ASME B31.1 と ASME B31.3: 配管設計規格を知る

導入

配管設計とエンジニアリングでは、安全性、効率性、業界標準への準拠を確保するために、適切な配管コードを選択することが重要です。最も広く認知されている配管設計コードには次の2つがあります。 ASME B31.1 そして ASME B31.3どちらもアメリカ機械学会（ASME）が発行する配管システムの設計と建設に関する規格ですが、その適用範囲は大きく異なります。 ASME B31.1 と ASME B31.3 発電所、化学処理、工業施設など、プロジェクトに適切なコードを選択するには、議論が不可欠です。

概要: ASME B31.1 と ASME B31.3

What is ASME B31.3 or Process Piping Code?

ASME B31.1 は、発電所の配管システムの設計、構築、保守を管理する規格です。発電所、工業プラント、および発電に関わるその他の施設の配管システムに適用されます。この規格は、高圧蒸気、水、高温ガスを扱うシステムの整合性に重点を置いています。

代表的な用途: 発電所、暖房システム、タービン、ボイラーシステム。
圧力範囲: 高圧蒸気および流体システム。
温度範囲: 特に蒸気およびガス用途向けの高温サービス。

What is ASME B31.1 or Power Piping Code?

ASME B31.3 applies to the design and construction of piping systems used in chemical, petrochemical, and pharmaceutical industries. It governs systems that transport chemicals, gases, or liquids under different pressure and temperature conditions, often including hazardous materials. This code also covers the associated support systems and the safety considerations of handling chemicals and dangerous substances.

代表的な用途化学処理工場、製油所、製薬施設、食品・飲料工場。
圧力範囲: 流体の種類と分類に応じて、通常は ASME B31.1 の圧力範囲よりも低くなります。
温度範囲: varies depending 化学流体では、通常、極端な条件よりも低くなります。 ASME B31.1.

Difference Between ASME B31.3 and ASME B31.1 (ASME B31.3 vs ASME B31.1)

Sr No	パラメータ	ASME B31.3-Process Piping	ASME B31.1-Power Piping
1	範囲	Provides rules for Process or Chemical Plants	Provides rules for Power Plants
2	Basic Allowable Material Stress	Basic allowable material stress value is higher (For example the allowable stress value for A 106 B material at 250 Deg C is 132117.328 Kpa as per ASME B31.3)	Basic allowable material stress value is lower (For example the allowable stress value for A 106 B material at 250 Deg C is 117900.344 Kpa as per ASME B31.3)
3	Allowable Sagging (Sustained)	The ASME B31.3 code does not specifically limit allowable sagging. An allowable sagging of up to 15 mm is generally acceptable. ASME B31.3 does not provide a suggested support span.	ASME B31.1 clearly specifies the allowable sagging value as 2.5 mm. Table 121.5-1 of ASME B31.1 provides suggested support span.
4	SIF on Reducers	Process Piping Code ASME B31.3 does not use SIF (SIF=1.0) for reducer stress calculation	Power Piping code ASME B31.1 uses a maximum SIF of 2.0 for reducers while stress calculation.
5	Factor of Safety	ASME B31.3 uses a factor of safety of 3; relatively lower than ASME B31.1.	ASME B31.1 uses a safety factor of 4 to have higher reliability as compared to Process plants
6	SIF for Butt Welded Joints	ASME B31.3 uses a SIF of 1.0 for buttwelded joints	ASME B31.1 uses a SIF of up to 1.9 max in stress calculation.
7	Approach towards SIF	ASME B31.3 uses a complex in-plane, out-of-plane SIF approach.	ASME B31.1 uses a simplified single SIF Approach.
8	Maximum values of Sc and Sh	As per the Process Piping code, the maximum value of Sc and Sh are limited to 138 Mpa or 20 ksi.	For the Power piping code, the maximum value of Sc and Sh are 138 Mpa only if the minimum tensile strength of the material is 70 ksi (480Mpa); otherwise, it depends on the values provided in the mandatory appendix A as per temperature.
9	Allowable Stress for Occasional Stresses	The allowable value of occasional stress is 1.33 times Sh	As per ASME B31.1, the allowable value of occasional stress is 1.15 to 1.20 times Sh
10	The equation for Pipe Wall Thickness Calculation	The equation for pipe wall thickness calculation is valid for t<D/6	There is no such limitation in the Power piping wall thickness calculation. However, they add a limitation on maximum design pressure.
11	Section Modulus, Z for Sustained and Occasional Stresses	While Sustained and Occasional stress calculation the Process Piping code reduces the thickness by corrosion and other allowances.	ASME B31.1 calculates the section modulus using nominal thickness. Thickness is not reduced by corrosion and other allowances.
12	Rules for material usage below -29 Deg. C	ASME B31.3 provides extensive rules for the use of materials below -29 degrees C	The power piping code provides no such rules for pipe materials below -29 degrees C.
13	Maximum Value of Cyclic Stress Range Factor	The maximum value of cyclic stress range factor f is 1.2	The maximum value of is 1.0
14	Allowance for Pressure Temperature Variation	As per clause 302.2.4 of ASME B31.3, occasional pressure temperature variation can exceed the allowable by (a) 33% for no more than 10 hours at any one time and no more than 100 hours/year, or (b) 20% for no more than 50 hours at any one time and no more than 500 hours/year.	As per clause 102.2.4 of ASME B31.1, occasional pressure temperature variation can exceed the allowable by (a) 15% if the event duration occurs for no more than 8 hours at any one time and not more than 800 hours/year or (b) 20% if the event duration occurs for not more than 1 hour at any one time and not more than 80 hour/year.
15	デザインライフ	Process Piping is normally designed for 20 to 30 years of service life.	Power Piping is generally designed for 40 years or more of service life.
16	PSV reaction force	ASME B31.3 does not provide specific equations for PSV reaction force calculation.	ASME B31.1 provides specific equations for PSV reaction force calculation.

結論

決定的な違いは ASME B31.1 と ASME B31.3 議論の対象は、業界の用途、材料要件、および安全性の考慮事項にあります。 ASME B31.1 機械的な完全性を重視した発電や高温システムに最適です。同時に、 ASME B31.3 is tailored for the chemical and process industries, emphasizing the safe handling of hazardous materials and chemical compatibility. By understanding the distinctions between these two standards, you can decide which code best suits your project’s requirements, ensuring compliance and safety throughout the project’s lifecycle. Whether you are involved in power plant design or system’ processing, choosing the correct piping code is crucial for a successful project.