This Section outlines the procedures to be followed when storage tanks for flammable or combustible liquids are removed permanently or taken temporarily out-of-service.
A tank must be emptied and the associated piping drained if the tank will be out-of-service for a period exceeding 180 days. Normal methods of emptying a tank are not adequate to remove all of the liquid. Additional requirements to remove the residual liquids plus the flammable vapours in the tank vapour are outlined. Underground tanks and the piping must be completely refilled with a combustible liquid or 1 kilogram of dry ice for each 500 liters of tank capacity should be added to the tank to displace the air in the vapour space with carbon dioxide. If the tank is filled with a combustible liquid, monthly measurements of the liquid level must be taken with written records maintained and available to the Chief Fire Official. Fill pipes, covers, gauging opening covers, dispensing facilities shall be securely locked when not in use and the vent line must be maintained.
Some underground storage tanks are only operated on a seasonal basis, such as the storage of heating oil. At the close of each storage season, the liquid level must be recorded and retained for inspection. Fill pipes covers, gauging opening covers, dispensing facilities shall be securely locked during the off season and the vent line for the tank must be maintained. Prior to the next operating season, the liquid level must be taken for each such tank and compared with the measurement taken at the close of the previous season. Immediate action must be taken if there is any loss of liquid or gain of water.
Before underground storage tanks go back into service after being out of service for a year or longer, the tank and its associated piping must be tested for leaks in conformance with Subsections 4.3.15. and 4.4.6.
Where aboveground tanks and associated piping will be out of service for a period not exceeding 180 days they must have all piping connected to the tank capped and valves locked in the fully closed position. The liquid level in the tank must be measured at least monthly and the readings compared to the previous readings.
If an aboveground storage tank is to be out of service for a period greater than 180 days it must be completely drained of all liquids and the vapour space purged of flammable vapours. The tank should be clearly marked "Empty".
Underground storage tanks may be abandoned in place if the Chief Fire Official determines that it is not practical to remove the tank. As much liquid as possible should be removed from the tank and then an inert material such as a sloppy concrete mixture should be packed into the tank. As much of the underground associated piping as practical should be removed. If the Chief Fire Official determines that the removal of the piping is impractical, the piping should be drained of all liquid and purged of vapours. The piping ends must be permanently capped or sealed.
When the Chief Fire Official is satisfied that it is impractical to remove underground tank or piping as required in Clause 4.10.3.1.(1)(c), such tanks can be filled with inert material or the pipes sealed. However, the requirements of Clauses 4.10.3.1.(1)(a) and (b) must be complied with.
Used storage tanks are not permitted to be reinstalled unless the tank complies with the prescribed standards. Riveted storage tanks should not be reused because rivets may become loose during the moving of the tank. Loose rivets cause leaks. Aboveground storage tanks may be reinstalled but must comply with Section 4.3.
Existing tanks cannot be reused where there is pitting or gouges that reduce the shell thickness by 0.8 millimetres, or where there are dents greater than 30 degrees of the original shape. These flaws represent shell weakness that could result in tank failure if reused. If the existing shell thickness is equal to or greater than the design thickness indicated in Subsection 4.3.1. even after subtraction of the greatest depth of any pitting, the tank could be reused if it is in conformance with Subsection 4.3.1. or has been refurbished in conformance with Sentence 4.10.4.2.(3).
SECTION 4.11 TANK VEHICLES
Subsection 4.11.1. - Scope
This Section applies to tank vehicles that are used to transport flammable and combustible liquids when the vehicle is located or parked on a property covered under this Code. Such vehicles include tanker trucks and fuel distribution trucks.
No hot work or smoking should be performed on or near these vehicles.
Unless the building is specifically designed for the parking of these tank vehicles, they should not be parked inside. A building specifically designed for this use must include ventilation features, spill control and drainage systems, control of all ignition sources, fire separation and fire protection features. Any tank vehicle that has a leak of a flammable or combustible liquid should never be parked inside a building. Other potential problems could occur if the vehicle tanks have been filled to their maximum capacity with flammable or combustible liquid during winter months and parked inside a heated building. The temperature change will result in the expansion of the liquid and could overflow. Space should always be provided in a tank to compensate for possible thermal expansion of the liquid.
Outdoor parking for tank vehicles is preferred. The vehicle operator cannot leave the vehicle unattended outdoors for more than one hour unless the following conditions are met:
Further information about static electricity is located at the end of this commentary (see Appendix B).
Usually, the vehicle operator loads and unloads the vehicle by manually operating a valve. There should be a fully trained person present and in a position to shut off the flow of liquid should there be a spill or emergency.
An operating engine can be a source of ignition for released flammable vapours because of their ignition system and hot exhaust manifold and pipe. For this reason, vehicle engines should be shut off while Class I liquids are loaded or unloaded. If the pump used to unload found in all types of occupancies a viscous liquid is driven by the vehicle engine, special safeguards must be taken to prevent released vapours from reaching the running engine.
The following loading/unloading procedure is provided as an example. This procedure must be displayed in a prominent location and be readable for drivers and employees. A similar procedure should be developed in keeping with the specific requirements of dispensing and good engineering practices.
A tank vehicle should be considered as a storage tank for the purpose of applying the requirements of Sentence 4.1.8.2.(2) in Article 4.11.3.2.
SECTION 4.12 LABORATORIES
Subsection 4.12.1. - Scope
Laboratories found in all types of occupancies that use or handle flammable or combustible liquids must comply with this Section as well as any applicable requirements in Sections 4.1 and 4.2. If there is a conflict between general requirements in Sections 4.1 or 4.2 and the specific requirements in Section 4.12, then the specific requirements override the general.
Subsection 4.12.2. - Separation
Fire separations
Laboratory storage containers must not exceed 5 L in volume and must conform to the design, construction and labeling requirements set out in Subsection 4.2.3.
Not more than 300 L of flammable and combustible liquids may be kept in the open area of a laboratory. Of this total, not more than 50 L may be flammable liquids.
Subsection 4.12.4. - Emergency Planning
Laboratories must conform to the requirements for emergency planning set out in Section 2.8 of the Ontario Fire Code with the following exceptions:
Experience has shown that ventilation systems require special attention for such problems as corrosion and build-up of combustible materials. General laboratory exhaust ventilation systems must be inspected at least annually. Inspection of fume hoods and similar local exhaust systems must occur at least every six months.
During the consultations held to develop these regulations, it was recognized that it would be exceedingly difficult, impractical and costly to upgrade some existing systems to comply with all of these requirements. Therefore, existing exhaust systems need not comply with Articles 4.1.7.3., 4.1.7.4., and 4.12.8.2. to 4.12.8.5. In addition, where make-up air is provided for existing ventilation systems, these systems shall be considered to be in compliance with the more onerous provisions outlined in Article 4.1.7.5. for make-up air. Similarly, existing ventilation systems that maintain a negative pressure within the ventilation system with respect to the surroundings, shall be considered to be in compliance with the more stringent requirements set out in Article 4.1.7.7. for exclusive use of the exhaust system.
Sentences 4.12.8.1.(2), (3) and (4) modify the application of Subsection 4.1.7. to existing conditions.
Both local and general exhaust systems are required in most laboratories. Local exhaust systems capture flammable gases and vapours at their source (e.g. fume hoods used for dispensing, processing, mixing). These local exhaust systems may require explosion proof electrical equipment where this equipment is exposed to these vapours. Flammable gases and vapours that escape capture by a local exhaust system, or are generated in small quantities outside a local exhaust system, are captured by the general exhaust system of the laboratory. This general exhaust system must be designed to prevent flammable gases and vapours from migrating to other parts of the building. The exhaust system must also be designed to prevent gases and vapours from re-entering the building via the make-up air system.
Refrigerated storage containing flammable or combustible liquids must be identified as containing flammable or combustible liquids.
Class I liquids stored in a refrigerator must be kept in closed containers. Depending on the temperature within the refrigerator and the vapour pressure of combustible liquids stored at that temperature, these liquids may need to be kept in closed containers to prevent the accumulation of vapours within this enclosed storage.
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