ガス供給ネットワーク用のフランジの選択

最新のガス供給ネットワークでは, フランジ play a crucial role in creating reliable, パイプライン間の耐圧接続, バルブ, 圧力調整器, および計量装置. The integrity of these connections is vital for maintaining system safety, minimizing leakage risk, and ensuring long-term performance under varying pressures and environmental conditions.

Choosing the right flange is not just a matter of matching dimensions—it requires careful consideration of pressure ratings, 材料の適合性, シール性能, 耐食性, 業界標準への準拠. この記事では, ササフランジ breaks down the key selection criteria for flanges in gas distribution applications, helping engineers and procurement teams make informed decisions.

Why Flange Selection Matters in Gas Networks

Gas distribution systems operate under conditions that demand 漏れのない, 耐食性, and pressure-tolerant connections. A failure in a flange connection can lead to:

Dangerous gas leaks
System shutdowns
Fire or explosion risks
Costly emergency repairs
Legal or regulatory violations

To prevent such outcomes, ササフランジ offers flanges that meet or exceed international gas safety and performance standards.

1. Pressure Class and System Operating Pressure

The most fundamental criterion in flange selection is pressure class compatibility. Flanges must be capable of withstanding the maximum operating pressure of the gas system plus a safety margin.

一般的な圧力クラスには次のものがあります。:

ANSI/ASME Classes: 150, 300, 600, 900
PN Ratings (1 つ/あなたの): PN10, PN16, PN25, PN40, PN64

For low-pressure residential distribution networks, クラス 150 or PN10 may suffice. In industrial or transmission-grade systems, クラス 600 or higher may be required.

ササフランジ manufactures a full range of forged steel and stainless-steel flanges across all pressure classes, with certified pressure-temperature ratings.

2. Material Selection Based on Gas Type and Environment

の type of gas そして external environment determine the appropriate flange material. Some gases are dry and inert, while others are wet, 腐食性の, or acidic.

Recommended Materials:

炭素鋼 (ASTM A105): For dry, non-corrosive gas
ステンレス鋼 (304, 316): For humid, 腐食性の, or coastal installations
二相ステンレス鋼: For sour gas or aggressive chemicals
Low-Temperature Carbon Steel (LTCS A350 LF2): For cryogenic LNG pipelines
ニッケル合金 (例えば, インコネル): In specialized high-corrosion environments

All materials used by ササフランジ are traceable with full EN 10204 3.1 または 3.2 certification and comply with gas utility requirements worldwide.

3. Flange Face Type and Gasket Compatibility

の flange face finish affects how well the gasket seals, especially under fluctuating temperatures and pressures. Common face types in gas applications include:

盛り上がった顔 (RF): 最も一般的な; compatible with spiral wound or compressed gaskets
平面 (FF): Used when mating with cast iron components
リング型ジョイント (RTJ): For high-pressure and critical gas systems
舌 & 溝 (T&G): Offers superior alignment and sealing integrity

The surface roughness of the face (typically 125–250 AARH) also affects gasket performance. ササフランジ machines all flange faces to precise standards for effective sealing.

4. Corrosion Resistance and Surface Protection

Gas networks often span 地下, 沿岸, and industrial zones, where corrosion is a significant risk. Protective measures include:

Hot-Dip Galvanizing: For carbon steel flanges used outdoors or underground
Epoxy or PTFE Coatings: For flanges in aggressive chemical or salt environments
Pickling and Passivation: For stainless steel to remove contaminants and improve corrosion resistance

ササフランジ offers custom coating and finishing services for all flange types, including NORSOK-compliant anti-corrosion solutions.

5. Temperature Ratings

Gas may be transported at ambient, elevated, or cryogenic temperatures, depending on the system. Flange materials and gaskets must perform consistently within the temperature range.

Examples:

Natural Gas Distribution: -20°C to +80°C
LNG and Cryogenic Gases: -196°C and below
Biogas and Flue Gas: Up to 250°C or higher

ササフランジ provides material selection guidance based on ASME B31.3 and B16.5 pressure-temperature charts.

6. Flange Standards and Certifications

To ensure interoperability and legal compliance, flanges must conform to the relevant international standards for gas systems:

ASME B16.5 / B16.47: Standard for forged flanges
EN 1092-1: ヨーロッパのフランジ規格 (PN rated)
ISO 7005: International metric flange system
API 6A / 6D: Flanges used in gas transmission pipelines
PED 2014/68/EU: For pressure equipment in EU markets
ISO 4437 / EN 1555: Gas-specific piping component guidelines

ササフランジ manufactures to all the above standards and maintains CE marking, PED certification, and third-party approvals (例えば, TUV, Lloyd’s).

7. Welding or Assembly Considerations

Flanges can be installed by welding, ボルト締め, or threading. For gas pipelines, butt-weld and socket-weld flanges are most common due to their strength and integrity.

Welding considerations:

Welding Procedure Qualification (WPS/PQR) must be in place
熱処理 may be required after welding
Radiographic or ultrasonic testing (RT/UT) may be specified for critical welds

ササフランジ supplies flanges with full welding data and can offer pre-welded flange spool assemblies リクエストに応じて.

8. Leak Prevention and Sealing Reliability

Gas systems require zero-leak performance, especially in populated or hazardous environments. Factors that enhance sealing integrity:

Proper bolt torque and tightening sequence
Use of anti-seize compounds on fasteners
High-quality gaskets matched to the gas type
Flange face flatness and parallelism checks

ササフランジ provides torque values, installation guides, and surface inspection reports to help achieve perfect seals in every installation.

9. Traceability and Quality Documentation

To meet compliance and maintenance standards, flange traceability is essential. Each flange should have:

Stamped or laser-marked serial number
Heat number and material grade
Certification package (EN10204 3.1 または 3.2)
Testing records: 静水圧, PMI, ユタ州, or MPI

ササフランジ ensures full traceability for every flange, supported by robust document control systems for audit-ready quality management.

10. Cost and Lifecycle Considerations

While initial flange cost is important, total lifecycle performance should be prioritized in gas networks. Factors such as:

耐食性
Sealing longevity
Ease of maintenance
互換性

all contribute to lower total cost of ownership.

By choosing high-quality flanges from ササフランジ, gas companies reduce unplanned downtime, maintenance costs, and environmental risks.

Application Examples in Gas Networks

City natural gas distribution mains
Gas metering and regulating stations
Compressor and booster stations
Above-ground installations at junctions or valves
LNG regasification units
CNG and hydrogen fuel stations

Each application demands carefully matched flange specifications to meet pressure, 温度, and environmental requirements.

結論

Flanges are not mere connecting parts in gas distribution networks—they are safety-critical components that ensure containment, 信頼性, 規制遵守と. Proper flange selection based on pressure class, 材料, 顔のタイプ, 耐食性, 標準, and testing is vital for system integrity.

ササフランジ offers a wide range of gas-certified flanges, backed by international standards, robust testing, and quality documentation. Whether for municipal networks, industrial complexes, or high-pressure gas pipelines, we deliver flanges engineered for performance and safety.