Flensa merupakan komponen penting dalam sistem perpipaan, memungkinkan sambungan antar pipa yang aman dan efisien, katup, pompa, dan peralatan. Untuk memastikan keamanan, kesesuaian, dan kinerja, the production and use of flanges are governed by standar internasional. Diantaranya, ANSI Dan ASME are the most widely recognized, but there are also other standards like DIN, JIS, BS, dan EN. Understanding these standards is essential for engineers, spesialis pengadaan, and industries dealing with global supply chains.

This article explains the major flange standards—ANSI, ASME, and others—highlighting their scope, fitur utama, and importance in industrial applications.

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Why Flange Standards Are Important

1. Safety and Reliability
   Standards ensure flanges can withstand the pressure and temperature conditions of different industries.

2. Dapat dipertukarkan
   Flanges from different manufacturers must fit together, which requires adherence to common standards.

3. Global Trade
   International projects often involve equipment from multiple countries, making standardized flanges critical for compatibility.

4. Quality Assurance
   Standards specify material composition, peringkat tekanan, ukuran, dan prosedur pengujian.

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ANSI Flange Standards

ANSI (Institut Standar Nasional Amerika) establishes guidelines for various products, termasuk flensa. ANSI flange standards specify:

• Ukuran (diameter, ketebalan, lingkaran baut, dll.)

• Peringkat tekanan-suhu

• Facing types (wajah terangkat, wajah datar, RTJ)

ANSI flange standards are widely used in the United States and in industries such as oil and gas, petrokimia, dan pembangkit listrik.

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ASME Flange Standards

ASME (Perkumpulan Insinyur Mekanik Amerika) issues detailed codes for pressure vessels, sistem perpipaan, dan flensa.

• ASME B16.5: Flanges up to 24 inches in diameter

• ASME B16.47: Flensa berdiameter besar (26–60 inci)

• ASME B16.36: Flensa lubang

• ASME B16.48: Line blanks

ASME standards are stricter than ANSI in terms of design rules, pengujian, and quality control. Many engineers today use the terms ANSI and ASME interchangeably, but technically, ASME has replaced ANSI for flanges in modern practice.

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Other International Flange Standards

1. DIN (Deutsches Institut für Normung – Germany)

• Common in Europe and Asia

• Specifies PN (Nominal Tekanan) ratings such as PN6, PN10, PN16, PN40

• Digunakan di pabrik kimia, kilang, dan pembangkit listrik

2. EN (European Norms)

• Harmonized standard across the European Union

• Replaces older DIN standards in many regions

• Ensures compatibility across EU member states

3. BS (British Standards)

• Historically used in the UK

• Meliputi flensa, gasket, and bolting specifications

• Now gradually aligned with EN standards

4. JIS (Standar Industri Jepang)

• Widely used in Japan and some Asian markets

• Specifies flanges for industrial piping systems

• Popular in shipbuilding, automotive, and petrochemical sectors

5. ISO (International Organization for Standardization)

• Provides global harmonization

• Ensures compatibility in international trade and projects

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Pressure Classes in Flange Standards

Different standards classify flanges by pressure capability:

• Kelas ANSI/ASME: 150, 300, 600, 900, 1500, 2500

• DIN/EN PN Ratings: PN6, PN10, PN16, PN25, PN40, PN64, PN100

• Peringkat Tekanan JIS: 5K, 10K, 16K, 20K, 30K

These classifications indicate the maximum pressure a flange can handle at a specific temperature.

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Flange Facing Types Defined by Standards

1. Wajah Terangkat (Federasi Rusia): Paling umum, allows better gasket compression.

2. Wajah Datar (FF): Used when bolting against cast iron or non-metallic surfaces.

3. Sambungan Tipe Cincin (RTJ): Untuk tekanan tinggi, aplikasi suhu tinggi.

4. Lidah dan Alur: Provides tight sealing in specialized applications.

Standards specify exact dimensions for these facings to ensure seal integrity and compatibility.

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Materials Specified in Flange Standards

• Baja Karbon: For general applications with moderate pressure and temperature

• Baja Tahan Karat (304, 316, 321, 347): For corrosive and high-temperature environments

• Baja Paduan (F11, F22, F91): For high-pressure and high-temperature service

• Baja Tahan Karat Dupleks dan Super Dupleks: For offshore and marine environments

• Paduan Nikel (tidak konel, Monel, Hastelloy): For extreme chemical and thermal conditions

By adhering to standards, manufacturers and buyers ensure materials match required service conditions.

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Key Differences Between ANSI, ASME, and Other Standards