Beneficial Management Practices: Environmental Manual for Alberta Farmsteads - Chapter 6 Fuel Storage and Handling

Diesel, gasoline, lubricants and oils are used extensively on farms today. In Alberta, there are at least 250 million litres of diesel and gasoline storage. Financial (increasing costs), environmental (potential for spills and leaks) and safety (potential fires) concerns are associated with handling and storing fuel on the farm.

At present, the Alberta Fire Code governs the storage and handling of petroleum products. Although Alberta producers are exempt from the Code, its standards are used as guidelines for producers to follow as beneficial management practices.

Siting and Setup

Proper siting and setup of your storage area is important in minimizing or eliminating risks associated with handling fuel (see Figure 6.1). When determining fuel storage locations on your farm, keep minimum separation distances from areas that could be affected by fire and fuel leaks and spills. Prior to installing storage tanks or facilities, ensure equipment such as tanks, support stands and dispensers are in accordance with the Alberta Fire Code.


Figure 6.1. A well planned farm fuel storage site
Courtesy of Resource Management Branch, British Columbia Ministry of Agriculture and Lands. Adapted.

Minimum Separation Distances
Fuel storage areas should be located well away from buildings, trees, ignition sources, other fuel tanks, water bodies and water sources to reduce environmental and safety risks. Keeping the storage area free of vegetation and away from buildings and ignition sources helps reduce the danger to fuel tanks in the event of a fire. Ignition sources include electric motors, road traffic, yard lights, power lines, cell phones, air conditioning or heating units and garbage burning barrels.

The following diagram (Figure 6.2) provides guidelines for distances when siting petroleum storage.


Figure 6.2. Minimum separation distances from fuel storage areas

Stands
Typically, many farm sites in Alberta have gravity-fed tanks on stands 1 to 3 m (4 to 9 ft) high. These tanks tend to become unstable because of the weight of the fuel, or they melt due to a fire, resulting in a spill. The best practice is to mount tanks at ground level, or on solid concrete or steel supports no higher than 0.3 m (1 ft) off the ground. Supports should provide a minimum two-hour fire-resistant rating and be on a firm foundation to help prevent uneven settling.


Aboveground or gravity-fed tanks located too close to trees increase fire hazards and damage from fallen trees
Courtesy of ARD

Secondary Containment
As a safety precaution, secondary containment that contains 110 percent of the maximum volume of the storage tank is recommended. Installing a double-walled tank or using a diking system can accomplish this goal.

Double-walled tanks provide excellent protection against leaks and also provide thermal insulation, reducing extreme changes in fuel temperature. Each double-walled tank has a space between two walls that will contain 10 percent more volume than the storage capacity of the tank.

A dike is an impermeable spill containment area or berm constructed of earth, steel, concrete, solid masonry or synthetic liner that will also hold 110 percent of the tank capacity. If there is more than one tank, then the containment area must hold 110 percent of the largest tank, or the capacity of the largest tank plus 10 percent of the total volume of the remaining tanks, whichever is greater.

Evaporation
Losses due to evaporation vary with the type of storage, fuel and management practices to prevent evaporation. Fuel losses range from minimal in underground tanks, to maximal in poorly located or maintained overhead tanks. The heating of aboveground tanks from the sun causes the fuel to evaporate (volatilize) into the atmosphere. The more the fuel temperature changes, the greater the potential for fuel losses and risk of contamination due to condensation. Evaporation losses are greater for gasoline than diesel because gasoline is more volatile. For estimations of evaporative losses due to different tank conditions in summer months for aboveground storage, refer to Table 6.1.

Table 6.1. Evaporative losses from a 1,200 litre (265 gallons) aboveground gasoline storage tank

Tank conditions			Evaporation lost per summer months		% of full tank lost
			Litres	Gallons	%
Dark tank	in sun		38	8.4	3.2
White tank	in sun		23	5.1	1.9
Dark tank	in sun	with pressure vent cap	21	4.6	1.8
White tank	in sun	with pressure vent cap	9	2	0.8
Dark tank	in shade		9	2	0.8
White tank	in shade	with pressure vent cap	5	1.1	0.4
For comparison purposes:
Underground tank			< 4	< 1	0.3
Double-walled aboveground tank			Losses similar to underground tank
Source: Farm Storage and Handling of Petroleum Products, Farm Mechanization Factsheet No. 210.510-1, Resource Management Branch, British Columbia Ministry of Agriculture and Lands.

• Paint the tank with reflective paint (silver or white) and reduce evaporation losses by up to 40 percent compared to a dark-coloured tank.
• Use a pressure ventilated cap to reduce evaporation losses by 50 percent. This type of cap restricts direct venting of tank fumes until a slight pressure has built up in the tank. Having a painted and pressure-vented tank has a 75 percent evaporation loss reduction compared to a dark-coloured tank.
• Locate a painted and pressure-vented tank in the shade to further reduce evaporation losses by over 40 percent. A shelter with a roof also helps reduce weathering of hoses and valves (see Figure 6.1).
• Do not fill the tank to more than 90 percent of its capacity; this practice reduces pressure in the tank, and thus, evaporative or spill losses.

• Use a hand or electric pump. If using an electric pump, it must be installed according to the Code of Electrical Installations at Oil and Gas Facilities.
• Close the valves on tank discharges when they are not in use to prevent leakage through the hose or nozzle.
• Never leave the area unattended even if automatic shut-off nozzles are being used. There is always the possibility of nozzles malfunctioning or getting knocked out of the tank.

• Protect tanks and piping against corrosion to prevent leaks.
• Protect all pumps, lines and tanks from collision damage by installing bollards (barriers constructed of a sturdy material, such as steel piping filled with cement, set up close to fuel tanks to guard against collision damage).
• Make sure fill-up hoses are long enough, so vehicles and farm equipment can be kept at a safe distance from the tanks.
• Keep fuel lines, hoses, valves and nozzles in good repair. Install anti-siphon valves between the pump and tank to prevent the tank from draining if the line breaks.
• Lock all fuel tanks when not in use to reduce the risk of spills caused by vandalism or theft.
• Ground the pumps and vehicles to avoid build up of static electricity, explosions and fires. Attach a bonding line to the vehicle prior to filling it from an aboveground fuel storage tank to reduce the risk of static electricity igniting fuel vapours (see Figure 6.1).

Fuel Inventory
Sample Fuel Inventory Control Sheet
Tank 1
Fuel Type
Fuel Dips (cm)		97		This value is determined by dipping your tanks with a measuring rod or tape. The measurement is taken in centimeters.
Actual Volume (L)		2,054		This value is determined from the chart supplied by tank manufacturers. A depth of 97 centimeters converts to a volume of 2,054 litres (for this example).
Previous Actual Volume		1,710		Obtained from actual volume figures on your last inventory sheet.
Deliveries	+	500		Fuel delivered since last inventory sheet.
Present Volume	=	2,210		Previous actual volume plus deliveries.
Usage	–	162		Fuel removed from the tanks since last inventory sheet.
Expected Inventory	=	2,048		The amount of fuel you expect to be in your tank (present volume minus usage).
Actual Volume (from dips)		2,054		Actual fuel in the tank as calculated from fuel dip.
Expected Inventory	–	2,048		This figure is the expected inventory as calculated above.
Today’s Variance*	=	6		The difference between actual volume and expected inventory.
Previous YTD Variance*	+	-52		Cumulative year-to-date (YTD) variance from the last inventory sheet.
YTD Variance*	=	-46		Current YTD variance.
Water Reading (cm)	=	0.5		The water reading in the tank using water-sensitive paste on the dipstick.

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