SECTION 4.3 – STORAGE TANKS
Section 4.3 Storage tanks
Subsection 4.3.1. Application and Storage Tank Design, Construction and Use
Application
4.3.1.1. This Section applies to storage tanks for flammable liquids and combustible liquids.
Atmospheric storage tanks
4.3.1.2. (1) Subject to Sentences (2), (3), (4), (5), (6), (7) and (8) and Section 4.9, atmospheric storage tanks shall be built in accordance with
(a) API 12B, “Bolted Tanks for Storage of Production Liquids”,
(b) API 12D, “Field Welded Tanks for Storage of Production Liquids”,
(c) API 12F, “Shop Welded Tanks for Storage of Production Liquids”,
(d) API 650, “Welded Tanks for Oil Storage”,
(e) CAN/ULC-S601, “Standard for Shop Fabricated Steel Aboveground Tanks for Flammable and Combustible Liquids”,
(f) CAN/ULC-S602, “Aboveground Steel Tanks for Fuel Oil and Lubricating Oil”,
(g) ULC-S603, “Standard for Steel Underground Tanks for Flammable and Combustible Liquids”,
(h) CAN/ULC-S603.1, “External Corrosion Protection Systems for Steel Underground Tanks for Flammable and Combustible Liquids”,
(i) ULC-S615, “Standard for Reinforced Plastic Underground Tanks for Flammable and Combustible Liquids”,
(j) CAN/ULC-S652, “Standard for Tank Assemblies for the Collection, Storage and Removal of Used Oil”,
(k) CAN/ULC-S653, “Standard for Aboveground Steel Contained Tank Assemblies for Flammable and Combustible Liquids”,
(l) ULC-S655, “Aboveground Protected Tank Assemblies for Flammable and Combustible Liquids”, or
(m) ULC/ORD-C142.5, “Concrete Encased Steel Aboveground Tank Assemblies for Flammable and Combustible Liquids”.
(2) Tanks built in conformance with Clauses (1)(a), (b) and (c) shall be used only for the storage of crude petroleum at oil fields.
(3) When necessitated by possible contamination of the liquid to be stored or possible rapid corrosion of the tank, storage tanks need not conform to Sentence (1), provided that they are designed and built in conformance with good engineering practice for the material being used.
(4) Atmospheric storage tanks shall not be used for the storage of flammable liquids or combustible liquids at temperatures at or above their boiling points.
(5) Existing in-service aboveground atmospheric storage tanks that do not comply with Sentence (1) may remain in-service if the tanks
(a) are not leaking,
(b) have no dents greater than 30 degrees or 35 mm in depth from the normal configuration,
(c) have no pitting in excess of 3 mm, and
(d) have metal thickness of at least 50% of the minimum permissible thickness specified in an applicable standard referred to in Sentence (1).
(6) Existing aboveground atmospheric storage tanks that do not comply with Sentence (1), (3), (5) or (9) shall be refurbished in conformance with Article 4.3.1.10. or be replaced.
(7) Existing in-service underground storage tanks that do not comply with Sentence (1) may remain in-service if the tanks are not leaking and steel storage tanks and associated piping are protected from external corrosion in accordance with Subsection 4.3.9.
(8) Existing underground storage tanks that do not comply with Sentence (1), (3) or (7) shall be refurbished in conformance with Article 4.3.1.10. or be replaced.
(9) Existing aboveground atmospheric storage tanks that comply with ULC/ORD-C142.16-1994, “Protected Aboveground Tank Assemblies for Flammable and Combustible Liquids”, are deemed to comply with Clause (1)(l).
(10) In-service atmospheric storage tanks that were installed on or before December 31, 2014 and that do not comply with Sentence (1) may remain in-service if they do not leak and if the tanks met the requirements of this Code on December 31, 2014, as it read on that day.
Low pressure storage tanks and pressure vessels
4.3.1.3. (1) Low pressure storage tanks shall be constructed in conformance with
(a) API 620, “Design and Construction of Large, Welded, Low-Pressure Storage Tanks”, or
(b) ASME BPVC, “Boiler and Pressure Vessel Code”.
(2) Pressure vessels shall be constructed in conformance with CSA-B51, “Boiler, Pressure Vessel, and Pressure Piping Code”.
(3) Low pressure storage tanks and pressure vessels are permitted to be used as atmospheric storage tanks.
Operating pressure
4.3.1.4. The normal operating pressure of a storage tank shall not exceed its design pressure.
Corrosion protection
4.3.1.5. The exposed surface of every aboveground storage tank for flammable liquids or combustible liquids which is fabricated of any ferrous substance shall be thoroughly coated with rust-resisting material compatible with the tank.
Floating roofs
4.3.1.6. Except for perimeter sealing material, floating roof assemblies or internal floating covers installed in storage tanks shall be constructed of metal, or other materials and design conforming to one of the tank construction standards set out in this Subsection.
Identification
4.3.1.7. A storage tank and its filling and emptying connections shall be identified in conformance with CPPI, “Using the CPPI Colour-Symbol System to Mark Equipment and Vehicles for Product Identification” or to CAN/CGSB-24.3, “Identification of Piping Systems”.
Overfill protection
4.3.1.8. (1) A storage tank that is not a tight-filled storage tank shall be prevented from being overfilled by
(a) continuous supervision of the filling operations by personnel qualified to supervise the filling operations, or
(b) an overfill protection device that complies with ULC/ORD-C58.15, “Overfill Protection Devices for Flammable Liquid Storage Tanks”.
(2) A tight-filled storage tank shall be prevented from being overfilled with a positive shut-off device that complies with CAN/ULC-S661, “Standard for Overfill Protection Devices for Flammable and Combustible Liquid Storage Tanks”.
(3) Sentence (2) does not apply to tight-filled storage tanks that were installed on or before December 31, 2014 and that meet the requirements of this Code as it read on December 31, 2014.
Installation and use
4.3.1.9. Unless otherwise specified in this Code, a storage tank shall be installed and used in conformance with the applicable installation and use provisions of the design document to which the storage tank was built as required by this Section.
Reuse
4.3.1.10. (1) A storage tank that has been taken out of service shall not be reused for the storage of flammable liquids or combustible liquids unless it has been
(a) refurbished so as to conform to one of the standards set out in Sentence 4.3.1.2.(1), or
(b) refurbished in conformance with Sentence (2) or (3).
(2) A storage tank is permitted to be refurbished for aboveground use in conformance with one of the following standards:
(a) ULC-S601(A), “Refurbishing of Steel Aboveground Horizontal Tanks for Flammable and Combustible Liquids”,
(b) ULC-S630(A), “Refurbishing of Steel Aboveground Vertical Tanks for Flammable and Combustible Liquids”.
(3) A storage tank is permitted to be refurbished for underground use in conformance with one of the following standards:
(a) ULC-S603(A), “Refurbishing of Steel Underground Tanks for Flammable and Combustible Liquids”,
(b) ULC-S615(A), “Refurbishing of Reinforced Plastic Underground Tanks for Flammable and Combustible Liquids”.
(4) A riveted storage tank shall not be relocated.
Subsection 4.3.2. Installation of Outside Aboveground Storage Tanks
Location
4.3.2.1. (1) Every outside aboveground storage tank for the storage of flammable liquids or combustible liquids shall be located in conformance with Sentences (2) to (5) with respect to the property line and any building on the same property.
(2) Except as provided in Sentences (6) and (7), every aboveground storage tank containing stable liquids and having a working pressure of not more than 17 kPa (gauge) shall be separated from a property line and any building on the same property by distances
(a) half those in Table 4.3.2.A. where protection is provided against fire or explosion in the tank in conformance with Sentence 4.3.2.5.(2), or
(b) equal to those in Table 4.3.2.A. where protection referred to in Clause (a) is not provided.
(3) Every aboveground storage tank containing unstable liquids and having a working pressure of not more than 17 kPa (gauge) shall be separated from a property line and any building on the same property by distances
(a) equal to those in Table 4.3.2.A., but not less than 7.5 m, where protection is provided against fire or explosion in the tank in conformance with Sentence 4.3.2.5.(2), or
(b) three times those in Table 4.3.2.A., but not less than 15 m, where protection referred to in Clause (a) is not provided.
(4) Every aboveground storage tank containing boil-over liquids shall be separated from a property line and any building on the same property by distances
(a) 0.75 times those in Table 4.3.2.A. where protection is provided against fire or explosion in the tank in conformance with Sentence 4.3.2.5.(2), or
(b) equal to those in Table 4.3.2.A. where protection referred to in Clause (a) is not provided.
(5) Where a storage tank containing stable liquids or unstable liquids has a working pressure greater than 17 kPa (gauge), the distances from a property line and any building on the same property shall be those specified in Sentences (2) and (3) multiplied by 1.5, but shall be not less than 7.5 m.
(6) The minimum distance required in Sentence (2) from a storage tank containing only Class II or IIIA liquids to a building on the same property is permitted to be reduced to
(a) 1.5 m provided the tank capacity is not more than 50000 L, or
(b) zero provided the tank capacity is not more than 2500 L.
(7) The minimum distance required in Sentence (2) is permitted to be waived provided the storage tank
(a) is in conformance with ULC-S655, “Aboveground Protected Tank Assemblies for Flammable and Combustible Liquids”, and
(b) has a capacity of not more than 50000 L.
(8) Where end failure of horizontal storage tanks may endanger adjacent property, the tanks shall be placed with the longitudinal axis parallel to such property.
Table 4.3.2.A.
Location of Aboveground Storage Tanks Forming Part of Article 4.3.2.1.
| Maximum Tank Capacity, L | Minimum Distance to a Property Line or to a Building on the Same Property, m |
| 250000 | 3 |
| 500000 | 4.5 |
| 2500000 | 9 |
| 5000000 | 12 |
| over 5000000 | 15 |
Spacing between storage tanks
4.3.2.2. (1) Except as required in Sentences (2) and (3) and in Article 4.3.2.3., the minimum distance between every combination of two aboveground storage tanks shall be 0.25 times the sum of their diameters, but shall be not less than 1 m.
(2) The minimum distance between any two storage tanks, neither of which has a capacity of more than 250000 L, shall be 1 m.
(3) Where either of the two aboveground storage tanks contains unstable liquids, the distance required in Sentences (1) and (2) shall be doubled.
Clearances from liquefied petroleum gas cylinders and tanks
4.3.2.3. (1) The minimum separation between a flammable liquid or combustible liquid storage tank and a liquefied petroleum gas cylinder or tank shall be 6 m.
(2) Secondary containments for flammable liquid or combustible liquid storage tanks shall not contain any liquefied petroleum gas cylinder or tank, and the centre line of the secondary containment wall shall be not less than
(a) 3 m away from a liquefied petroleum gas cylinder, and
(b) 7 m away from a liquefied petroleum gas storage tank.
Fire department access
4.3.2.4. (1) Except as provided in Sentences (2) and (3), storage tanks for flammable liquids or combustible liquids shall be spaced so that each storage tank is accessible for fire fighting purposes.
(2) An access route constructed in conformance with Subsection 3.2.5. in Division B of the Building Code shall be provided in outdoor storage areas to permit the approach of fire department vehicles to within 60 m of any storage tank.
(3) Where fire fighting access to storage tanks containing Class I or II liquids is not provided, fire extinguishing measures conforming to Sentence 4.3.2.5.(2) shall be provided.
Fire protection systems
4.3.2.5. (1) Where the diameter of a storage tank exceeds 45 m, the storage tank shall be provided with protection against fire or explosion in conformance with Sentence (2).
(2) Protection against fire or explosion required for a storage tank shall consist of fixed protection systems designed in conformance with good engineering practice such as described in
(a) NFPA 11, “Standard for Low‑, Medium‑, and High‑Expansion Foam”,
(b) NFPA 15, “Standard for Water Spray Fixed Systems for Fire Protection”, and
(c) NFPA 69, “Standard on Explosion Prevention Systems”.
Leakage testing
4.3.2.6. At the time of installation, aboveground storage tanks and associated piping shall be tested for leakage in conformance with Subsections 4.3.15. and 4.4.6.
Subsection 4.3.3. Supports, Foundations and Anchorage for Aboveground Storage Tanks
Foundations and supports
4.3.3.1. (1) Storage tanks shall rest on the ground or on foundations, supports or piling made of concrete, masonry or steel.
(2) Tank supports shall be installed on firm foundations designed to minimize uneven settling of the tank and to minimize corrosion of the part of the tank resting on the foundation.
(3) If the clearance below the base of a storage tank exceeds 300 mm, the supports for the storage tank shall have a fire-resistance rating not less than 2 h.
(4) Every aboveground storage tank shall be supported in a manner that will prevent the allowable design stress of the tank from being exceeded.
Earthquake protection
4.3.3.2. (1) In areas subject to earthquake forces, storage tanks, supports and connections shall be designed to resist such forces in conformance with
(a) Part 4 in Division B of the Building Code, and
(b) Appendix A2 of CAN/ULC-S601, “Standard for Shop Fabricated Steel Aboveground Tanks for Flammable and Combustible Liquids”.
Protection against flooding
4.3.3.3. Aboveground storage tanks located in an area that may be subject to flooding shall be securely anchored.
Subsection 4.3.4. Normal and Emergency Venting for Aboveground Storage Tanks
Design and installation
4.3.4.1. (1) Atmospheric and low pressure storage tanks shall be provided with normal and emergency venting in conformance with
(a) API 2000, “Venting Atmospheric and Low-Pressure Storage Tanks”, or
(b) the appropriate tank design standard set out in Sentence 4.3.1.2.(1).
Unstable liquids
4.3.4.2. When unstable liquids are stored, the effects of heat or gas resulting from polymerization, decomposition, condensation or self-reactivity shall be included in the determination of the total venting capacity.
Subsection 4.3.5. Vent Piping for Aboveground Storage Tanks
Materials and construction
4.3.5.1. Except at distilleries covered in Section 4.9., vent piping materials and construction shall conform to Subsections 4.4.2., 4.4.3. and 4.4.5.
Location of vent pipe outlets
4.3.5.2. (1) Normal vent pipe outlets for storage tanks of Class I liquids
(a) shall be located outside buildings, not less than
(i) 3.5 m above the adjacent ground level, and
(ii) 1.5 m from any building opening, and
(b) shall discharge so that flammable vapours will not enter the building or be trapped near any part of the building.
(2) Normal vent pipe outlets for storage tanks of Class II or IIIA liquids shall discharge outside buildings, not less than
(a) 2 m above the adjacent ground level, and
(b) 1.5 m from any building opening.
(3) Emergency vent outlets for storage tanks shall discharge outside buildings not less than 1.5 m from any building opening and from any combustible component of a building exterior wall.
Interconnection of vent piping
4.3.5.3. (1) Except as provided in Sentence (2), two or more storage tanks are permitted to be connected to a common vent pipe for normal relief venting provided the vent pipe size is designed to vent the combined vapours produced in the connected tanks without exceeding the allowable stresses of the tanks.
(2) Vent piping for storage tanks for Class I liquids shall not be connected to vent piping for storage tanks for Class II or IIIA liquids unless an effective arrangement is provided to prevent the vapours from the Class I liquids from entering the other tanks.
Subsection 4.3.6. Openings Other than Vents in Aboveground Storage Tanks
Provision of valves
4.3.6.1. (1) Each connection to an aboveground storage tank through which liquid can normally flow shall be provided with an internal or external shut-off valve located as close as practical to the shell of the tank.
(2) Each connection that is located below the liquid level of the aboveground storage tank and through which liquid does not normally flow shall be provided with a liquid-tight closing device.
Materials
4.3.6.2. (1) Valves and their connections to a storage tank shall be made of steel, except that when the chemical characteristics of the liquid stored are incompatible with steel, materials other than steel shall be used.
(2) Materials for valves and their connections to a storage tank shall be suitable for the pressures, stresses and temperatures that may be expected, including those of possible fire exposure.
Openings for liquid level measurements
4.3.6.3. Openings for measuring liquid levels in storage tanks for Class I liquids shall be equipped with caps or covers which shall be opened only when measuring the liquid level.
Connections for filling and emptying
4.3.6.4. (1) Except as provided in Sentence (3), connections used as part of normal operating conditions for filling or emptying storage tanks for flammable liquids and combustible liquids shall be located
(a) outside buildings,
(b) at a location free of sources of ignition, and
(c) not less than 1.5 m from building openings.
(2) Connections for filling or emptying storage tanks shall be kept closed to prevent leakage when not in use.
(3) A filling connection described in Sentence (1) is permitted to be located inside a building where
(a) made necessary
(i) by a process or activity located indoors and to which the tank is directly associated, or
(ii) for the collection of used liquids, and
(b) the fill piping is provided with means to prevent flammable vapours from returning to the building.
Subsection 4.3.7. Secondary Containment for Aboveground Storage Tanks
General
4.3.7.1. (1) The area surrounding a storage tank or group of storage tanks shall be designed to accommodate accidental spillage in conformance with Subsection 4.1.6.
(2) Where barriers described in Sentence 4.1.6.1.(1) are provided to contain accidental spillage from above-ground storage tanks, they shall conform to the requirements for secondary containment in this Subsection.
(3) A storage tank conforming to Sentence 4.3.7.4.(2) shall be considered as conforming to this Subsection provided it is used and maintained in conformance with Articles 4.3.7.8. and 4.3.7.9.
Construction
4.3.7.2. (1) Except as provided in Sentence (2), the base and walls of a secondary containment shall be made of noncombustible materials, and shall be designed, constructed and maintained to
(a) withstand full hydrostatic head, and
(b) provide a permeability of not more than 10-6 cm/s to the flammable liquids or combustible liquids contained in the storage tanks.
(2) Where a membrane provides the level of impermeability required in Sentence (1), the membrane shall
(a) conform to ULC/ORD-C58.9, “Secondary Containment Liners for Underground and Aboveground Flammable and Combustible Liquid Tanks”, and
(b) if combustible, be covered with a noncombustible material of such nature and thickness that the membrane will not fail when the secondary containment is exposed to fire.
(3) Subject to Sentence (4), there shall be no openings in a secondary containment.
(4) Where piping passes through a secondary containment, such passages shall conform to Sentences (1) and (2).
Capacity
4.3.7.3. (1) Except as permitted in Sentence (3), a secondary containment for a single storage tank shall have a volumetric capacity of not less than 110% of the capacity of the tank.
(2) Except as permitted in Sentence (3), a secondary containment for more than one storage tank shall have a volumetric capacity of not less than the sum of
(a) the capacity of the largest storage tank located in the contained space, and
(b) 10% of the greater of
(i) the capacity specified in Clause (a), or
(ii) the aggregate capacity of all other storage tanks located in the contained space.
(3) When the secondary containment is designed to prevent the entry of precipitation and water used for fire fighting purposes into the contained space, it shall have a volumetric capacity of not less than the capacity of the largest storage tank located in the contained space.
Clearances
4.3.7.4. (1) Except as provided in Sentence (2), no part of a secondary containment wall shall be less than 1.5 m from a storage tank shell.
(2) It is permitted to waive the distance required in Sentence (1) provided the storage tank
(a) is constructed in accordance with
(i) Clause 4.3.1.2.(1)(j), (k), (l) or (m), incorporating secondary containment, or
(ii) Clause 4.3.1.2.(1)(e) for double-walled storage tanks,
(b) has a capacity of not more than 50000 L, and
(c) is protected by posts or guardrails when exposed to collision damage.
Access to storage tanks and ancillary equipment
4.3.7.5. (1) A secondary containment shall be constructed so that it does not interfere with
(a) access to storage tanks, valves and ancillary equipment,
(b) egress from the contained space, and
(c) access for fire fighting as specified in Article 4.3.2.4.
(2) Where a storage tank contains Class I liquids, provision shall be made for the normal operation of valves and for access to the storage tank roof without entering the contained space created by the secondary containment when
(a) the average height of the secondary containment exceeds 3.5 m, measured from the ground level of the interior of the contained area, or
(b) the distance between the tank shell and the top inside edge of the secondary containment wall is less than the height of this wall.
Emergency venting
4.3.7.6. Where the secondary containment is not open to the atmosphere, emergency venting shall be provided to relieve any buildup of internal pressure in the contained space when exposed to heat or fire.
Leak detection
4.3.7.7. (1) The secondary containment shall be equipped with a monitoring device that activates a visual or audible alarm in an attended area in the event of a loss of integrity of the secondary containment unless
(a) the contained space created by the secondary containment is accessible for an internal visual examination, and
(b) the secondary containment is sloped so that liquid would flow to a specific location that can be monitored.
Drainage
4.3.7.8. (1) Liquids, debris and precipitation shall not be accumulated in the contained space created by the secondary containment.
(2) Provisions shall be made for removing liquid from the secondary containment in conformance with Subsection 4.1.6.
(3) Controls for the liquid removal system required in Sentence (2) shall be
(a) normally closed,
(b) accessible under fire exposure conditions, and
(c) located so they can be operated from outside the contained space.
Use of secondary containment
4.3.7.9. The contained space created by a secondary containment shall not be used for storage purposes.
Subsection 4.3.8. Installation of Underground Storage Tanks
Location
4.3.8.1. (1) Subject to Sentence (2), underground storage tanks shall be double-walled and shall be built in accordance with the underground storage tank standards in Sentence 4.3.1.2.(1).
(2) In-service underground storage tanks that do not comply with Sentence (1) may remain in-service if the tanks are not leaking and if the tanks met the requirements of this Code on December 31, 2014, as it read on that day.
(3) Underground storage tanks shall be located so that
(a) the foundations of buildings will not be undermined during excavation, and
(b) loads from building foundations and supports are not transmitted to the tank.
(4) Underground storage tanks shall be separated by a horizontal distance of not less than
(a) 600 mm from adjacent underground tanks or structures,
(b) 1 m from a building foundation or a street line, and
(c) 1.5 m from other property lines.
Ground cover
4.3.8.2. (1) Subject to Sentences (2) to (4), underground storage tanks shall be installed with not less than 600 mm of ground cover over the tank.
(2) Subject to Sentence (3), underground storage tanks subject to vehicular traffic shall be installed not less than 1 m below finished ground level.
(3) An underground storage tank subject to vehicular traffic may be installed under a 150 mm reinforced concrete slab or a 200 mm unreinforced concrete slab over not less than 450 mm of sand if the slab extends at least 300 mm beyond the underground storage tank.
(4) If it is not practical to install an underground storage tank completely below adjacent ground level due to subsurface conditions, an underground storage tank shall be built so that at least
(a) 75% of its mass is below adjacent ground level, provided there is not less than 600 mm of ground cover over the portion of the tank above adjacent ground level, or
(b) 50% of its mass is below adjacent ground level, provided there is not less than 1 m of ground cover over the portion of the tank above adjacent ground level.
Damage repair
4.3.8.3. (1) Underground storage tanks that are in the process of being installed shall be inspected, and any damage to the tank shell, protective coating, fittings or anodes shall be repaired before they are lowered into the excavation.
(2) Damage to underground storage tank shells shall not be repaired on site.
Damage prevention
4.3.8.4. (1) Underground storage tanks shall be lowered into the excavation by the use of lifting lugs and hooks and, where necessary, spreader bars to prevent damage to the tank shell, protective coating, fittings or anodes.
(2) Any method of handling that may result in damage to the protective coating of the tank shall not be used.
Installation
4.3.8.5. (1) Underground steel storage tanks shall be installed in conformance with Appendix B of CAN/ULC-S603.1, “External Corrosion Protection Systems for Steel Underground Tanks for Flammable and Combustible Liquids”.
(2) Underground reinforced plastic storage tanks shall be installed in conformance with Appendix A of ULC-S615, “Standard for Reinforced Plastic Underground Tanks for Flammable and Combustible Liquids”.
(3) Underground storage tanks shall not be placed in direct contact with reinforced concrete slabs but shall be separated by not less than 150 mm of sand or other suitable material to distribute evenly the weight of the tank on the supporting base.
Leakage testing
4.3.8.6. (1) At the time of installation, underground storage tanks and associated piping shall be tested for leakage in conformance with Subsections 4.3.15. and 4.4.6.
Filling
4.3.8.7. (1) Flammable liquids or combustible liquids shall not be placed in an underground storage tank until
(a) the fill pipe and vent line have been installed in the tank, and
(b) all other openings have been sealed.
Spillage
4.3.8.8. If a spillage occurs involving an underground storage tank, the escaped liquid and all soil contaminated by the spill shall be removed in accordance with Subsection 4.1.6.
Anchorage
4.3.8.9. (1) Underground storage tanks shall be protected against hydrostatic forces which can cause uplift of the tanks when they are empty.
(2) Where anchors and ground straps are used to resist the uplift forces referred to in Sentence (1), they shall be
(a) electrically isolated from the tank, and
(b) installed in such a manner that they do not damage the tank shell, protective coating, fittings or anodes.
Subsection 4.3.9. Corrosion Protection of Underground Steel Storage Tanks
Corrosion protection
4.3.9.1. (1) Underground steel storage tanks and integral fittings subject to corrosion shall be protected
(a) in accordance with CAN/ULC-S603.1, “External Corrosion Protection Systems for Steel Underground Tanks for Flammable and Combustible Liquids”, or
(b) by impressed current in accordance with NACE RP0285, “Corrosion Control of Underground Storage Tank Systems by Cathodic Protection”.
Subsection 4.3.10. Vents for Underground Storage Tanks
Vent design
4.3.10.1. Underground storage tanks shall be provided with vent openings and piping of sufficient cross-sectional area designed to vent the tanks during the maximum filling or withdrawal rate without causing the allowable stress for the tank to be exceeded.
Materials and construction
4.3.10.2. Except at distilleries as provided in Section 4.9., vent piping materials and construction shall conform to Subsections 4.4.2., 4.4.3. and 4.4.5.
Installation
4.3.10.3. (1) Vent pipe outlets from underground storage tanks for Class I liquids shall
(a) be located outside buildings higher than the fill pipe openings but not less than
(i) 3.5 m above the adjacent ground level,
(ii) 1.5 m from any building opening, and
(iii) 7.5 m from any dispenser, and
(b) discharge so that flammable vapours will not enter building openings or be trapped near any part of the building.
(2) Vent pipes from underground storage tanks for Class II or IIIA liquids shall be located outside buildings at a height that is above the fill pipe opening but not less than 2 m above finished ground level.
(3) Vent pipes from underground storage tanks for flammable liquids or combustible liquids shall not be obstructed by any device that may cause excessive back pressure, except that vent pipes from underground storage tanks for Class II or Class IIIA liquids may be fitted with return bends, coarse screens or other devices to minimize the entry of foreign material.
(4) Vent piping shall enter an underground storage tank through the top of the tank and shall not extend more than 25 mm into the tank.
(5) Vent piping shall be
(a) installed so that any nominally horizontal run shall slope towards the underground storage tank,
(b) constructed without traps,
(c) adequately supported to prevent sagging, and
(d) where necessary, protected against mechanical damage.
(6) The requirements of Sentence (4) do not apply to vent piping with an operational vent alarm if the vent piping met the requirements of this Code on December 31, 2014, as it read on that day.
Interconnection of vent pipes
4.3.10.4. (1) Subject to Sentence (2), if vent piping connects two or more underground storage tanks, pipe sizes shall be designed to vent the combined vapours produced in the connected underground storage tanks without exceeding the allowable stresses of the tanks when being filled simultaneously.
(2) If it is not possible to fill the connected underground storage tanks referred to in Sentence (1) simultaneously, or if the connected vents have a vapour recovery system, the vent piping shall be sized to accommodate the maximum vapour flow possible in the system.
(3) Vent piping for an underground storage tank containing a Class I liquid shall not be connected to the vent piping for an underground storage tank containing a Class II or IIIA liquid unless an effective method is provided to prevent the vapours from the Class I liquid storage tank from entering the other tank.
Subsection 4.3.11. Openings Other than Vents in Underground Storage Tanks
Connections
4.3.11.1. Connections for all openings in underground storage tanks shall be liquid and vapour tight.
Openings for measuring liquid level
4.3.11.2. Openings for measuring liquid levels in underground storage tanks if independent of the fill pipe shall be equipped with a vapour-tight cap or cover which shall be opened only when measuring the liquid level.
Fill piping and discharge piping
4.3.11.3. (1) Fill piping and discharge piping shall enter underground storage tanks only through the top of the tank and discharge piping used in suction systems shall be sloped toward the storage tanks.
(2) The fill point of an underground storage tank shall not be located higher than the discharge point of the tank’s vent.
(3) Subject to Sentence (5), connections used as part of normal operating conditions for filling or emptying underground storage tanks shall be located
(a) outside buildings,
(b) at a location free of sources of ignition, and
(c) not less than 1.5 m away from building openings.
(4) Connections for filling or emptying storage tanks described in Sentence (3) shall be kept closed to prevent leakage when not in use.
(5) A filling connection described in Sentence (3) may be located inside a building if
(a) made necessary
(i) by a process or activity located indoors and to which the tank is directly associated, or
(ii) for the collection of used liquids, and
(b) the fill piping is provided with means to prevent flammable vapours from returning to the building.
(6) If a fill piping system has an offset component from the fill point on the underground storage tank, fill pipes shall be
(a) double-walled,
(b) sloped to the storage tank, and
(c) electronically monitored for leak detection.
(7) If the fill point is below the normal liquid level in the underground storage tank,
(a) the fill line shall be equipped with a manual or automatic valve located at the fill point to prevent spillage when the fill cap is removed, and
(b) the fill line drop tube shall be equipped with a method to prevent siphoning of the tank’s contents should a leak occur in the fill line.
(8) In-service fill piping systems that do not comply with Sentences (6) and (7) may remain in-service if the piping does not leak and if the fill piping system met the requirements of this Code on December 31, 2014, as it read on that day.
Subsection 4.3.12. Installation of Storage Tanks Inside Buildings
Application
4.3.12.1. This Subsection applies to the installation of storage tanks in buildings.
Occupancy
4.3.12.2. (1) Subject to Sentence (2), storage tanks in buildings shall only be located in industrial occupancies.
(2) A storage tank containing a Class I liquid fuel that is connected to a stationary engine may be installed in any occupancy of a building if the installation complies with NFPA 37, “Standard for the Installation and Use of Stationary Combustion Engines and Gas Turbines”.
Maximum static head
4.3.12.3. The static head imposed on a storage tank inside a building shall not exceed 70 kPa (gauge) at the bottom of the tank when the vent or fill pipe is filled with liquid unless the tank is designed for greater pressures.
Maximum quantities and location
4.3.12.4. (1) Except as provided in Subsection 4.2.8. and in Sentence (2), storage tanks for flammable liquids or combustible liquids shall be
(a) located in dedicated rooms conforming to Subsection 4.3.13., and
(b) located in conformance with Table 4.3.12.A.
(2) When quantities greater than are permitted for incidental use in Subsection 4.2.8. are required for special process operations, storage tanks for flammable liquids or combustible liquids are permitted to be located outside of a storage room referred to in Sentence (1), provided that
(a) total quantities per fire compartment are not more than one-half the quantities permitted in Table 4.3.12.A.,
(b) they are located on the first storey, and
(c) the installation conforms to Articles 4.3.12.7. to 4.3.12.10. and Article 4.3.13.4.
(3) Table 4.3.12.A. does not apply to the storage of distilled beverage alcohol.
Table 4.3.12.A.
Indoor Tank Storage in Industrial Occupancies Forming Part of Article 4.3.12.4. and 4.3.12.6.
| Class of Liquid | Storage Level | Maximum Quantity per Storage Room(1), L, One or More Tanks, Protected Storage(2) | Maximum Quantity per Storage Room(1), L, One or More Tanks, Unprotected Storage |
| Class I | First Storey | 40000 | 25000 |
| Class I | Storeys above the first storey | 7500 | Not permitted |
| Class I | Basement | Not permitted | Not permitted |
| Class II and IIIA | First Storey | 200000 | 100000 |
| Class II and IIIA | Storeys above the first storey | 20000 | Not permitted |
| Class II and IIIA | Basement | 20000 | Not permitted |
Notes to Table 4.3.12.A.:
(1) See Subsection 4.3.13.
(2) See Article 4.2.7.7.
Fire compartments
4.3.12.5. Fire compartments referred to in this Subsection shall have a fire-resistance rating not less than 2 h.
Mixed storage
4.3.12.6. (1) When two or more classes of liquids are stored in a single storage room referred to in Sentence 4.3.12.4.(1), the total quantities of stored liquids shall meet the requirements of the following equation:
qI/QI + qII+IIIA/QII+IIIA ≤ 1
where
qI = the actual quantity of Class I liquid present,
qII+IIIA = the actual quantity of Class II and IIIA liquid present,
QI = the maximum quantity of Class I liquid permitted in Table 4.3.12.A., and
QII+IIIA = the maximum quantity of Class II and IIIA liquid permitted in Table 4.3.12.A.
Storage tanks outside storage rooms
4.3.12.7. (1) Where storage tanks for flammable liquids or combustible liquids are located outside of storage rooms conforming to Subsection 4.3.13.,
(a) provision shall be made, in conformance with Subsection 4.1.6., to contain a spill equal to at least 100% of the volume of the largest storage tank or to drain away spilled flammable liquids or combustible liquids,
(b) all electrical equipment and wiring in the vicinity of the storage tank and the exterior vent shall be installed in conformance with Subsection 4.1.4., and
(c) the area in which the storage tank is located shall be ventilated in conformance with Subsection 4.1.7., where designated a Class I, Zone 0, 1 or 2 hazardous location under the Electrical Safety Code made under the Electricity Act, 1998.
Vents
4.3.12.8. (1) Except as provided in Sentence (2), normal and emergency vents for storage tanks in buildings shall be provided in conformance with Subsections 4.3.4. and 4.3.5.
(2) Weak roof-to-side shell seams that are designed to rupture before the allowable design stress of the storage tank is reached shall not be used as a means of emergency venting of storage tanks inside buildings.
Supports, foundations and anchorage
4.3.12.9. (1) Except as provided in Sentence (2), where storage tanks for flammable liquids or combustible liquids are installed inside buildings, the supports, foundations and anchorage for such storage tanks shall be in conformance with Subsection 4.3.3.
(2) Where a storage tank is suspended, rather than supported on a foundation, supports shall be designed and installed in conformance with good engineering practice.
Bonding and grounding
4.3.12.10. (1) Where storage tanks for flammable liquids or combustible liquids are installed inside buildings, tanks, piping and discharge equipment shall be bonded and grounded.
Subsection 4.3.13. Rooms for Storage Tanks
Design and construction
4.3.13.1. (1) Rooms for storage tanks inside buildings shall be
(a) separated from the rest of the building by a fire separation having a fire-resistance rating of not less than 2 h,
(b) designed to contain a spill equal to at least 100% of the volume of the largest storage tank, or to drain away spilled flammable liquids or combustible liquids in conformance with Subsection 4.1.6.,
(c) made liquid-tight where the walls join the floor,
(d) provided with natural or mechanical ventilation in conformance with Subsection 4.1.7., and
(e) used for no other purposes than the storage and handling of flammable liquids or combustible liquids.
Clearances
4.3.13.2. A minimum clear space of 550 mm shall be maintained between the walls of a room described in Article 4.3.13.1. and the sides of any storage tanks within the room.
Explosion venting
4.3.13.3. Where Class IA or IB liquids are dispensed within a storage room, the room shall be designed to prevent critical structural and mechanical damage from an internal explosion in conformance with NFPA 68, “Standard on Explosion Protection by Deflagration Venting”.
Hose stations and portable extinguishers
4.3.13.4. (1) In buildings not required to be equipped with a standpipe system by the Building Code, hose stations conforming to Articles 3.2.9.2. to 3.2.9.7. of the Building Code, as it read on August 21, 2000, shall be provided in the vicinity of the storage room, such that all parts of the room are within reach of a hose stream.
(2) Portable extinguishers for Class B fires shall be provided in conformance with Section 6.2.
Placards
4.3.13.5. (1) Placards conforming to the Transportation of Dangerous Goods Regulations made under the Transportation of Dangerous Goods Act, 1992 (Canada) shall be posted in a conspicuous location outside the room containing storage tanks.
(2) Placards required in Sentence (1) shall identify the
(a) liquids stored as flammable liquids or combustible liquids, and
(b) capacities of the storage tanks.
(3) Despite Clause (2)(a), where storage consists of a single product, placards that identify the liquid using the UN Product Identification Number (PIN) shall be acceptable.
(4) Despite Clause (2)(a), where storage consists of multiple products within the same class, placards that identify the class of liquids shall be acceptable.
(5) Despite Clause 2(a), where storage consists of more than one class of liquid, placards that indicate the danger symbol or individual placards for each class of liquid shall be acceptable.
(6) Rooms for storage tanks and the information described in Sentence (2) shall be identified in the fire safety plan required in Article 4.1.5.6.
Subsection 4.3.14. Openings Other than Vents in Storage Tanks in Buildings
Connections
4.3.14.1. (1) Connections for all openings in storage tanks in buildings shall be liquid and vapour tight.
(2) Connections to storage tanks through which liquid can flow shall be provided with valves located as close as practical to the tank.
Openings for liquid level measurement
4.3.14.2. (1) Openings that are independent of the fill pipe and are used for measuring the liquid level in storage tanks containing Class I or II liquids shall be equipped with a vapour-tight cap which shall be opened only when measuring the liquid level.
(2) Openings referred to in Sentence (1) shall be protected against overflow and vapour pressure by means of a spring-loaded check valve.
Subsection 4.3.15. Leakage Testing of Storage Tanks
Leakage testing
4.3.15.1. (1) Every storage tank shall be tested for leakage in conformance with Sentences (2) to (4)
(a) whenever a leak is suspected, and
(b) at the time of installation
(i) before backfilling in the case of an underground tank, or
(ii) before filling or putting into service in the case of an aboveground tank.
(2) When a leakage test is required by Sentence (1) on an aboveground storage tank, it is permitted to determine the source of leakage
(a) by a visual examination of the tank shell, and
(b) where the bottom is not amenable to such examination, by testing the bottom of the tank in conformance with Sentence (3).
(3) Except as provided in Articles 4.3.15.4. and 4.3.15.5., when a leakage test is required by Sentence (1) on an underground storage tank, it shall be done by qualified personnel using equipment conforming to
(a) ULC/ORD-C58.12, “Leak Detection Devices or (Volumetric Type) for Underground Flammable Liquid Storage Tanks”, or
(b) ULC/ORD-C58.14, “Nonvolumetric Leak Detection Devices for Underground Flammable Liquid Storage Tanks”.
(4) Where field test methods are included in the tank construction standards referred to in Articles 4.3.1.2. and 4.3.1.3., such tests shall be permitted for storage tanks conforming to those standards.
4.3.15.2. RESERVED
Remedial action
4.3.15.3. (1) When a leak is detected in a storage tank by a leakage test required in this Subsection or by a leakage detection measure required in Subsection 4.3.16.,
(a) the storage tank shall
(i) be replaced, in the case of an underground tank, or
(ii) be repaired or replaced in the case of an aboveground tank, and
(b) the escaped liquid shall be removed in conformance with Article 4.1.6.3.
(2) The Chief Fire Official shall be notified within 24 h of detection of a leak referred to in Sentence (1).
Pneumatic leakage tests
4.3.15.4. (1) Pneumatic leakage tests shall not be performed on field-erected aboveground storage tanks.
(2) Pneumatic leakage tests shall not be performed on storage tanks with flammable liquids or combustible liquids in the tanks.
(3) Where a pneumatic leakage test is performed on an underground storage tank, the tank shall be considered to be leaking when the test indicates a pressure drop within a 2 h period after steady temperature conditions have been established and the source of pressure has been removed.
(4) Pneumatic test pressures applied to underground storage tanks shall be measured by an instrument calibrated in increments of not more than 1 kPa.
(5) If a pneumatic leakage test is conducted before an underground tank is backfilled in the case of a new tank, or after the tank is uncovered in the case of a previously installed tank, the test pressure shall comply with the production testing requirements of
(a) ULC-S603, “Standard for Steel Underground Tanks for Flammable and Combustible Liquids”, or
(b) ULC-S615, “Standard for Reinforced Plastic Underground Tanks for Flammable and Combustible Liquids”.
(6) Where a pneumatic leakage test is performed on a completely buried storage tank, the test pressure shall be not less than 35 and not more than 70 kPa (gauge).
(7) Measures shall be taken to guard against the hazards associated with pneumatic leakage testing where explosive mixtures of vapours from flammable liquids or combustible liquids and air may be present in the area of a tank that has been in use.
Liquid media leakage tests
4.3.15.5. (1) Where a leakage test incorporating a liquid test medium, including a flammable liquid or combustible liquid, is performed on an underground storage tank, the tank shall be considered to be leaking when, with compensation for volume differentials caused by effects of temperature and tank shell distortion, the test indicates a liquid loss.
(2) The pressure at the bottom of a storage tank shall not exceed 70 kPa (gauge) during the leakage test referred to in Sentence (1).
Subsection 4.3.16. Leakage Detection of Storage Tanks
Liquid level measurements
4.3.16.1. (1) Except as provided in Article 4.3.16.2., the liquid level in any storage tank shall be measured at intervals not greater than seven days in conformance with Sentences (2) to (4), except that at fuel dispensing stations, the measurements shall be taken each day the station is in operation.
(2) The level of water at the bottom of an underground storage tank shall be measured at intervals not greater than seven days, except that at fuel dispensing stations, the measurement shall be taken each day the station is in operation.
(3) A comparison of the measurements described in Sentences (1) and (2) with meter readings and a computation of any gain or loss of liquid shall be done each time a required measurement is taken.
(4) A record for each storage tank showing the measurements and computations described in Sentence (3) shall be retained for examination by the Chief Fire Official, in conformance with Subsection 1.1.2.
Continuous leakage detection
4.3.16.2. (1) The measurements described in Article 4.3.16.1. are not required for an underground storage tank when
(a) it is provided with a continuous leakage detection device conforming to
(i) ULC/ORD-C58.12, “Leak Detection Devices (Volumetric Type) for Underground Flammable Liquid Storage Tanks”, or
(ii) ULC/ORD-C58.14, “Nonvolumetric Leak Detection Devices for Underground Flammable Liquid Storage Tanks”, and
(b) its associated underground piping is provided with continuous leakage detection conforming to Article 4.4.6.7.
Corrective action
4.3.16.3. (1) Immediate corrective action shall be taken in conformance with Subsection 4.3.15. when
(a) a loss of liquid or a gain of water is indicated by any of the leakage detection measures described in Articles 4.3.16.1. and 4.3.16.2., or
(b) the level of water at the bottom of an underground storage tank exceeds 50 mm.
Subsection 4.3.17. Out of Service
Underground storage tanks
4.3.17.1. (1) When underground storage tanks will be out of service for a period not exceeding 180 days,
(a) the liquid level in the storage tank shall be measured at intervals not greater than one month and a record of such measurements shall be retained for inspection,
(b) fill pipe covers and covers over openings to measure liquid levels, dispensers and power controls shall be kept locked when not in use, and
(c) vent piping shall be kept open.
(2) Except as provided in Sentence (3), when underground storage tanks will be out of service for a period exceeding 180 days,
(a) the storage tanks, connected piping and dispensers shall be emptied of Class I liquid,
(b) the storage tanks, piping and dispensers shall be refilled with a Class II or IIIA liquid, or not less than 1 kg of dry ice for each 500 L of tank capacity shall be added to the storage tank,
(c) measurements of the liquid level of each storage tank containing a Class II or IIIA liquid shall be made at intervals not greater than one month, and a record of such measurements shall be retained for inspection, and
(d) fill pipe covers and covers over openings to measure liquid levels, dispensers and power controls shall be locked.
(3) Where underground storage tank facilities are operated on a seasonal basis,
(a) at the close of each season of operation,
(i) the liquid level of each storage tank shall be measured,
(ii) a record of such measurements shall be retained for inspection, and
(iii) all fill pipe covers and covers over openings for measuring liquid levels, dispensers and power controls shall be locked, and
(b) prior to the start of an operating season,
(i) the liquid level in each storage tank shall be measured,
(ii) the measurements shall be compared with those recorded at the close of the previous season, and
(iii) when a loss of liquid or water intrusion is apparent, immediate action shall be taken to determine and correct the condition.
(4) Where a storage tank has been out of service for more than 12 months, the tank and piping shall be tested for leakage in conformance with Subsections 4.3.15. and 4.4.6.
Aboveground storage tanks
4.3.17.2. (1) When an aboveground storage tank will be out of service or unsupervised for a period not exceeding 180 days, the piping from the tank shall be capped or the valves necessary to achieve similar isolation of the tank shall be closed and securely locked.
(2) When a storage tank referred to in Sentence (1) contains flammable liquids or combustible liquids, the liquid level in the tank shall be measured and the readings compared at intervals not greater than one month.
(3) Where an aboveground storage tank will be out of service or unsupervised for a period exceeding 180 days,
(a) all liquid and vapours shall be removed from the storage tank and its connected piping, and
(b) the storage tank markings shall clearly indicate that the tank is empty.
Disposal
4.3.17.3. Where a storage tank is to be permanently disposed of, sufficient openings shall be cut in the tank to render it unfit for further use.
Removal
4.3.17.4. (1) When underground storage tanks have no further use or have been out of service for two years or longer, such tanks, together with connected piping and dispensers, shall
(a) have all flammable liquids and combustible liquids removed from them,
(b) be purged of vapours, and
(c) except as permitted in Article 4.3.17.5., be removed from the ground.
(2) If contaminated, soil surrounding the storage tanks described in Sentence (1) shall be replaced with clean fill.
Abandonment in place
4.3.17.5. (1) Where the Chief Fire Official determines that it is impractical to remove an underground storage tank described in Sentence 4.3.17.4.(1), such tank shall be filled with an inert material.
(2) Where the Chief Fire Official determines that it is impractical to remove underground piping described in Sentence 4.3.17.4.(1), such piping shall have the ends permanently sealed by capping or plugging.
Corrosion protection
4.3.17.6. Corrosion protection systems shall be maintained in operating condition when a storage tank is temporarily out of service and during seasonal shutdowns.