Canada Standards Association C282-09
CSA Required Testing
CSA guideline 282-09 states as a minimum all fuel supplied to emergency generator sets shall be clean, clear, bright and tested annually as part of your annual fuel oil inventory maintenance program. If the fuel fails the test, the tank shall be flushed to remove built-up sludge and impurities. Unfortunately, draining the fuel without cleaning the tank leaves behind a layer of microbial growth on the tank walls and bottom. Adding fresh fuel feeds the organisms that flourish their growth.
CSA guidelines call for the fuel to be full-filtered to remove water, scale, bacteria growth and oxidization (gums/resins) to minimize fuel filter clogging. Ambiguity arises because the CSA testing (Clear and Bright Test) assumes that all water and all particulate will be removed through full filtration. However, the only way to be sure that your fuel is fully filtered is to perform an independent lab analysis on your fuel to guarantee the filtration process is complete.
Common interpretation of the above regulation has some sites burning off their excess fuel just before their annual testing/maintenance. True, turning over fuel is beneficial if done regularly, but doing it just before the annual testing/maintenance to meet code requirements is increasing the chance of a fuel issue, not mitigating them. Further, you are operating equipment with no real benefit to the business and generating additional emissions. New fuel acts as fresh food for the organisms and the creation of ideal conditions for a microbial bloom. This excess growth can mix with the fuel and overpower generator lines and/or filters.
Excerpt from the Canada Standards Guide pertaining to stored diesel fuel maintenance and code compliance:
The fuel shall meet the engines manufacturer’s specifications. Note: (see clause B.10for commentary on this Clause)
11.5.5 visual Inspection of fuel (clear and bright test)
All fuel supplied to the emergency generator set shall be clean and clear and bright as specified in clause 188.8.131.52. Immediately upon completion of the annual fuel oil inventory maintenance specified in Table 5, the fuel oil shall be tested to verify that it is clear and bright. If the fuel fails the test, the tank shall be flushed to remove built-up sludge and impurities. Note: The purpose of this test is to detect possible water and solid contamination in diesel fuel by visual inspection. The test method is based on ASTM D4176.
The fuel shall be placed in a transparent bottle or container (see Clause 184.108.40.206) and examined to determine whether it is clear and bright. Samples for the clear and bright test shall be obtained from the bottoms of the storage and day tanks.
A dry, capped, clear glass bottle or container capable of holding 250 to 1000 ml of liquid shall be used. The bottle or container shall have a clear, undistorted bottom and be thoroughly washed before the test.
The following procedure shall be followed:
a) Wash the fuel sample bottle or container before gathering each sample.
b) Let the sample settle for 1 minute to remove air bubbles.
c) Observe the sample against a light background for a clear and bright condition. Swirl the bottle or container to create a vortex (free water and solids tend to collect beneath the vortex).
220.127.116.11 Interpretation of the test results
The samples shall be clear and bright. The visual clarity shall be recorded as clear and bright or not clear and bright. It shall be recorded whether particulate matter or water was seen at the bottom of the vortex. Note: the tern “clear and bright” has no relation to the natural fuel oil colour. Fuel oil colour varies from water white, to straw colour, to amber, depending on the processing and/or crude source. Clear and bright fuel has no floating or suspemded matter. Brighteness is a quality independent of the sample colour and refers to the lack of suspended or free water in sample. Bright fuel tends to sparkle.
Note: The following is an excerpt from table 5 concerning diesel fuel storage tanks and not the table in its entirety.
Annual inspection, test, and maintenance requirements(See clause B.22)
4. Diesel fuel storage tank(s)
The fuel oil in any storage tank (and day tank , if used) shall be tested in accordance with clause 11.5.5, and if the fuel oil fails the test, it shall be
a) Drained and refilled with fresh fuel in accordance with article 18.104.22.168 of the National Fire Code of Canada, or
b) Full filtered to remove water, scale, bacteria, and oxidized gums/resins in order to minimize filter clogging and ensure diesel start-up (see clause B.22 for commentary).
When the fuel is filtered, it shall be treated with a suitable conditioner and stabilizer to minimize degradation while in storage. Note: The bottom(s) of the tank(s) shall be also tested chemically for water.
B.22 (Table 5, Item 4(b))
Diesel fuel has a limited storage life depending upon initial fuel quality, contaminant levels, and storage conditions. To extend fuel life, it is recommended that periodic filtering and treatment of the fuel be conducted to remove water, scale, and bacterial growth.
Where possible, fuel stored outdoors and supplying emergency generator sets should be non-seasonal to avoid pour point and cloud point issues associated with long-term diesel storage.
When fuel is being filtered, the following procedures should be followed:
a) The fuel should be filtered to a maximum particulate size of 20 µ, and the filter media should be capable of removing water.
b) The fuel (if it is being recirculated in the same tank when being filtered) should be filtered for a period of time at least three times longer than the period necessary to process the volume of fuel in the tank once. For example, if the volume of fuel is X and the filter unit will process X volume in 30 minutes, the filter unit should be run for at least 1.5h. This will achieve a reasonably good level of filtration. At the same time, an effort should be made to agitate the fuel and any contamination at the bottom of the tank to ensure treatment.
c) Provision should be made by the designers and installers of the fuel tanks(s) for easy access to the fuel by the filter unit suction and return probes, with sufficient overhead clearance above the tank(s) and also suitable blank plugs or similar devices in the top(s) of the tank(s) for the probes to be easily inserted without extensive work.