Print PDF
Favorite
Email
Step 11Safety considerations
Safety Considerations:
Ventilation
Respiratory protection
Eye Protection
Heat Protection
Danger of welding galvanized metal (from cutting, welding, and brazing) You are heating galvanized metal, which is coated in zinc. The zinc will burn off and oxidize in the air, creating zinc oxide. Breathing zinc oxide can cause Metal Fume Fever. According to the American Welding Society, Metal Fume Fever causes flu-like symptoms including headache, fever, chills, muscle aches, thirst, nausea, vomiting, chest soreness, fatigue, gastrointestinal pain, weakness, and tiredness. Symptoms start several hours after exposure and last 6 to 24 hours. The American Welding Society claims that there are no known long-term affects from Metal Fume Fever.
Ventilation:
*Braze outside. Portability is one nice thing about oxy-acetylene torches.
*Keep air moving across the work, with a fan or align yourself with wind so that the smoke blows sideways. (If your back is to the wind, your body will stop the airflow in front of your face.)
*Don't breathe the smoke plume.
*Keep your head back from and never above the area that you are brazing.
*Watch the ends of tubes, because fumes will escape from them.
In the process of designing and learning to build bike trailers with galvanized conduit, I got metal fume fever twice, through carelessness. You should be careful, and I think it is possible to braze EMT conduit safely. The sickness felt like the head and body ache that are symptoms of influenza. I felt dehydrated and tired. I felt fine the next morning.
Respiratory Protection:
If you cannot ensure adequate ventilation, wear an N95 (or higher) type respirator. You can buy a N99 filter respirator from McMaster-Carr for $11.09 (Part #53565T2). The instructions say it;s good for 8 hours of breathing through, or until it gets hard to breathe through. 2 replacement filters are $5.61. I don;t like buying from large mail-order corporations, but if the tradeoff is getting sick or not building a bike cart, I will do it.
Eye protection:
Use #5 shade eye protection. If you look at the flame for a second, you;re not going to lose your sight, but it;s bright and bad for your eyes, a bit worst than looking at the sun. I've heard that you're eyes are safe 10 feet back from the flame.
Heat Protection:
Use gloves to touch the metal that you are working on. The brazing rod will get hot close to the end.
Metal Fume Fever Information
According to the American Welding Society, Metal Fume Fever is an illness caused by exposure to zinc oxide, a chemical present in fumes from welding and brazing galvanized metal. The symptoms of metal fume fever are flu-like, including headache, nausea, fever, fatigue, and chills. Symptoms start several hours after exposure and last 6 to 24 hours, although total recovery might not be for 48 hours. High levels of exposure may cause metallic taste in mouth, dry and irritated throat, and coughing. Several hours after exposure, you may have a fever (lower than 102 degrees F, then chills before returning to normal). The OSHA standard for zinc oxide exposure is 5 miligrams per cubic meter of air averaged over an 8 hour work shift. NIOSH uses the same 5 mg per m3 (cubic meter), but suggests that it is permissible for 10 hours per day, or 40 hours per week. They further permit a STEL (short term exposure limit) of 10 mg/m3 averaged over a 15 minute period. There is no published information about long term effects of zinc oxide exposure. (American Welding Society. Safety and Health Fact Sheet No. 25) Even though there are no known long term effects, it doesn't make sense to expose yourself to zinc oxide and potentially suffer from Metal Fume Fever, because it's easy to prevent exposure. Brazing, as opposed to welding, produces fewer fumes because of the lower temperatures.
Ventilation
Respiratory protection
Eye Protection
Heat Protection
Danger of welding galvanized metal (from cutting, welding, and brazing) You are heating galvanized metal, which is coated in zinc. The zinc will burn off and oxidize in the air, creating zinc oxide. Breathing zinc oxide can cause Metal Fume Fever. According to the American Welding Society, Metal Fume Fever causes flu-like symptoms including headache, fever, chills, muscle aches, thirst, nausea, vomiting, chest soreness, fatigue, gastrointestinal pain, weakness, and tiredness. Symptoms start several hours after exposure and last 6 to 24 hours. The American Welding Society claims that there are no known long-term affects from Metal Fume Fever.
Ventilation:
*Braze outside. Portability is one nice thing about oxy-acetylene torches.
*Keep air moving across the work, with a fan or align yourself with wind so that the smoke blows sideways. (If your back is to the wind, your body will stop the airflow in front of your face.)
*Don't breathe the smoke plume.
*Keep your head back from and never above the area that you are brazing.
*Watch the ends of tubes, because fumes will escape from them.
In the process of designing and learning to build bike trailers with galvanized conduit, I got metal fume fever twice, through carelessness. You should be careful, and I think it is possible to braze EMT conduit safely. The sickness felt like the head and body ache that are symptoms of influenza. I felt dehydrated and tired. I felt fine the next morning.
Respiratory Protection:
If you cannot ensure adequate ventilation, wear an N95 (or higher) type respirator. You can buy a N99 filter respirator from McMaster-Carr for $11.09 (Part #53565T2). The instructions say it;s good for 8 hours of breathing through, or until it gets hard to breathe through. 2 replacement filters are $5.61. I don;t like buying from large mail-order corporations, but if the tradeoff is getting sick or not building a bike cart, I will do it.
Eye protection:
Use #5 shade eye protection. If you look at the flame for a second, you;re not going to lose your sight, but it;s bright and bad for your eyes, a bit worst than looking at the sun. I've heard that you're eyes are safe 10 feet back from the flame.
Heat Protection:
Use gloves to touch the metal that you are working on. The brazing rod will get hot close to the end.
Metal Fume Fever Information
According to the American Welding Society, Metal Fume Fever is an illness caused by exposure to zinc oxide, a chemical present in fumes from welding and brazing galvanized metal. The symptoms of metal fume fever are flu-like, including headache, nausea, fever, fatigue, and chills. Symptoms start several hours after exposure and last 6 to 24 hours, although total recovery might not be for 48 hours. High levels of exposure may cause metallic taste in mouth, dry and irritated throat, and coughing. Several hours after exposure, you may have a fever (lower than 102 degrees F, then chills before returning to normal). The OSHA standard for zinc oxide exposure is 5 miligrams per cubic meter of air averaged over an 8 hour work shift. NIOSH uses the same 5 mg per m3 (cubic meter), but suggests that it is permissible for 10 hours per day, or 40 hours per week. They further permit a STEL (short term exposure limit) of 10 mg/m3 averaged over a 15 minute period. There is no published information about long term effects of zinc oxide exposure. (American Welding Society. Safety and Health Fact Sheet No. 25) Even though there are no known long term effects, it doesn't make sense to expose yourself to zinc oxide and potentially suffer from Metal Fume Fever, because it's easy to prevent exposure. Brazing, as opposed to welding, produces fewer fumes because of the lower temperatures.
| « Previous Step | Download PDFView All Steps | Next Step » |
 |
Add Comment
|
