20 November 2018 / Safety Alert

Silica Dust Awareness

Inhalable dust, respirable dust and Respirable Crystalline Silica (RCS / Silica Dust) remains an important risk factor for respiratory disease amongst construction workers. 

The following information has been compiled in order to address some of the queries that arise on the topic of silica dust management.

An Introduction to Silica Dust

FAQs

Question 1 / Why has silica dust become an issue now?

In recent years it has been proven that Respirable Silica Dust (RCS) is a material that, when inhaled, cannot be expelled from the human lung and causes irreparable scarring of lung tissue and permanent loss of lung capacity and resulting in a medical condition referred to as ‘silicosis’.

There is no cure for, and no recovery from, silicosis.
Exposure to RCS also involves the risk of lung cancer and Chronic Obstructive Pulmonary Disease (COPD).
There is no cure for COPD.

Question 2 / What makes silica dust different?

It's a very small size compared to other dust. RCS dust is less than 1 micron (1 um) and is not visible to the naked eye under normal lighting due to its extremely small size. For comparison, the diameter of human hair ranges from 17 – 180 um, and 1 um = 1 millionth of a metre.

Question 3 / Is there a level where it's too dangerous?

The current standard in Australia is 0.1mg / m3 which is equivalent to about half a match head. 

Question 4 / How should silica dust be controlled on site as a whole?

By designing out the activities that produce silica dust and by using alternative methods and materials such as cast in fitments.

Question 5 / What controls will protect construction workers on site?

Where silica dust is present above the standard every employer has an obligation to:

  • ensure that workers have the appropriate equipment, training and RPE (including the associated certification for a fit test for the specific RPE device that is intended to be used) for the activities in question.
  • instigate controls such as collection of the silica dust at the source by using dry or wet vacuum cleaners and vacuum attachments for certain tools,
  • exclude all but those workers who are directly involved in the activity that is generating silica dust, and who are trained and authorised to work in areas where silica dust is present in hazardous volumes.

Question 6 / What vacuum should be used?

There are 2 classes of vacuum that can be used for collection of silica dust at the source - H & M. 

H Class are the superior of the two, however sometimes these units aren't available or not practical for use on site.

M Class have been deemed sufficient, and are suited to site with tool attachments. However, it's important that the right M class vacuum is chosen, with disposable bags so that silica dust can be disposed of safely.

Question 7 / What is fit testing?

A process where a site worker's face mask or respirator is tested to make sure its doing its job. 

Question 8 / Does everyone on site need to be fit tested?

Only the people who are directly exposed to silica dust - such as a site worker who is grinding concrete, and anyone in the immediate vicinity of the activity. 

Question 9 / Will facial hair affect a fit test?

Yes - it's highly likely that having facial hair will affect the seal of a respirator or a face mask. The seal is important so no silica dust enters the lungs. 

Question 10 / Why were monitors used on general site workers?

Those tests were undertaken to understand what the priorities were and what needed to be addressed first. To no surprise, the tests showed grinding of concrete and drilling of concrete overhead exceeded the safe levels of silica dust. 

Question 11 / Who is best to implement the testing?

Anyone or any company that's accredited to deliver those tests are able to be engaged. 

Question 12 / How can I make sure subbies are protecting their workers?

Keep raising awareness via the materials Hutchies has developed so subbies have the opportunity to promote the information to their workforces. 

Question 13 / What does all the terminology mean?

RCSRespirable Crystalline Silica; Silica Dust

OEL

OES

WES

Occupational Exposure Level

Occupational Exposure Standard

Workplace Exposure Standard

These three terms, and the respective acronyms, refer to the maximum contaminant level that a person can be exposed to in an 8 hour period. However where the shift length exceeds 8 hours, or where the working week is longer than 40 hours, the exposure standard may need to be adjusted to compensate for greater exposure and less recovery time.

The WES in Australia is currently 0.1mg/1.0m3, however it is a legal requirement to apply control measures as for the full WES once airborne particulate levels reach 50% of the WES, in this case when readings reach 0.05mg/1.0m3.

In this document we will use WES as the inclusive term for OEL, OES and WES.

RPE

Respiratory Protective Equipment

PAPR

Powered Air Purifying Respirators

‘H’ Class Vacuum


‘H’ Class vacuum cleaners are for use with dust representing a high risk.

The vacuum cleaner filter traps over 99.995 % of dust with a grain size of under 1 micron (it includes carcinogenic dusts and dusts contaminated with carcinogens and/or pathogens). Additionally ‘H’ Class units include a hepa-filter in the exhaust air circuit.

‘M’ Class Vacuum


‘M’ Class vacuum cleaners are for use with dust representing a medium risk.

The vacuum cleaner filter traps over 99.9 % of dust with a grain size of under 2 microns.

1 micron

1 micron (um) = one millionth of a metre.

The diameter of human hair ranges from 17 – 180 um.

COPD

COPD (Chronic Obstructive Pulmonary Disease) is a long-term disease of the lungs which causes shortness of breath. COPD is an umbrella term for conditions including emphysema, chronic bronchitis and chronic asthma which is irreversible.

There is no cure for COPD.

Question 14 / Where can I find more information?

Within the Toolbox and Document Library

You can also contact our National Health & Safety Manager, Danny O'Reilly on +61 408 920 496 or danny.oreilly@hutchinsonbuilders.com.au for more information.