Canola and rapeseed: Determination of dockage
Dockage is assessed and recorded to the nearest 0.1%.
Dockage is defined under the Canada Grain Act as “any material intermixed with a parcel of grain, other than kernels of grain of a standard of quality fixed by or under this Act for a grade of that grain, that must and can be separated from the parcel of grain before that grade can be assigned to the grain”. Dockage is removed by following the cleaning procedures described in this section of the manual.
The sample as it arrives is referred to as the uncleaned or dirty sample. Its weight is the gross weight of the sample. Dockage is assessed on the gross weight of the sample.
Dockage is assessed in two stages.
- Follow Normal cleaning procedures, using the Carter dockage tester.
- Follow procedures for Cleaning for grade improvement. This cleaning can be done at any time after the cleaning assessment has been completed.
Dockage not reported
Important: Dockage is not reported for
- Canola, Sample Canada Account Fireburnt
- Canola, Sample Salvage
- Canola, Sample Condemned
- Unofficial samples declared as processed
Normal cleaning procedures
Important: Wear gloves and a mask to handle any sample which you suspect may contain hazardous substances.
- Set up the Carter dockage tester as follows:
Carter dockage tester specifications Feed control Number 3 Air control Number 5 Riddle Number 000 Top sieve Blank tray Centre sieve None Bottom sieve None Sieve cleaner Off
- You also need the following hand sieves:
Carter dockage tester specifications Round-hole sieves Slotted sieve No. 5 No. .028 No. 5.5 No. 6 No. 6.5 No. 7 No. 7.5
- Using a Boerner-type divider, divide the uncleaned sample to obtain a representative portion.
- Official samples shall be at least 1 kg.
- Unofficial samples shall be at least 1 kg.
- For hand sieving use approximately 250 g per sieving
- Select the appropriately sized round hole sieves.
- When you use the slotted hand sieve, move the sieve from left to right 30 times, using a sifting motion. One time is one complete motion from the centre to one side, to the other side, and back to the centre. The total distance from left to right is 20 cm, or about eight inches.
- Sieve each portion over the round-hole sieve that will allow reasonably sound canola to pass through the sieve while removing large material.
- Sieve each portion over the .028 slotted sieve 30 times, as described above.
- Combine the separated, cleaned 250-g portions.
- Turn on the Carter dockage tester.
- Run the entire working sample through the Carter dockage tester for aspiration only.
- Using a Boerner-type divider, divide the sample to a portion of not less than 10 g.
- Analyze the 10-g portion to determine the percentage by weight of conspicuous admixture and soft earth pellets.
- Determine the dockage, using the list under Composition of dockage.
Composition of dockage
- Material that remains on top of the round-hole sieve
- Material that passes through the .028 slotted sieve
- Material removed by aspiration
- Material that passes over the Number 000 riddle
- Conspicuous admixture, up to established grade tolerances, handpicked from the cleaned sample
- In Canola, Rejected (grade) Account Stones, dockage includes Conspicuous admixture handpicked from the cleaned sample up to the tolerance for the grade of the sample.
- In Sample grades, Conspicuous admixture is not included as dockage. When the weight of the Conspicuous admixture exceeds 2.0% of the net weight, the Conspicuous admixture becomes a second reason for the sample grade. This is recorded in Remarks.
- Soft earth pellets handpicked from the cleaned sample
- Material removed by Cleaning for grade improvement
Primary elevator samples, commercially clean
Commercially clean samples exiting primary elevators can have up to 0.5% for broken and reasonably sound canola or rapeseed deducted from the gross weight of the dockage. There is no deduction applicable to producer deliveries or submitted samples.
Samples exiting primary elevators are considered commercially clean when meeting the requirements set out in the table below after following Cleaning Procedures.
|Material other than canola remaining on top of the round-hole sieve and over number 000 riddle %
|Total net dockage %
|Roughage material such as wild oats, seed pods, knuckles
|number 1 Canada
|number 2 Canada
|number 3 Canada
Primary elevator samples, not commercially clean
In not commercially clean samples exiting primary elevators, there is no allowance for broken and reasonably sound canola or rapeseed. All the material removed by the slotted sieve is assessed as dockage.
Cleaning for grade improvement
If the grade of a sample can be improved by additional cleaning, perform the cleaning and add the additional material to dockage. Cleaning for grade improvement can be done at any time after the cleaning assessment has been completed, including on export.
- After the cleaning assessment has been completed, examine the material to be removed and select your equipment according to the material you want to remove. See the table Cleaning for grade improvement—Canola for the list of equipment.
- Sieve the sample by hand or pass it through the Carter dockage tester, depending on the material. When using a slotted sieve, select the sieve that will reduce the admixture of conspicuous inseparable material to within the grade tolerance with a minimum loss of reasonably sound canola.
Note: Canola seeds that do not meet the definition of Damage as defined in the Grading factors section of this chapter are considered to be reasonably sound.
Important: When you use a slotted hand sieve, move the sieve from left to right 30 times, using a sifting motion. One time is one complete motion from the centre to one side, to the other side, and back to the centre. The total distance from left to right is 20 cm, or about eight inches.
- Weigh the additional dockage and add it to the original dockage.
|Material to be removed
|Effect on composition of dockage
|Conspicuous admixture or damaged seeds
|No. .032 slotted hand sieve
No. .035 slotted hand sieve
No. .038 slotted hand sieve
No. .040 slotted hand sieve
Carter dockage tester as described in Normal cleaning procedures but with air setting at # 7, or alternate round-hole sieves.
Note: The material originally removed by aspiration is to be reconstituted back into the sample prior to cleaning for improvement.
|Damaged seeds and other material, including canola, are added to dockage. Not more than 5.0% of sound canola may be removed for each single grade improvement achieved.
Cleaning sample grade canola
For canola that qualifies only for Sample Canada, Account Admixture after cleaning for grade improvement, dockage is assessed using the number .035 slotted sieve, the round-hole sieve appropriate for the admixture, and the Carter dockage tester with air control set at number 5.
For canola that qualifies only for Sample Canada, Account Damaged after cleaning for grade improvement, dockage is assessed using the appropriate round-hole and slotted sieves and the Carter dockage tester with air control set at number 5. Use the slotted sieve appropriate for removing material consisting mainly of weed seeds and small broken grain. Also consider the maximum tolerance for inseparable admixture for these samples.
Important: Variations from the above settings require authority from the Chief Grain Inspector.
Where a shipper requests special cleaning of a carlot of grain at a terminal elevator, and the elevator manager agrees, dockage material will be analyzed for the presence of grain. The percentage and grade of any grain contained in the dockage will be reported.
- Analyze the official sample.
- Record the following on inspection records:
- The percentage by gross weight to the nearest 0.1% and the grade of canola.
- The percentage by gross weight to the nearest 0.1% and the grade of grain separable from dockage.
- The percentage of dockage.
- 95.0% Canola, number 1 Canada
- 4.0% Barley, number 1 Canada Western
- 1.0% dockage
- Date modified: