DIN 3015 Pipe Clamp Dimensions: Part 1 and Part 2 Reference Tables

DIN 3015 defines pipe clamp geometry for hydraulic and pneumatic systems on mobile machinery — a category that includes wind turbine nacelles. This article provides a dimensional reference table for the bore sizes most commonly encountered in wind turbine hydraulic, cooling and pneumatic circuits, for both Part 1 (single-bolt) and Part 2 (double-bolt) configurations. Values given are nominal per the standard; always verify against your supplier's inspection report for safety-critical installations.

§ 01 — Standard scope and part structure

DIN 3015 is structured in three parts:

• Part 1 — Light series (single bolt). Single clamping bolt, suited to general hydraulic, cooling and pneumatic lines with moderate vibration.
• Part 2 — Heavy series (double bolt). Two clamping bolts symmetrically placed, providing higher clamping force and superior vibration resistance. Mandatory for gearbox-adjacent and high-pressure locations in most wind OEM specifications.
• Part 3 — Insert elements. Defines the elastomeric liner geometry, hardness and material coding — not a structural clamp dimension.

The bore dimension d₁ in DIN 3015 refers to the pipe outside diameter the clamp is designed to grip, not an internal bore. When ordering, always specify the actual measured pipe OD in millimetres — not the nominal pipe size or DN designation, which may not match the OD you need.

§ 02 — Key dimensions explained

The following dimensions appear in DIN 3015 drawings and on supplier datasheets:

• d₁ — nominal pipe OD the clamp grips (mm). This is the primary ordering parameter.
• L — overall clamp width (flange-to-flange length, mm). Determines the space the clamp occupies along the pipe axis.
• H — installed height from mounting surface to top of clamp body (mm). Critical for clearance checks in tight nacelle routing.
• a — bolt-hole centre distance from clamp centreline (mm). For Part 1, this is the single bolt; for Part 2, it is the spacing between the two bolts. Determines backplate or rail hole pattern.
• Bolt size — metric thread designation of the clamping bolt (M6–M16 depending on bore).
• Approx. weight — carbon steel HDG body only, without insert or fasteners (grams). Useful for weight budget calculations on hub and blade assemblies where every kilogram is counted.

§ 03 — DIN 3015 Part 1 dimensions (single bolt, light series)

Common wind turbine bore range. Values are nominal; tolerances per § 05.

§ 04 — DIN 3015 Part 2 dimensions (double bolt, heavy series)

Part 2 uses two symmetrically placed bolts. The key differences from Part 1 are a wider flange (larger L), the two-bolt hole pattern (dimension a is the distance from centreline to each bolt hole), and higher body mass. Height H is similar to Part 1 for the same d₁.

§ 05 — Tolerances and fit considerations

DIN 3015 specifies the bore dimension d₁ as a nominal pipe OD. The insert element (Part 3) provides the dimensional compliance between the clamp shell and the pipe — the steel body itself is not in direct contact with the pipe. Key tolerance considerations:

• Bore tolerance. The steel clamp body halves are typically stamped or formed with a tolerance of ±0.5 mm on the d₁ dimension. The elastomeric insert compensates for this and for pipe OD variation within the standard pipe OD tolerance band (typically ±0.25–0.5 mm per EN 10305 or equivalent).
• Insert compression. A correctly installed clamp with the correct insert should achieve a metal-to-metal contact between the two clamp halves — or a gap of no more than 0.5–1.0 mm — when tightened to the specified bolt torque. Excessive gap indicates an insert that is too thick for the bore, or a pipe OD that is undersized.
• Backplate / rail hole pattern. The mounting hole spacing (dimension a) has a tolerance of ±0.5 mm. For rail mounting systems carrying multiple clamps, verify that accumulated hole-position tolerances remain within the rail slot width.
• Non-standard OD pipe. If the pipe OD falls between two standard d₁ sizes, always select the clamp size above (i.e., the next larger bore), and specify the insert hardness and geometry for the actual OD. Never compress an undersized insert to fit an oversized bore — the clamping force distribution will be incorrect.

§ 06 — Goods-in dimensional verification

For wind turbine projects subject to IEC 61400-1, DNV-ST-0126 or equivalent structural documentation requirements, incoming clamp dimensions should be verified as part of goods-in inspection. A practical verification procedure:

1. Bore check. Use a calibrated go/no-go gauge or vernier calliper to verify the internal bore of each clamp half. Sample size: 5% of batch or per project QC plan, minimum 3 pieces.
2. Flange width (L). Measure with vernier calliper. Should be within ±1.0 mm of the nominal value in the table above.
3. Bolt-hole spacing (a). Measure centre-to-centre (Part 2) or centre-to-body centreline (Part 1). Verify against backplate or rail drawing.
4. Visual inspection. Check coating continuity (no bare steel, no runs or sags), insert seating (insert fully seated with no delamination at edges), and bolt thread condition.
5. Weight spot-check. A batch weight discrepancy of more than ±10% from the nominal values above may indicate a material substitution. Cross-check against the MTC if available.

How to measure pipe OD for clamp selection