Working with engineered stone

Making repairs may include fixing a chip or crack in a legacy engineered stone benchtop, panel or slab. It may also involve resurfacing or polishing to remove a scratch, etch, mark or stain on a benchtop or panel.

Modification of a legacy engineered stone benchtop, panel or slab may include altering its original form. Examples may include:

• cutting into already installed engineered stone benchtop or panel to create a cavity for the placement of a larger tap, cooktop or powerpoint
• cutting into an already installed benchtop or panel to change the configuration, for example, an L-shape bench to an island bench

Removal can involve disassembling or breaking apart a legacy engineered stone benchtop, panel or slab with the intention of disposing of it. For example, a worker uses power tools to remove an engineered stone benchtop and splash back as part of a kitchen renovation.

Engineered stone that has been removed cannot be supplied, processed or installed.

Disposal of legacy engineered stone benchtops, panels or slabs can occur whether installed or not. For example, an employee removes an engineered stone bathroom countertop and takes it to a landfill.

The uncontrolled dry cutting of legacy engineered stone is not permitted in Victoria.

If a power tool or other form of mechanical plant is used to undertake an engineered stone process, an employer or a self-employed person must ensure that the power tool or mechanical plant is used with:

• an integrated water delivery system that meets the requirements in this guidance, or
• an on-tool dust extraction system that meets the requirements in this guidance, or
• if these controls are not reasonably practicable, another type of local exhaust ventilation (LEV)

An integrated water delivery system, also known as on-tool water suppression is one of the most effective ways to reduce exposure to crystalline silica dust.

It works by using water at the point of dust generation to dampen down or suppress dust before it is released into the air.

An integrated water delivery system must:

• deliver a continuous supply of water to the point of contact with the stone while the power tool or mechanical plant is in use, and
• if the system uses recycled or recirculated water, adequately treat that water

Suitable water suppression: grinder being used to cut slab

Suitable water suppression: polisher being used to finish benchtop

Inappropriate water suppression: separate hose being directed at work

Inappropriate water suppression: use of spray bottle

On-tool dust extraction removes the dust from the source as it is being produced. It is fitted directly onto the tool, with extraction attached to a high efficiency particulate air (HEPA) filtered Dust Class H vacuum cleaner.

An on-tool dust extraction system must:

• be commercially available, and
• be connected to a Dust Class H vacuum or another system that captures any dust generated by the power tool

Dust Class H vacuum means a vacuum that complies with the Class H requirements in AZ/NZS 60335.2.69:2017 Household and similar electrical appliances—Safety—Part 2.69: Particular requirements for wet and dry vacuum cleaners, including power brush, for commercial use or its equivalent.

Figure: Grinder fitted with on-tool extraction

Local exhaust ventilation (LEV) is an engineering control that captures the emission of an airborne contaminant at its source and transports it to a safe emission point, filter or scrubber. On-tool dust extraction is one form of LEV.

While this control measure may reduce background levels of silica dust, it is not as effective as water suppression or on-tool dust extraction in reducing the exposure of employees and is generally not recommended.

Where legacy engineered stone processes are undertaken, another type of LEV, such as a portable LEV system, should be used if it is not reasonably practicable to use an integrated water delivery system or a commercially available on-tool dust extraction system.

LEV that is not on-tool requires proper design, installation, use and maintenance to ensure dust is effectively captured as close as possible to the source, so far as is reasonably practicable, eliminate or reduce the risk of exposure to crystalline silica dust.

Employers must provide employees with any necessary information, instruction, training, or supervision required to enable them to perform their work in a way that is safe and without risks to health. This duty also extends to independent contractors (including any employees of the independent contractor) engaged by the employer in relation to matters over which the employer has control.

An employer must ensure that employees who are likely to be exposed to risks associated with high-risk crystalline silica work are given information, instruction, and training in:

• the health risks associated with exposure to crystalline silica dust
• the need for, and proposer use of risk control measures
• how the risk control measures are to be implemented

An employer must ensure that an employee who uses a power tool or other form of mechanical plant to undertake a permitted engineered stone process is provided with information, instruction and training in:

• the use of that power tool or mechanical plant with an integrated water delivery system or an on-tool dust extraction system or local exhaust ventilation
• the use, fit, maintenance and storage of respiratory protective equipment

An employer must ensure that an applicant who applies for employment involving high risk crystalline silica is given information about:

• the health risks associated with exposure to crystalline silica dust
• the need for, and details of measures to control those risks

Training programs need to be practical and 'hands on'. The structure, content and delivery of the training needs to take into account any special requirements of the employees and independent contractors being trained. For example, information, instruction, and training may need to be provided in a language other than English.

Other considerations for how training is delivered include specific skills or experience, disability, literacy, and age. Training programs should also be reviewed periodically and as required to ensure suitable information, instruction and training is provided to employees.

Refresher training needs to be provided as appropriate for the workplace. The frequency of refresher training should be determined having regard to the complexity of the work, the skills required and the frequency with which the tasks or work is carried out.

Employers must provide supervision to employees where supervision is necessary to enable those employees to undertake their work safely. This is particularly important with employees who are more vulnerable such as new, inexperienced, or young employees.

Figure: Safety signage at a worksite with permitted engineered stone processes occurring.

Employers must provide an employee who undertakes an engineered stone process with respiratory protective equipment (RPE) that:

• is designed to protect the wearer from the inhalation of airborne contaminants
• complies with AS/NZS 1716 – Respiratory protective devices, or an equivalent standard

The employer must also ensure the employee uses the RPE.

It is important to check the product information to make sure the RPE meets the requirements of AS/NZS 1716 or an equivalent standard. If it is not clear, contact the supplier or the manufacturer.

RPE needs to have at least a P2 filter and be fit tested for each person to ensure a correct fit. RPE that requires a facial seal, such as half-face respirators, should not be used by people with beards or facial stubble. Where facial hair interferes with the fit of the RPE, a powered air purifying respirator (PAPR) that does not rely on a facial seal needs to be used, such as a PAPR loose fitting helmet.

RPE needs to be selected, used and maintained in accordance with AS/NZS 1715 – Selection, use and maintenance of respiratory protective equipment or equivalent standard.

Employers need to provide employees with information, instruction and training in the use, fit and maintenance of RPE, including the system for storage.

For RPE that requires a facial seal, such as a half-face powered air purifying respirator, a fit check is a quick check to ensure it is properly positioned on the face where it is put on.

Employees should do a fit check every time they put on their respirator in accordance with the manufacturer's instructions.

Recommended RPE for working with engineered stone

PAPR loose fitting helmet

High level of protection:

• positive pressure reduces fatigue
• can be worn with facial hair
• does not require fit testing

PAPR loose fitting hood

High level of protection:

• positive pressure reduces fatigue
• can be worn with facial hair
• does not require fit testing

Half face PARP

Medium level of protection:

• more comfortable over longer periods
• positive air pressure reduces fatigue
• cannot be worn with facial hair
• requires fit testing
• needs to be fit checked with each wearer

Half face negative pressure respirator

Minimum level of protection:

• does not impair vision or mobility
• cannot be worn with facial hair
• requires fit testing
• needs to be fit checked with each wear

Note: When undertaking an engineered stone process, filters used in respirators must be of a particulate type. When undertaking a gluing process, organic type filters may also be required.

An employer or a self-employed person must not use compressed air or other compressed gases to clean the following, unless the use of that air or gas does not result in a concentration of respirable crystalline silica that exceeds the exposure standard for crystalline silica:

• a work area where an engineered stone process has been undertaken
• clothing a person wore in a work area where an engineered stone process was undertaken

It is not recommended to use compressed air in any situation where respirable crystalline silica dust may have been produced.

When carrying out permitted work with engineered stone, the work area should be cleaned after each job is completed. This is to ensure there is no build-up of respirable crystalline silica dust on equipment such as power tools, working surfaces or the floor. RPE needs to be worn during clean-up activities.

Ensure clean-up and housekeeping processes do not generate dust in the air. For example, use a HEPA filtered Dust Class H vacuum, low pressure hosing, mopping, squeegeeing or wet wiping down surfaces. It is not recommended to ever use compressed air, dry sweeping or high-pressure water to clean up as this is likely to generate airborne dust.

Bags used for containing waste need to be strong enough to ensure they will not tear and release dust. To minimise the risk of a bag tearing or splitting, bags should not be filled more than half full and excess air gently evacuated from the bag in a way that does not cause the release of dust.

When carrying out permitted work with engineered stone, personal protective equipment such as RPE, aprons and boots need to be cleaned after each use to ensure dust does not accumulate. For example, by using a low pressure hose or wiping down with wet rags.

Work clothes should not gather dust if exposure is appropriately controlled during processing work. However, if dust has settled on clothing, the contaminated clothing should be dampened, bagged, and labelled with 'Silica dust hazard'.

Contaminated clothing should not be taken home. It should be sent to a commercial laundry. If a commercial laundry is used, the employer or self-employed person needs to inform the laundry that the clothing is contaminated with silica and ask how they would like to receive the clothing.

Employers must control the risk of exposure to crystalline silica dust during legacy engineered stone waste management and disposal. For example, when wet slurry is collected, or dust captured by an extraction system is ready for disposal, it needs to be contained and handled in a way that minimises the release of dust. Containers of waste contaminated by silica dust must be identified, for example by a label that clearly states 'Silica dust hazard'.

Wet slurry is the waste from dust generating processes that are water suppressed. While it is wet, the slurry is not hazardous. If it is allowed to dry, some dust may be disturbed and become airborne. If there is any risk of exposure to dust for people who may handle the waste (eg employees, waste collectors or waste transfer station staff) the waste needs to be bagged and sealed before it is disposed

When carrying out permitted work with engineered stone, wet slurry needs to be managed using containment measures such as using plastic drop sheets to prevent contamination of the work area and collection of wet slurry by using a HEPA filtered Dust Class H vacuum or mopping, squeegeeing or wet wiping down surfaces.