Guidelines for the safe operation of vertical steel tanks. Download the Safety Guide for Vertical Cylindrical Steel Tanks for Oil and Petroleum Products. Branch pipes and hatches in the roof of the tank

I General provisions
1.1. Scope and purpose
1.2. Classification and types of tanks
II Materials
2.1. General recommendations for materials
2.2. Chemical composition and weldability
2.3. Recommended sheet gauge
2.4. Design metal temperature
2.5. Recommended steel grades
2.6. Recommendations for impact strength
2.7. Recommended mechanical properties and hardness
2.8. Recommendations when ordering rolled metal products
2.9. Welding consumables
2.10. Bolt and nut material
III Design and calculation of tanks
3.1. Welded joints and seams
3.2. Recommended Connections
3.3. Recommended input data for design
3.4. Bottom design
3.5. Wall construction
3.6. Recommended design of stiffening rings on the wall
3.7. Fixed roofs
3.8. pontoons
3.9. floating roofs
3.10. Recommended branch pipes and manholes in the wall
IV Manufacture of steel structures for tanks
4.1. General recommendations
4.2. Recommendations for acceptance, storage and preparation of rolled metal products
4.3. Rolled metal processing
4.4. Recommendations for the manufacture of structural elements
4.5. Production of rolled sheets
4.6. Marking
4.7. Package
4.8. Transportation and storage of tank structures
V Recommendations for foundations and foundations
5.1. General recommendations
5.2. Recommendations for design solutions for foundations
5.3. Recommendations for design solutions for foundations
5.4. Recommended calculation of loads on the base and foundation of the tank
VI Installation of steel structures
6.1. General recommendations
6.2. Acceptance of foundations and foundations
6.3. Acceptance of metal structures of the tank (incoming control)
6.4. Installation of tank structures
VII Tank welding
7.1. General recommendations
7.2. Recommended Welding Methods
7.3. Recommendations for the preparation and assembly of metal structures for welding
7.4. Recommendations for the technology of making welded joints
7.5. Recommendations for the mechanical properties of welded joints
VIII Quality control of welded joints
8.1. General recommendations
8.2. Organization of control
8.3. Visual and measuring control
8.4. Leak test
8.5. Physical methods of control
IX Equipment for the safe operation of tanks
9.1. General recommendations
9.2. Breathing equipment
9.3. Instrumentation and automation
9.4. Fire Protection Recommendations
9.5. Lightning protection devices and protection against static electricity
X Recommendations for Testing and Acceptance of Tanks
XI Recommendations for anti-corrosion protection
XII Recommendations for thermal insulation
XIII Recommendations for the service life and ensuring the safe operation of tanks
Annex No. 1. List of abbreviations
Annex No. 2. Terms and their definitions
Appendix No. 3. Recommended steel grades (plates) for the main structures of groups A and B
Appendix No. 4. Assignment for tank design
Appendix No. 5. Journal of step-by-step control of installation and welding work during the construction of a vertical cylindrical tank
Appendix No. 6. Act for the acceptance of the base and foundations
Appendix No. 7. Quality protocol on tank design
Annex No. 8. Conclusion on the quality of welded joints based on the results of radiographic testing
Annex No. 9. Quality control act of the mounted (assembled) tank structures
Appendix No. 10. The act of hydraulic testing of the reservoir
Appendix No. 11. The act of testing the tank for internal overpressure and vacuum
Appendix No. 12. Certificate of completion of installation (assembly) of structures
Appendix No. 13. Passport of a steel vertical cylindrical tank
Annex No. 14. Acceptance certificate of the metal structures of the tank for installation
Appendix No. 15. Recommended list of documentation to be submitted when submitting a tank for strength tests
Appendix No. 16. Recommended grades of welding wires I General provisions
1.1. Scope and purpose
1.2. Classification and types of tanks
II Materials
2.1. General recommendations for materials
2.2. Chemical composition and weldability
2.3. Recommended sheet gauge
2.4. Design metal temperature
2.5. Recommended steel grades
2.6. Recommendations for impact strength
2.7. Recommended mechanical properties and hardness
2.8. Recommendations when ordering rolled metal products
2.9. Welding consumables
2.10. Bolt and nut material
III Design and calculation of tanks
3.1. Welded joints and seams
3.2. Recommended Connections
3.3. Recommended input data for design
3.4. Bottom design
3.5. Wall construction
3.6. Recommended design of stiffening rings on the wall
3.7. Fixed roofs
3.8. pontoons
3.9. floating roofs
3.10. Recommended branch pipes and manholes in the wall
IV Manufacture of steel structures for tanks
4.1. General recommendations
4.2. Recommendations for acceptance, storage and preparation of rolled metal products
4.3. Rolled metal processing
4.4. Recommendations for the manufacture of structural elements
4.5. Production of rolled sheets
4.6. Marking
4.7. Package
4.8. Transportation and storage of tank structures
V Recommendations for foundations and foundations
5.1. General recommendations
5.2. Recommendations for design solutions for foundations
5.3. Recommendations for design solutions for foundations
5.4. Recommended calculation of loads on the base and foundation of the tank
VI Installation of steel structures
6.1. General recommendations
6.2. Acceptance of foundations and foundations
6.3. Acceptance of metal structures of the tank (incoming control)
6.4. Installation of tank structures
VII Tank welding
7.1. General recommendations
7.2. Recommended Welding Methods
7.3. Recommendations for the preparation and assembly of metal structures for welding
7.4. Recommendations for the technology of making welded joints
7.5. Recommendations for the mechanical properties of welded joints
VIII Quality control of welded joints
8.1. General recommendations
8.2. Organization of control
8.3. Visual and measuring control
8.4. Leak test
8.5. Physical methods of control
IX Equipment for the safe operation of tanks
9.1. General recommendations
9.2. Breathing equipment
9.3. Instrumentation and automation
9.4. Fire Protection Recommendations
9.5. Lightning protection devices and protection against static electricity
X Recommendations for Testing and Acceptance of Tanks
XI Recommendations for anti-corrosion protection
XII Recommendations for thermal insulation
XIII Recommendations for the service life and ensuring the safe operation of tanks
Annex No. 1. List of abbreviations
Annex No. 2. Terms and their definitions
Appendix No. 3. Recommended steel grades (plates) for the main structures of groups A and B
Appendix No. 4. Assignment for tank design
Appendix No. 5. Journal of step-by-step control of installation and welding work during the construction of a vertical cylindrical tank
Appendix No. 6. Act for the acceptance of the base and foundations
Appendix No. 7. Quality protocol on tank design
Annex No. 8. Conclusion on the quality of welded joints based on the results of radiographic testing
Annex No. 9. Quality control act of the mounted (assembled) tank structures
Appendix No. 10. The act of hydraulic testing of the reservoir
Appendix No. 11. The act of testing the tank for internal overpressure and vacuum
Appendix No. 12. Certificate of completion of installation (assembly) of structures
Appendix No. 13. Passport of a steel vertical cylindrical tank
Annex No. 14. Acceptance certificate of the metal structures of the tank for installation
Appendix No. 15. Recommended list of documentation to be submitted when submitting a tank for strength tests
Appendix No. 16. Recommended grades of welding wires

6. Requirements for tank design

6.1 Tank designs

6.1.1 General requirements

6.1.1.1 The nominal thicknesses of the structural elements of the tanks in contact with the product or its vapors are assigned taking into account the minimum structural or design thicknesses, corrosion allowances (if necessary) and minus rental tolerances.

6.1.1.2 Nominal thicknesses of structural elements of outdoor tanks (stairs, platforms, fences, etc.) shall not be less than the minimum structurally required thicknesses specified in the relevant sections of this standard. The specified thicknesses of rolled products must meet the requirements of building codes and regulations.

6.1.1.3 Tank walls and bottoms of all types volume 10000 m 3 and more must be manufactured and assembled by sheet assembly.

6.1.2 Welds and seams

6.1.2.1 Main types of welded joints and seams.

For the manufacture of tank structures, butt, corner, tee and lap welded joints are used.

Depending on the length of the welds along the line of connecting parts, the following types of welds are distinguished:

continuous seams performed over the entire length of the welded joint;
intermittent seams performed in alternating sections with a length of at least 50 mm;
temporary (tack) welds, the cross section of which is determined by the assembly technology, and the length of the welded sections is not more than 50 mm.

The shape and dimensions of the structural elements of welded joints are recommended to be taken in accordance with the standards for the type of welding used:

for manual arc welding - according to GOST 5264;
for arc welding in shielding gas - according to GOST 14771;
for submerged arc welding - according to GOST 8713.

Images of welded joints and symbols of welds in the drawings must unambiguously determine the dimensions of the structural elements of the prepared edges of the parts to be welded, which are necessary for making welds using a particular type of welding.

6.1.2.2 Restrictions on welds and seams.

The presence of tack welds in the finished structure is not allowed.

Minimum legs of fillet welds (without corrosion allowance) are accepted in accordance with the current regulatory documents *.

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The maximum legs of fillet welds must not exceed 1.2 times the thickness of the thinner part in the joint.

An overlap joint welded with a continuous seam on one side is only allowed for joints of bottom or roof elements, while the overlap value must be at least 60 mm for joints of bottom panels or roof panels and at least 30 mm for joints of bottom sheets or roof sheets in sheet assembly, but not less than five thicknesses of the thinnest sheet in the joint.

6.1.2.3 Vertical web connections

Vertical joints of wall sheets should be made with double-sided butt welds with full penetration. Recommended types of vertical welded joints are shown in Figure 2.

Vertical joints of sheets on adjacent wall chords must be offset relative to each other by the following value:

for walls constructed by the method of rolling - at least 10 t(where t- sheet thickness of the underlying wall belt);
for the walls of sheet assembly - not less than 500 mm.

Vertical factory and assembly seams of the walls of tanks with a volume of less than 1000 m 3, constructed by the method of rolling, can be placed on the same line.

6.1.2.4 Horizontal web connections

Horizontal joints of wall sheets should be made with double-sided butt welds with full penetration. Recommended types of horizontal welded joints are shown in Figure 3.

For reservoirs of sheet assembly, the wall chords should be aligned in one vertical line along the inner surface or along the axis of the chords.

For the walls of tanks produced by the rolling method, it is allowed to combine a common vertical line with the inner or outer surface of the chords.

6.1.2.5 Bottom lap joints

Bottom lap joints are used to connect rolled bottom panels, sheets of the central part of the bottoms when they are assembled by sheet assembly, as well as to connect the central part of the bottoms (rolled or sheet) with annular edges.

The lap joints of the bottoms are welded with a continuous one-sided fillet weld only from the upper side. In the zone of intersection of the lap joints of the bottom with the lower wall chord, a flat surface of the bottom should be formed, as shown in Figure 4.

Figure 4. Transition from lap to butt joint of panels or bottom sheets in the zone of wall support

6.1.2.6 Bottom butt joints

Bilateral butt joints are used for welding of rolled panels of bottoms or bottoms of sheet assembly, during installation of which canting is possible for welding the reverse side of the seam.

One-sided butt joints on the remaining lining are used to connect the annular edges to each other, as well as for sheet-by-sheet assembly of the central part of the bottoms or bottoms without edges. The remaining lining must have a thickness of at least 4 mm and be joined with an interrupted seam to one of the joined parts. When performing a butt joint on the remaining lining without cutting the edges, the gap between the edges of the joined sheets with a thickness of up to 6 mm must be at least 4 mm; for joined sheets with a thickness of more than 6 mm - at least 6 mm. If necessary, metal spacers should be used to provide the required clearance.

For butt joints of annular fringes, a variable wedge-shaped gap should be provided, varying from 4-6 mm along the outer contour of the fringes to 8-12 mm along the inner contour, taking into account the shrinkage of the fringe ring during welding.

For linings, materials should be used that correspond to the material of the parts to be joined.

6.1.2.7 Wall-to-bottom connection

To connect the wall to the bottom, a two-sided tee joint without beveled edges or with two symmetrical bevels of the lower edge of the wall sheet should be used. The leg of the fillet weld of a tee joint must be no more than 12 mm.

When the thickness of the wall sheet or the bottom sheet is 12 mm or less, a joint without beveled edges with a leg of a fillet weld equal to the thickness of the thinner of the joined sheets is used.

When the thickness of the wall sheet and the bottom sheet is more than 12 mm, a joint with beveled edges is used, while the sum of the leg of the fillet weld A and the depth of the bevel B is equal to the thickness of the thinner of the joined sheets (Figures 5, 6). It is recommended that the depth of the bevel be taken equal to the leg of the fillet weld, provided that the blunting of the edge is at least 2 mm.

Figure 5. Wall-to-bottom connection with wall and bottom plate thicknesses of 12 mm or less

Figure 6. Connection of the wall with the bottom when the thickness of the wall sheet and the bottom sheet is more than 12 mm

The junction of the wall with the bottom must be accessible for inspection during the operation of the tank. If there is thermal insulation on the wall of the tank, it should not reach the bottom at a distance of 100-150 mm in order to reduce the possibility of corrosion of this unit and ensure monitoring of its condition.

6.1.2.8 Roof deck connections

Roof decking is allowed to be made from separate sheets, enlarged cards or prefabricated panels.

The assembly joints of the flooring should be carried out, as a rule, with an overlap with welding of a continuous fillet weld only from the upper side.

The overlap of the sheets in the direction of the roof slope should be performed in such a way that the top edge of the bottom sheet is superimposed over the bottom edge of the top sheet in order to reduce the possibility of condensation penetrating into the overlap (Figure 7).

Figure 7. Lap joint of roof deck sheets in the direction of the roof pitch

At the request of the customer, assembly joints of the decking of frameless conical or spherical roofs can be made with double-sided butt or double-sided lap joints.

The factory welded seams of the flooring shall be full penetration butt welds.

Intermittent fillet welds can be used to connect the flooring to the roof frame if the degree of influence of the internal environment of the tank is low or when the frame is located on the outer surface of the flooring in the open air. When the frame is located on the inner side of the flooring and the frame is exposed to a medium and highly aggressive environment, the specified connection should be made with continuous fillet welds of the minimum section with the addition of a corrosion allowance.

When making a roof with an easily dropped flooring, the flooring should be welded only to the upper annular wall element with a fillet weld with a leg no more than 5 mm. Welding of the decking to the roof frame is not allowed.

6.1.3 Bottoms

6.1.3.1 Tank bottoms can be flat (for tanks up to 1000 m 3 inclusive) or conical with a slope from the center to the periphery with a recommended slope of 1:100.

At the request of the customer, it is allowed to slope the bottom to the center of the tank, subject to special consideration in the project of the issues of foundation settlement and bottom strength.

6.1.3.2 The bottoms of tanks up to 1000 m 3 inclusive are allowed to be made from sheets of the same thickness (without borders), while the protrusion of the bottom sheets beyond the outer surface of the wall should be taken as 25-50 mm. The bottoms of tanks with a volume of more than 1000 m 3 should have a central part and annular edges, while the protrusion of the edges beyond the outer surface of the wall should be taken as 50-100 mm. The presence of sheets of different thicknesses in the rolled panel bottom is not allowed.

6.1.3.3 The nominal thickness of plates of the central part of the bottom or the bottom without edges, minus the corrosion allowance, shall be 4 mm for tanks with a volume of less than 2000 m 3 and 6 mm for tanks with a volume of 2000 m 3 and more.

6.1.3.4 The dimensions of the edge ring of the bottom are determined from the condition of the strength of the joint of the wall with the bottom, taking into account the deformability of the edge sheet and the bottom of the tank wall. For class 3a tanks, the calculation of the rim is performed based on the strength condition within the framework of the theory of plates and shells in accordance with the requirements of the current regulatory documents *.

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* On the territory of the Russian Federation, SP 16.13330.2011 "SNiP II-23-81* Steel structures" is in force.

6.1.3.5 Allowed nominal thickness tb the annular edges of the bottom take not less than the value determined by the formula

where k 1 =0.77 - dimensionless coefficient;
r- tank radius, m;
t 1 - nominal thickness of the lower wall belt, m;
Δ tcs- allowance for corrosion of the lower belt of the wall, m;
Δ tcb- bottom corrosion allowance, m;
Δ tmb- minus tolerance for bottom edge rolling, m

6.1.3.6 The annular edges shall have a width in the radial direction that ensures the distance between the inner surface of the web and the welding seam of the central part of the bottom to the edges of not less than:

300 mm for tanks with a volume of less than 5000 m 3;
600 mm for tanks with a volume of 5000 m 3 and more;
quantities L 0 , m, determined by the relation.

where k 2 =0.92 - dimensionless coefficient.

6.1.3.7 The distance from the welded joints of the bottom, located under the bottom edge of the wall, to the vertical seams of the bottom chord of the wall shall not be less than:

100 mm for tanks up to 10000 m 3 inclusive;
200 mm for tanks with a volume of over 10,000 m 3 .

6.1.3.8 Butt or lap joints of three bottom elements (sheets or panels) shall be located at a distance of at least 300 mm from each other, from the tank wall and from the field joint of the annular edges.

6.1.3.9 The connection of structural elements to the bottom shall meet the following requirements:

a) welding of structural elements should be carried out through sheet overlays with rounded corners with welding along a closed contour;

b) the leg of fillet welds for fastening structural elements should not exceed 12 mm;

in) It is allowed to impose a permanent structural element on the welded seams of the bottom, subject to the following requirements:

the seam of the bottom under the structural element must be ground flush with the base metal,
seams of welding of linings to the bottom should be controlled for tightness;

G) temporary structural elements (technological devices) should be welded at a distance of at least 50 mm from the welds;

e) technological devices must be removed before hydraulic testing, and the resulting damage or surface irregularities must be eliminated by grinding with an abrasive tool to a depth that does not bring the thickness of the rolled products beyond the minus tolerance for rolled products.

6.1.3.10 Bottoms shall have a circular edge along the outer contour.

6.1.3.11 Along the inner perimeter of the annular edges, the shape of the central part of the bottom may be circular or multifaceted, taking into account the overlap of the central part of the bottom on the edges of at least 60 mm.

6.1.4 Walls

6.1.4.1 The nominal thicknesses of the tank wall sheets are determined in accordance with the requirements of the current regulatory documents*:

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* On the territory of the Russian Federation there are: SP 20.13330.2011 "SNiP 2.01.07-85* Loads and Impacts", SP 16.13330.2011 "SNiP II-23-81* Steel Structures", RB 03-69-2013 "Safety Guide vertical cylindrical steel tanks for oil and oil products".

for the main combinations of loads - by calculating the strength and stability under normal operation and hydraulic tests;
for special combinations of loads - by calculating the strength and stability under earthquake conditions;
if it is necessary to determine the service life of the tank - by calculating the low-cycle strength.

6.1.4.2 Nominal thicknesses of web chords t should be taken from the assortment for sheet metal so that the following inequalities are observed:

where td, tg, ts- design thicknesses of the wall chords under the action of static loads during operation, hydraulic tests and seismic action, respectively;
th- minimum structural wall thickness, determined from table 3;
tc- allowance for wall metal corrosion;
Δtm- minus tolerance for sheet metal specified in the certificate for the supply of metal (if Δtm≤0.3, then it is allowed to take into account Δtm=0).

Table 3 - Minimum structural thicknesses of web sheets

6.1.4.3 Design thickness i-th belt of the wall from the condition of strength under the action of the main combinations of loads should be determined at a level corresponding to the maximum hoop stresses in the middle surface of the belt according to the formulas:

, . (4)

For tanks with a diameter of more than 61 m, calculation of the thickness i-th belt of the wall from the strength condition is allowed to be carried out according to the formulas:

, , (5)

(6)

where r - tank radius, m;
tdi, tgi- calculated thicknesses i-th belt for operation and hydraulic tests, m;
t i-1 - belt thickness i-1 assigned according to formula (3), m;
z i - distance from the bottom to the bottom edge i-th belt, m;
i- distance from the bottom to the level at which the hoop stresses in the middle surface i-th belts take the maximum value, m;
Hd, Hg- calculated levels of filling of the product (water) for operation and hydraulic tests, m;
ρ d, ρ g- density of the product (water) for operation and hydraulic tests, t/m 3 ;
g- acceleration of gravity, g\u003d 9.8 m / s 2;
R- normative excess pressure in the gas space, MPa;
Δ tc , i -1 - belt corrosion allowance i-1m;
Δ tm , i -1 - minus tolerance for belt rental i-1m.

The calculation according to formulas (5) is carried out sequentially from the lower to the upper belt of the wall.

6.1.4.4 Design parameter R, MPa, should be determined by the formula

Where Rγn- normative resistance, taken equal to the guaranteed value of the yield strength according to the current standards and specifications for steel;
Υ c - dimensionless coefficient of the working conditions of the wall chords;
Υ m- dimensionless safety factor for the material (determined in accordance with the requirements of the current regulatory documents *);

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* On the territory of the Russian Federation, SP 16.13330.2011 "SNiP II-23-81* Steel structures" is in force.

Υ n- dimensionless coefficient of reliability by responsibility;
Υ t- dimensionless temperature coefficient, determined by the formula:

(8)

here σ T, σ T ,20 - allowable stresses of steel at the design temperature of the metal, respectively T and 20°C.

6.1.4.5 The safety factor for liability and the factors for the working conditions of the web chords should be assigned in accordance with tables 4 and 5.

Table 4. Reliability factor by liability Υ n

Table 5. Coefficients of working conditions of wall chords Yc

6.1.4.6 The stability of the wall for the main combinations of loads (weight of structures and thermal insulation, weight of snow cover, wind load, relative vacuum in the gas space) is checked by the formula:

, (9)

where σ 1, σ2- meridional (vertical) and hoop stresses in the middle surface of each wall chord, MPa, determined from the action of the indicated loads in accordance with the requirements of the current regulatory documents *;

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* On the territory of the Russian Federation, SP 16.13330.2011 "SNiP II-23-81* Steel structures" is in force.

σ cr 1 , σ cr 2 - critical meridional and hoop stresses, MPa, obtained by the formulas:

, , , (10)

(11)

Here E- modulus of elasticity of steel, MPa;
t min is the thickness of the thinnest wall belt (as a rule, the upper one), representing its nominal thickness minus the corrosion allowance and minus tolerance for rolled products, m;
Hr- reduced wall height, m;
n- number of wall belts;
h- belt height, m;
index i in the notation indicates that the corresponding quantity belongs to i-th belt of the wall.

If there is a stiffness ring within i th belt as hi take the distance from the edge of this belt to the stiffening ring. In floating roof tanks for the top chord as hi designate the distance from the lower edge of the belt to the wind ring.

6.1.4.7 The seismic resistance of the tank body is determined for a specific combination of loads, including seismic action, the weight of the stored product, the weight of structures and thermal insulation, overpressure, and the weight of snow cover.

increased pressure in the product from low-frequency gravity waves on the free surface that occur during horizontal seismic action;
high-frequency dynamic action due to the joint fluctuation of the mass of the product and the circular cylindrical shell;
inertial loads from tank structural elements involved in the general dynamic processes of the hull and product;
hydrodynamic loads on the wall due to vertical vibrations of the soil.

Seismic stability calculation of the tank should provide:

wall strength in terms of hoop stresses at the level of the lower edge of each chord;
stability of the 1st belt of the wall, taking into account additional compression in the meridional direction from the seismic overturning moment;
stability of the tank body from capsizing;
conditions under which the gravitational wave on the free surface does not reach the structures of the stationary roof and does not lead to the loss of operability of the pontoon or floating roof.

The seismic overturning moment is defined as the sum of the moments from all forces contributing to the overturning of the tank. The rollover test is carried out relative to the lower point of the wall located on the axis of the horizontal component of the seismic action.

6.1.4.9 Local concentrated loads on the tank wall shall be distributed by means of sheet overlays.

6.1.4.10 Permanent structural elements shall not impede the movement of the wall, including in the area of the lower chords of the wall under hydrostatic load.

6.1.4.11 The connection of structural elements to the wall must meet the following requirements:

a) welding of structural elements should be carried out through sheet overlays with rounded corners with welding along a closed contour;

b) the leg of fillet welds for fastening structural elements should not exceed 12 mm;

c) permanent structural elements (except for stiffening rings) must be located no closer than 100 mm from the axis of the horizontal seams of the wall and bottom of the tank and no closer than 150 mm from the axis of the vertical seams of the wall, as well as from the edge of any other permanent structural element on the wall;

d) temporary structural elements (technological devices) must be welded at a distance of at least 50 mm from the welds;

6.1.5 Stiffening rings on the web

6.1.5.1 To ensure the strength and stability of the tanks during operation, as well as to obtain the required geometric shape during installation, it is allowed to install the following types of stiffening rings on the walls of the tanks:

upper wind ring for tanks without a fixed roof or for tanks with fixed roofs that have increased deformability in the plane of the roof base;
upper support ring for tanks with fixed roofs;
intermediate wind rings to ensure stability when exposed to wind and seismic loads.

6.1.5.2 The upper wind ring is installed outside the tank on the upper wall chord.

The cross section of the upper wind ring is determined by calculation, and the width of the ring must be at least 800 mm.

For tanks with a floating roof, it is recommended to install an upper wind ring at a distance of 1.25 m from the top of the wall, while at the top of the wall an annular corner with a cross section of at least 63x5 mm should be installed with a thickness of the upper wall chord up to 8 mm and at least 75x6 mm with a thickness of the upper belt of the wall is more than 8 mm.

When using the upper wind ring as a service platform, the design requirements for the elements of the ring (width and condition of the running surface, fence height, etc.) must comply with the requirements of 6.1.11.

6.1.5.3 The upper support ring of stationary roofs is installed in the area of the upper edge of the tank wall to absorb the support reactions of compression, tension or bending when external and internal loads are applied to the roof.

In the event that the installation of a fixed roof is carried out after the completion of the installation of the tank wall, the cross section of the support ring must be checked by calculation, as for a tank without a fixed roof.

6.1.5.4 Intermediate wind rings are installed in cases where the thickness of the wall chords does not ensure the stability of the empty tank wall, and an increase in the thickness of the wall chords is technically and economically inexpedient.

6.1.5.5 Stiffening rings on the web shall be closed (have no cuts along the entire perimeter of the web) and meet the requirements specified in 6.1.4.11. Installation of ring ribs in separate sections, including in the area of mounting joints of the wall of rolled tanks, is not allowed.

6.1.5.6 The joints of stiffening ring sections shall be butt joints with full penetration. Connection of sections on overlays is allowed. The mounting joints of the sections must be located at a distance of at least 150 mm from the vertical seams of the wall.

6.1.5.7 Stiffening rings shall be located at a distance of at least 150 mm from the horizontal seams of the web.

6.1.5.8 Stiffening rings, the width of which is 16 or more times greater than the thickness of the horizontal element of the ring, shall be supported in the form of ribs or struts. The distance between the supports should not exceed more than 20 times the height of the outer vertical flange of the ring.

6.1.5.9 If the tank has fire irrigation systems (cooling devices), stiffening rings installed on the outer surface of the wall must have a design that does not prevent wall irrigation below the level of the ring.

Rings of a design that is capable of collecting water must be provided with drain holes.

6.1.5.10 Minimum section modulus of the upper wind ring Wzt, m 3 , floating roof tanks are determined by the formula

, (12)

where 1.5 is the coefficient taking into account the vacuum from the wind in the tank with an open top;
pw- standard wind pressure, taken depending on the wind area in accordance with the current regulations *;

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D- tank diameter, m;
H S- tank wall height, m;
design parameter R- according to 6.1.4.4.

If the upper wind ring is connected to the wall with continuous welds, it is allowed to include sections of the wall with a nominal thickness in the section of the ring t and width 15( t-Δt c) down and up from the ring installation site.

In the case of installing an intermediate wind ring, it is recommended to have such a design in which its cross section meets the requirements:

for fixed roof tanks:

; (13)

for floating roof tanks:

, (14)

where H r max- the maximum of the reduced height of the wall section above or below the intermediate ring, determined according to 6.1.4.6.

6.1.5.11 At the moment of resistance of the intermediate stiffening ring, parts of the wall with a width L s \u003d 0.6√r (t- Δt c) above and below the installation site of the ring.

6.1.6 Fixed roofs

6.1.6.1 General requirements

This paragraph establishes general requirements for fixed roof structures, which are divided into the following types:

frameless conical roof, the bearing capacity of which is provided by the conical decking shell;
frameless spherical roof, the bearing capacity of which is provided by rolled flooring elements forming the surface of the spherical shell;
frame conical roof, close to the surface of a gentle cone, consisting of frame elements and flooring;
framed domed roof, consisting of radial and annular frame elements inscribed in the surface of a spherical shell, and flooring, freely lying on the frame or welded to its elements;
other types of roofs, subject to the requirements of this standard and building codes.

Depending on the steel used, stationary roofs can be made in the following versions:

carbon steel roof;
stainless steel roof;
carbon steel roof for frame and stainless steel decking.

Use of stationary roofs from aluminum alloys is allowed.

6.1.6.2 Fundamentals of calculation

The calculation of stationary roofs is carried out for the following combinations of loads*:

_________________
* On the territory of the Russian Federation, SP 20.13330.2011 "SNiP 2.01.07-85* Loads and Impacts" is in force.

a) the first main combination of impacts from:

weight of thermal insulation;
weight of snow cover with symmetrical and asymmetrical distribution of snow on the roof;
internal relative vacuum in the gas space of the tank;

b) the second main combination of impacts from:

own weight of roof elements;
weight of stationary equipment;
weight of thermal insulation;
excess pressure;
negative wind pressure;

c) a special combination of actions from the inertial vertical loads of the roof and equipment, as well as from the loads of the first main combination of actions with the corresponding coefficients of combinations of actions from the current regulatory documents *.

________________
* On the territory of the Russian Federation, SP 14.13330.2014 "SNiP II-2-7-81* Construction in seismic regions" is in force.

The calculation of the bearing capacity of stationary roofs is carried out in accordance with the requirements of the current regulatory documents * with the coefficient of working conditions Υ c =0,9.

________________
* On the territory of the Russian Federation, SP 16.13330.2011 "SNiP II-23-81* Steel structures" is in force.

It is recommended to model and calculate roofs for all combinations of loads using the finite element method. The calculation scheme includes all the bearing rod and plate elements provided for by the design solution. If the flooring sheets are not welded to the frame, then only their weight characteristics are taken into account in the calculation.

Roof elements and units must be designed in such a way that the maximum forces and deformations in them do not exceed the limit values for strength and stability, regulated by the normative document*.

________________
* On the territory of the Russian Federation, SP 16.13330.2011 "SNiP II-23-81* Steel structures" is in force.

6.1.6.3 Frameless conical roof

A frameless conical roof is a smooth conical shell not supported by radial stiffeners.

The geometric parameters of a frameless conical roof must meet the following requirements:

roof diameter in plan - no more than 12.5 m;
the angle of inclination of the roof generatrix to the horizontal surface should be set in the range from 15° to 30°.

The nominal thickness of the roof shell should be between 4 and 7 mm (when the shell is made by rolling) and more (when the flooring is made on the installation site). In this case, the shell thickness tr should be determined by the stability calculation according to the following formula:

, (15)

where α - the angle of inclination of the conical roof;
Rr- design load on the roof for the first main combination of actions, MPa;
Δ tcr- allowance for corrosion of the roof deck, m.

In case of insufficient bearing capacity, the smooth conical shell must be reinforced with annular stiffening ribs (frames), determined by calculation and installed on the outside of the roof in such a way as not to impede the removal of precipitation.

The roof shell should be made in the form of a rolled panel (from one or more parts). It is allowed to manufacture the roof panel during installation, while the thickness of the roof shell can be increased up to 10 mm.

6.1.6.4 Frameless spherical roof

The frameless spherical roof is a flat spherical shell.

The radius of curvature of the roof must be between 0.7 D up to 1.2 D, where D is the inner diameter of the tank wall. The recommended range of application of frameless spherical roofs are tanks with a volume of up to 5000 m 3 and a diameter of not more than 25 m.

The nominal thickness of the roof shell is determined by strength and stability calculations and must be at least 4 mm.

The surface of a spherical roof can be made of shaped petals of double curvature (rolled in the meridional and annular direction) or cylindrical petals, rolled only in the meridional direction, while the deviation of the surface of the cylindrical petal from a smooth spherical surface (in the annular direction) should not exceed three shell thicknesses .

The connection of the petals to each other should be done with double-sided butt or lap joints.

6.1.6.5 Framed conical roof

Frame conical roofs can have two versions:

a) execution with the lower location of the frame relative to the flooring;
b) execution with the upper frame position relative to the flooring, providing increased corrosion resistance of the roof due to the creation of a smooth surface on the side of the stored product and its vapors.

The values of the nominal thicknesses of structural elements of frame roofs are given in Table 6.

Table 6. Nominal thicknesses of structural elements of frame roofs

*Note: Dtcr- allowance for corrosion of roof elements.

Frame conical roofs are made in two versions:

shield - in the form of shields, consisting of interconnected elements of the frame and flooring, while the frame can be located both on the inside and on the outside of the flooring;
frame - in the form of frame elements and flooring, not welded to the frame, while the flooring can be made of individual sheets, large-sized cards or rolled panels, and two diametrically opposite frame elements must be unfastened in plan by diagonal braces.

6.1.6.6 Framed dome roof

The domed roof is a radial-annular frame system inscribed in the surface of a spherical shell.

Dome roofs must meet the following requirements:

the radius of curvature of the spherical surface of the roof must be between 0.7 D up to 1.5 D, where D- tank diameter;
nominal thicknesses of elements of framed domed roofs are specified in table 6;
the frame of domed roofs must have connecting elements that ensure the geometric invariability of the roof.

6.1.7 Branch pipes and manholes in the tank wall (cut-ins into the wall)

6.1.7.1 General requirements

For the manufacture of branch pipes and hatches, seamless or straight-seam pipes and shells made of rolled sheet should be used.

Longitudinal seams of shells made of rolled sheet must be controlled by the RK method in the amount of 100%. For tanks of class KS-2b, RK is allowed not to be carried out.

When welding a shell or pipe to the tank wall, penetration of the wall must be ensured (Figure 8).

6.1.7.2 Reinforcement of the web at the tie-in points

Holes in the wall for the installation of branch pipes and hatches must be reinforced with sheet overlays (reinforcing sheets) located along the perimeter of the hole. It is allowed to install branch pipes with a nominal diameter up to 65 mm inclusive in a wall with a thickness of at least 6 mm without reinforcing sheets.

It is not allowed to strengthen the tie-ins by welding stiffeners to the shells (pipes).

Outside diameter D R reinforcing sheet should be within 1.8 D0£ D R£2.2 D0, where D0 is the diameter of the hole in the wall.

The thickness of the reinforcing sheet shall not be less than that of the corresponding wall sheet and shall not exceed the thickness of the wall sheet by more than 5 mm. The edges of the reinforcing sheet with a thickness exceeding the thickness of the wall sheet must be rounded or processed in accordance with Figure 8. It is recommended that the thickness of the reinforcing sheet be taken equal to the thickness of the wall sheet.

The cross-sectional area of the reinforcing sheet, measured along the vertical axis of the hole, must be not less than the product of the vertical size of the hole in the wall and the thickness of the wall sheet.

The reinforcing sheet must have an inspection hole with M6-M10 thread, closed with a screw plug and located approximately on the horizontal axis of the branch pipe or hatch or in the lower part of the reinforcing sheet.

The leg of the fillet weld for fastening the reinforcing sheet to the shell (pipe) of the branch pipe or hatch ( K 1, Figure 8) is assigned in accordance with Table 7, but should not exceed the shell (pipe) thickness.

Table 7

Dimensions in mm

Figure 8. Details of branch pipes and hatches in the wall

The leg of the fillet weld for fastening the reinforcing sheet to the tank wall ( K 2, Figure 8) must be at least as specified in Table 8.

For a reinforcing sheet reaching the bottom of the tank, the leg of the fillet weld of the reinforcing sheet to the bottom (K 3, figure 8) should be equal to the smallest thickness of the welded elements, but not more than 12 mm.

Table 8

Dimensions in mm

It is allowed to strengthen the wall by installing an insert - a wall sheet of increased thickness, determined by the appropriate calculation. The thickness of the insert must not exceed 60 mm.

6.1.7.3 Restrictions on the location of wall inserts

No more than four inserts with a nominal diameter of more than 300 mm can be located in one wall sheet. For more taps, the web plate shall be heat treated in accordance with 9.6.

The distances between the parts of adjacent branch pipes and hatches welded to the tank wall (shells, pipes, reinforcing sheets) must be at least 250 mm.

The distance from the parts of branch pipes and hatches welded to the tank wall (shells, pipes, reinforcing sheets) to the axis of the vertical seams of the wall must be at least 250 mm. and to the axis of the horizontal seams of the wall and to the bottom of the tank (except for the version of the design of the reinforcing sheet reaching the bottom) - at least 100 mm.

In the case of heat treatment of wall sheets with tie-ins in accordance with 9.6, the above distances may be reduced to 150 mm (instead of 250 mm) and to 75 mm (instead of 100 mm).

The distance from the details of branch pipes and hatches welded to the tank wall (shells, pipes, reinforcing sheets) to other parts welded to the wall must be at least 150 mm.

When repairing tanks, it is allowed as an exception (in agreement with the CM developers) to install branch pipes and hatches with the intersection of wall welds (horizontal and vertical) in accordance with Figure 9, while the crossed seam must be subjected to RC for a length of at least three hole diameters in wall symmetrically about the vertical or horizontal axis of the branch pipe or hatch.

Figure 9, sheet 1 - Installation of pipes and hatches at intersections
with vertical or horizontal wall welds
(conditionally shows the intersection with a vertical seam)

Notes
1. For intersections with vertical joints, the values BUT and AT must be at least 100 mm and at least 10 t, where t- thickness of the wall sheet.
2. For intersections with horizontal joints, the values A and B must be at least 75 mm and at least 8 t, where t- thickness of the wall sheet.

Figure 9, sheet 2

6.1.7.4 Pipes in the tank wall

Branch pipes in the wall are designed for connection of external and internal pipelines, instrumentation and other devices that require making holes in the wall.

The number, dimensions and type of nozzles (Figure 11) depend on the purpose and volume of the tank and are determined by the customer of the tank.

The most responsible in terms of ensuring the reliability of the tank are the nozzles for receiving and distributing the product, located in close proximity to the bottom in the zone of the vertical bend of the wall and perceiving significant technological and temperature loads from the connected pipelines.

The calculation and design of nozzles, taking into account the internal hydrostatic pressure of the product and the loads from the connected pipelines, should be carried out in accordance with the requirements of specialized standards.

In-wall branch pipes are recommended with a nominal diameter of 50, 80, 100, 150, 200, 250, 300, 350, 400, 500, 600, 700, 800, 900, 1000, 1200 mm. The design of the nozzles in the wall must comply with figures 8, 10, 11, 12 and table 9.

Branch pipe flanges in the wall should be made in accordance with GOST 33259: types 01 and 11. version B, row 1 for a nominal pressure of 16 kgf / cm 2, unless otherwise specified in the design specification.

At the request of the customer of the tank, branch pipes in the wall can be equipped with temporary plugs according to ATC 24.200.02-90* for a nominal pressure of 6 kgf/cm 2, designed to seal the tank during testing after installation is completed.

____________
ATK 24.200.02-90 Flanged steel plugs. Design, dimensions and technical requirements.

Figure 10. Pipes in the wall (nozzles with flanges type 01 are conventionally shown)

Figure 11. Types of nozzles in the wall (nozzles with D1 flanges and round reinforcing sheets are conventionally shown)

Figure 12. Connection of the nozzle flange with the shell (pipe)

Table 9. Structural parameters of nozzles in the tank wall

Dimensions in mm

Nominal nozzle diameter DN	D P	tp, (see note 1)	Dr	BUT, not less		AT, not less (see note 2)	FROM, not less
Nominal nozzle diameter DN	D P	tp, (see note 1)	Dr	With round reinforcing sheet	With reinforcing sheet to the bottom	AT, not less (see note 2)	FROM, not less
50	57	5	—	—	—	150	100
80	89	6	220	220	150	200	100
100	108; 114	6	260	250	160	200	100
150	159; 168	6	360	300	200	200	125
200	219	6	460	340	240	250	125
250	273	8	570	390	290	250	150
300	325	8	670	450	340	250	150
350	377	10	770	500	390	300	175
400	426	10	870	550	440	300	175
500	530	12	1070	650	540	350	200
600	630	12	1270	750	640	350	200
700	720	12	1450	840	730	350	225
800	820	14	1660	940	830	350	225
900	920	14	1870	1040	930	400	250
1000	1020	16	2070	1140	1050	400	250
1200	1220	16	2470	1340	1240	450	275

Notes:
1) tp— minimum structural thickness without allowance for corrosion;
2) with thermal insulation wall size AT should be increased by the thickness of the thermal insulation;
3) deviations from the dimensions indicated in the table should be confirmed by calculation.

6.1.7.5 Manholes in the tank wall

Manholes in the wall are intended for penetration into the tank during its installation, inspection and repair work.

The tank must be equipped with at least two hatches providing access to the bottom of the tank.

A tank with a pontoon must also have at least one hatch located at a height. providing access to the pontoon in its repair position. At the request of the customer of the tank, this hatch can be installed on a tank with a floating roof.

Flanges of round hatches should be made in accordance with GOST 33259: type 01, version B, row 1 for a nominal pressure of 2.5 kgf / cm 2. unless otherwise specified in the design specification.

Round manhole covers should be made according to ATK 24.200.02-90 for a nominal pressure of 6 kgf/cm 2, unless otherwise specified in the design specification.

For ease of operation, manhole covers should be equipped with handles and swivel devices.

The design of manholes in the wall must comply with Figures 8, 13, 14, 15 and Table 10.

Figure 13. Manhole hatches in the wall (conditionally shown reinforcing sheets not to the bottom)

Figure 14. Design of manhole hatches in the wall (conditionally shows flanges and covers for round hatches)

Notes

1 In the presence of thermal insulation of the wall, the size b should be increased by the thickness of the insulation.
2 Minimum values of size A - according to table 9.
3 Bend the reflector along the radius of the wall.
4 The thickness of the reflector sheet is taken according to the thickness of the wall sheet, but not more than 8 mm.

Figure 15. Manhole flange connection in the wall with a shell and a cover

Table 10. Design parameters of manholes in the tank wall

Dimensions in mm

Options	Dimensions
Options	Hatch DN 600	Hatch DN 800		Hatch 600×900
Shell outer dimension Dp	Ø 630	Ø 820		630×930
Minimum structural thickness of the shell, t p *, with the thickness of the wall sheet
5-6 mm	6	8
7-10 mm	8	10
11-15 mm	10	12
16-22 mm	12	14
23-26 mm	14	16
27-32 mm	16	18
33-40 mm	20	20
Reinforcing sheet size	Dr= 1270	Dr= 1660	1270×1870

* Excluding corrosion allowance.

6.1.8 Pipes and hatches in the roof of the tank

The number, dimensions and types of nozzles (Figure 16) depend on the purpose and volume of the tank and are determined by the customer of the tank.

Roof nozzles with nominal diameters of 50, 80,100, 150, 200, 250, 300, 350, 400, 500, 600, 700, 800, 900,1000 mm are recommended. The design of the branch pipes in the roof must comply with figures 12, 16, 17 and table 11.

Table 11. Design parameters of nozzles in the roof of the tank

Dimensions in mm

Nominal nozzle diameter DN	Dp	t p (see note 1)	D r	B, not less (see note 2)
50	57	5	—	150
80	89	5	200	150
100	108; 114	5	220	150
150	159; 168	5	320	150
200	219	5	440	200
250	273	6	550	200
300	325	6	650	200
350	377	6	760	200
400	426	6	860	200
500	530	6	1060	200
600	630	6	1160	200
700	720	7	1250	250
800	820	7	1350	250
900	920	7	1450	250
1000	1020	7	1500	250

Notes:

1 tp— minimum structural thickness without allowance for corrosion;
2 in the presence of thermal insulation of the roof, dimension B should be increased by the thickness of the thermal insulation;
3 deviations from the dimensions indicated in the table must be confirmed by calculation.

Figure 16. Nozzles and roof hatches (nozzles with Type 01 flanges are tentatively shown)

Figure 17. Details of pipes and hatches in the roof

Flanges of branch pipes in the roof should be made in accordance with GOST 33259: types 01 and 11, version B, row 1 for a nominal pressure of 2.5 kgf / cm 2, unless otherwise specified in the design specification.

If the spigot is used for ventilation, the shell (pipe) must be cut at the bottom flush with the roof deck (type "F").

At the request of the tank customer, branch pipes in the roof of the tank without a pontoon, operated at an overpressure in the gas space, can be equipped with temporary plugs according to ATC 24.200.02-90 for a nominal pressure of 6 kgf/cm 2, designed to seal the tank during testing after installation is completed.

To inspect the interior of the tank, ventilate it during interior work, as well as for various installation purposes, the tank must be equipped with at least two hatches in the roof.

For ease of use, skylight covers should be equipped with swivel devices, and mounting hatch covers with handles.

Table 12. Design parameters of hatches in the roof of the tank

6.1.9 Pontoons

6.1.9.1 pontoons used in tanks for the storage of easily evaporating products and are designed to reduce evaporation losses. Pontoons must meet the following basic requirements:

the pontoon should cover the surface of the stored product as much as possible;
tanks with a pontoon must be operated without internal pressure and vacuum in the gas space of the tank:
all pontoon joints exposed to direct exposure to the product or its vapors must be tight and checked for tightness;
any material sealing the pontoon joints must be compatible with the product being stored.

6.1.9.2 The following main types of pontoons are used:

a) a single-deck pontoon having a central single-layer membrane (deck), divided, if necessary, into compartments and annular boxes located along the perimeter (open or closed at the top);

b) a two-deck pontoon, consisting of sealed boxes located over the entire area of the pontoon;

c) a combined pontoon with open or closed radially arranged boxes and single-cell inserts connecting the boxes;

d) pontoon on floats with sealed flooring;

e) block pontoon with a thickness of at least 60 mm with sealed compartments, hollow or filled with foam or other material;

f) pontoon made of non-metallic composite or synthetic materials.

6.1.9.3 The design of the pontoon shall ensure its normal operation along the entire height of the working stroke without distortions, rotation during movement and stops.

6.1.9.4 The side of the pontoon and side rails of all devices passing through the pontoon (supports of the fixed roof, guides of the pontoon, etc.), taking into account the calculated subsidence and heel of the pontoon in working condition (without breaking the tightness of individual elements), must exceed the level of the product by at least 100 mm. The same excess should have nozzles and hatches in the pontoon.

6.1.9.5 The space between the tank wall and the side of the pontoon, as well as between the side rails and the elements passing through them, shall be sealed using special devices (gates).

6.1.9.6 The pontoon shall be designed in such a way that the nominal clearance between the pontoon and the tank wall is between 150 and 200 mm with a tolerance of ±100 mm. The gap value must be set depending on the design of the valve used.

6.1.9.7 The minimum structural thickness of the steel elements of the pontoon shall not be less than: 5 mm for surfaces in contact with the product or its vapors (lower deck and side of the pontoon); 3 mm - for other surfaces. When using elements of stainless steel, carbon steel with metallization coatings or aluminum alloys in pontoons, their thickness should be determined on the basis of strength and deformation calculations, as well as taking into account corrosion resistance. The thickness of such elements must be at least 1.2 mm.

6.1.9.8 The pontoon shall have supports allowing it to be fixed in two lower positions — service and maintenance.

The working position is determined by the minimum height at which the structures of the pontoon are at least 100 mm away from the upper parts of the devices located on the bottom or wall of the tank and preventing further lowering of the pontoon.

The repair position is determined by the minimum height at which a person can freely pass over the entire surface of the bottom of the tank under the pontoon - from 1.8 to 2.0 m.

The working and repair positions of the pontoon are fixed with the help of supports that can be installed in the pontoon, as well as on the bottom or wall of the tank. It is possible to fix the lower positions of the pontoon by hanging it on chains or cables to the stationary roof of the tank.

By agreement with the customer, supporting structures of one fixed position (not lower than the repair one) are used.

Supports made in the form of racks from a pipe or other closed profile must be plugged or have holes in the bottom to allow drainage.

6.1.9.9 In the case of use of support legs for distributing concentrated loads transmitted by a steel pontoon to the bottom of the tank, steel pads (thickness equal to the bottom thickness) welded to the tank bottom with a continuous seam shall be installed under the support posts. The size of the pads should be determined by the tolerances for deviations of the pontoon support legs.

6.1.9.10 To prevent the rotation of the pontoon, it is necessary to use guides in the form of pipes, which can simultaneously perform technological functions - they can contain control, measurement and automation devices.

It is also allowed to use cable or other structural systems as pontoon guides.

In places where the guides pass through the pontoon, seals should be provided to reduce evaporation losses during vertical and horizontal movements of the pontoon.

6.1.9.11 Pontoons shall have safety vent valves that open when the pontoon is on supports and protect the pontoon and the sealing gate from overvoltage and damage when filling or emptying the tank. The dimensions and number of ventilation valves are determined by the performance of the receiving and dispensing operations.

6.1.9.12 In the stationary roof or wall of a tank with a pontoon, ventilation openings shall be provided, evenly spaced around the perimeter at a distance of no more than 10 m from each other (but not less than four), and one opening in the center of the roof. The total open area of all openings must be greater than or equal to 0.06 m 2 per 1 m of tank diameter. The openings of the openings must be closed with a stainless steel mesh with 10 × 10 mm cells and protective covers for weather protection. The installation of flame arresters on ventilation openings is not recommended (unless otherwise specified in current national standards).

The design of ventilation openings must provide reliable ventilation above the pontoon space and provide for the possibility of opening the protective cover and using the openings as inspection hatches.

6.1.9.13 For access to the pontoon, the tank shall be provided with at least one manhole in the wall, located in such a way that through it it is possible to get to the pontoon in the repair position.

The pontoons must have at least one hatch with a nominal diameter of at least 600 mm, allowing ventilation and passage of service personnel under the pontoon when the product is removed from the tank.

6.1.9.14 All conductive parts of the pontoon shall be electrically interconnected and connected to the tank wall or roof.

This can be achieved with flexible cables running from the fixed tank roof to the pontoon (minimum two). When selecting cables, consideration should be given to their flexibility, strength, corrosion resistance, electrical resistance, connection reliability and service life.

6.1.9.15 Closed pontoon boxes shall be equipped with inspection hatches with quick-release covers or other devices to monitor possible loss of tightness of the boxes.

On the pontoons of tanks with a volume of 5000 m 3 or more, an annular barrier must be installed to retain the foam supplied from above in case of fire to the annular gap zone. The location and height of the annular barrier should be determined from the condition of creating a calculated foam layer in the zone of the annular gap between the barrier and the tank wall.

The top of the barrier must be at least 200 mm higher than the sealing gate.

6.1.9.16 The pontoon shall be designed in such a way that it can provide the bearing capacity and buoyancy for the loads indicated in Table 13 in the position afloat or on supports.

Table 13. Design combinations of actions on the pontoon

Combination number		Position	Note
1	Double own weight	floating	—
2		floating	—
3		floating	—
4		floating	Type "a" pontoons
5	Self weight and flooding of any three boxes	floating	Pontoons type "b" and "c"
6	Self weight and flooding 10 % floats	floating	Pontoons type "g"
7	Self-weight and the effect of the gas-air cushion on an area of at least 10% of the area of the pontoon (the density of the gas-air fraction is not more than 0.3 t / m 3)	floating	At the request of the customer
8	Self weight and 2.0 kN per 0.1 m2 anywhere on the pontoon	On supports	—
9	Self weight and 0.24 kPa uniformly distributed load	On supports	—

6.1.9.17 The density of the product for calculations is assumed to be 0.7 t/m 3 .

6.1.9.18 Elements and assemblies of the pontoon shall be designed in such a way that the maximum forces and deformations in them do not exceed the limit values for strength and stability established by the current regulatory documents*.

____________
* On the territory of the Russian Federation, SP 16.13330.2011 "SNiP 11-23-81* Steel structures" and SP 128.13330.2012 "SNiP 2.03.06-85 Aluminum structures" are in force.

6.1.9.19 The buoyancy of the pontoon in the absence of damage is considered to be ensured if, in the afloat position, the excess of the top of the side element above the product level is at least 100 mm.

6.1.9.20 The buoyancy of the pontoon in the presence of damage is considered to be ensured if, in the afloat position, the top of the side member and bulkheads is located above the product level.

6.1.9.21 Calculation of the pontoon is performed in the following sequence:

a) selection of the structural scheme of the pontoon and preliminary determination of the thicknesses of the elements based on functional, structural and technological requirements;

b) the appointment of combinations of actions given in Table 13, taking into account the value and nature of the acting loads, as well as the possibility of loss of tightness of individual compartments of the pontoon;

c) modeling of the pontoon structure by the finite element method (FE);

d) calculation of the equilibrium positions of the pontoon immersed in the liquid for all design combinations of actions;

e) checking the buoyancy of the pontoon: if the buoyancy of the pontoon is not ensured, change its design scheme and repeat the calculation, starting with listing a);

f) checking the bearing capacity of the structural elements of the pontoon for the obtained equilibrium positions: in case of a change in the thickness of the elements, the calculation is repeated, starting from listing c);

g) checking the strength and stability of supports.

6.1.10 Floating roofs

6.1.10.1 Floating roof tanks are an alternative to fixed roof and pontoon tanks, the choice between these tank types should be based on a comparison of their performance and operating conditions.

6.1.10.2 The following types of floating roofs are used:

a) a single-deck floating roof, consisting of sealed annular boxes located along the perimeter of the roof, and a central single-layer membrane (deck), which has an organized slope to the center;

b) two-deck floating roof, which has two versions;

c) a combined floating roof with radial sealed boxes and single-deck inserts between them.

6.1.10.3 Maximum allowable design snow load:

240 kg / m 2 - for single-deck floating roofs;
without restrictions - for two-deck and combined floating roofs.

6.1.10.4 The floating roof shall be designed in such a way that when filling or emptying the tank, the roof does not sink or damage its structural components and fixtures, as well as structural elements located on the wall and bottom of the tank.

6.1.10.5 In the working position, the floating roof shall be in full contact with the surface of the stored product.

The upper mark of the peripheral wall (side) of the floating roof must exceed the level of the product by at least 150 mm.

When the tank is empty, the floating roof must rest on stands resting on the bottom of the tank. The structures of the bottom and base must ensure the perception of loads when the floating roof is supported on the racks.

6.1.10.6 The buoyancy of a floating roof shall be ensured by its tightness on the product side, as well as by the tightness of the boxes and compartments included in the roof structure.

6.1.10.7 Each box or compartment of the floating roof at the top shall have an inspection hatch with an easily removable cover for visual control of possible loss of tightness.

The design of the cover and the height of the shell of the inspection hatch should exclude the ingress of rainwater or snow into the duct or compartment, and also exclude the ingress of oil and oil products to the top of the floating roof.

6.1.10.8 Access to the floating roof shall be provided by a ladder which automatically follows any height position of the roof. One of the recommended types of ladders used is a rolling ladder, which has an upper hinged attachment to the tank wall and lower rollers that move along guides installed on the floating roof (rolling ladder path).

6.1.10.9 The design of the floating roof shall ensure the runoff of storm water from its surface and their removal outside the tank. For this purpose, the floating roof must be equipped with a main drainage system, consisting of storm water inlets and discharge pipelines (the number of storm water inlets is determined by calculation). Storm inlets can be connected to one pipeline.

The slope of surfaces in the position of the roof afloat, along which precipitation is carried out. must be at least 1:100. The storm water intake must be equipped with a valve (valve) that prevents the stored product from getting onto the floating roof in case of leakage of the water outlet pipelines.

In addition to the main outlet, floating roofs must have emergency outlets to discharge storm water directly into the stored product.

The diameter of the pipelines of the main water outlet system must be at least:

80 mm - for tanks with a diameter of up to 30 m;
100 mm - for tanks with a diameter of over 30 to 60 m;
150 mm - for tanks with a diameter of more than 60 m.

6.1.10.10 Floating roofs shall have at least two safety vent valves that open when the floating roof is on its support legs and protect the floating roof and the sealing gate from overvoltage and damage when the tank is filled or emptied. The dimensions and number of ventilation valves are determined by the performance of the receiving and dispensing operations.

6.1.10.11 Floating roofs must have support posts that allow fixing the roof in two lower positions - working and repair. The working position is determined by the minimum height at which the floating roof structures are at least 100 mm away from the upper parts of the devices located on the bottom or on the tank wall and preventing further lowering of the floating roof. The repair position is determined by the minimum height at which a person can freely pass along the bottom of the tank under a floating roof - from 1.8 to 2.0 m.

Support posts made of pipe or other closed profile must be plugged or have holes in the bottom to allow for drainage.

To distribute the loads transmitted by the floating roof to the bottom of the tank, steel pads shall be installed under the support posts (see 6.1.9.9).

6.1.10.12 Floating roofs shall have at least one hatch with a nominal diameter of at least 600 mm, allowing ventilation and passage of personnel under the floating roof when the product is removed from the tank.

6.1.10.13 To prevent the rotation of the floating roof, guides in the form of pipes, which also perform technological functions, should be used. It is recommended to install one guide.

6.1.10.14 The space between the wall of the tank and the outer side of the floating roof shall be sealed with a special device - a shutter, which also has a weatherproof cap from the direct impact of atmospheric precipitation on the shutter (installation is carried out at the request of the customer).

The nominal gap between the wall of the tank and the vertical side of the floating roof for the installation of the gate should be from 200 to 275 mm with a tolerance of ±100 mm.

6.1.10.15 An annular barrier shall be installed on the floating roof to retain foam delivered in the event of a fire into the annular gap area. The location and height of the annular barrier should be determined from the condition of creating a calculated foam layer in the zone of the annular gap between the barrier and the tank wall.

The height of the barrier must be at least 1 m. Drainage holes should be provided in the lower part of the barrier for the drainage of foam destruction products and atmospheric water.

6.1.10.16 All conductive parts of the floating roof, including the rolling ladder, shall be electrically interconnected and connected to the tank wall.

The design of the fastening of the grounding cables of the floating roof must exclude damage to the cable during the operation of the tank.

6.1.10.17 The minimum structural thickness of the steel elements of floating roofs shall be not less than 5 mm for the lower deck and outer edge of the floating roof; 4 mm - for other structures.

6.1.10.18 The floating roof shall be designed in such a way that, when afloat or supported, it can provide the bearing capacity and buoyancy under the loads specified in Table 14.

6.1.10.19 The density of the product for calculations is assumed to be 0.7 t/m 3 .

Table 14 Design Combinations of Floating Roof Actions

Combination number	Design combination of actions	Position	Note
1	Self-weight and evenly or unevenly distributed snow load	floating
2	Self weight and 250 mm atmospheric water	floating	In the absence of an emergency drainage system
3	Self weight and two flooded adjacent compartments and evenly distributed snow load	floating	For double deck roofs
3	Self-weight and flooding of the center deck and two adjacent compartments	floating	For single deck roofs
4	Self-weight and evenly or unevenly distributed snow load	On support stands	Snow load is taken at least 1.5 kPa. Uneven load is accepted in accordance with Figure 18

Figure 18. Uneven distribution of snow load on a floating roof

6.1.10.20 The distribution of uneven snow load over the surface of the floating roof p sr , MPa, is taken in accordance with the formula:

p sr = μ p s , (16)

where p s is the design snow load on the earth's surface, determined in accordance with the current regulations *;
μ is a dimensionless coefficient, which, depending on the position of the design point on the roof (Figure 18), takes the following values:

Here D, H s are the diameter and height of the tank.

______________
* On the territory of the Russian Federation, SP 20.13330.2011 “SNiP 2.01.07-85* Loads and impacts” is in force.
** SP 16.13330.2011 "SNiP 11-23-81 Steel structures" is in force on the territory of the Russian Federation.

6.1.10.22 The buoyancy of a floating roof, in the absence of damage, is recommended to be considered ensured if, in the floating position, the excess of the top of any side element (including bulkheads) above the product level is at least 150 mm.

6.1.10.23 The buoyancy of a floating roof in the presence of damage shall be considered ensured if, in the floating position, the top of any side member and bulkheads is located above the product level.

a) selection of the design scheme of the floating roof and preliminary determination of the thickness of the elements based on functional, structural and technological requirements;

b) the appointment of combinations of actions given in table 14 of this standard, taking into account the value and nature of the acting loads, as well as the possibility of loss of tightness of individual compartments of the floating roof;

c) simulation of the floating roof structure by the FE method;

d) calculation of the equilibrium positions of a floating roof immersed in a liquid for all design combinations of actions;

e) checking the buoyancy of the floating roof: if the buoyancy of the roof is not ensured, change its design scheme and repeat the calculation, starting with listing a);

f) verification of the bearing capacity of the structural elements of the floating roof for the obtained equilibrium positions: in case of a change in the thickness of the elements, the calculation is repeated, starting from listing c);

g) checking the strength and stability of the supports, taking into account the actions of the snow load.

6.1.11 Platforms, walkways, stairs, fences

6.1.11.1 The tank shall be equipped with platforms and ladders.

6.1.11.2 Tanks with a fixed roof shall have a circular platform on the roof or wall providing access to the equipment located along the perimeter of the roof and a ladder for climbing to the circular platform, as well as, if necessary, additional platforms on the roof and on the wall.

6.1.11.3 Tanks with a floating roof shall have a circular platform along the top of the wall, an external ladder for climbing to the circular platform, and an internal rolling ladder for descending to the floating roof.

6.1.11.4 In the case of a compact arrangement, the tanks can be connected to each other by transition platforms (transitions), while each group of connected tanks must have at least two ladders located on opposite sides.

6.1.11.5 Landings (including walkways and intermediate landings of stairs) must comply with the following requirements:

platforms connecting any part of the tank with any part of the adjacent tank or other free-standing structure must have support devices that allow free movement of the connected structures;
the width of the platforms at the level of the flooring must be at least 700 mm;
for platforms, the use of grating is recommended;
the value of the gap between the flooring elements should be no more than 40 mm;
the design of the platforms must withstand a concentrated load of 4.5 kN or a uniformly distributed load of 550 kg/m 2 .

6.1.11.6 Sites located at a level of more than 0.75 m from the ground or any other surface onto which a fall from the site is possible must have fences on the sides where a fall is possible.

6.1.11.7 For climbing to the circular area of the tank, separate (shaft) or located along the wall (circular) stairs are used.

6.1.11.8 Shaft ladders have their own foundation, to which they are attached with anchor bolts. Shaft ladders must be fastened at the top to the tank wall with spacers. The design of the spacers should take into account the possibility of uneven settlement of the tank base and the ladder foundation.

It is allowed to use shaft ladders as a technological element (framework) for winding up rolled panels (walls, bottoms, etc.) for their transportation to the installation site. In this case, the stairs must have ring elements with a diameter of at least 2.6 m.

6.1.11.9 Single-flight ladders are used for tanks with a wall height of not more than 7.5 m.

6.1.11.10 Circular ladders fully rest on the tank wall, and their lower flight should not reach the ground at a distance of 100 to 250 mm.

Circular stairs of tanks with a height of more than 7.5 m must have intermediate platforms, the distance between which in height should not exceed 6 m.

Ring ladders, in which the gap between the tank wall and the ladder exceeds 150 mm, must have a fence both on the outside and on the inside (at the wall) side.

6.1.11.11 Marches of shaft and circular stairs must comply with the following requirements:

angle relative to the horizontal surface - no more than 50 o;
march width - not less than 700 mm;
step width - not less than 200 mm;
the distance in height between the steps should be the same and should not exceed 250 mm;
steps should have an inward slope of 2 to 5 o;
the march structure must withstand a concentrated load of at least 4.5 kN.

6.1.11.12 Fences of platforms and flights of stairs, consisting of posts, railings, intermediate strips and side (lower) strip, must comply with the following requirements:

racks should be located at a distance of no more than 2.0 m from each other;
the top of the railing should be at a distance of at least 1.25 m from the level of the platform flooring and at least 1.0 m from the level of the step of the flight of stairs (vertical distance from the toe of the step to the top of the handrail, Figure 19);
the boarding strip of the platform fencing must be at least 150 mm wide and located with a gap of 10 to 20 mm from the flooring, it is allowed to use stringers (strings) for which the excess over the toe of the step must be at least 50 mm (see .figure 19);
the distances between the railings, intermediate strips, side strip (or stringer) should be no more than 400 mm (see Figure 19);
fences must withstand a load of 0.9 kN. applied in any direction to any point on the handrail.

6.1.11.13 Rolling ladders of tanks with floating roofs shall provide access from the transition platform to the floating roof when changing its position from the lower to the upper working levels.

Rolling ladders must meet the following requirements:

permissible angle with respect to the horizontal surface - from 0 to 50 o;
the width of the march (length of the step) of the stairs - not less than 700 mm;
tread value (horizontal distance between the toes of the steps) - not less than 250 mm;
allowable height distance between steps - from 0 to 250 mm;
steps should be made of lattice metal that prevents slipping;
railings located on both sides of the rolling ladder must comply with the requirements set out in 6.1.11.12;
the design of the rolling ladder must be designed to withstand the forces that arise during the movement of the floating roof, as well as a concentrated load of at least 5.0 kN and the load from the calculated weight of the snow cover.

6.1.11.14 Step-ladders (vertical tunnel-type ladders) are used to ascend or descend to the platforms (for example, to the platforms of foam generators or manholes).

Ladder must meet the following requirements:

the width of the ladder must be at least 600 mm;
the distance between the steps should be no more than 350 mm;
starting from a height of 2 m, ladders must have guards in the form of safety arches with a radius of 350 to 450 mm, located in height at distances of no more than 800 mm from each other and vertical strips, the distance between which should be no more than 200 mm.

6.1.12 Wall anchoring

6.1.12.1 Anchoring of the tank wall shall be carried out on the basis of calculations under the following actions:

seismic loads;
internal overpressure;
wind loads.

6.1.12.2 The main anchor point is the tank wall, not the bottom plates.

6.1.12.3 The design of the anchor fastening is performed in the following versions, shown in Figures 20, 21:

anchor tables with anchor bolts;
ring anchor plate with anchor bolts;
wall anchoring using anchor strips.

Figure 20, sheet 1 - Fastening the wall with anchor bolts

Figure 21, sheet 1 - Fastening the wall with anchor strips

6.1.12.4 Calculation of the anchor fastening should be carried out in such a way that in case of excessive loads on the tank exceeding the calculated ones, the anchor bolt is destroyed, but not the support table and the seams of its connection with the tank wall.

6.1.12.5 The allowable value of tensile stress in anchor bolts shall not exceed half the yield strength or one third of the ultimate strength of the bolt material.

6.1.12.6 Anchor bolts shall be evenly tightened when the tank is completely filled with water after the hydraulic tests are completed, but before internal overpressure is created. The calculated tightening force of the anchor bolts must be at least 2100 N. The tightening force must be specified in KM.

6.1.12.7 The diameter of the anchor bolts shall not be less than 24 mm.

6.1.12.8 Anchor fastenings should be placed evenly along the perimeter of the wall. The distance between anchor bolts should not exceed 3 m, except for tanks with a diameter of up to 15 m when they are designed for seismic, when the specified distance should not exceed 2 m.

6.1.12.9 The recommended number of anchor bolts to be installed on the tank should be a multiple of four. Anchor bolts should be located symmetrically about the main axes of the tank and not coincide with the main axes on the plan.

6.1.13 Tanks with protective wall

6.1.13.1 Tanks with a protective wall provide an increased level of safety for people and the environment in the event of a tank failure and spills of the stored product. The use of tanks with a protective wall is recommended for increased safety requirements, for example, when tanks are located near residential areas or along the banks of water bodies, as well as at production sites, when there is insufficient space for dikes or squares around the tanks.

6.1.13.2 Tanks with a protective wall consist of a main inner tank designed to store the product and a protective outer tank designed to hold the product in the event of an accident or leakage of the main tank.

The main tank can be made with a fixed or floating roof.

6.1.13.3 The diameter and height of the protective tank wall must be calculated so that in the event of damage to the inner tank and a part of the product overflowing into the protective tank, the product level is 1 m below the top of the protective tank wall, while the width of the interwall space should be at least 1.8 m.

6.1.13.4 The bottom of the main tank may rest directly on the bottom of the containment tank.

The slope of the bottoms of tanks with a protective wall should only be outward (from the center to the periphery).

6.1.13.5 It is recommended to block the interwall space between the outer and inner walls with a weatherproof canopy to prevent snow from falling from the roof of the main tank into the interwall space.

6.1.13.6 Steel emergency ropes can be installed on the main wall (as specified by the customer), the section and location of which are determined by calculation. The ropes must be installed without pre-tensioning and without sagging between the nodes of their fastening to the wall.

6.1.13.7 Stiffening rings shall be installed on the protective wall, designed for hydrodynamic impact of the product in the event of an accident of the main tank.

6.1.13.8 To remove atmospheric precipitation in the interwall space, flume or round stripping sumps shall be installed.

6.1.13.9 When placing tanks with a protective wall as part of tank farms of oil and oil products storage facilities, the diameter of the main tank should be taken as the diameter of the tank with a protective wall.

Tanks with a protective wall do not require a reinforced concrete box to protect against hydrostatic impact of the product in case of instantaneous brittle destruction of the tank, but require conventional protection for hydrostatic containment and organized removal of the spreading liquid.

To control possible product leaks in the interwall space of the tank, at least four gas analyzers should be installed along the perimeter of the main tank, as well as branch pipes to control the tightness of the space between the main and protective bottoms.

For quick access of maintenance personnel to the inter-wall space on the protective wall of the tank, it is recommended to install quick-opening hatches with bayonet-type closures in the amount of at least two. Hatches must be calculated and tested at the factory for a pressure of 0.25 MPa.

6.1.13.11 Testing of tanks with a protective wall should be carried out in two stages:

1st - test of the main tank;
2nd - testing of the protective tank.

Hydraulic testing of the protective reservoir should be carried out by pouring water from the main reservoir into the interwall space until the levels in the main and protective reservoirs are equal (until the design level in the protective reservoir is reached).

1 - main wall; 2 - protective wall; 3 - main bottom; 4 - protective bottom; 5 - stationary roof;
6 - emergency ropes; 7 - stiffening rings; 8 - wind ring; 9 - tray sump, 10 - weatherproof visor

Figure 22. Tank with protective wall

Based on the test results, test reports of the main tank and a separate act of hydraulic testing of the protective tank are drawn up.

6.1.13.12 Calculation of the bearing capacity of tanks with a protective wall in an emergency situation associated with the destruction of the main tank should be carried out in accordance with the requirements of specialized standards.

8.5.3. Ultrasonic testing (UT)

8.5.3.1. Ultrasound is performed to detect internal defects

(cracks, lack of penetration, slag inclusions, gas pores) with the indication
number of defects, their equivalent area, conditional
length and location coordinates.

8.5.3.2. Ultrasound is carried out in accordance with GOST 14782-86 "Con-

troll is non-destructive. Connections are welded. Ultrasound methods
vye ”, approved by the resolution of the State Standard of the USSR of 17 de-
October 1986 No. 3926. Norms of permissible defects according to SNiP 3.03.01.

8.5.4. Magnetic particle testing or penetrating testing

substances (PVC)

lead in order to identify surface defects of the main mechanism
tall and welded seams, invisible to the naked eye. Mag-
Nitropowder control or PVC are subject to:

all vertical wall welds and wall joint seams

ki with the bottom of tanks operated at a storage temperature
silent product over 120 °C;

welded seams for welding manholes and branch pipes to the wall of the tank

moat after their heat treatment;

places on the surface of the sheets of the walls of the tanks with a limit

fluidity over 345 MPa, where the removal of technological
hygienic devices.

8.5.5. Control during hydraulic testing of the tank

8.5.5.1. During hydraulic testing of the tank, the

all places where leaks and sweats appear are discarded and rejected. By-
after the tank has been emptied, repairs are carried out in these places and
control.

8.5.5.2. Defective spots in fixed roof decking and in

the zone of its adjoining to the wall, identified in the process of pneumatic
ical tests of the reservoir, are fixed by the appearance of
bubbles on joints coated with a foaming solution.

IX. EQUIPMENT FOR SAFE

OPERATION OF RESERVOIRS

the following devices and equipment for the safe ex-
operation:

respiratory equipment;
level control devices;
fire safety devices;
lightning protection devices and protection against static electricity

trinities.

Complete set of tank-mounted devices

9.2. Breathing equipment

on the fixed roof of the tanks, it provides the values
internal pressure and vacuum, installed in the design do-
documentation, or lack thereof (for atmospheric tanks and
tanks with a pontoon). In the first case, breathing apparatus
performed in the form of combined breathing valves (valve-
new pressure and vacuum) and safety valves, in the second
rum case - in the form of ventilation pipes.

9.2.2. Minimum respiratory capacity

valves, safety valves and ventilation
tubes are recommended to be determined depending on the maximum
performance of receiving and distributing operations (including
emergency conditions) according to the following formulas:

internal pressure capacity of the valve

steel tanks for oil and oil products

Q = 2,71M

0,026V; (52)

vacuum capacity of the valve Q, m

Q = M

0,22V; (53)

throughput of the ventilation pipe Q, m

Q = M

0,02V (54)

Q = M

0,22V(that more),

where M

The productivity of filling the product into the tank, m

Product discharge capacity from the tank, m

V- the total volume of the tank, including the volume of gas

spaces under a fixed roof, m

It is not allowed to change the performance of the receiving

adjustment operations after the reservoir is put into operation
without recalculation of the throughput of the respiratory equipment,
as well as an increase in the productivity of draining the product in an emergency
conditions.

The minimum number of ventilation pipes for the reserve

Ares with a pontoon are specified in clause 3.8.12 of this Manual.

Safety valves are adjusted to higher

(5 to 10%) internal pressure and vacuum to
safety valves worked together with breathing valves.

9.2.3. Breathing and safety valves are recommended

can be installed together with fire fuses, providing
sintering protection against the penetration of flame into the tank in
during a given period of time.

9.2.4. To reduce losses from evaporation of the product under the respiratory

9.2.5. On tanks with a fixed roof that does not have

easily dumped flooring, must be installed emergency
valves in accordance with B.4.1 GOST 31385-2008.

Safety Guide for Vertical Cylindrical

9.3. Instrumentation and automation

9.3.1. To ensure safe operation on the reserve

9.3.2. Level control devices provide operational

product level control. The maximum level of the product con-
controlled by level detectors (at least two), transmitting
mi a signal to turn off the pumping equipment. In the RVSP re-
It is recommended to install at equal distances of at least three
level switches operating in parallel.

9.3.3. In the absence of signaling devices of the maximum level

overflow devices connected to the reserve are provided
tank or drain pipeline, excluding pre-
raising the level of the bay of oil and oil products in excess of the design level.

9.3.4. To place the instrumentation on the tank, it is recommended

provide installation and fastening structures: branch pipes,
brackets, etc.

9.3.5. Limit deviations of the location of structures

To prevent the occurrence, spread and liquidation

identification of a possible fire should be guided by the Federal
Law of July 22, 2008 No. 123-FZ "Technical Regulations
on fire safety requirements, according to which
for elimination and localization of possible fires in tanks
and tank farms should provide for the installation of fire
rotation and water cooling.

steel tanks for oil and oil products

9.5. Lightning protection devices and protection against static

electricity

9.5.1. Tank lightning protection devices recommended

design as part of the design documentation section “Equipment
tank testing" in accordance with the provisions of SO 153-34.21.122-2003
industrial communications”, approved by the order of the Ministry of
Energy of Russia dated June 30, 2003 No. 280.

pour in accordance with SO 153-34.21.122-2003 "Instructions for
lightning protection device for buildings, structures and industrial
communications” range from 0.9 to 0.99 depending on the type
tank, stored product and storage capacity (categories
warehouse) in accordance with the table. 31 of this Guide.

be free-standing or cable-operated (protection level I or II in accordance with
in accordance with SO 153-34.21.122-2003 "Instructions for the device
protection of buildings, structures and industrial communications”,
approved by order of the Ministry of Energy of Russia dated June 30, 2003 No. 280)
installed lightning rods (lightning rods), down conductors
which do not have contact with the tank. Wire lightning
collectors (lightning rods) are used to reduce the height of lightning
taps on extended objects when installed in a row of more than three
tanks in accordance with the feasibility study.

At protection level III (in accordance with SO 153-34.21.122–2003

"Instructions for the arrangement of lightning protection of buildings, structures and
industrial communications”, approved by order of the Ministry of
energy of Russia dated June 30, 2003 No. 280) the lightning rod can be
install on the tank.

perform based on the required level of protection in accordance with
with SO 153-34.21.122-2003 "Instructions for the installation of lightning protection
buildings, structures and industrial communications”, approved
by order of the Ministry of Energy of Russia dated June 30, 2003 No. 280.

Safety Guide for Vertical Cylindrical

tanks and equipment on the roof, as well as:

for RVSPK - a space 5 m high from the level of flammable liquids in

an annular gap;

for RVS with flammable liquids at protection levels I and II - space above

each breathing valve, limited by a hemisphere of the radius
mustache 5 m.

to organize grounding systems and equalization of potential
fishing, ensuring distances from lightning rods to conductive
structures, using a protection device against impulse
overvoltages.

9.5.5. Between the floating roof, pontoon and reservoir hull

at least two - for tanks with a diameter of up to 20 m;
at least four - for tanks with a diameter of more than 20 m.

Table 31

Characteristic

reservoir

Protection level

Reliability of protection

Warehouse of oil and oil products category I

RVS for LVZH

RVS for GJ

Warehouse of oil and oil products category II

RVS for LVZH

RVS for GJ

Warehouse of oil and oil products category III

RVS for LVZH

RVS for GJ

steel tanks for oil and oil products

9.5.6. The lower belt of the tank wall is connected with a

cutting down conductors to earthing switches installed at a distance of not
more than 50 m along the perimeter of the wall, but not less than two dia-
metrically opposite points. Down conductor connections and
ground electrodes are made by welding. Joining allowed
tank to grounding conductors to be carried out on brass bolts and washers -
bang through copper or galvanized down conductors and welded
to the tank wall of the grounding boss with a diameter of 45 mm with a threaded
bore hole M16. contact resistance
connections - no more than 0.05 Ohm.

days laid in the ground are given in Table. 32 present
Guides.

9.5.7. In the section of project documentation "Equipment of the reserve

voir” (subsection “Lightning protection”), measures are being developed
to protect the tank from electrostatic and electromagnetic
induction depending on the electrical characteristics of the product
that, performance and conditions for filling the product, the properties of the material
rial and protective coatings of the inner surfaces of the tank.

To ensure electrostatic safety, oil and non-

oil products are recommended to be poured into the tank without splashing -
dipping, spraying or vigorous agitation (with the exception of
cases where the technology provides for mixing and both
special electrostatic safety measures are sintered).

Table 32

Material

Section profile

Square
cross-

leg section

Steel
galvanized
bathroom

for vertical earthing

for horizontal earthing

Rectangular

Safety Guide for Vertical Cylindrical

the remnant in it. When filling an empty tank
oil and oil products are supplied at a speed of not more than 1.0 m/s up to
the moment the intake pipe is filled or until the ponto-
on or floating roof.

9.5.9. Maximum filling capacity (empty-

neniya) tanks with a floating roof or a pontoon
is measured by the speed of movement of the floating roof (pontoon)
and more than 3.3 m3/h is recommended for tanks up to 700 m

6 m/h - for tanks with a volume of 700 to 30,000 m3

switch-

but also 4 m/h - for tanks with a volume of more than 30,000 m

When finding

floating roof (pontoon) on racks lifting speed
(decrease) of the liquid level in the tank is not more than 2.5 m3/h.

AND RECEIVING TANKS

personal test. RVS operated with installed
on the roof with breathing valves, tested for internal
excess pressure and relative vacuum.

voirs are given in table. 33 of this Guide.

Table 33

Types of tank tests

Type of test

RVS RVSP RVSPK

1. Tank body leak test
when flooded with water

2. Testing the strength of the tank body at
hydrostatic load

3. Fixed roof tightness test
RVS pressurized air

4. Testing the stability of the tank shell
the creation of a relative vacuum inside the re-
reservoir