Читать книгу Welding For Dummies - Steven Robert Farnsworth - Страница 53

With all the extreme heat and sparks created during a welding job, you shouldn’t be surprised if something catches fire at some point. Because fires are a very real threat, keep a fire extinguisher on hand at all times.

Four main types of fire extinguishers (shown in Figure 3-2) work on four different kinds of fires:

 Class A: Class A extinguishers take care of any fires that produce ash. These fires usually involve wood, cloth, or paper.

 Class B: Class B fire extinguishers are for fighting fires caused by flammable liquids, such as gasoline, oils, and paints.

  Class C: Electrical fires call for Class C fire extinguishers. Don’t use any water- or foam-based extinguishers on an electric fire, or you put yourself at risk of serious shock.

 Class D: Use Class D extinguishers on metal fires. Combustible metals like magnesium, potassium, and sodium are extremely flammable, and fires based on these materials are very dangerous. Class D extinguishers are best for these fires because the other classes often disperse a metal fire instead of putting it out, and that makes the situation worse.

You should keep a Class C extinguisher nearby when you’re welding, in case an electrical fire breaks out. I recommend also keeping a Class B on hand for oil fires.

In addition to fire extinguishers, keep a water source (a hose, for example) and a bucket of sand nearby when you’re welding. They can come in handy when you need to control ash and metal fires, respectively, without the need for special extinguishers.

The best way to avoid needing an extinguisher is to cut down on the flammability of your project in the first place. For example, you may find the need to weld a metal 55-gallon drum. (It’s a common welding task.) If so, take care to ensure that the drum doesn’t have residual flammable materials on the interior. Before welding, be sure to clean the interior with steam or a chemical cleaner.

FIGURE 3-2: Four classes of fire extinguishers.