Technical guide for specifiers, contractors, and distributors of EN877 cast iron soil and drainage pipes.
When you specify an EN877 cast iron pipe for a soil, waste, or ventilation system, the internal coating is not a finishing touch — it is the first line of defence against corrosion, scaling, and flow loss. A poorly controlled cast iron pipe coating fails from the inside out, long before the pipe body shows any sign of trouble. This article breaks down the two tests that actually matter — dry film thickness (DFT) and adhesion — exactly as they are applied to finished cast iron soil pipe products, and shows how DINSEN verifies every batch in-house.
1. Dry Film Thickness (DFT) — Tested Only on Finished Product
Internal coating thickness can only be measured on a finished cast iron drainage pipe or fitting, never on a lab panel. DINSEN uses the instrument specified in EN ISO 2808 and applies the following sampling rules:
- Pipes: Measure at least 10 points across the bore, excluding the last 20 mm at each end. The reported value is the average.
- Fittings: Take at least 5 evenly distributed points on the coated surface and average them.
The average must stay at or above the manufacturer’s declared minimum factory thickness. For every standard coating, the internal DFT of an EN877 cast iron pipe must not exceed 400 µm — coatings built for special service conditions are the only exception.
This is where DINSEN’s supply chain stands apart: DINSEN is the only foreign-trade company that owns its own imported coating thickness gauge. Thickness is verified on real production samples before shipment, not estimated from a datasheet — a level of in-house control most traders simply cannot offer.
2. Adhesion — EN ISO 2409 Cross-Cut Test
Thickness means nothing if the coating does not stay attached. Adhesion is checked only on a finished, coated sample using the EN ISO 2409 cross-cut method:
- Sample: Cut a length of ≥ 100 mm from a coated pipe or fitting; DN100 and above is preferred.
- Grid: 6 cuts in each direction.
- Spacing: 2 mm as standard; switch to 3 mm when the manufacturer’s minimum specified coating thickness is ≥ 120 µm.
- Pass criterion: Result meets Class 1 per clause 4.11.2.
DINSEN’s results:
- Inner paint: adhesion reaches Class 1 or better.
- Outer paint: adhesion reaches Class 2 or better.
For a ductile cast iron pipe or grey-iron soil pipe operating in humid, aggressive, or high-temperature drainage environments, a Class 1 inner bond is what keeps the lining from blistering, peeling, or harbouring bacteria over a 50-year service life.
3. Why This Matters When You Buy
Two cast iron pipe lines can look identical on a quotation yet perform completely differently in the wall. The difference is almost always in the coating controls above. Specifying EN877 is the starting point; demanding verified DFT and Class 1 inner adhesion is what protects your project. Ask any supplier for the actual measured values on finished product — not just the standard number.
Frequently Asked Questions
Q: What is the maximum internal coating thickness allowed on an EN877 cast iron pipe?
A: For standard industrial drainage coatings, the internal coating DFT must not exceed 400 µm, while the average must not drop below the manufacturer’s stated minimum. Coatings for special service conditions are the only exception.
Q: How is adhesion of a cast iron pipe coating tested under EN ISO 2409?
A: A coated sample ≥ 100 mm long is cross-cut with a 6-line grid (2 mm spacing, or 3 mm when min thickness ≥ 120 µm). The result must reach Class 1 per clause 4.11.2. DINSEN’s inner paint meets Class 1; the outer paint meets Class 2.
Q: What are DINSEN’s cast iron pipe coating thickness specifications?
A: Pipes: 130 µm internal / 60 µm external. Fittings: 60 µm inner and outer. DINSEN is the only foreign-trade supplier with its own imported thickness gauge, verifying every batch in-house.
Get Verified EN877 Cast Iron Pipes for Your Project
Need EN877 cast iron pipe and fittings with documented DFT and Class 1 inner adhesion — measured on real product, not assumed? DINSEN supplies fully tested cast iron soil and drainage systems to 50+ countries, with in-house coating verification on every batch.
Request a Quote & Test Report →
Post time: Oct-13-2026
