Which code or standard applies to your shop?

An abundance of codes and standards are available for use by nearly all manufacturers and fabricators. Some are mandated by state law, and some are selective. Some states mandate by law that any producer of pressure vessels or piping must be an "authorized" code-compliant company. The end product determines the codes and standards to be followed.

To state that a product is constructed or repaired to a certain code, you must follow all "mandatory" instructions of that particular code. The word shall in a code or standard indicates a mandatory rule. The word should indicates a nonmandatory recommendation that requires you to make your "best engineering judgment."

ASME and Pressure Vessels, Piping Fabrication

The current oil and gas boom in the U.S. has spiked interest in piping and pressure vessel fabrication. Pipe and vessel shops are popping up everywhere. Cross-country pipe welding (American Petroleum Institute, API) and instrumentation and compressor fabrication (American Society of Mechanical Engineers, ASME) are booming. From Pennsylvania down through the Ohio Valley to the Gulf Coast, new companies are starting up, and existing shops are gearing up with modern equipment.

With the new Environmental Protection Agency (EPA) rules, these companies are rapidly learning that adhering to codes and standards is more important than ever. Leaky pipelines and noisy compressor stations no longer are tolerated. Companies that comply with the codes and standards are the preferred suppliers for oil and gas companies.

The codes and standards were established to protect society from the hazards caused by product failure. For instance, ASME was established in the early 1900s following several catastrophic boiler failures. Some of these failures occurred in homes and other buildings that used steam boilers for heating. Some were on ships powered by steam. Railway steam engines that failed caused serious damage to communities adjacent to the railways. Many of these failures resulted in deaths.

Two ASME codes are used to assure the safety of fired and unfired pressure vessels and pressure piping. The most prominent for fired pressure vessels and pressure piping is Section I. The other is Section VIII, which applies to unfired pressure vessels.

Several related codes and standards deal with piping that contains specific materials and pressures. Once referred to as the American National Standards Institute (ANSI) B31.1 and B31.3 codes, they now are under the ASME insignia.  

For your shop to become an ASME Authorized Code Facility, you must engage an authorized insurance agency, such as Hartford Steam Boiler. The insurer provides an authorized inspector (AI) who makes sure that all code requirements are met. You must inform the AI at the very beginning of a code-compliant job, even to determine whether the job is to be constructed, repaired, or altered to the proper section of the code.

For repairs and alterations, the ASME joins with the National Board of Boiler and Pressure Vessel Inspectors (NBIC) to determine methods of performance and documentation. This is extremely important, especially if your company is at the beginning stage of becoming an authorized facility. The AI is involved in each step of production, from the receipt of the purchase order for the material to tracking each step on a document, called a shop traveler. The AI must sign off on each process as it is performed.

Although the authorizing agency bears no liability for the final product, it is there to ensure that the proper rules are followed throughout the job from start to final inspection, testing, and shipping documentation. The agency and AI are added expenses that are well worth the investment.

Figure 1

Understand that the ASME Code Committee does not rule on whether a component shall or shall not be constructed to the provisions of the code. That is the responsibility of sound engineering judgment. However, to "stamp" a component or refer to it as an "ASME Code Component," you must comply with the ASME rules. The AI is most helpful in determining whether the engineering judgment call is code-compliant.

Perhaps the most frequently used ASME code is Section IX. This code is strictly for establishing welding procedures, welder qualification and certification, and welding materials usage with compatible base materials.

Your shop does not necessarily need to be an authorized ASME facility to use Section IX. It is a set of rules that are designed to join materials with the proper welding process safely and effectively.

This code does not reference a particular shape of material, such as pipe, beam, or plate. It does, however, recommend testing to determine the best weld joint type and process for joining all types of material. It also recommends the thickness of the testing material for determining the welder's skill on thin and thick material using several processes.

All current processes are addressed in Section IX. It is the most versatile of all available welding codes in that it allows certain alternative rules for the type of welding and base materials usable under differing conditions.

AWS and Structures

The U.S. is gaining new interest in structural fabrication, partly because of its aging infrastructure. Many older buildings were built before the oversight of any codes or standards. Because it is difficult to repair or update the buildings, many are being torn down and new ones built in their place. This scenario has become less complicated with the modern cranes that have a very small footprint and can be used in large cities with very little space for equipment. Fabrication shops are able to fabricate assemblies that these cranes can readily lift to the erection point.

It is estimated that 30 percent of all bridges in the U.S. are in need of major repairs or replacement. The increase in automobile traffic makes this a difficult task.

A good example of the modern method of replacing a large (megasized) bridge is the Ravenel Bridge that crosses over the harbor in Charleston, S.C. This bridge is part girder-style welded plate and part suspension. It is said to be a modern miracle in bridge building. The old bridge stayed in service until the new one was completed.

Most new bridges won't be of this magnitude in fabrication and erection, but building a new bridge adjacent to an existing bridge no doubt will be a common method. One bridge in Pittsburgh is deteriorating so badly that a cover has been placed under the bridge to protect traffic below from the falling debris. This situation must be rectified.

Building smaller bridges could create many jobs. They can be fabricated and erected by small companies that comply with the existing standards. Some bridges might require reinforcing the girders or trusses only, rather than constructing a whole new bridge.

Figure 2
All in one gas processing plant: The skid and the building is to AWS; D1.1
; The vessel to the left is to ASME VIII
; The piping is to B31.1 and B31.3; The smaller vessels are to API 620

Currently required even for small bridges, the AWS D1.5: Bridge Welding Code covers both repair and fabrication of bridges.

The first AWS code, published in 1928, was named The Code for Fusion Welding and Gas Cutting in Building Construction, and was titled Code 1 Part A. The reason for the code was similar to that of the ASME code, except that it addressed failures in structures instead of pressure vessels. The code was revised in 1941, and the first D1.0 was published.

In 1967 the code was combined with the D2.0: Specifications for Welded Highway and Railway Bridges. In 1972 the revision was named D1.1: Structural Welding Code, which remains today's designation.

The first AWS code that I personally was involved with was D2.0-69. The states became deeply engaged with this specification and mandated special training courses for all their project managers and inspectors. The majority of the U.S. interstate system bridges were constructed and erected in compliance with this document.

In 1988 the new AASHTO/AWS D1.5: Bridge Welding Code was published. The D1.1 was changed to address statically loaded and dynamically loaded structures.Today the title is D1.1 D1.1M (year): Structural Welding Code—Steel. The 2010 edition is the 22nd year for the D1.1 publication.

The D1.1 code differs from ASME Section IX in that it includes much more than the welding specifications. It covers the design differences for statically loaded structures versus dynamically loaded structures. For example, the number of stiffeners is specified for both fascia and intermediate girders.

D1.1 also includes many design specifications, unlike ASME Section IX. ASME publishes codes such as Section 1 and Section VIII for this type of information.

D1.1 details in-depth methods and procedures for nondestructive testing in several processes. The code specifies testing angles and transducer sizes for the ultrasonic process, the placement of radiographic film, and the image quality indicators (IQI). ASME Section V is a separate code for nondestructive testing that addresses all these issues.

D1.1 comprises prequalified welding procedures for certain joint and material types. This information is relevant if your shop is looking to make these weld types. Some procedures may allow qualification of the welders in all positions and for unlimited thicknesses. Unlimited thickness is from 1/8 in. upward. D1.1 does not address thicknesses less than 1/8 in. The sheet metal codes address the thinner materials.

Joint tolerances are listed for root openings, root face size, and bevel angle. No prequalified joints without backing or backgouging exist. The prequalified joints are well- defined with drawings and groove details.

In addition to D1.1 and D1.5, AWS has many other publications—too many to list in this article. Among them are a railway code, sheet metal codes, machinery codes, stainless codes, and aluminum codes.

API and Pipelines and Related Facilities

The American Petroleum Institute (API) publishes more than one standard, but API 1104 is the standard for cross-country pipelines. As mentioned previously, the oil and gas industry is booming.

Because of its cost, ease of use, and size, API 1104 is the most popular standard candidates use when seeking to become AWS certified welding inspectors. It is common knowledge that a candidate who uses this book for the certification exam also is able to use the other codes and standards.

This publication is described as a "Standard" on the title page, unlike the AWS D1.1, which is titled Structural Welding Code. If the material is not round, it is not addressed in API 1104.

Probably the most common misconception is that all API 1104 welding must be performed by downhill progression. This is not true, although it is the most common progression that pipeline welders use. The progression actually is defined by the welding procedure. Several coupons are required for procedure and welder qualification (Figure 1).

Like the AWS D1.1, this standard addresses base material grouping, AWS electrode classifications, and specifications. Also, nondestructive criteria and several sketches are presented for joints and destructive testing. The destructive tests for this standard are quite different from the other codes and standards. The welder may test for single or multiple qualification.  

If your interest is thinner-walled, non-pressure containing-vessels, 1104 is not the only standard that API produces. There are standards for petroleum storage vessels and other items, such as lime silos. These standards are API 620 and 650, respectively.

The welding procedures and qualifications for such jobs are to the ASME Section IX code. The quality standards are nearly the same as ASME Section VIII, except for the nondestructive testing methods. One method that seems to be common to API is the use of vacuum box testing. This test requires access to both sides of the weld. The vacuum box pulls the soap bubbles or other medium through the flaw and shows up in the transparent box, usually constructed from Plexiglas®.

These vessels usually are constructed from thinner materials (0.187 in. to 0.375 in.) and have flat bottoms and floating tops. They typically are not pressure-containing.

The vessels often are fabricated to joint standards with the American Water Works Association (AWWA), as their usage is comparable. Many who fabricate them also erect these vessels because the equipment required to position them is not as large as the equipment required for the greater thicknesses needed for pressure-containing vessels.

The Changing Outlook for the Fabricator

The oil and gas boom has created a desire and a need for more versatility in the fabrication industry. The codes and standards are being utilized in the various types of construction and erection. Even the equipment for digging pipeline ditches is different from a standard backhoe.

The AWS D14 series for machinery is being used more than ever. The base for the instrument skids lends itself to AWS D1.1, while the instrumentation and vessel portion is well-suited to ASME Sections VIII and the B31 series.

When preparing an RFQ (request for quotation), be very careful to consider the code or standard required to comply with the job specifications. Make sure that your company has all the necessary personnel and equipment to meet the job requirements economically.

Each shop must consider which type of fabrication and erection is the most economically feasible. The tide can turn very quickly. Utilizing what you have and are familiar with usually is the best way to take advantage of any new boom (Figure 2).