Presentation is loading. Please wait.

Presentation is loading. Please wait.

Fiber Escape from Asbestos Abatement Enclosures - Quantitative Results Paul Bozek, PEng CIH ROH Andrea Sass-Kortsak, PhD CIH ROH PO 131 Industrial Hygiene.

Similar presentations


Presentation on theme: "Fiber Escape from Asbestos Abatement Enclosures - Quantitative Results Paul Bozek, PEng CIH ROH Andrea Sass-Kortsak, PhD CIH ROH PO 131 Industrial Hygiene."— Presentation transcript:

1 Fiber Escape from Asbestos Abatement Enclosures - Quantitative Results Paul Bozek, PEng CIH ROH Andrea Sass-Kortsak, PhD CIH ROH PO 131 Industrial Hygiene General Practice

2 Background - Abatement Containment in “Type 3” Indoors:

3 Background - Abatement Fiber level inside removal enclosures are well known and studied Fiber levels outside enclosures are not Limited, published, old data suggests fiber levels outside can be elevated, depend* on Poor worker decontamination procedures Insufficient negative pressure inside enclosures Problems with negative air machines/filters * Applied OEH 13(1) p 32, 1998

4 Study Method Observe practices /take pairs of air samples in Type 3 abatement projects (N=23) during: Abatement (cutting, scraping, etc) Worker decontamination at breaks Asbestos Waste removal from enclosure NIOSH 7400 (PCM): 20 min to 1 hour, dependent on task Air samples are short term samples, not TWA! Gather data on project: # workers, pressures, type of ACM, size

5 Study Method – Data Assumption for “overloaded samples” Use air volume and NIOSH 7400 max fibre density Assumption for None detected (“ND”) Use air volume and ½ x lab-specific fibre density LOD

6 Results 21 x “Type 3” Abatement Projects (Indoor) – 2 projects dropped due to short duration – 11 spray-on fireproofing – 4 plaster ceiling/wall removal (non-friable) – 5 friable ACM paper (e.g. “aircell”, sheet ) – 2 friable “magblock” plus non-friable cement Toronto, Ontario between Some data missing (due to timing of work)

7 Results – Observations (1) Failure to wet ACM during abatement: N = 5 of 21 Inadequate negative pressure: (-5 Pa = -0.02”WG) – During Abatement, N = 8 of 21 – During Garbage removal, N = 6 of 16

8 Results – Observations (2) Worker decontamination at breaks or end of shift: Zero of 21 observed/reported to pre-clean suits/respirators in the “dirty room” before entering shower None had rags/buckets of water nor HEPA vacuums placed in the “dirty room” for this purpose Most workers took <1 minute to shower

9 Results – Observations (3) Asbestos waste removal from shower or garbage chute: Zero of 20 observed workers receiving waste bags wore protective suits/respirators 8 of 20 observed to be passing out garbage bags that had not been cleaned (wet wipe or HEPA) 6 of the 8 observed double bagging in the “dirty room” but not cleaning the outer bag

10 “Dirty” Room Air Results: Abatement Mean: 0.65 f/cc Median 0.39 f/cc 10 overloaded Outside Enclosure Mean: f/cc Median f/cc 2 overloaded, 9 ND

11 “Dirty” Room 2 overload 2 ND Air Samples: Worker Decontamination Task Mean: 0.20 f/cc Median: 0.03 f/cc Mean: 0.04 f/cc Median: 0.03 f/cc 3 ND

12 “Dirty” Room 6 overload 1 ND Air Samples: Garbage Removal Task Mean: 0.26 f/cc Median 0.11 f/cc Mean: f/cc Median: f/cc 3 ND

13 Air Samples: Univariate Analyses Few variables were truly normally distributed Abatement pressure Fibre count on dirty side during garbage removal Log-normal not apparent either Too few samples? Non-parametric testing : some correlations significant, mostly relating to garbage removal

14 Air Samples: Multivariate Analyses - Garbage Removal Fibre Count - Clean side was a function of (p<0.05) – Fibre Count (dirty side) – Number of workers in project – Negative Pressure – ACM type (non-friable, spray-on, mixed) Other models (abatement, worker decon) were not significant (p>0.05)

15 Conclusions Observed practices could lead to fibre escape and exposure to those in immediate vicinity of the abatement enclosures, but levels generally acceptable (with some exceptions) 3 rd party on-site consultants need to observe work practices, not just conduct milestone inspections

16 Limitations Short term tasks = short term sampling Small dataset Timing of sampling with respect to tasks variable High variability of tasks = 21 sites representative? Assumption for “overloaded samples” Could be overloaded due to non-fibrous aerosols

17 Acknowledgements Co-Investigator: Mike Russo and Enzo Garritano Infrastructure Health and Safety Assoc. of Ontario Grant Funding: Workplace Safety and Insurance Board of Ontario


Download ppt "Fiber Escape from Asbestos Abatement Enclosures - Quantitative Results Paul Bozek, PEng CIH ROH Andrea Sass-Kortsak, PhD CIH ROH PO 131 Industrial Hygiene."

Similar presentations


Ads by Google