Metal Dust Collection Systems
Muza Sheet Metal Co. has been designing, fabricating and installing dust collection systems for the metal working industry since 1928. Dust collection in the metal working industry has been a very important part of our business. We believe in “Customer first” and will do so far into the future. Here are some important reasons to have an efficient dust collection system.
Safety Hazards
In many shops, "dust collection" means breaking out a broom and dust pan at the end of the day. Too many metalworkers spend years climbing over metal debris or standing on a slippery carpet of metal filings while they polish throughout the day.
It's easy to put off clearing away a hazardous mess when you're busy working. You know that it only takes a second to slip or stumble over a pile of debris. You can end up with an injury that could keep you out of the shop for a long time. Dust Collection keeps your shop safe and clear of debris. This helps you concentrate on your work. Now that is important!
Not only will you have an easier time finding and getting to things in your shop, you'll spend more time polishing, sanding, grinding, or routing and less time picking up dust.
Elements of a Dust Explosion
Elements Needed for a Fire (the familiar "Fire Triangle"):
- Combustible dust (fuel)
- Ignition source (heat)
- Oxygen in air (oxidizer)
Additional Elements Needed for a Combustible Dust Explosion:
- Dispersion of dust particles in sufficient quantity and concentration
- Confinement of the dust cloud
The addition of the latter two elements to the fire triangle creates what is known as the "explosion pentagon" (see Figure 1). If a dust cloud (diffused fuel) is ignited within a confined or semi-confined vessel, area, or building, it burns very rapidly and may explode. The safety of employees is threatened by the ensuing fires, additional explosions, flying debris, and collapsing building components.
An initial (primary) explosion (see Figure 2) in processing equipment or in an area were fugitive dust has accumulated may shake loose more accumulated dust, or damage a containment system (such as a duct, vessel, or collector). As a result, if ignited, the additional dust dispersed into the air may cause one or more secondary explosions (see Figure 2). These can be far more destructive than a primary explosion due to the increased quantity and concentration of dispersed combustible dust.
If one of the elements of the explosion pentagon is missing, a catastrophic explosion can not occur. Two of the elements in the explosion pentagon are difficult to eliminate: oxygen (within air), and confinement of the dust cloud (within processes or buildings). However, the other three elements of the pentagon can be controlled to a significant extent, and will be discussed further in this document.
Facility Dust Hazard Assessment
A combustible dust explosion hazard may exist in a variety of industries, including: food (e.g., candy, starch, flour, feed), plastics, wood, rubber, furniture, textiles, pesticides, pharmaceuticals, dyes, coal, metals (e.g., aluminum, chromium, iron, magnesium, and zinc), and fossil fuel power generation. The vast majority of natural and synthetic organic materials, as well as some metals, can form combustible dust. NFPA’s Industrial Fire Hazards Handbook5 states that "any industrial process that reduces a combustible material and some normally noncombustible materials to a finely divided state presents a potential for a serious fire or explosion."
Respiratory Health
Research identifies the health consequences of long-term exposure to metalworking dust. The Occupational Safety and Health Administration (OSHA) used this warning in its introduction to the topic of Metal Dust and Health
"Exposure to metal dust has long been associated with a variety of adverse health effects, including dermatitis, allergic respiratory effects, mucosal and nonallergic respiratory effects, and cancer..."
Controlling Two Kinds of Dust
The dust a metal shop produces is divided into two general categories: (1)Large dust particles, chips and shavings, and (2) fine metal dust. These two kinds of dust require a different strategy for adequate control.
