The equipment or machinery used for water suppression should :
− have an appropriate ingress protection ( IP ) rating for use with water suppression − have the water feed attached and an adequate number of water feeds directed at the material and / or tool to prevent dust being released during the process − have a consistent water flow and adequate water pressure during operation ( usually at least 0.5 L / min ) − be fitted with guards , plastic flaps or brush guards designed to manage the water spray or mist containing silica dust , and − be maintained according to manufacturer ’ s instructions .
Note : Only tools and machinery that have been designed for use with water attachments should be used with water suppression . Handheld spray bottles , sponges or garden hoses are inadequate at suppressing silica dust . They are also dangerous if used with power tools that are not designed for use with water .
While water suppressed machinery and tools provide an effective means of reducing exposure to silica dust , their use needs to be controlled to ensure other hazards are not created . Potential hazards arising from the use of water suppression are electrical hazards , water mist hazards and recycled water hazards .
A PCBU must eliminate electrical risks or , if that is not reasonably practicable , minimise the risks so far as is reasonably practicable . When working with water suppression machinery and tools , electrical hazards can be introduced . A PCBU should :
−
− − only use tools and machinery that are specifically designed for use with water attachments consider the current electrical equipment ’ s IP rating if retrofitting or introducing water suppression into an existing process as a new control , and thoroughly check electrical equipment , including electrical cords , to ensure safety when undertaking wet cutting or other processing .
As a consequence of applying water to power tools with rotating blades , contaminated water mist can be generated .
This water mist can expose workers to silica dust by :
− − − breathing in contaminated water mist particle laden mist drying in the air and being breathed in , and particle laden mist depositing on surfaces , including clothing , and later drying , then becoming airborne again when disturbed .
If recycled water is used for water suppression , this may introduce an additional risk for workers . Without an appropriate filtration system , there is a risk that the continual recycling of water will increase the concentration of silica dust in the water over time , and subsequently the level of silica dust in the mist generated from water suppressed activities .
More information on managing the risks of recycled water can be found in section 6.2 of this Code .
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