Lead solder in plumbing is defined as solders and flux containing which of the following?

Lead solder in plumbing is defined as solders and flux containing which of the following?

• A. 10% lead
• B. 20% lead
• C. 2/10 of lead
• D. 0% lead

Answer: (C)

Lead solder in plumbing is defined by the lead content in the alloy. The presence of lead lowers the melting point and improves flow, and a common leaded Sn-Pb plumbing solder uses about 80% tin and 20% lead. That means the lead content is 2/10 by weight, or 20%. The flux is separate and affects cleaning and wetting, not the lead percentage. So the option stating 20% lead best matches how leaded solder is defined. In modern practice for potable water, lead-free solders are required, but historically lead content around 20% is what this term describes.

Lead solder in plumbing is defined by the lead content in the alloy. The presence of lead lowers the melting point and improves flow, and a common leaded Sn-Pb plumbing solder uses about 80% tin and 20% lead. That means the lead content is 2/10 by weight, or 20%. The flux is separate and affects cleaning and wetting, not the lead percentage. So the option stating 20% lead best matches how leaded solder is defined. In modern practice for potable water, lead-free solders are required, but historically lead content around 20% is what this term describes.