Code Requirements

To comply with the Code of Practice, a vessel owner is required  

Appendix 1 gives the checklist of requirements for the Code of Practice for the safety of small 

Decked vessels 10m and above registered length to less than 12m registered length. 

Open vessels less than 7m registered length. 

---

The compact textual coding requires no graphical input and additionally permits a fast transmission. These are important advantages of using SMILES in chemical applications via the Internet and in online services. SMILES is also used for the input of structures in the Daylight Toolkit [22]. 

NWChem uses ASCII input and output files. The input format allows geometry to be input as Cartesian coordinates or a Z-matrix. If symmetry is specified, only the Cartesian coordinates of the symmetry-unique atoms are included. Some sections of the code require additional input files. 

A small amount of particleboard is made with a fire-retardant treatment for use in locations where codes require this material, as in some offices and elevators. Particleboards receive overlay and finishing treatments with ease. Wood veneers, melamine overlays, printed paper overlays, vinyl overlays, foils, and direct grain printing can all be done quite simply. A small amount of particleboard is also made in the form of shaped, molded articles such as furniture parts, paper roU plugs, bmsh bases, and even toilet seats. There is another small increment of particleboard made by the extmsion process. These products are made in small captive operations owned by furniture manufacturers which consume all of this production in their furniture. The extmsion process differs from conventional flat-pressed particleboard in that the wood furnish is forced between two stationary heated surfaces. The mats are formed from one edge and this edge is alternately formed and pushed between the heated platens, which are maintained at a distance equal to the thickness of board produced. This is an old, slow, small-scale process, but is stiU in use in at least one location. 

Cables are available in a variety of constmctions and materials, in order to meet the requirements of industry specifications and the physical environment. For indoor usage, such as for Local Area Networks (LAN), the codes require that the cables should pass very strict fire and smoke release specifications. In these cases, highly dame retardant and low smoke materials are used, based on halogenated polymers such as duorinated ethylene—propylene polymers (like PTFE or FEP) or poly(vinyl chloride) (PVC). Eor outdoor usage, where fire retardancy is not an issue, polyethylene can be used at a lower cost. 

Cross-country gas pipelines generally must odorize the normally odorless, colorless, and tasteless gas ia urban and suburban areas, as is required of gas distribution companies. Organosulfur compounds, such as mercaptans, are usually used for this purpose, and code requires that the odor must be strong enough for someone with a normal sense of smell to detect a gas leak iato air at one-fifth the lower explosive limit of gas—air mixtures. The latter is about 5%, so the odorant concentration should be about 1%, but most companies odorize more heavily than this as a safety precaution. 

The need to ensure that the stresses ia piping systems meet the appropriate code requirements and the concern that cycHc stresses resulting from events such as periodic heating and cooling of the piping may lead to fatigue failures, make accurate evaluation of the stresses and strains ia piping systems a necessity. 

Tank Shell. Another example of where thickness is set by minimums for fabricabihty but not for strength is in small-diameter tanks. For example, a water storage tank built using a steel of an allowable stress of 20,000 psi (138 mPa), 9 ft (3 m) in diameter by 21-ft (7-m) high, requires a shell thickness to resist hoop stress of only 0.023-in. (0.58-mm) thick. However, if built to API Standard 650, the shell would be fabricated at least 0.1875-in. (4.76-mm) thick. The code requires this thickness so that when fabrication, welding, and tolerances are considered, a tank of acceptable quaUty and appearance meeting the requirements of most services in most locations is provided. 

Tank Roof. The roof of a vertical cylindrical tank is treated like a building stmcture and uses the same basic rules as the building codes. For example, the API codes require a roof to be designed for the dead load plus a 122-kg/m (25-lb /ft ) Hve load. The minimum fabrication thickness of roof plates is 3/16 in. (4.8 mm). 

Building code requirements for fire performance are mainly concerned with noncombustibiUty (41), fire endurance (42,43), and surface burning characteristics (44). Wood, even in its treated form, does not meet the building code requirements for a noncombustible material. However, for some specific apphcations where noncombustible materials are required, the codes permit the substitution of fire retardant treated wood. 

Some of the more significant requirements of ANSI B31.3 (1980 edition) have been summarized and incorporated in this section of the Handbook. For a more comprehensive treatment of code requirements engineers are referred to the B31.3 code and the standards referenced therein. 

Table 10-58 is a digest of code requirements for the quality of welds. The defects referred to are illustrated in Fig. 10-175. 

Impact Testing Materials conforming to ASTM specifications listed in the code may generally be used at temperatures down to the lowest temperature listed for that material in the stress table without additional testing. When welding or other operations are performed on these materi s, additional low-temperature toughness tests may be reqiiired. The code requirements are listed in Table 10-57. 

Safety in Design Designing a pressure vessel in accordance with the code will, under most circumstances, provide adequate safety. In the code s own words, however, the rules cover minimum construction requirements for the design, fabrication, inspection, and certification of pressure vessels. The significant word is minimum. The ultimate responsibility for safety rests with the user and the designer. They must decide whether anything beyond code require-... 

Care of Pressure Vessels Protection against excessive pressure is largely taken care of by code requirements for relief devices. Exposure to fire is also covered by the code. The code, however, does not provide for the possibility of local overheating and weakening of a vessel in a fire. Insulation reduces the required relieving capacity and also reduces the possibihty of local overheating. 

Construction Codes Rules for Construction of Pressure Vessels, Division 1, which is part of Section T11 of the ASME Boiler and Pressure Vessel Code (American Society of Mechanical Engineers), sei ves as a construction code by providing minimum standards. New editions of the code are usually issued every 3 years. Interim revisions are made semiannually in the form of addenda. Compliance with ASME Code requirements is mandatoiy in much of the United States and Canada. Originally these rules were not prepared for heat exchangers. However, the welded joint between tube sheet and shell of the fixed-tube-sheet heat exchanger is now included. A nonmandatoi y... 

Introduction An accurate quantitative analysis of the discharge of pollutants from a process must be determined prior to the design and/or selection of control equipment. If the unit is properly engineered by utilizing the emission data as input to the control device and the code requirements as maximum-effluent limitations, most pollutants can be successfully controlled. 

For the EPR design, the ASME pressure vessel code requires design to be done at two-thirds of the alloy s yield strength (see Fig. 

The PTC 22 establishes a limit of uncertainty of each measurement required the overall uncertainty must then be calculated in accordance with the procedures defined in ASME PTC 19.1 Measurement Uncertainty. The code requires that the typical uncertainties be within a 1.1% for the Power Output, and 0.9% in the heat rate calculations. It is very important that the post-test uncertainty analysis should be also performed to assure the parties that the actual test has met the requirement of the code. 

The instrumentation will be calibrated as per the requirements of the test codes. All the instrumentation must be calibrated before a test and certified that they meet the code requirements. The ASME PTC 19 series outlines the governing requirements of all instrumentation for an ASME Performance Test to be within the governing band of uncertainty. 

While some video display screens such as liquid crystal, gas plasma or vacuum fluorescent displays do not present the same charged screen hazards as CRTs, this does not imply that they are safe for use in hazardous locations. This requires special design and certification for use with a given flammable atmosphere. Non-certified equipment used in locations classified as hazardous under Article 500 of NFPA 70 National Electrical Code require a purged or pressurized enclosure to control ignition hazards as described in NFPA 496 Standard for Purged and Pressurized Enclosures for Electrical Equipment. The screen in this case is located behind a window in the enclosure. 

The code requires the submission of an instrument and piping (low sheet. All instruments should be numbered for identification and ihe actual instruments labeled. The code is very helpful in recommending the range and sensitivity required, and close adherence is recommended. 

The ASTM fired pressure vessels code requires pressure-relief devices to prevent pressures from rising more than 6% above the maximum allowable working pressure. 

A PR valve is not required for protection against fire on any vessel which normally contains little or no liquid, since failure of the shell from overheating would occur even if a PR valve where provided. Examples are fuel gas knockout drums and compressor suction knockout drums. (Note Some local codes require pressure relief valve protection for "dry drum" situations.)... 

Set Pressure - The set pressure (the pressure at whieh the PR valve is designed to open) is speeified in accordance with Code requirements. In most vessel apphcations, the set pressure of at least one PR valve is equal to the design pressure. However, this set pressure is adjusted (up or down) for any effect of static pressure and friction pressure drop that may apply when the valve is installed elsewhere than directly on the vessel. For example, if a PR valve is installed in a non-flowing line above a liquid-filled vessel, the PR valve set pressure would be reduced sufficiently to allow for the liquid static head between the vessel and the valve. 

Many building and health and safety codes require the use of gas storage cabinets, exhausted enclosures, and/or separately ventilated gas storage rooms for toxic gases. These controls are also recommended for flammable and corrosive gases. 

The Uniform Fire Code requires that pyrophoric, flammable, or highly toxic gases be within ventilated gas cabinets, laboratory fume hoods, or exhausted enclosures. ... 

The Uniform Mechanical Code requires that ducts carrying explosive or flammable gases be ducted directly to the outside of the building. 

Most refrigeration plants use freon as the refrigerant anti limit the lowest temperature to -20°F. This is because the ANSI piping codes require special metallurgy considerations below -20 F to assure ductility. 

In federal water of the U.S. and in a few states, all pressure vessels must be designed and inspected in accordance with the ASME Code. In many states, however, there is no such requirement. It is possible to purchase "non-code vessels in these states at a small savings in cost. Noncode vessels are normally designed to code requirements (although there is no certainty that this is true), but they are not inspected by a qualified code inspector nor are they necessarily inspected to the quality standards dictated by the code. For this reason, the use of non-code vessels should be discouraged to assure vessel integrity. 

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. 

---