Safely ASME codes

Code Administration The American Society of Mechanical Engineers has written the ASME Boiler and Pressure Vessel Code, which contains rirles for the design, fabrication, and inspection of boilers and pressure vessels. The ASME Code is an American National Standard. Most states in the United States and all Canadian provinces have passed legislation which makes the ASME Code or certain parts of it their legal requirement. Orrly a few jurisdictions have adopted the code for all vessels. The others apply it to certain types of vessels or to boilers. States employ inspectors (usually under a chief boiler inspector) to enforce code provisions. The authorities also depend a great deal on insurance company inspectors to see that boilers and pressure vessels are maintained in a safe condition. 

Note that the intent of the ASME Code is to ensure that under those circumstances where a pressure relieving device can be isolated by a block valve from its pressure, or its discharge, that a responsible indhadual lock and unlock the block valve to the safe open position and that this individual remain at the block valve the entire time that the block valve is closed. 

Stress analysis is the determination of the relationship between external forces applied to a vessel and the corresponding stress. The emphasis of this book is not how to do stress analysis in particular, but rather how to analyze vessels and their component parts in an effort to arrive at an economical and safe design—the difference being that we analyze stresses where necessary to determine thickness of material and sizes of members. We are not so concerned with building mathematical models as with providing a step-by-step approach to the design of ASME Code vessels. It is not necessary to find every stress but rather to know the... 

The criteria applied in the design of the Reactor Coolant System supports are that the specific function of the supported equipment be achieved during all normal, earthquake, safety valve actuation and Branch Line Pipe Break (BLPB) conditions. (BLPB includes feedwater line breaks and all loss-of-coolant-accident conditions resulting from breaks not eliminated by leak-before-break analysis in piping to branch nozzles of the reactor coolant system.) Specifically, the supports are designed to support and restrain the Reactor Coolant System components under the combined Safe Shutdown Earthquake and Branch Line Pipe Break loadings in accordance with the stress and deflection limits of Section III, ASME Code. 

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). 

A new edition of the code is issued every 3 years. Between editions, alterations are handled by issuing semiannual addenda, which may be purchased by subscription. The ASME considers any issue of the code to be adequate and safe, but some government authorities specify certain issues of the code as their legal requirement. 

Safely Valve normally used for steam service, but suitable for gases or vapors. When used in steam generation and process steam service the valves conform to the ASME Power Boikr Code as well as the ASME Pressure Vessel... 

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. 

Internal pressure stresses. Stresses due to internal pressure shall be considered safe when the wall thickness of the piping component, including any reinforcement, meets the requirements of the pressure design of components defined by the ASME B31.3 code. 

When the internal design pressure of a container exceeds 15 psig (101.3 kPa), it is called a pressure vessel. The ASME Boiler and Pressure Vessel Code is one of the primary standards used throughout the world to ensure safe storage vessels. Various substances, such as ammonia (qv) and many hydrocarbons (qv), are frequently stored in spherically shaped vessels that are often referred to as tanks. Most often the design pressure is 15 psig (101.3 kPa) or above. These are really spherical pressure vessels and fall under the rules of the ASME Boiler and Pressure Vessel Code. Discussion of pressure vessels are available (5,6) these are not covered in detail herein. 

As already mentioned in the previous chapter, SRVs are completely governed by local codes and regulations. However, since 2002 the two major worldwide codes are ASME and PED. Both are laws and are, in any case, the basis of most international codes. There might be detailed but usually irrelevant differences, but if it complies with either or both ASME and PED, it is my opinion that your system is safe. The main problem is that a lot of installations do not comply with ASME, PED or local codes because of misinterpretations of these codes, which we will try to address and clarify further in this handbook. The worldwide governing standards and recommended practices are API 520 and EN4126, and here the reasoning is the same as with the codes. 

If the plant safety shutdown is not rapid enough and an overpressure situation develops, then the pressure relief system is activated. Pressure vessel design codes such as the ASME Boiler and Pressure Vessel Code require relief devices to be fitted on all pressure vessels (see Section 13.17). If the relief system has been properly designed and maintained, then in the event of an overpressure incident, the plant contents will be vented via relief valves or bursting disks into the relief system, where liquids are recovered for treatment and vapors are sent to flare stacks or discharged to the atmosphere if it is safe to do so. The pressure relief system should allow the plant to be relieved of any source of overpressure before damage to process equipment (leaks, bursting, or explosion) can occur. 

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