Abrasive Blasting – Ventilation Design & Dust Control

What is Abrasive Blasting?

Abrasive Blasting is a common industrial process used to remove the surface coating from materials or structures to prepare them for final finishing such as painting, machining, or assembly. The most common method uses compressed air to propel abrasive material from a blast pot, through a blasting hose to a nozzle that is controlled by an operator. Automated blasting machines are also in use, these use a centrifugal wheel system and tumblers to prepare surfaces.

Why is dust control important during Abrasive Blasting?

Abrasive Blasting generates large volumes of respirable dust that can be toxic and small enough to be inhaled into lungs and become hazardous to workers. Crystalline silica and lead are typical examples of toxic dusts that can be generated during abrasive blasting activities. Installing a quality dust collection system removes unsafe contaminants from the air and keeps the workplace safe for operators.

High health risks occur when the abrasive blasting process uses sand which contains crystalline silica. Silica dust produced by this sand medium can cause irreparable respiratory disease, sometimes resulting in permanent injury or death.

Substances commonly encountered during abrasive blasting include:

• asbestos
• crystalline silica
• cadmium
• inorganic arsenic
• inorganic chromium, and
• inorganic lead.

In addition to using a dust collector to provide a safe environment, abrasive blasting operators are required to wear a high-end respirator which covers their head, neck and shoulders, protective clothing, gloves, safety footwear, earplugs, and protective eyewear.

Where is Abrasive Blasting work undertaken?

Abrasive Blasting can be performed in open sites for example on buildings, bridges, tanks, dock yards etc or it can be performed within enclosed environments such as blasting chambers, cabinets, or dedicated blast rooms.

When dealing with high risk products abrasive blasting is undertaken in dedicated blasting rooms with a pneumatic recovery system connected via ducting to a fixed dust collection unit. A pneumatic recovery system uses duct work and a vacuum system to recover garnet which is then transported by dilute phase pneumatic conveying through thick-walled piping. Cyclonic action is used to separate the used garnet from the air stream, down the hopper, and back into the blast pots to be reused. There are no filters in the recovery system, so exhausted air is fed back into the dust collector to be filtered

What determines the ventilation and dust control required for Abrasive Blasting?

Sizing the dust collector is critical. After establishing the correct airflow, air velocity, pressure resistance and air-to-cloth ratios the air blast room is attached to the appropriate size dust collection system and can then filter all dust and fume particulates from the room to ensure a safe working environment.

The blasting material and process used will also dictate the type of ventilation and air flow required to capture the airborne dust and fume along with the environment where blasting work is taking place. Extracted air can be ducted to a dust collector located outside a blast booth or drawn directly into a mobile dust collector by incorporating a hood.

For blasting operations where the process is contained, keeping the enclosure volume under a negative pressure with sufficient capture velocities on all open areas can be an effective method to control the contaminant.

What are the key components of a Grydale Dust Collector?

Grydale Dust Collectors comprise of a modular design that typically comprises of a Filter House, High Efficiency Cartridge Filters, Reverse Pulse Filter Cleaning System, Centrifugal Fan, Variable Speed Drive (VSD) (to allow power consumption to be regulated) and a Dust Discharge System.

Right is an outline schematic of a Grydale Fixed unit Dust Collector (JMS F-Series) that are installed alongside custom blast booths:

Why Grydale?

Grydale has a wealth of experience designing both fixed and mobile solutions for industrial dust collection solutions for Abrasive Blasting works.

Example Project: Coastal Powder Coating

Coastal Powdercoating refreshes old metal items using sandblasting and powdercoating services.

Grydale designed, manufactured and installed a steel blast room equipped with a media recovery system and suitable dust collection system. This allowed the client to bring their blasting operations in-house controlling the quality of the end powdercoated product.

Key Benefits of Grydale Fixed and Mobile Dust Collectors.

• Reduce dangerous dust.
• Improve visibility.
• Units available for sale or rental.
• Extensive range of fixed and mobile units.
• Various air volumes available.
• Easily transported worldwide.
• Full service, training, and ongoing support.

Exposure standards for workers are based on the concentration levels of individual substances. You can find out more about chemicals with workplace exposure standards through Safe Work Australia.

For more information on dust control for abrasive blasting contact our team enquiries@grydale.com.au

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