5 MORE Engineering Materials You Must Never Use

  • Unwittingly using a dangerous material in a design can result in serious injury or death. No engineer wants this to happen.
  • Did you know there are forms of chrome that can increase the chances of cancer if exposed to it at regular intervals?
  • Depleted uranium is denser than most metals, including lead, and as such is perfect for use as an armour piercing projectile. Or is it? Read the article to learn more.

Are you using Dangerous Materials? When the time comes to select a material for a new design, as engineers we’re often left drowning in a sea of choice. Just choosing the correct stainless steel for a job is challenging. What makes things more challenging is the fact that some materials can cause serious harm to the people that are exposed to them. We recently told you about 5 engineering materials you must NEVER use, and listed below are 5 more. These are dangerous materials that should never be used as they can have a detrimental effect on your health and the health of those who will be exposed to your designs.

1.    Hexavalent Chromium

Hexavalent chromium is a chemical compound that contains chromium in the 6th oxidation state. This is typically produced during stainless steel welding where the chrome that is present is not initially hexavalent but becomes so due to the high temperatures created during the welding process. Some other typical uses of chromium VI include anti corrosion additives for paint, electro plating and paint pigment. Chromium VI is a carcinogen which means that exposure to it increases the risk of cancer. It also causes damage to the eyes, nasal passages and respiratory system.

5 more engineering materials you must NEVER use

2.    Depleted Uranium

Depleted uranium (DU) is produced as a by-product of the manufacture of enriched uranium. It should be noted that DU tends to be only 60% as radioactive as naturally occurring uranium.

It is most often used as armour and armour piercing rounds in military applications. Its high density is one of the reasons it is effective as a weapon (it is denser than lead) as it has more penetrating power. Depleted uranium is radioactive and as such is seen as a controversial choice for weapons. When a DU shell impacts a target, it tends to contaminate the area around the target and as such increases the possibilities of inhalation by civilians. This can increase their risk of cancer.

3.    Mercury

Mercury is a fascinating metal. It melts at -38.9oC and only boils at 356.6oC. Therefore, it saw widespread use in thermometers, barometers and level switches in the past. More recently mercury can be found in lighting and some electronics. But there is a reason it is always kept in a sealed glass tube. This is because it is a dangerous material and extremely toxic. Mercury can be fatal if ingested and causes damage to the central nervous, immune and digestive systems. Mercury is currently in the process of being phased out and soon we will no longer see it being used in any capacity except for the odd niche application.

4.    Polyvinyl Chloride (PVC)

PVC is a thermoplastic. A thermoplastic is a plastic that can be melted and reformed without significant loss of mechanical properties. PVC is used almost everywhere and is supplied both as a rigid and soft plastic. It is used in piping, food packaging and in some places as a substitute for rubber. Although testing on animals has shown no serious health effects, there has been no conclusive testing on humans and as such there is a lot of confusion as to whether PVC is a health hazard during normal use. The end of the lifecycle of a PVC product is a different matter as it cannot be incinerated since hazardous fumes are released during burning. Furthermore, if left in land fill sites harmful chemicals used during the manufacture of the PVC begin to leach into the ground. This in turn contaminates drinking water.

5.    Polychlorinated biphenyls (PCB’s)

PCB’s refer to a group of manmade chemicals that were widely used in industry. Some of the more typical applications include, but are not limited to; plasticizers, heat transfer, adhesives and plastics. PCB’s have been proven to cause cancer in animals and as such the EPA banned numerous uses. However, this does not mean that these chemicals are completely out of the picture. Care must be taken when using PCB’s as they are a suspected carcinogen and must be treated with respect.

In Summary

Engineers take on massive responsibility, a single misstep during the design process can cause fatal accidents and exposure to toxic materials. There are many dangerous materials on the market that can cause serious harm to the public if misused and misunderstood. This article has brought to light another 5 materials that should not be used if at all possible. If there is no choice, then every step must be taken to ensure that the risks are reduced to acceptable levels. Always make sure that you understand the limits and dangers of the materials you use.

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