A Step-by-Step Guide for Engineers and Industrial Buyers

플랜지는 배관 시스템의 필수 구성 요소입니다., acting as mechanical connectors that ensure secure, 누출 방지, and serviceable joints between pipes, 밸브, 슬리퍼, 및 장비. But with so many standards, 압력 등급, and sizes available, one key question arises — how to know the correct flange size

이 기사에서는, SASAFLANGE explains how to identify the correct flange size for your application, including the key dimensions, measurement techniques, and reference standards. Whether you are sourcing parts for a new project or replacing an existing flange, this guide will help you avoid errors and ensure proper system performance.

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Why Choosing the Right Flange Size Matters

Selecting the wrong flange size can lead to misalignment, pressure failures, increased leakage risk, and costly rework. Getting the flange size right is critical to

• Ensuring system compatibility

• Meeting pressure and temperature requirements

• Achieving proper sealing with gaskets

• Simplifying installation and maintenance

• Avoiding costly downtime or safety issues

~에 SASAFLANGE, we support customers in choosing flange dimensions that comply with global standards such as ASME, EN, DIN, 그리고 JIS.

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What Are the Key Flange Size Parameters

To identify or confirm the correct flange size, you need to understand and measure several key dimensions

1. 공칭 파이프 크기 (NPS) or DN

This refers to the size of the pipe the flange is intended to connect. 북미 지역, NPS (in inches) is used. In Europe and other regions, DN (diameter nominal in mm) applies.

2. 압력 등급 (클래스 또는 PN)

Defines the maximum pressure a flange can withstand. Common ASME classes are 150, 300, 600, 900, 그리고 1500. For EN/DIN standards, pressure ratings are shown as PN10, PN16, PN40, 등.

3. 외경 (의)

The total diameter of the flange face, important for proper alignment with mating components.

4. 볼트 원 직경 (BCD or PCD)

The diameter of the circle passing through the center of each bolt hole.

5. Number and Size of Bolt Holes

Bolt quantity and diameter must match exactly to ensure tight, leak-free assembly.

6. Flange Thickness

Measured from face to back, thickness affects strength and gasket compression.

7. Bore or Inner Diameter

Should match the outside diameter of the connecting pipe to maintain flow continuity.

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How to Determine the Correct Flange Size

Follow these steps to ensure you choose the correct flange size

단계 1: Identify the Pipe Size

Check the nominal pipe size (NPS 또는 DN). If you’re replacing an existing flange, measure the inside diameter and wall thickness of the pipe it connects to.

단계 2: Confirm the Pressure Rating

Refer to the piping system design or operating conditions. If the system operates under high pressure or temperature, a higher class (예를 들어, 수업 300 or PN40) is required.

단계 3: Measure the Flange Dimensions

Use calipers or a measuring tape to determine

• 외경

• Bolt circle diameter

• Number and size of bolt holes

• Bore and thickness

Compare your measurements with a standard flange dimension chart (~와 같은 ASME B16.5 또는 EN 1092-1) to verify the size.

단계 4: Check the Flange Type and Face

Is it a weld neck, 슬립온, 눈이 먼, 소켓 용접, or threaded flange Is it raised face, 평평한 얼굴, or ring-type joint This affects both installation and gasket compatibility.

단계 5: Confirm Standards and Material

Ensure the flange material (예를 들어, 스테인레스 스틸, 탄소강, 합금강) and manufacturing standard match your system requirements.

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Flange Size Chart Example (ASME B16.5, 수업 150, NPS 4)