ALLLAND Steel Pipe Supply
Welcome to ALLLAND Steel Pipe Manufacturing. The DIN 30678 polypropylene coating system (3LPP Coating System) is capable of long-term, stable operation even in high-temperature and highly corrosive environments. Based on proven coating technologies and rigorous quality control processes, ALLLAND provides high-quality 3LPP-coated steel pipes that meet DIN 30678 requirements to customers worldwide. To address diverse project requirements, ALLLAND also offers customization services with a variety of coating options available.
Alllandsteel is a steel pipe manufacturer based in China with 25 years of experience.
The facility spans 22,000 square meters, represents a RMB 700 million investment, and operates four production lines (JCOE, ERW, SMLS, SSAW) alongside five coating lines.
With an annual production capacity of 250,000 tons, the factory covers specifications ranging from Ø406 to Ø1524 and holds multiple international certifications (API/ASTM/EN/ISO/JIS). Focused on steel pipes, creating value for you!
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DIN 30678 is one of the key standards in the German Industrial Standards system for external anti-corrosion coatings on steel pipelines (External Coating System for Buried or Submerged Steel Pipelines). It belongs to the same system as standards such as DIN 30670 (3LPE) and DIN 30671, and is applied to buried anti-corrosion protection systems for gas, water, and industrial pipelines.
DIN 30678 primarily specifies the technical requirements and testing methods for multi-layer polypropylene/polyethylene coating systems (3LPP / thermoplastic coating system), and is particularly suitable for higher temperatures or more severe environmental conditions.
O.D.:
114.3 mm – 1422 mm (mainstream)
W.T.:
3.0 mm – 40 mm (standard)
Length:
6 m – 18 m (most common)/custom
Cathodic Disbondment:
Test conditions: 60°C / 80°C / 95°C
Surface Preparation:
Sa 2.5 sandblasting (ISO 8501-1)
Surface roughness: 50–100 μm (typical)
Preheating Temperature:
180°C – 240°C（depending on pipe thickness）
Coating Thickness::
FBE: 100 – 250 μm
Adhesive layer: 150–300 μm (typical)
PP outer sheath: 1.5 mm–4.0 mm (standard)
Holiday Test:
100% inspection;
Voltage: 5–25 kV (depending on coating thickness)
DIN 30678 specifies the corrosion protection requirements for thermoplastic multilayer coating systems applied to the outer surfaces of steel pipelines.It is primarily applicable to:
DIN 30678 typically specifies a 3-layer system:
First Layer: Epoxy Primer (FBE Layer)
Fusion-Bonded Epoxy (FBE): This layer serves as the primary corrosion barrier for the steel pipe and provides adhesion to the pipe.
The thickness is typically approximately 100–250 μm.
Second Layer: Adhesive Layer
Copolymer Adhesive: This layer bonds the FBE to the PP outer protective layer, providing interfacial adhesion.
Third Layer: Polypropylene Top Coat (PP Top Coat)
Polypropylene (PP Top Coat): Provides mechanical protection and impact resistance. This layer has higher temperature resistance than PE, with a thickness typically ranging from 1.5 mm to 4.0 mm (depending on pipe diameter and grade).
| Pipe Diameter Range | PP Thickness |
| Small-diameter （≤219mm） | 1.5 – 2.0 mm |
| Medium-diameter（219–610mm） | 2.0 – 3.0 mm |
| Large-diameter （≥610mm） | 3.0 – 4.0+ mm |
When installed underground or in high-temperature environments, DIN 30678 requires that the coating must not crack, peel, or fail.
DIN 30678 requires that the coating have an extremely low water vapor transmission rate in order to provide long-term protection against soil corrosion media and prevent the propagation of cathodic underfilm corrosion.
This is one of the key performance indicators of DIN 30678. In tests simulating a cathodic protection environment, the coating must not exhibit interfacial propagation failure, and the radius of disbondment must be controlled.
The coating must not fail under the specified impact test, ensuring the overall structure’s impact resistance.
DIN 30678 also requires that the coating must not fail due to rapid abrasion under soil friction or gravel conditions. This is of critical importance in applications such as horizontal directional drilling (HDD) and rocky soil environments.
This is the key distinction between DIN 30678 and DIN 30670 (3LPE).
DIN 30678 is applicable to environments ranging from 50°C to 110°C. Additionally, the thermal aging stability of the coating must be ensured; for example, in high-temperature oil and gas transmission pipelines, the coating must not soften or become brittle over the long term.
DIN 30678 emphasizes that performance depends not only on the materials but also on construction control.
The surface preparation of the substrate—sandblasted to Sa 2.5 grade—must meet the standard requirements. Surface roughness must be controlled within the optimal adhesion range.
The PP layer must be applied uniformly, and any localized thin spots must not compromise the corrosion protection system.
DIN 30678 emphasizes the long-term stability of a three-layer coating system, primarily covering three aspects: corrosion protection, mechanical integrity, and temperature stability.
The standard specifies comprehensive and rigorous testing procedures for performance evaluation.
Holiday Test: Detects pinholes in the coating; the test voltage is typically 5–25 kV (depending on thickness).
Peel Strength Test: Tests the interlayer adhesion between the FBE, adhesive, and PP layers to ensure the corrosion resistance stability of the overall structure.
Cathodic Disbondment Test: Simulates a cathodic protection environment to evaluate the coating’s resistance to failure, ensuring long-term protective performance.
Impact and Indentation Test: Simulates mechanical damage caused by transportation or underground construction in actual operating conditions to ensure the coating’s basic mechanical properties.
Oil & Gas Transmission Pipelines
· Hot crude oil pipelines: The PP outer coating compliant with DIN 30678 offers superior thermal resistance compared to PE, effectively preventing coating softening and creep.
· Natural Gas Transmission Pipelines: The DIN 30678 standard offers strong resistance to cathodic disbonding and a long service life, thereby reducing maintenance costs.
· Oilfield Gathering Systems: These systems must meet the dual requirements of resistance to chemical corrosion and mechanical damage.
Offshore / Subsea Pipelines
The PP layer provides high mechanical protection and excellent impact and compression resistance.
· Subsea oil and gas pipelines
· Subsea transmission systems
High-Temperature Industrial Pipelines
DIN 30678 is capable of withstanding long-term elevated-temperature service in these environments and prevents the PE coating from softening and failing.
· Chemical process pipelines
· Thermal/heating pipelines
Crossing Applications
This is a typical “high-stress scenario” as defined by DIN 30678. The PP layer offers excellent scratch resistance, outperforming PE systems.
· Horizontal Directional Drilling (HDD) pipeline installation
· Microtunneling / Pipe jacking
DIN 30678 is not a standard for general-purpose corrosion-resistant pipelines; rather, it is a specification designed for applications under severe operating conditions.
Essentially, it addresses the corrosion protection requirements for steel pipelines operating in environments characterized by high temperatures, high mechanical stress, and long-term burial or submersion.
| Item | DIN 30670 | DIN 30678 |
| Outer layer | PE (Polyethylene) | PP (Polypropylene) |
| Temperature resistance | Moderate (≤80°C) | High (≤110°C+) |
| Mechanical strength | Good | Higher |
| Cost | Lower | Higher |
| Application | General pipeline applications | High-temperature / harsh environments |
DIN 30678 is a German standard that specifies a three-layer polypropylene (3LPP) coating system for the external corrosion protection of steel pipelines, designed for high-temperature and harsh underground/subsea pipeline applications.
The standard design temperature range is typically 50°C – 110°C, though higher temperatures are possible with special designs.
3-layer polypropylene coating system (3LPP).
