sundstrom SR510 P3 filter investigation

Testing carried out by TestSafe Australia confirmed that the SR510 particulate filter complies with the requirements for a P3 particulate filter rating as specified in Australian Standard AS1716:2003.

Extensive simulation testing of the Sundstrom SR510 P3 filter was carried out by both Sundstrom Safety in Sweden and the Australian supplier Safety Equipment Australia (S.E.A.) Group. The Sundstrom Safety testing showed that the decontamination process used on the particular worksite would not affect the functionality and performance of the respirator or particulate filter. However, the testing did show that after repeated cycles of contamination, wetting and drying the particulate filter may result in its performance dropping from a P3 to a P2 rating. This is not unusual – degradation of filters over time with use, especially where they are harshly treated, is expected.

The testing carried out by S.E.A. Group examined particle loading on the filter medium both after repeated loading and after a single 100% loading. The results showed that the filter medium met the required efficiency when subjected to repeated particle loading, wetting and drying cycles as used for personal decontamination on asbestos removal sites.

The test methodology and results were examined by SAI Global, Product Certification Assurance Services (an independent group) who verified that the test methodology used and reported results were valid.

In summary, Sundstrom SR510 P3 filter testing results indicate that the filters are effective for their intended use. The reported deterioration of the filter may have been related to the extent of re-use and insufficient inspection and maintenance.

Can respirator filters be re-used after becoming wet?

If you are planning to re-use respirator filters after they have become wet (for example after going through a decontamination/shower), you need to:

• contact the supplier of the respirator to ensure that the respirator and filter has been designed so that their performance will not be affected by becoming wet

NOTE: Some respirator manufacturers have specific filters that are reported to repel water. Some manufacturers also have a shield that attaches to their respirator to protect the filter from getting wet.

• assume that the filters will deteriorate and do not re-use them if the supplier can not re-assure you that the filters can be re-used after becoming wet
• regularly inspect the filters for any signs of deterioration, particularly before and after use
• dispose of filters that are suspected of, or show any sign of, deterioration or result in an increase in breathing resistance
• notify the supplier of any concerns related to the respirator or filter
• ensure that the appropriate respirator/filter is used for your workplace and work process and ensure that the respirator is maintained so that its performance is not adversely affected.

General respirator use

If you are using, or planning to use respirators, ensure you have a respiratory protection program, regardless of whether or not the filters become wet. The requirements of such a program are detailed in AS/NZS 1715, Selection, use and maintenance of respiratory protective devices.

Further information

Refer to AS/NZS 1715 Selection, use and maintenance of respiratory protective devices, visit the WorkSafe website at www.worksafe.vic.gov.au and view Guidance Note on Respiratory protective devices. Call us on 1800 136 089.