Slant/Fin Oil Hot Water - Manual (Page 12)

12
FUEL OIL STORAGE FACILITIES
Local codes usually govern the installation of fuel oil storage
facilities. However, for areas where no rules have been established,
the following information can provide assistance to the system
designer.
Storage tank sizing
When calculating minimum fuel oil storage capacity, several
variables must be considered. These include: maximum fuel
consumption rate, storage space limitations, availability, distance
from source of supply, and method of delivery (truck or railroad tank
car). Large storage tanks, of course, cost more than smaller ones
but the cost is not proportional (e.g., a 10,000 gal. tank does not
cost twice as much as a 5,000 gal. tank). And larger tank capacity
allows oil purchases usually at lower per gallon rates.
Generally, the storage tank should hold enough oil to sustain
continuous operation for 10 days (plus an additional 10% margin to
allow for suction stub clearance).
To determine the minimum storage requirement, proceed as
follows:
a) Refer to Table 1 to find the maximum hourly oil consumption
(GPH) of the system being installed.
b) Multiply the maximum hourly consumption by the probable
maximum daily hours of operation to achieve maximum daily
consumption.
c) Multiply the maximum daily consumption by 10 (days) and add
10% to obtain the MINIMUM storage capacity.
Requirements for fuel oil storage tanks.
Data in this section is based on the use of steel storage tanks.
Where no local codes apply, take the following data into
consideration.
a) Inside tanks are usually located in the lowest part of the building.
When supply and return lines are piped through the top of the
tank, spillage is minimized in the event of leaks.
b) Unenclosed tanks should be at least 7 feet from any open
flames or fires.
c) Most fire codes prohibit unenclosed inside tanks exceeding 275
gallons each. Where multiple tanks are installed, the total storage
capacity should not exceed 550 gallons unless vaulted.
d) If inside tanks are properly enclosed, the maximum storage
capacity can be increased to 5,000 gallons in non-fire-resistant
buildings, and to 15,000 gallons in fire-resistant structures.
NOTE: An enclosure shall consist of walls constructed of 6"
reinforced concrete or 8-inch thick masonry with the space
between tank and walls filled with sand. If floor above has a
load-bearing capacity of 150 lbs./sq. inch or greater and is
constructed of fire-resistant material, 1 foot of sand fill over the
tank is sufficient. If not, a 5-inch concrete slab, or equivalent,
must be employed. An alternative method is to pour a 6-inch
thick concrete enclosure directly over the tank (no air spaces).
e) Underground tanks (Figure 14) are to be buried at least 2 feet
below grade.
f) Tanks buried beneath buildings ALWAYS require 4-inch
reinforced concrete slab covers that extend 1 foot beyond tank in
all directions.
g) Fiberglass and/or double-walled tanks may be required. Check
your local codes. Underground metal tanks should be painted
with heavy asphaltum, rust-resistant paint or be of double walled
construction (check local codes). DO NOT install tank in bed of
cinders (cinders contain sulphur, which becomes corrosive when
wet).
NOTE: Before installing underground tanks, check local surface
water conditions. Where potential problems exist, concrete
anchors should be provided.
FUEL OIL DELIVERY SYSTEMS
FOR SINGLE FUEL BURNERS
General
Three methods for delivering oil to the individual burners are
described herein. These methods are chosen to provide tempered,
filtered and air-free oil to the individual burners. Consistent oil
quality will optimize burner operation over longer periods.
There are variations to the methods described herein which, if
applied properly, will result in acceptable operation. These methods
are for reference only. Local codes vary. It is important to check all
codes for compliance.
Information herein has been compiled using data from industry
sources, including companies such as Mitco, Webster, Suntec and
Tuthill. For additional information on these products, contact the
representative in your area.
MFG data and safety codes vary with regard to maximum fuel unit
inlet pressure. Pay particular attention to the gravity oil head. Be
sure to add oil pressure reducing valves in the event that codes or
MFG data will be exceeded. 5 psi is equivalent to approximately 12
feet in height. (See "H" dimension.)
Storage tank above burners (Figure 15)
A simple one pipe connection from the supply tank to each burner
helps to eliminate air in the oil line and tempers the oil in the pipe
as it travels slowly to the burners.
FUEL OIL PIPING
Figure 14. Typical example of properly installed
underground fuel tank