WHS Asbestos Risk Matrix

WHS Asbestos Exposure Risk Assessment
WHS uses a risk matrix provided below to evaluate the potential exposure to asbestos and determined that the overall risk level was low to moderate. This is a generic risk matrix which can be used with wipe samples, and/or bulk sampling results and incorporates the requirements of BC and Alberta, which have slightly different definitions of Low, Moderate and High-Risk Work.

Conditions for each criteria identified above, and the estimated worker exposure during demolition activities with no additional cleaning or controls implemented to reduce the release of dust and debris and based on details provided in image below.

Risk Matrix for potential worker and the requirement for additional controls.

Conditions for each criteria identified above, and the estimated worker exposure during demolition activities with no additional cleaning or controls implemented to reduce the release of dust and debris and based on details provided in table above.
Green – Minimal Risk/ Background Levels.

• Typical Airborne Concentration: at background levels
• Wipe Samples <10,000 structures/cm2

Yellow 1 - Low Risk of Exposure

• Typical Airborne Concentration: <0.01 fibres per cc.
• Wipe Samples >10,000 structures/cm2 but <100,000 structures/cm2

Yellow 2 – Low Risk of Exposure

• Typical Airborne Concentration: <0.01 fibres per cc.
• Wipe Samples >10,000 structures/cm2 but <100,000 structures/cm2

Orange 1 – Moderate Risk of Exposure

• Typical Airborne Concentration: between 0.01 fibres per cc and 0.02 fibres per cc.
• Wipe Samples >100,000 structures/cm2 but <1,000,000 structures/cm2
• Bulk samples Asbestos content is between 0.5% and 50% chrysotile and the material is non-friable.  Amosite, and Crocidolite present at <5%, vermiculite is bound in the matrix (plaster/stucco)

Orange 2 – Moderate Risk of Exposure

• Typical Airborne Concentration: between 0.01 fibres per cc and 0.05 fibres per cc.
• Wipe Samples >1,000,000 structures/cm2
• Bulk samples Asbestos content is between 0.5% and 50% chrysotile and the material is non-friable. Amosite, and Crocidolite present at <5%, vermiculite is bound in the matrix (plaster/stucco)

Orange 3 – Moderate Risk of Exposure (with a containment)

• Typical Airborne Concentration: between 0.01 fibres per cc and 0.05 fibres per cc.
• Bulk samples Asbestos content is between 0.5% and 50% chrysotile and the material is friable.
• Removal of friable Amosite, via glove bags.
• Potential for excessive dust (drywall dust and debris), occupied school or hospital. Infection Prevention Controls are required.

Red 1 – High Risk

• Typical Airborne Concentration: between 0.1 fibres per cc and 1.0 fibres per cc.
• Work can be performed with a half mask

Red 2 – High Risk

• Typical Airborne Concentration: between 1.0 fibres per cc and 10 fibres per cc.
• Work can be performed with a PAPR

Red 3 – High Risk

• Typical Airborne Concentration: >10 fibres per cc.
• Work can be performed with a PAPR/Supplied Air
• Dry Removal of Chrysotile, Amosite or Crocidolite