1. Thailand Economy report on rice moisture meters Warachai Triarun Weights and Measures Officer Central Bureau of Weights and Measures APLMF Training Course on Traceability in Rice Moisture Measurement 25 - 29 November, 2013 Imperial Mae Ping Hotel, Chiang Mai, Thailand

2. Rice production in Thailand Rice production in Thailand represents a significant portion of the Thai economy labor force. Thailand has a strong tradition of rice production. It has the fifth-largest amount of land under rice cultivation in the world and is the world's second largest exporter of rice. Rice growing areas around 9.2 million hectares. Paddy yield around 30 million tons per year The most produced strain of rice in Thailand is jasmine rice, which is a higher quality type of rice. However, jasmine has a significantly lower yield rate than other types of rice, but it also normally fetches more than double the price of other strains in a global market. Source: Wikipedia

3. Thai rice production Source: United States Department of Agriculture (USDA) MT

4. Thai rice trade system Paddy 55% 45% 25% 10% 65% 30% 35% 10% 35% 2% 22% 3% 5% 20% 30% 10% 35% Farmers Paddy traders Local brokers Millers Agricultural cooperatives Government agencies Exporters Brokers Wholesalers Retailers Export market Domestic market Milled rice Source: Thai Rice Exporters Association, 2010

5. Importance of rice moisture meters The paddy trade is based on weight but the buyers will measure the moisture content of paddy to determine the price of paddy, If the moisture content is above the set limit of safe storage at 15% wet basis, the buyers will reduce the weight of paddy to compensate for the drying cost and weight loss after the drying, – if the moisture content of paddy does not exceed 15 %, the farmer will receive full payment without the weight reduction. – if the moisture content of paddy exceeds 15 %, the weight of paddy is reduced by 15 kg per 1,000 kg for every percent exceeding 15 %. If the rice moisture meters have a 1 % error, this will cause a loss or gain of about 6.75 USD per ton (1 ton = 450 USD), Thus the accuracy of rice moisture measurement contributes to fair trade.

6. Laws The laws concerning the rice moisture meters used in trade transactions consisting of: 1.Weights and Measures Act 1999 Section 25 In selling, purchasing or exchanging commodities with others, providing weighing and measuring services, or using weighing and measuring instruments for the purpose of calculating remuneration, taxes and revenues and fees, no person shall use any weighing and measuring instrument not verified under Section 30 of the verification has expired under Section 33, whether or not it is a weighing and measuring instrument exempted by the Ministerial Notifications under the second paragraph of Section 29.

7. Laws Section 34 The operators of the following businesses shall submit their weighing and measuring instruments to the competent officer for verification under Section 30 within the time period prescribed under Section 36 : 1)The manufacturers of weighing and measuring instruments, except the manufacture for exports under Section 65 ; 2)The importers of the weighing and measuring instruments which have not been verified ; 3)The sellers of weighing and measuring instruments which have the instruments which have not been verified in possession ; 4)The repairers of weighing and measuring instruments.

8. Laws 2.Ministerial regulation no.2 2004 Article 55/6 Maximum Permissible Errors for rice moisture meters Article 89 Rice moisture meters are required to be re-verified every 2 years. Standards MPEs VerificationInspection Standard rice sample moisture content  16% 0.8 % in moisture content 1.0 % in moisture content moisture content  16% 0.05 of the percent moisture content 0.06 of the percent moisture content Standard rice moisture meter 0.8 % in moisture content 1.0 % in moisture content

9. Legal metrology control system verification and inspection verification and inspection verification and inspection NEWMC lab /calibration CBWM lab /calibration NWMC lab /calibration NEWMC and branch offices 1 unit/place, total 8 units NWMC and branch offices 1 unit/place, total 8 units + CBWM lab /calibration = = = = CBWM 3 units NEWMC 2 units Reference standard Working standard NWMC 2 units Commercial meter Commercial meter Commercial meter Working standard Commercial meter Commercial meter CBWM, EWMC, SWMC and branch offices 1 unit/place, total 16 units Reference standard Oven dry method Oven dry method Standard sample set Reference standard Northern region Central, Eastern and Southern region Northeastern region CBWM: Central Bureau of Weights and Measures EWMC: Eastern Weights and Measures Center NWMC: Northern Weights and Measures Center SWMC: Southern Weights and Measures Center NEWMC: Northeastern Weights and Measures Center

10. Oven dry method Following the international standard ISO 712-1998 (E) Laboratory conditions – Temperature 25 ± 2 o C – Humidity 50 ± 10 % Instruments – Electric grinding mill, not absorb moisture, not generate heat and not in contact with the outside air during the grinding process – Analytical balance, maximum capacity 220 g, resolution 0.1 mg – Fan forced oven, temperature stability and uniformity ≤ ± 0.5 o C

11. Oven dry method Procedure – Grind the test sample having the particle size less than 1.8 mm. without pre-conditioning before grinding, if the moisture content of test sample  15 o C with pre-conditioning before grinding, if the moisture content of test sample  15 o C – Weight the test sample before drying in the oven – Dry the test sample in the oven at 130 o C for 2 h – Cool down the test sample in the desiccator after completing the drying – Weight the test sample after drying in the oven

12. Oven dry method Calculation and expression of result without pre-conditioning w = (1 – (m 1 /m 0 )) x 100 % with pre-conditioning w = (1 – ((m 1 /m 0 ) x (m 3 /m 2 ))) x 100 % where w is the moisture content based on wet basis, % m 0 is the mass of the test sample before drying, g m 1 is the mass of the test sample after drying, g m 2 is the mass of the test sample before pre-conditioning, g m 3 is the mass of the test sample after pre-conditioning, g

13. Oven dry method Uncertainty source of uncertainty uncertainty contribution without pre-conditioning with pre-conditioning weighing mass of test sample before drying0.002 % weighing mass of test sample after drying0.002 % weighing mass of test sample before pre-conditioning-0.001 % weighing mass of test sample after pre-conditioning-0.001 % repeatability of moisture measurement of test sample0.043 %0.058 % oven capability to dry test sample0.043 % moisture loss in the grinding process of test sample0.010 % combined uncertainty0.062 %0.073 % expanded uncertainty, k=2 0.124 % (  0.13 %)0.146 % (  0.15 %)

14. Standard sample set Following the international recommendation OIML R59 Standard sample set used for developing the calibration curve of rice moisture meters and making the calibration of reference and working standards is as the following conditions -Variety: Khao Dowk Mali 105 (Jasmine rice) -Growing place: Northern region and Lower northeastern region -Moisture condition: Natural moisture content -Moisture adjusting method: Drying in room temperature for decreasing high moisture content to 20 % Drying in oven at 40 o C for decreasing moisture content from 20 % to 16 % Drying in oven at 60 o C for decreasing moisture content from 16 % to 12 % Not use moistening method

15. Standard sample set 1. collect the sample at high moisture content as harvesting 2. clean the sample by winnower 3. dry the sample in the room temperature4. homogenize the sample moisture by rolling machine

16. Development of calibration curve of rice moisture meters Objectives -To develop the accuracy of rice moisture meters to higher level with Thai rice. -To provide the high accuracy reference and working standards using for verification and inspection.

17. Development of calibration curve of rice moisture meters New calibration curve of auto hopper type

18. Development of calibration curve of rice moisture meters New calibration curve of manual hopper type

19. Calibration of reference standard rice moisture meter Procedure – Adjust the temperature of the samples and the reference standard until stabilized at the laboratory temperature. Simultaneously measure the moisture content of the samples by the oven dry method and the reference standard. Uncertainty source of uncertaintyuncertainty contribution variance of reference standard reading error * 0.368 % limited resolution of reference standard0.029 % sample moisture determination by oven dry method0.075 % combined uncertainty0.377 % expanded uncertainty, k=2 0.754 % (  0.8 %) Note The variance of reading error in the measuring range between 15% - 25% of the reference standard model PM-499(4166) auto hopper type.

20. Calibration of working standard rice moisture meter Procedure – Adjust the temperature of the samples, the reference standard and the working standard until stabilized at the laboratory temperature. Measure the moisture content of the samples using the reference standard and the working standard continuously. Uncertainty source of uncertaintyuncertainty contribution variance of working standard reading error * 0.200 % limited resolution of working standard0.029 % uncertainty of reference standard0.377 % repeatability of reference standard0.032 % limited resolution of reference standard0.029 % combined uncertainty0.430 % expanded uncertainty, k=2 0.860 % (  0.9 %) Note The variance of reading error in the measuring range between 15% - 25% of the working standard which is the same model with the reference standard.

21. Verification and inspection of commercial rice moisture meter Procedure – Adjust the temperature of the samples, the working standard and the meter under test equally about 30 min. Measure the moisture content of the samples using the working standard and the meter under test continuously. – Maximum Permissible Errors for verification   ± 0.8  % for inspection   ± 1.0  % importer checks the capacitance reading of meters importer checks the weight reading of meters weights and measures officer tests the accuracy of meters

22. Example: Accuracy test of the verification process testing range working standard reading before measuring meter under testmpe time 1time 2time 3time 4time 5average – 0.8 % average + 0.8 % 15 % - 20 %15.015.215.015.2 15.114.315.9 20 % - 25 %24.524.724.924.724.524.723.925.5 25 % - 30 %28.728.529.028.528.7 27.929.5 testing range meter under test readingresult time 1time 2time 3passfail 15 % - 20 %15.215.015.2/ 20 % - 25 %24.924.7 / 25 % - 30 %28.328.528.7/ testing range working standard reading after measuring meter under test  ave   ave   0.2 % time 1time 2time 3time 4time 5averagepassfail 15 % - 20 %15.015.215.0 15.1 0.0/ 20 % - 25 %24.324.724.5 24.724.50.2/ 25 % - 30 %28.5 28.728.528.728.60.1/

23. Statistics 2013

24. Future plans Substitute the reference and working standards in the control system to new calibration curve of auto hopper type completely in 2013. Revise the ministerial regulation no.2 2004 to conform to new edition of OIML R59 in 2014. Draft the ministerial regulation for corn moisture meters in 2014.

25. Thank you for your attention