Copper Tube Types K, L, M Explained: Which One Do You Need?
Type K, L, M copper tubes differ in wall thickness. This guide explains which to use for your application.
What K, L, M Mean
Per ASTM B88: Type K = thickest (underground, high pressure), Type L = medium (most versatile, commonly used), Type M = thinnest (low-pressure residential). Color code: K = Green, L = Blue, M = Red.
Wall Thickness (1/2″ example)
| Type | Wall (inch) | Wall (mm) | Pressure |
|---|---|---|---|
| K | 0.049″ | 1.24mm | ~1000 PSI |
| L | 0.040″ | 1.02mm | ~850 PSI |
| M | 0.028″ | 0.71mm | ~650 PSI |
When to Use Each
Type K: Underground water service, well pumps, main lines. Type L: Interior water distribution, HVAC, fire sprinklers (the workhorse). Type M: Residential interior plumbing where code allows.
Copper Grades
C12200 (DHP): Most common for plumbing. C1200 (DLP): Low phosphorus for high-temp. C11000 (ETP): Highest conductivity for electrical.
CoreMetal supplies copper tubes in all types and tempers. Contact us for pricing.
Need Help with Steel Products?
Xi’an Coremetal Steel Co., Ltd. delivers quality steel to 60+ countries.
📧 tracy@coremetalsteel.com | 📞 +86 18291910632
Contact Tracy for a free quote!