Awwa d100-11 download

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Select the Upgrade with Redline option aswa the cart pop awwa d The areas of low film thickness could not be determined or located with traditional awwa d detection. Wwwa Description This standard describes coating systems for coating awwa d recoating the inside and outside surfaces of steel tanks used for potable water storage in water supply service.

Again, neither condition can be easily awwa d effectively monitored by traditional means. This standard describes coating systems for coating and recoating the inside and outside surfaces of steel tanks used for potable awwa d storage in water supply awaw.

They were placed on your computer when you launched this website. Identify unmet needs and discover next-generation technologies Improve quality by leveraging consistent standards to meet awwa d and market requirements Minimize risk: Your shopping cart is empty. Select your desired number of users. Illumination of the OAP coat would point out areas with insufficient film thickness or areas where the substrate, the epoxy or zinc-rich primer is visible through the fluorescing film.

If the lines of action of the horizontal girder, the top section columns, and the tank shell do not meet at the work point, then provisions shall be made in the design of each of these for stresses resulting from any eccentricity.

If the horizontal girder is used as a balcony, it shall be a minimum of 24 in. Plates for elevated tank bottoms, shells, and roofs may be any desired shape.

Tank plates shall be designed on the basis of the following maximum unit stresses, which shall be reduced for the joint efficiencies set forth in Table Plates subject to complete stress analysis shall be designed on the basis of a maximum unit tensile stress of 15, psi Such plates include those not stressed by the concentrated reactions of supporting members or riser pipes.

Plates not susceptible to complete stress analysis shall also be designed on the basis of the maximum unit tensile stress of 15, psi The maximum unit stress shall in no case exceed 11, psi Example: According to this standard, in an elevated tank having a vertical cylin- drical shell supported by four columns attached to the shell and bottom, and having a suspended bottom with a central riser and a cone roof uniformly supported by the tank shell, the stresses in the ring of the cylindrical shell and the bottom to which the columns attach cannot be accurately determined.

The stresses in the roof and remainder of the shell can be completely determined. The shell and bottom shall be designed on the basis of 15, psi The hoop stresses caused by the weight or pressure of the tank contents, assuming that the cylindrical tank shell is uniformly supported on its entire lower circumference.

The stresses in the cylindrical shell and ellipsoidal bottom, considering them acting together as a circular girder supported by the column reactions and subjected to torsion because of the portions projecting outward and inward from the chords connecting the columns.

The horizontal inward component of the pull from the tank bottom in conical or segmental bottoms causing compression in the tank shell. Stresses from any other causes. For this assumption, the thicknesses of the ring of the cylindrical shell to which the columns attach and the bottom shall be increased, if necessary, so that the maximum calculated unit stress shall not exceed 11, psi Welded-column connections to the tank shall be designed on the basis of values given in Sec.

NOTE: It is recognized that no specifications for the design of elevated tanks can be sufficiently specific and complete to eliminate the necessity of judgment on the part of the designer. It is also recognized that strain-gauge surveys are a proper source of design information. If the design of the riser plates is controlled by hoop tension, 30 percent of the compression in the vertical direction shall be added to the full calculated tension in the horizontal direction in determining the thickness.

If controlled by axial load, the column compressive stress shall not exceed the allowable stress calculated in accordance with Sec. The reduction in allowable stress recognizes the importance of the riser when acting as a support.

An additional corrosion allowance may be specified by the purchaser. Longitudinal and circumferential joints in risers that are also used as a column to support substantial vertical loads shall be butt joints, welded for complete joint penetration.

For risers on suspended-bottom tanks where the riser supports only nominal vertical loads, the circumferential joints may be partial- penetration butt joints or double-welded lap joints with full fillet welds on both edges. If applicable, stability under seismic loading shall also be checked with the tank full. Adequate stiffening shall be provided to exclude ovalling or gross buckling of the pedestal. Openings other than manholes through the support pedestal shall be minimized to ensure adequate shear transfer and vertical load transfer to the foundation.

Unless a detailed analysis is performed, the following limitations shall apply: 1. Total perimeter removal when measured at the top of the opening shall not exceed 10 percent of the pedestal circumference. Other than manholes of 36 in. Centerline spacing of adjacent openings shall be at least twice the sum of the width of the openings.

In other locations and unless a small pipe is specified, a steel riser not less than 36 in. Where the riser pipe supports a considerable load, the riser diameter and thickness shall preferably be determined by the constructor.

The minimum riser diameter of 36 in. In extremely cold climates, a minimum diameter of 72 in. Large-diameter risers shall contain a manhole about 3 ft 0. The manhole shall not be less than 12 in.

A safety grill is intended to prevent a person from falling down the riser and shall be exempt from the design loads specified in Sec. When a safety grill is used in the top of the riser during erection, it shall be removed if the tank is located in climates where freezing is likely to occur.

When grills are left in place, they shall be provided with a hinged door that is at least 18 in. Where the riser is non-load bearing, flexibility to accom- modate differential movements of the tank and riser foundation must be included. This flexibility may be provided by an expansion joint or by riser layouts that have sufficient offset to be axially deformed without overstressing the riser, tank, or foundation.

Connection to the piping furnished by the tank constructor shall be performed by the purchaser. If a removable silt stop is required, it shall be at least 6 in. If a removable silt stop is not required, the connect- ing pipe shall extend at least 6 in. On risers 36 in. The circular plate shall be attached to the pipe, silt stop, or riser bottom with a suitable bracket or welded bars. Adequate clearance shall be provided between the ends of the elbow or from the edge of the circular plate to the wall of the riser pipe to permit proper flow of water through the inlet pipe.

Pipe connections to the riser shell are permitted, as long as adequate protection against freezing has been provided. A properly operated tank should not overflow during normal operation. An overflowing tank is considered an emergency condition and the malfunction causing the overflow should be determined and corrected as soon as possible.

The tank shall be equipped with an overflow of the type and size specified by the purchaser. If a stub overflow is specified, it shall project at least 12 in.

For tanks equipped with balconies, the overflow shall be extended to discharge below the balcony. If an overflow to ground is specified, it shall be placed down the tank shell and supported at proper intervals with suitable brackets. The overflow shall be located such that it will not be obstructed by snow or ground clutter. It shall terminate at the top in a weir box or other appropriate type of intake.

The top angle shall not be cut or partially removed. The overflow pipe and intake shall have a capacity at least equal to the inlet rate as specified by the purchaser, with a head not more than 6 in. The overflow pipe shall terminate at the bottom with an elbow, which shall be directed away from the foundation.

Unless otherwise specified by the purchaser, the overflow pipe shall be steel pipe, with screwed or welded connections if less than 4 in. Overflows may be either internal or external as specified by the purchaser. Internal overflows are not recommended when tank usage and climatic conditions are such that ice damage may occur to the overflow or its attachments. When specifying an internal overflow, the purchaser should consider the conse- quences of an overflow failure, which can empty the tank contents.

A tower ladder shall be furnished with side rails no less than 2 in. The tower ladder shall extend from a point 8 ft 2. The ladder may be vertical, but shall not in any place have a backward slope. In all cases, a ladder shall be provided on the outside of the tank shell connecting either with the balcony or with the tower ladder, if no balcony is included.

The outside tank ladder shall have side rails not less than 2 in. The tank ladder may be attached to the roof ladder.

Unless otherwise specified, the constructor shall furnish access to roof hatches and vents. Such access shall be reached from the outside tank ladder or riser ladder on pedestal tanks according to the following: 1. For slopes 5 in 12 or greater, a ladder or stairway shall be provided. Slopes less than 5 in 12 and greater than 2 in 12 shall be provided with a single handrail and nonskid walkway.

Slopes 2 in 12 or less do not require a handrail or nonskid surface. NOTE: Regardless of the access protection provided to tank roof hatches and vents, weather conditions on tank roofs are extremely variable and workers and their supervisors are expected to exercise good judgment in matters of safety.

Among other things, this may include the use of safety lines when windy, icing, or other hazardous conditions exist. None of these devices are advisable when submerged inside tanks in low-temperature climates. An opening shall be provided above the top capacity level. It shall have a clear dimension of at least 24 in. The opening shall have a curb of at least 4 in. An additional opening with a removable cover having an opening dimension or diameter of at least 20 in.

This opening may also be used for the attachment of exterior paint rigging. Where con- veniently accessible to an outside balcony or platform, a shell manhole may be substi- tuted for the additional opening. If properly designed, the shell manhole may be placed below the top capacity level. The overflow pipe shall not be considered a tank vent. WARNING: An improperly vented tank may cause external pressures to act on the tank that can cause buckling even at a low-pressure differential.

One tank vent shall always be located near the center of the roof, even if more than one tank vent is required. For tanks with centrally located access tubes, a reasonable offset of the vent is permissible. The vent shall be designed and constructed to prevent the entrance of birds or animals. When governing health authorities require screening against insects, a pressure-vacuum screened vent or a separate pressure-vacuum relief mechanism shall be provided that will operate in the event that the screens frost over or become clogged with foreign material.

The screens or relief mechanism shall not be damaged by the occurrence and shall return automatically to operating position after the blockage is cleared. NOTE: The purchaser should clean the screens and check the pallets or relief mechanism for operation at least once a year, but preferably each spring and fall.

Exceptions to the provisions of this section may be specified by the purchaser to suit special situations. Increments less than 1-ft mm in shell height are not recommended. The exact height shall be determined by the constructor. Increments less than 1-ft mm in diameter are not recommended. If any access cover weighs more than 50 lb Manholes may be either circular, 24 in.

The shell plate where the manholes are located shall be reinforced to comply with Sec. Additional manholes may be required for ventilation during painting.

If specified by the purchaser, flush-type cleanouts shall be furnished for ground-supported tanks see Sec. Point of attachment shall be designated by the purchaser.

Connections to the tank or piping furnished by the tank constructor shall be performed by the purchaser. If a removable silt stop is required, it shall be at least 4 in.

If a removable silt stop is not required, then the fitting or connecting pipe, or both, shall extend above the floor at least 4 in. Shell connections are permitted as long as the pur- chaser makes adequate provisions to protect the pipe from freezing and provides adequate pipe flexibility to account for shell rotation and deflections of the shell when filled.

Sufficient piping flexibility to accommodate seismic movements and settlement in the piping system shall be provided to protect the connection to the shell. Bottom connections shall comply with Sec. An overflowing tank is considered an emergency condition, and the malfunction causing the overflow should be determined and corrected as soon as possible. If an overflow to ground is specified, it shall be placed down the side of the tank shell and supported at proper intervals with suitable brackets.

The overflow discharge shall be located such that it will not be obstructed by snow or other ground clutter. The overflow to the ground shall discharge over a drainage inlet structure or a splash block.

A top stiffener shall not be cut or partially removed. The overflow pipe and intake shall have a capacity at least equal to the pumping rate as specified by the purchaser with a head not more than 6 in.

The overflow pipe shall terminate at the bottom with an elbow. Unless otherwise specified by the purchaser, the overflow pipe shall be steel pipe with screwed or welded connections if less than 4 in. The pur- chaser shall specify the maximum flow rate, in gallons per minute, for which the overflow shall be designed. Overflow pipes may be either internal or external as specified by the purchaser.

Internal overflow pipes are not recommended when tank usage and climatic conditions are such that ice damage may occur to the overflow pipe or its attachments. When specifying an internal overflow pipe, the purchaser should con- sider the consequences of an overflow failure which can empty the contents of the tank.

The end of the overflow pipe may also be covered with a flap valve or as specified by the purchaser. The constructor shall furnish a tank ladder on the out- side of the shell beginning 8 ft 2. The side rails shall not be less than 2 in.

Inside tank ladders are not recommended for cold climates where ice may form. If an inside ladder is required, the side rails shall not be less than 2 in. For standpipes and reservoirs with roofs, unless otherwise specified, the constructor shall furnish access to roof hatches and vents.

Such access shall be reached from the outside tank ladder. Refer to Sec. The constructor shall furnish a roof opening that shall be placed near the outside tank ladder and that shall be provided with a hinged cover and a hasp for locking.

The opening shall have a curb at least 4 in. Additional openings may be required for ventilation during painting. WARNING: An improperly vented tank may create external pressures to act on the tank that can cause buckling, even at low-pressure differential. Even if more than one vent is required, one tank vent shall always be located near the center of the roof.

The vent shall be designed and con- structed to prevent the entrance of birds or animals. When governing health authorities require screening against insects, a pressure-vacuum screened vent or a separate pressure-vacuum relief mechanism that will operate in the event that the screens frost over or become clogged with foreign material shall be provided. The screens or relief mechanism shall not be damaged by the occurrence and shall return automatically to operating position after the clogging is cleared.

Exceptions to the provisions of this section may be specified by the pur- chaser to suit special situations. The welding inspector shall have prior tank-inspection experience and shall be a certified welding inspector CWI in accor- dance with the provisions of AWS QC1. The welding may be performed manually, semiautomatically, automat- ically, or by machine welding. The constructor or manufacturer shall choose which of the welding qualification procedures are to be used and shall conduct tests of the procedures to demonstrate their suitability in making welds that conform to the specified requirements.

The procedure shall be qualified by the reduced-section tension test only. IX, paragraph QW The constructor or manufacturer shall conduct tests for all welders assigned to manual or semiautomatic welding and all welding operators assigned to automatic or machine welding in order to demonstrate their ability to make acceptable welds.

Tests conducted by one constructor or manufacturer shall not qualify a welder or welding operator to perform the work for another constructor or manufacturer. The constructor or manufacturer shall maintain a record of the welders and welding operators employed, showing the date and results of tests and the identifying mark assigned to each. The records shall be certified by the constructor or manufacturer and shall be included in the inspection report required in Sec.

If such a record is kept, it shall be included in the inspection report required in Sec. Butt joints subject to primary stress, such as longitudinal joints of cylindrical tank shells and roof knuckles, and all joints below the point of support in suspended bottoms of elevated tanks, shall have complete joint penetration welds.

Such welds may be double welded or single welded with a backing strip or equivalent means to ensure complete joint penetration. Butt joints subject to secondary stress, such as circumferential joints of cylindrical tank shells, shall be welded as follows: 1. In addition, complete joint pene- tration welds shall be provided for a distance of at least 3 in.

In partial joint penetration welds, the effective throat shall exceed two-thirds of the thickness of the thinner plate. The unwelded portion shall be located near the center of the thinner plate. Partial joint penetration welds shall have a strength at least equivalent to two-thirds that of a complete joint penetration weld.

Alternatively, complete joint penetration welds used in lieu of partial joint penetration welds shall be made using filler metal compatible with the base metal and shall have a strength at least equivalent to two-thirds the strength of the base metal.

Lap joints subject to primary stress, such as longitudinal joints of cylindrical tank shells and all joints below the point of support in suspended bottoms of elevated tanks, shall have continuous fillet welds on both edges of the joint. Lap joints subject to secondary stress, such as circumferential joints of cylindrical tank shells and roof knuckles, shall be welded on both sides with continuous fillet welds.

They shall be designed to develop an efficiency of at least 50 percent based on the thickness of the thinner plate joined. Bottom plates need to be welded on the top side only with continuous fillet welds on all seams. Butt joints may be welded from the top side, using a suitable backing strip or equivalent means to ensure at least percent joint fusion.

The three-plate joints in the tank bottoms shall be at least 12 in. The minimum size of each fillet weld shall be either the nominal thickness of the thinnest plate joined or the size given in Table 18, whichever is larger. The required fillet sizes have no reference to any requirements for minimum plate thick- nesses.

The bottom plate shall extend outside the tank shell a distance of at least 1 in. Where seismic uplift may occur, the tank design shall be checked to determine whether minimum weld size is adequate. In roofs not subject to hydro- static pressure under normal operation from tank contents, lap joints may be welded on the top side only, with continuous fillet welds.

Butt joints shall be single-groove welds, using suitable backing or equivalent means to ensure at least percent joint penetration. In roofs subject to hydrostatic pressure under normal operation from tank contents, roof-plate joints shall be designed to conform to the efficiency values given in Sec. The roofs may use lap joints welded with continuous double-fillet welds or butt joints with complete joint penetration welds to suit the strength requirements.

Butt joints may be used for welding all thicknesses of material permitted to be welded under the provisions of this standard. The maximum thickness of plates, except structural components and base plates, permitted to be welded under this standard shall be 2 in. Structural components that are part of the primary container, primary support systems, or both may exceed 2 in.

Structural components that attach to the primary container to balance membrane discontinuities and base plates are excluded from these requirements. IX, and Sec. The maximum plate lap in single welded roof lap joints shall not exceed 4 in. Seal welding, when desired, shall be accomplished by a continuous weld combining the functions of sealing and strength with weld sections changed only as the required strength may necessitate.

Seal welds shall be of minimum size, but sufficient to prevent cracking from thermal shrinkage; seal weld acceptance shall be the same as for visual inspection of structural welds.

The effective length of a fillet weld shall not include the length of tapered ends. Seal welds in accordance with Sec. All seams that are to have intermittent welds shall have con- tinuous lengths of welds at each end for a distance of at least 6 in.

Minor cold straightening is permitted. Cold straightening may be performed by hammering or, preferably, by rolling or pressing.

Heat may be used in straightening more severe deformations. Edges of irregular contour may be prepared by manually guided oxyfuel gas or plasma arc cutting. When edges of plates are oxyfuel gas or plasma arc cut, the surface obtained shall be uniform and smooth and shall be cleaned of slag accumulation before welding. All cutting shall follow closely the lines prescribed. Edges shall be square, with all burrs removed before welding. Plates do not require rolling for tanks having a diameter larger than the minimum diameter indicated in Table 19 and for the plate thicknesses given therein.

For ground-supported tanks, limits of Table 19 may be extended by the constructor provided the erection tolerances of Sec. Welding shall not be performed when the surfaces of the parts to be welded are wet from rain, snow, or ice; when rain or snow is falling on such surfaces; or during periods of high winds, unless the welder or welding operator and the work are properly protected. Low-hydrogen electrodes or low-hydrogen welding processes shall be used. In addition, the area extending on both sides of the weld joint a distance of four times the plate thickness, but not less than 3 in.

Peening of weld layers may be used to prevent undue distortion. Surface layers shall not be peened. The surface beads shall merge smoothly into each other in all welds. The thickness of the reinforcement of the welds on all butt joints shall not exceed the thicknesses given in Table The reinforcement need not be removed except to the extent that it exceeds the maximum acceptable thickness or when required for radiographic inspections.

In no case shall the face of the weld lie below the surface of the plates being joined. Gouging at the root of welds and gouging of welds to remove defects may be performed with a round-nosed tool or by arc or oxygen gouging. Each bead of a multiple-pass weld shall be cleaned of slag and other loose deposits before the next bead is applied. A light film of deoxaluminate or equivalent spatter film compound may be disregarded. Such surfaces shall also be smooth, uniform, and free of fins, tears, and other defects that adversely affect proper welding.

A fine film of rust adhering on cut or sheared edges after wire brushing need not be removed. If protective coatings, deoxyaluminate, or equivalent are to be used on surfaces to be welded, then the protective coating shall be included Table 20 Maximum thickness of reinforcement for butt joints Maximum Thickness of Reinforcement Plate Thickness Vertical Joints Horizontal Joints in.

When the designated low-hydrogen covered electrodes are used, preheating of the steel, as required by Sec. After filler metal has been removed from its original package, it shall be protected or stored so that its characteristics or welding properties are not affected. Tack welds used in the assembly of joints subject to secondary stress, such as those used in flat bottoms, roofs, and circumferential seams of cylindrical tank shells, need not be removed, provided that they are sound, cleaned of all welding slag, and that the subsequently applied weld beads are thoroughly fused into the tack welds.

Any clips, jigs, or lugs welded to the shell plates for erection purposes shall be removed without damaging the plates, and any por- tion of weld beads remaining shall be chipped or ground smooth.

The bottom plates for elevated tanks shall be assembled and welded together by a procedure that will result in a minimum of distortion from weld shrinkage. The bottom plates for flat-bottom tanks, after being laid out and tacked, shall be joined by welding the joints in a sequence that the constructor has found to result in the least distortion due to shrinkage of the weld.

Out-of-plane distortion equal to 1 percent of the tank radius is considered acceptable. For welding in the vertical position, the progression of welding shall be either upward or downward, according to the direction specified in the welding procedure and used for welder performance qualification. Shell tolerances may be waived by agreement between the purchaser and the manufacturer.

Radii measured at 1 ft 0. Peaking is the out-of-plane distor- tion across a vertical weld seam. Banding is the out-of-plane distortion across a circumferential weld seam. Using a horizontal sweep board 36 in. Using a vertical sweep board 36 in. Flat spots that deviate from the theoretical shape measured in the vertical plane shall not exceed the appropriate plate flatness and waviness requirements in ASTM A6 and A20, whichever is applicable.

Double-curved, axisymmetrical, conical, and cylindrical sections governed by Sec. Alignment shall comply with Sec. The plates forming a lap joint shall be held in as close contact as possible during welding. Where plate separation occurs, the size of weld shall be increased by the amount of the separation. The adjoining edges of butt joints shall be aligned accurately and retained in position during welding, so that the offset tolerances of Table 22 are not exceeded in the welded joint.

Weld seams need not be chipped or ground, provided they can be satisfactorily cleaned and painted. The space shall be wetted thoroughly and filled with a The grout shall be forced under the bases until the space is filled completely. The constructor shall furnish material and labor for grouting. Copies of the mill test reports shall be furnished to the purchaser, if requested.

If shop inspection is required by the purchaser, it shall consist of a visual inspection of the fabricating practices and operations to determine compliance with this standard. Welds made in the shop that carry stress from the weight or pressure of the tank contents across the welded joint shall be inspected in accordance with the methods described in Sec.

It is recommended that the inspection of the radiographs or the sectional segments be made immediately after the first vertical joints are welded to prevent possible unacceptable welding that would later have to be removed. If the first welds by any operator are unsatisfactory, the inspector shall require additional tests as specified in Sec. If such tests continue to be unsatis- factory, the inspector shall have the right to prohibit that welder from doing further welding.

After the initial welding has been satisfactorily completed, the inspector may leave the job and return only at such times as, in his or her judgment, it is necessary to confirm the quality of the welding on the remaining seams. Section 4 addresses the sizing and design of elevated tanks. Accessories for elevated tanks are discussed in Section 5. Section 6 covers sizing of ground-supported standpipes and reservoirs.

Accessories for ground-supported standpipes and reservoirs are detailed in Section 7.