Pipe Bore Size Chart - Copper, Steel, MDPE & Multi-Layer

Pipe Bore Size Chart

Quick Reference Guide for Selecting the Correct Insulation Size

Choosing the correct insulation bore size is critical for proper fit and thermal performance. This chart helps you match pipe outside diameter (OD) to the correct insulation bore size for copper, steel, MDPE, and multi-layer pipes.

📐 How to Use This Chart

  1. Measure your pipe's outside diameter (OD) using a tape measure or caliper
  2. Find your pipe type in the table below
  3. Match the OD to the correct insulation bore size
  4. Select your insulation thickness (13 mm, 19 mm, 25 mm, or 32 mm)

Important: Insulation bore size refers to the internal diameter of the insulation tube, not the pipe size.

🔵 Copper Pipe (Most Common for HVAC & Plumbing)

Pipe Size (Nominal) Outside Diameter (OD) Insulation Bore Size
15 mm 15 mm 15 mm
22 mm 22 mm 22 mm
28 mm 28 mm 28 mm
35 mm 35 mm 35 mm
42 mm 42 mm 42 mm
54 mm 54 mm 54 mm
76 mm 76.1 mm 76 mm
108 mm 108 mm 108 mm

🔴 Steel Pipe (Common for Commercial HVAC & Heating)

Pipe Size (Nominal) Outside Diameter (OD) Insulation Bore Size
1/2" 21.3 mm 22 mm
3/4" 26.9 mm 28 mm
1" 33.7 mm 35 mm
1 1/4" 42.4 mm 42 mm
1 1/2" 48.3 mm 48 mm
2" 60.3 mm 60 mm
2 1/2" 76.1 mm 76 mm
3" 88.9 mm 89 mm
4" 114.3 mm 114 mm

🟢 MDPE & Multi-Layer Pipe (Domestic Plumbing)

Pipe Size (Nominal) Outside Diameter (OD) Insulation Bore Size
15 mm 16-18 mm 18 mm or 22 mm
20 mm 20-22 mm 22 mm
25 mm 25-28 mm 28 mm
32 mm 32-35 mm 35 mm

Note: MDPE and multi-layer pipes vary by manufacturer. Always measure the OD to confirm.

📊 How to Measure Pipe OD Correctly

Method 1: Tape Measure (Quick Estimate)

  1. Wrap a tape measure around the pipe
  2. Divide the circumference by 3.14 (π) to get the diameter
  3. Round up to the nearest standard size

Method 2: Caliper (Most Accurate)

  1. Use a digital caliper to measure across the widest part of the pipe
  2. Match the measurement to the chart above

✅ Insulation Thickness Selection

Once you know the bore size, choose the correct thickness:

  • 13 mm: Domestic hot/cold water, HVAC heating
  • 19 mm: Chilled water, heat pumps
  • 25 mm: Refrigeration, high-humidity areas
  • 32 mm: Low-temperature refrigeration, extreme condensation risk

See full thickness guide →

🛒 Shop by Bore Size

📚 Related Guides

Still not sure which size you need? Contact our technical team for help.