Abrasive blasting is used in a wide range of industries for many different purposes, including cleaning surfaces such as steel, bricks, cement and concrete. However, workers that are tasked with abrasive blasting work can be exposed to several safety hazards including dust, hazardous chemicals and risks associated with the use of plant and equipment.
While it is an important and necessary part of manufacturing and maintenance work, abrasive blasting presents a high danger and risk to workers, often leading to dust exposure, injury and fatigue. The physical demands of blasting can also result in low productivity, with subsequent impact on costs to businesses in carrying out this work.
According to Australian Workplace Health and Safety (WHS) Regulations, a business that carries out abrasive blasting must eliminate risks arising from the practice, or minimise the risks so far as is reasonably practicable. The regulations have been designed to manage the risks of hazardous chemicals, airborne contaminants and plant, as well as other hazards associated with abrasive blasting activities.
Industry responsibilities under whs regulations
Designers, manufacturers, importers and suppliers of plant or substances used in abrasive blasting must ensure that the plant or substance is without risks to health and safety. This includes carrying out testing and analysis as well as providing specific information.
Officers, such as company directors, have a duty to ensure that the business complies with the WHS Act and Regulations by taking steps to ensure that the business has and uses appropriate resources and processes to eliminate or minimise risks that arise from abrasive blasting.
Workers also have a duty to take reasonable care for their own health and safety so they do not adversely affect the health and safety of other persons. Workers must comply with instructions and cooperate with policies or procedures relating to health and safety at the workplace. Furthermore, if personal protective equipment is provided, the worker must use it in accordance with the information, instruction and training provided.
Abrasive blasting materials and methods
There are reportedly many facilities and asset owners who are unfamiliar with what material is being used as part of their maintenance and repair work, such as in abrasive blasting practices.
There are many types of materials used for abrasive blasting, but some of these can contain toxic materials that are hazardous to workers. Silica sand (crystalline silica), for example, can cause silicosis, lung cancer, and breathing problems if workers are exposed to it. Coal slag, copper slag and nickel slag (the by-product of metal smeltering or coal fired power stations) are other common materials used for abrasive blasting and may also cause lung damage.
Using these materials can have a significant consequence on the health of workers that are oblivious to any potential risks, but can also be unsafe for the environment.
Some hazardous chemicals used in an abrasive blasting process, including silica sand, are prohibited and restricted under Australian WHS Regulations. It is therefore important to select an abrasive blasting medium with qualities that will generate minimum dust levels. Metallic abrasives have proven characteristics that resist shattering on impact, which is the major cause of the dust produced during blasting. Environmentally clean and recyclable abrasives, such as chilled iron grit or cast steel grit, are recommended to be used where reasonably practicable.
Non-slag abrasives such as garnet and glass are generally chemically inert, and contain no hazardous compounds and are often specified for offshore oil and gas platforms and near water bodies. Good quality garnet in particular create less dust, is cost effective, achieves a cleaner finish, is highly recyclable and has a low health safety and environmental risk profile.
Continued use of hazardous blasting materials
Although hazardous abrasive blasting materials have been legislated against in many regions in the world, they still continue to be used in some countries because they are considered to be both inexpensive and effective.
Official figures have confirmed that about 62,000 workers in the U.S. are exposed to beryllium in their workplaces, including approximately 11,500 construction and shipyard workers during abrasive blasting operations. Beryllium is known as a toxic, carcinogenic element which is laced through the coal waste which is used in abrasive blasting grits.
As a result, the Occupational Safety and Health Administration (OSHA) in the U.S proposed the introduction of a standard in 2015 which would reduce the permissible exposure limit (PEL) for beryllium to 0.2 micrograms per cubic metre of air, averaged over eight hours. Estimates showed it would save 90 lives from beryllium-related diseases and prevent 46 new cases of chronic beryllium disease each year, once the effects of the standard were to be fully realised.
However, the beryllium standards for general industry and construction and shipyards are in flux and have gone through several changes.
On 9 January 2017, OSHA published its final rule, the Occupational Exposure to Beryllium and Beryllium Compounds, in the Federal Register. After a review of stakeholder feedback received and a review of the applicability of existing OSHA standards. OSHA published a direct final rule to clarify aspects of the general industry standard in May 2018. But in June 2018, OSHA proposed to revoke ancillary provisions applicable to the construction and shipyard sectors, while retaining the new lower PEL and the short-term exposure limit (STEL) for those sectors. This was followed by proposed additional revisions to certain provisions in the standard in December 2018. The agency is currently reviewing comments received in response to the proposal to finalise the rulemaking and it is expected the final rule will be published in December this year.
Is robotics the answer?
Along with major developments in robotics in other sectors, advanced technologies are also increasingly being used in the abrasive blasting process to eliminate the health associated risks for operators.
New developments in this area allow robots to operate in manual, semi-autonomous and autonomous or unsupervised modes and are having an impact on performance, asset downtime and worker safety.
After seven years of intensive research and development by the University of Technology Sydney (UTS), the world’s first autonomous grit-blasting robots began operating in 2013. Over 150 days, they blasted about 3500 square metres of steel surfaces, equivalent to nearly 16 tennis courts. Work practices were reviewed and changed as a result, with workers no longer required within the blasting environment (except to hand-blast small areas which the robots cannot reach).
The robots have brought significant productivity gains, particularly when performing tasks difficult for manual workers, such as blasting hard to reach areas. In such environments, where workers are limited by fatigue and the need to concentrate on the blasting direction, the robots can be up to six times more productive per hour – meaning an area can be covered in a fraction of the time (with the associated cost reductions), or a significantly greater area can be covered at the same cost (with the associated additional value for end-users).
The biggest advantage, though, is a dramatic reduction (up to 90 per cent) in worker exposure time, compared to manual blasting. While no data is available yet on the decrease in OHS incidents, removing workers from the potentially dangerous blasting environment has clear safety benefits, which also result in cost savings.
The robots’ deployment in the field to improve worker safety has inspired efforts to further develop the technology for wider applications. The UTS is now looking at developing a multi-robot collaboration and robot inspection of blasting quality in real-time to further refine the core technology so it can be adapted for more markets.
Robotic technology is addressing a key challenge in the international abrasive blasting industry by removing workers from a prolonged risk through manual blasting. As a result, end-users have enjoyed, and will enjoy, cost savings from fewer workplace injuries and illnesses, as well as substantial productivity gains.
Sources: Occupational Safety and Health Administration, Updated Interim Enforcement Guidance for the Beryllium Standards, December 11, 2018; Protecting Workers from the Hazards of Abrasive Blasting Materials, OSHA; A Robot for the Unsupervised Grit-Blasting of Ship Hulls, Daniel Souto et al.; Mark Your Calendar: OSHA Beryllium Enforcement About to Ramp Up, Guy Burdick, EHS Daily Advisor; Engagement and Impact 2018, University of Technology Sydney
