What is EN 1092-1 Loose Plate Flange Type 04?
EN 1092-1 Type 04 is a loose plate flange designed for use with a Type 34 weld-neck collar. It is a non-welded, rotatable flange plate that fits around the weld-neck collar and provides easy bolt hole alignment during installation.
This flange does not contact the conveying medium directly, as the sealing and pressure resistance are provided by the matching weld-neck collar. Type 04 is widely used in European piping systems for corrosion-resistant lines, easy assembly, and frequent maintenance scenarios.
Design Features of Type 04 Loose Plate Flange
Type 04 loose plate flange has clear and practical structural characteristics.
- Loose and rotatable design for easy bolt hole alignment
- No welding required on the flange itself
- Works only with Type 34 weld-neck collar
- Flat and simple plate structure
- Reduces installation difficulty and on-site labor time
- Protects expensive alloy or stainless steel pipes
- Standard dimensions ensure interchangeability
- Suitable for medium-pressure piping systems
The rotatable feature is especially useful in large-bore or restricted installation spaces.
How Loose Plate Flange Works with Type 34 Weld-Neck Collar
EN 1092-1 Type 04 loose plate flange must be used together with Type 34 weld-neck collar. The Type 04 flange plate is placed over the pipe first, and then the Type 34 weld-neck collar is welded to the pipe end.
The loose flange can rotate freely to align bolt holes easily during installation. The sealing surface is provided by the face of the Type 34 collar, while the Type 04 flange provides the clamping force. This combination is widely used for stainless steel and alloy pipelines to protect expensive piping materials and simplify assembly.
EN Approved Materials for Flange Type 04
Type 04 loose plate flanges are produced using common EN standard materials to meet industrial requirements.
Carbon steel materials
- S235JR
- P235GH
- P265GH
Stainless steel materials
- 1.4301 (304)
- 1.4401 (316)
- 1.4404 (316L)
Material selection depends on the application environment, including temperature, pressure, and corrosion level. The matching Type 34 collar is usually made of the same material as the pipeline.
Sealing Surface Options
Type 04 loose plate flanges support standard sealing faces in line with EN 1092-1.
- Raised Face (RF) – Most commonly used for general applications
- Flat Face (FF) – Used for low-pressure systems
- Other types available upon specific project requirements
Sealing performance depends on the matching gasket and the end face of the Type 34 weld-neck collar.
Where to Use Type 04 Loose Plate Flange?
EN 1092-1 Type 04 loose plate flanges are widely used in many industrial fields.
- Stainless steel and alloy piping systems
- Chemical and petrochemical processing lines
- Food, beverage, and pharmaceutical industries
- Water treatment and utility pipelines
- Corrosive medium applications
- Systems requiring frequent disassembly and maintenance
- Large-bore pipelines where alignment is difficult
Type 04 flanges are especially preferred where installation convenience and corrosion resistance are both required.
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