The Aluminum Association, and the aluminum industry, has long made the safety and well-being of its employees a top priority.
Injury and illness data gathered by the Aluminum Association indicate that aluminum plants are a relatively safe place to work. Millions of pounds of aluminum are melted and cast safely everyday in casthouses, foundries, recycling and reclamation plants all over the world. However, just like any manufacturing process, there are inherent risks and hazards involved with the production and fabrication of our metal.
The Aluminum Association believes that these hazards can be minimized or eliminated entirely by careful attention to safe handling practices and the sharing of best practices. To that end, the Association’s safety programs include:
Below is some general information on the aluminum industry safety as well as relevant technical material. Please contact Association Senior Director for Regulatory Affairs Curt Wells with any specific questions.
Failure to use proper procedures in melting and casting aluminum can be dangerous. Molten Aluminum is typically handled at 1300-1450 degrees Fahrenheit to avoid premature solidification. Contact with molten aluminum can cause severe burns and create a serious fire hazard. Mixing water or other contaminants with molten aluminum can cause explosions. Explosions can also occur in the aluminum scrap re-melting process due to moisture and contamination in scrap.
These explosions range widely in violence and can result in injury or death as well as destruction of equipment and plant facilities. Where there is possibility of splash or other direct exposure, personnel working with molten aluminum must wear eye and face protection as well as protective clothing.
The Aluminum Association releases an annual molten metal incident report to report information regarding hazardous events that occur at facilities melting aluminum. The report is the product of a voluntary program started in 1985 to share safety information among facilities. Although not intended to be statistically representative of the entire industry, the report provides useful information to help guide safety efforts in molten aluminum environments. The latest Molten Metal Incident Report is below.
Fundamentals of Casthouse Safety
The Association now has available a 40-minute online training module titled Fundamentals of Casthouse Safety, which was developed from a presentation originally made at the 2017 AluminumUSA trade show. This module is designed to provide an introduction to the principles of aluminum casting safety for individuals not involved directly in the casting process and/or to provide an accessible refresher in the interim between in-person casthouse safety workshop training sessions. Its availability is accompanied by a companion worksheet that can be used to validate comprehension of the material presented. If you have any questions about this information, please contact the Association’s Senior Director of Regulatory Affairs, Curt Wells, at firstname.lastname@example.org.
Scrap Metal Recycling Safety
Recycling aluminum – the acquiring, preparing and melting of aluminum scrap for use in making new aluminum products – plays a vital part in the economic and sustainability attributes of aluminum. A key part of aluminum recycling’s sustainability is keeping workers safe throughout the process and the Aluminum Association publishes a variety of safety guidance which is supplemented by safety guidance from others. In the U.S., the Occupational Health and Safety Administration (OSHA) has published “Guidance for the Identification and Control of Safety and Health Hazards in Metal Scrap Recycling” (available here for free download), which is another resource to help improve recycling industry safety.
Aluminum Sow Casting and Charging
Bulk aluminum intended for re-melting is often cast in the form of large shapes, weighing 700 to 2000 pounds, commonly known as sows. The sow-casting process generally results in unavoidable internal shrinkage cavities, which can become reservoirs for collecting large amounts of water. Sows are also subject to surface moisture and other contaminants. This contamination can result in dangerous explosions during the re-melt process. Therefore, operators must make every effort to avoid charging sows that contain moisture, either entrapped or on the surface, into molten aluminum.
The Aluminum Association discourages the practice of drying sows by placing them on furnace sills containing molten aluminum. Explosions may occur from sows slipping into the molten baths before fully dry or from water condensing between stacks of sows.
Protective Coatings for Casting Pits and Equipment
Several types of protective coatings have been tested to date and found to be effective in preventing molten metal-water explosions where molten metal comes in contact withe steel or concrete following bleed-outs and spills during DC casting. Details regarding this testing and further testing to investigate the effect of coating cure time on adhesion and explosion avoidance can be found in the two reports below.
Aluminum Fines & Powder
Activities including the grinding, polishing, sawing, cutting, sanding and scratch brushing of aluminum generate fine aluminum particles, some of which are potentially explosive. These particles are known as “fines”, “dust” or “powder.”
In the case of aluminum, explosions can result if ignition occurs while particles are suspended in the air as a dust cloud, as the burning extends from one particle to another with extreme speed. Potential sources of ignition include open flames, welding equipment, cutting torches, matches, cigarettes, faulty electrical equipment and static electrical charges.
Qualified personnel can determine the degree of hazard in any operation through laboratory testing. Dust collections systems, of the dry or the wet type, safely capture potentially explosive aluminum fines. Enclosures or exhaust hoods provide efficient pick-up of the fines from the machine or equipment.
Below are several resources on the safe handling of aluminum fines and powder.
To develop information on the combustibility and flammability of aluminum alloys, the Aluminum Association commissioned testing in accordance with the ASTME 136-11 "Standard Test Method for Behavior of Materials in a Vertical Tube Furnace at 750°C" on common alloys 3003, 5052, 5083 and 6061. The testing indicated that all four alloys met the performance criteria presented in ASTM E 136-11. In 2020, alloys commonly used in building construction were tested in accordance with updated ASTM E 136-19. Alloys 5005, 6005/6105, 6005A, 6061, 6063, and 6351 as well as commercial purity, P1020A, aluminum were tested and passed. Links to the individual test reports are provided below.
As aluminum is increasingly used in construction, concerns have arisen regarding its potential combustibility. These perceptions are mistaken. Unfortunately, this has resulted in erroneous information spreading among both the general public and professional circles. This white paper aims to explain these origins and provides scientific evidence to highlight aluminum’s safety and reliability.