API-ASME code

For the design of internal-pressure cylindrical vessels, the API-ASME Code for Unified Pressure Vessels recommends the following equations for determining the minimum wall thickness when extreme operating pressures are not involved ... 

The first boiler code was published in 1915, the first Code (Section VIII) for Unfired Pressure Vessels in 1925. The allowable stresses were based on a factor of 5 on tensile strength. In 1934, the joint API-ASME code. Unfired Pressure Vessels for the Petroleum Industry, was published. It was based on a factor of 4 on tensile strength. In 1950, the ASME published a new edition of Section VIII which was also based on a factor of 4 on tensile strength. 

Container type may be increased by increments of 25. The minimum design pressure of containers shall per 100% of the container type designation when constructed under 1949 or earlier editions of the ASME Code (Par. U-68 and U-69). The minimum design pressure of containers shall be 125% of the container type designation when constructed under (1) the 1949 ASME Code (Par. U-200 and U-201), (2) 1950, 1952, 1956, 1959, 1962, 1965, and 1968 (Division 1) editions of the ASME Code, and (3) all editions of the API-ASME Code. 

Construction of containers under the API-ASME Code is not authorized after July 1, 1961. 

Fig. 1.1. Example of a cylindrical vessel with formed ends designed to the original API-ASME code. (Courtesy of Amer. Pet. Inst.)...

Hg. t.7. Examine of welded jeMs. (Nofe- the two types of lop welds diown moy be used only f[Pg.7]

In 1931 a joint API-ASME Cumniilloe on Unfired Pressure Vessels was uppoiiitod to prepare a code for safe pnic-tice in the design, construction, inspection, and repair of unfired pressure vessels for petroleum liquids and gases. The API-ASME code was first published in September, 1934, and was revised in 1936, 1938, 1943, and 1951. The rly API-ASME code was considerably more lenient than section VIII of the then-existing ASME code. This resulted in the reduction of fabrication (x ts for vessels designed to tbe joint code. In recent y irs tbe ASME code has been broadened and improved so that it more completely covers the petroleum industry s pressure vessel needs and is in some respects more advanced (186). In May, 1956, the API-ASME code was officially discontinued, the discontinuation to beexime effective December 31, 1956, (186) and was supplanted by the 1956 edition of section VIII of the ASME Boiler and Pressure Ve el Code (11). 

Stationary Storage Containers for Compressed Gases. Minimum recommended requirements for pressure relief devices for storage containers constructed in accordance with the ASME or API-ASME codes. Includes information on application requirements, design and construction requirements, testing and maintenance for pressure relief devices. Previous edition cited in 29 CFR (29 pages). 

The first ASME Code for pressure vessels was issued as Rules for the Construction of Unfiied Pressure Vessels, Section VIII, 1925 edition. The rules applied to vessels over 6 in. in diameter, volume over 1.5 ft and pressure over 30 psi. In December 1931, a Joint APl-ASME Committee was formed to develop an unfiied pressure vessel code for the petroleum industry. The first edition was issued in 1934. For the next 17 years, two separate unfired pressure vessel codes existed. In 1951, the last API-ASME Code was issued as a separate document. In 1952, the two codes were consolidated into one code— the ASME Unfired Pressure Vessel Code, Section VIII. This continued until the 1968 edition. At that time, the original code became Section VIII, Division 1, Pressure Vessels, and another new part was issued, which was Section VIII, Division 2, Alternative Rules for Pressure Vessels. 

API-ASME Code, Unfired Pressure Vessels for Petroleum Liquids and Gases. 5th ed., American Society of Mechanical Engineers and American Petroleum Institute, New York, 1951. 

Special operating conditions and miscellaneous items Table 10-12 is based on the API and ASME codes. 

Shell and Tube Heat Exchangers for General Piefineiy Seivices, API Standard 660, 4th ed., 1982, is published by the American Petroleum Institute to supplement both the TEMA Standards and the ASME Code. Many companies in the chemical and petroleum processing fields have their own standards to supplement these various requirements. The Jnterrelation.ships between Codes, Standards, and Customer Specifications for Proce.ss Heat Tran.sfer Equipment is a symposium volume which was edited by F. L. Rubin and pubhshed by ASME in December 1979. (See discussion of pressure-vessel codes in Sec. 6.)... 

NFPA 30 and API Standard 2000 provide gmdance for design of overpressure protec tion involving storage tanks that operate at or near atmospheric pressure. In particular, NFPA 30 focuses on flammability issues, while API 2000 addresses both pressure and vacuum requirements. The ASME code (Sections I and TII) and API RP 520 are the primaiy references for pressure rehef device sizing requirements. 

The ASME code provides the basic requirements for over-pressure protection. Section I, Power Boilers, covers fired and unfired steam boilers. All other vessels including exchanger shells and similar pressure containing equipment fall under Section VIII, Pressure Vessels. API RP 520 and lesser API documents supplement the ASME code. These codes specify allowable accumulation, which is the difference between relieving pressure at which the valve reaches full rated flow and set pressure at which the valve starts to open. Accumulation is expressed as percentage of set pressure in Table 1. The articles by Rearick and Isqacs are used throughout this section. 

All pressure vessels should be equipped with one or more pressure safety valves (PSVs) to prevent overpressure. This is a requirement of both the ASME Code and API RP 14C (refer to Chapter 14). The PSV should be located upstream of the mist extractor. If the PSV is located downstream of the mist extractor, an overpressure situation could occur when the mist extractor becomes plugged isolating the PSV from the high pressure, or the mist extractor could be damaged when the relief... 

The ASME code requires every pressure vessel that can be blocked in to have a relief valve to alleviate pressure build up due to thermal expan sion of trapped gases or liquids. In addition, the American Petroleum Institute Recommended Practice (API RP) 14C, Analysis, Design, Installation and Testing of Basic Surface Safety Systems on Offshore Production Platforms, recommends that relief valves be installed at vari ous locations in the production system and API RP 520, Design and Installation of Pressure Relieving Systems in Refineries, recommends various conditions for sizing relief valves. 

All operating parameters must be considered to make certain that an acceptable operating compressor and process fit exists. The key parameter must be evaluated as part of an overall operating analysis and considered independently. Peters 2 points out that the API Specification 617, the ASME codes, and other applicable codes may require some modification when applied to side load compressors. 

The process designer and project engineer should classify the various areas of a plant following NEPA-70, Article 50528.29 order to advise the electrical and other project team members of the degree of electrical hazards anticipated. The appropriate equipment (motors, instruments, conduit, wiring, etc.) should be specified according to NEPA-70, Article 500 and others as applicable, the ASME Code and the API Code as appropriate. See NEPA-497A and... 

A = required orifice area in square inches. This is as defined in the ASME Code and ANSI/API Std 526. 

Sensors/Detectors UL, CSA, NFPA Fuel specifications CGA. SAE, API, ASTM Weights/Measures NIST API, ASME Dispensers NFPA. SAE.CSA. UL, API Non-vehicle Dispensing CGA Codes for Built Environment ICC. NFPA. CGA, ASHRAE... 

Recognized international codes and standards applicable to petroleum facilities should be used (e.g., API, ASME, NACE, NFPA, etc.) in the design and in any proposed modifications. However it should be realized that compliance with applicable codes and standards is not sufficient in itself to ensure a safe design is provide. 

While the ASME code was the law, the API practices became the internationally recognized recommendations still used today. 

Today the ASME codes are still mandatory in the United States and Canada. Both ASME and API are applied worldwide. Many European countries also developed their own national rules for the protection against overpressure of process equipment and these remained in force well into the twentieth century. Most were based on the ASME code, but they were sometimes also developed to protect national trade (see also Appendix M). 

Most SRVs especially installed in the oil, gas and petrochemical industry both in the United States and in Europe have been designed around this ASME code and the API recommendations. Of course most also comply with the European PED, which is also not specific on this particular subject. 

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