Procedure Instruction of program Pressurized Enclosure - Test Round 2017 Provider: Physikalisch-Technische Bundesanstalt Address: Bundesallee 100 38116 Braunschweig Country: Germany Place, date Braunschweig, 2018-05-07 Author: Released by: Document-ID: Lisa Zater M.Eng. Tim Krause M.Eng. PI-PE2017-A4 PTB Working Group 3.54 2018-05-07 Page 1 of 31
This fourth edition (PI-PE2017-A4) cancels and replaces the third edition (PI-PE2017-A3), published in April 2018. The changes between the procedure instruction PE Edition 4 and Edition 3 are as listed below: Explanation of the significance of the changes Clause/Figure/Table Update of coordinates of measuring points Table 2 Addition of tolerance when checking position of measuring points: Check if all measuring point tubes are still attached to their intended position (See Table 2, tolerane: ± 20 mm). If not, please adjust accordingly and note in PE Test Setup. See section 4.1 Point 2. Addition of Figure 3 Position of inlet and outlet Figure 3 PTB Working Group 3.54 2018-05-07 Page 2 of 31
Content 1 General Performance... 4 2 Measurand / Characteristic of interest... 4 3 Test Item and Configurations... 4 3.1 Components... 5 3.1.1 Test setup example... 7 3.1.2 Position of measuring points... 8 3.2 Homogeneity and Stability... 9 3.2.1 Homogeneity test... 9 3.2.2 Stability... 9 3.3 Identification... 9 4 Procedure... 10 4.1 First steps before starting the measurement... 10 4.2 Flowchart for leakage rate measurement... 11 4.3 Flowchart for filling (measurement of CO 2)... 12 4.4 Flowchart for purging (measurement of CO 2)... 14 4.5 Flowchart for filling (measurement of He)... 16 4.6 Flowchart for purging (measurement of He)... 18 5 Data acquisition and Transmission... 20 5.1 Records and additional documentation... 20 6 Additional Instructions... 21 7 Data analysis and evaluation... 21 8 Reporting... 21 9 Annex... 23 9.1 Example of filled in templates... 23 PTB Working Group 3.54 2018-05-07 Page 3 of 31
1 General Performance In the program Pressurized Enclosure, the quantity selected which is to be compared (measurand of interest), is the gas concentration (CO 2 and He). As already mentioned in the "Roll Out Paper", the general routine procedure is described by the standard Explosive atmospheres Part 2: Equipment protection by pressurized enclosure p - IEC 60079-2 Edition 6. This type of ignition protection prevents the formation of an explosive atmosphere inside an enclosure by maintaining an internal overpressure against the surrounding atmosphere. This can be achieved by means of an ignition protective gas and, if necessary, supplying the interior of the housing with ignition protection gas in such a way that the dilution of combustible mixtures is reached. The measurement of dilution and determination of gas concentration is therefore an important aspect of testing pressurized enclosures and thus the quantity to be compared for the program PE. The general routine procedure to perform dilution tests and measure the gas concentration is described in clause 16.4 of IEC 60079-2. The measurand of interest is the gas concentration (CO 2 and He) and the participants are asked to indicate whether a certain gas concentration is reached or not reached at each measuring point. The PE program consists of 3 parts: A maximum leakage rate test and two dilution tests (one with CO 2 and one with Helium as the test gas). Each of these two dilution tests consists of a filling phase with the test gas and a purging phase with air. There are seven measuring points predefined by the coordinator and three additional measuring points for personal configuration. As an add on, the participants are asked to identify and indicate the worst case measuring point for each of the two dilution tests. The workload to perform this program is approximately three working days. 2 Measurand / Characteristic of interest The measurand of interest is the gas concentration (CO 2 and He). This is the quantity selected which is to be compared in the program. 3 Test Item and Configurations To ensure comparability and homogeneity, all PE Test Samples are completely developed and prepared by the coordinator. Every participating laboratory of the Pressurized Enclosure program will receive all components of the PE Test Sample, which are needed to perform the program, directly from the coordinator. PTB Working Group 3.54 2018-05-07 Page 4 of 31
3.1 Components The test sample is a 600 x 400 x 300 mm enclosure (see Figure 1). It contains components with different geometries that shall represent the setup of p enclosures. The test sample PE has an inlet and outlet for the gas flow. A few measuring points will be predefined by the coordinator. Additionally, the participant can add own measuring points in critical areas to identify the worst case measuring point. Table 1: List of components of PE Test Sample No. Component description Quantity 1 Enclosure (Sheet steel distribution cabinet, body 1.5 mm, door 1.5 mm) 1 2 Components (8 plates and 2 angle plates, material: aluminium, 1.0 mm) 10 3 Cable duct (material: length 140.00 mm) 1 4 PG gland 10 5 PU-tube (diameter: 6 mm, length: 10 x 2 m, 2 x 1 m) 12 6 Pressure regulator M5, 0,2-2 R 1 7 quick-action fitting CK-M5-PK-4 3562 2 8 Festo push-on caps 10 9 Elbow gland (inlet, outlet) 2 10 Cable clips (10+3) 13 11 Key 1 Total 61 PTB Working Group 3.54 2018-05-07 Page 5 of 31
120,00 100,00 80,00 120,00 180,00 120,00 600,00 40,00 80,00 120,00 100,00 100,00 180,00 140,00 60,00 PTB Ex PT Scheme 400,00 160,00 120,00 120,00 25,00 320,00 320,00 120,00 80,00 40,00 120,00 20,00 20,00 Figure 1: Drawing of enclosure with components PTB Working Group 3.54 2018-05-07 Page 6 of 31
3.1.1 Test setup example Figure 2: Test setup example Figure 3: Position of inlet and outlet PTB Working Group 3.54 2018-05-07 Page 7 of 31
3.1.2 Position of measuring points Figure 4: Position of measuring points Measuring point 1 2 3 4 5 6 7 Table 2: Coordinates of measuring points Height Width depth y x z y x z y x z y x z y x z y x z y x z Coordinates in mm 585 70 65 10 370 135 290 330 95 190 20 120 470 390 150 80 250 150 490 60 80 PTB Working Group 3.54 2018-05-07 Page 8 of 31
3.2 Homogeneity and Stability To ensure homogeneity and stability in accordance with ISO/IEC 17043, homogeneity tests are carried out for each test sample before sending it to the participants. 3.2.1 Homogeneity test The homogeneity test consists of a visual check to control the processing of the sample and a linear measurement to control the geometry and dimensions of the respective components. The following parameters have been checked to assure homogeneity: - Visual check - Position of measuring points (See Section 3.1.2) - Dilution measurements identification of each Test Sample s fitting purging times (See individual Annex in Mail) - leakage rate measurement The tolerances of the parameters have been determined related to preliminary tests performed at PTB. Scattering within the range of tolerance has no measurable influence on the gas concentration. Please note: To comply with the parameters to be reached, each PE Test Sample has been assigned with suitable individual purging times. These individual purging times (PC1, PC2, PC3, PH1, PH2, PH3) will be sent to each participant as an Annex in an individual Email. Please reply to this Email to let us know that you have received your individual purging times, which are essential for performing the PE program. 3.2.2 Stability Due to the robust construction of the test sample and the used high-quality materials, long-term stability can be assumed. Furthermore, preliminary investigations and extensive measurement series on the test sample have not caused any changes in the geometry. Therefore, no further special stability test has been performed. 3.3 Identification Each PE Test Sample is marked with an unique identification number. The identification number is structured as follows: Figure 5: Structure of identification number of PE Test Sample PTB Working Group 3.54 2018-05-07 Page 9 of 31
4 Procedure To perform the program, the individual routine procedure of each test laboratory needs to be applied (used every day for achieving the test results for real projects). Additionally, detailed guidance how to perform the tests together with the test samples provided in this paper is to be applied. The test method for program Pressurized Enclosure Test Round 2017 consists of four parts: 1. Determination of leakage flow rate according to IEC 60079-2, Clause 16.3.1 2. Filling with CO 2 until concentration of 70 % is reached at each measuring point. Purging with air until concentration of CO 2 is less than 0.25 % (IEC 60079-2, Clause A.2) according to IEC 60079-2, Clause 16.4. 3. Filling with He until concentration of 70 % is reached at each measuring point. Purging with air until concentration of He is less than 1 % (IEC 60079-2, Clause A.2) according to IEC 60079-2, Clause 16.4. 4. Determination of worst case measuring point. This can be performed with additional measuring points (8, 9 and 10) either simultaneously during part 2 and 3 (Purging with CO 2 and He) and/or at own defined purging times. The following program flowcharts show the single steps for the performance of the tests for program Pressurized Enclosure Test Round 2017. 4.1 First steps before starting the measurement 1. Check if enclosure and additional equipment has been damaged during shipment (deformed tubes, loose rivets, broke off parts, etc.). Contact us if this is the case. 2. Check if all measuring point tubes are still attached to their intended position (See Table 2, tolerane: ± 20 mm). If not, please adjust accordingly and note in PE Test Setup. 3. Check if you have received Email with individual purging times. 4. Check supplied pressure regulator. If the pressure is not set at 0.3 bar, adjust accordingly with incoming pressure of 2 bar until outcoming pressure of pressure regulator is 0.3 bar ± 0.01 bar. Please note in PE Test Setup (photo) and PE Test Record (comments). 5. When performing part 4 Determination of the worst case measuring point the participants can use measuring points 8, 9 and 10 either during their test 2 and 3 and/or perform additional tests with own defined purging times. This should be noted and described in Table 7 of the PE Test Record. PTB Working Group 3.54 2018-05-07 Page 10 of 31
4.2 Flowchart for leakage rate measurement Start 1. Record gas humidity and temperature 2. Close outlet. 3. Adjust the pressure to 10 mbar. 4. Measure the leakage flow rate at inlet. End Figure 6: Flowchart for leakage flow rate measurement Table 3: Explanations of the flowchart for the measurement of leakage flow rate Step Explanation Note 1 The recording of the temperature and humidity of the incoming gas can be helpful for further analysis of the test results. ; 2 To measure the leakage rate, the outlet has to be closed. See IEC 60079-2, Section 16.3.1 3 The pressure is to be set at 10 mbar. 4 After step 2 and 3 the leakage flow rate can be measured at the inlet. ; PTB Working Group 3.54 2018-05-07 Page 11 of 31
4.3 Flowchart for filling (measurement of CO2) Start 1. Record gas pressure, humidity and temperature 2. Connect test gas (CO 2) to inlet. 3. Keep all measuring gas tubes closed 13. Open enclosure door to and wait for 1 min until gas has exchanged. Close door. 4. Open outlet 5. Check and record incoming pressure after pressure regulator (0.3 bar) 6. Fill for 3:00 min 7. Close incoming test gas and outlet 8. Measure gas concentration starting at measuring point 1 12. Measurement has to be repeated with 30 sec added to previous filling time 9. Is gas concentration (CO 2) of 70% reached? No Yes 10. Switch one by one to each of the 7 measuring points. 11. Is gas concentration (CO 2) of 70% reached at all measuring points? No Yes End Figure 7: Flowchart for filling (measurement of CO 2) PTB Working Group 3.54 2018-05-07 Page 12 of 31
Table 4: Explanations of the flowchart for filling with CO 2 Step Explanation Note 1 The recording of the temperature, humidity and pressure of the incoming gas can be helpful for further analysis of the test results. ; 2 Connection of test gas (CO 2) to the inlet. See section 3.1.1 3 To prevent unpredictable gas flow, all measuring tubes have to be See section 3.1.1 closed during filling. 4 For gas exchange during filling, the outlet has to be opened. For See section 3.1.1 safety reasons it is advised to direct the outcoming gas outside. 5 The provided pressure regulator has been set to 0.3 bar at an incoming pressure of 2 bar. Please check and record the pressure in the PE test record. See section 3.1.1 6 The filling time for CO 2 is 3:00 min. Start the timer as soon as 0.3 bar have been reached. 7 Closing of incoming test gas and outlet after the filling time of CO 2 has elapsed. See section 3.1.1 8 Measurement of each of the seven (or ten) measuring points. Starting with measuring point 1. Please make sure to measure in the exact order (1, 2, 3, 4, 5, 6, 7, (8), (9), (10)) and start directly after filling. Make sure to not measure for a longer period than 2:00 min per measuring point. The total time period for the measurement should therefore not exceed 20:00 min. 9 The measurement for each measuring point is to be stopped when a) the gas concentration (CO 2) of 70% has been reached or b) the 2:00 measuring time has elapsed. 10 Switch one by one to each of the seven (or ten) measuring points. Please make sure to measure in the exact order (1, 2, 3, 4, 5, 6, 7, (8), (9), (10)) and start directly after filling. 11 If the gas concentration (CO 2) of 70% has been reached at each of the seven measuring points, the test has been completed and the filling process was successful. 12 If the 70% (CO 2) have not been reached at each measuring point, the whole test and procedure test has to be repeated with an updated filling time of 3:00 min plus 0:30 min (=3:30 min). If the test fails again, add again 0:30 min to the last filling time (=4:00 min), and so on. Please note the final filling time (where filling was successful) in the PE Test Record. 13 Before repeating the test, open the enclosure door and wait at least for one minute until gas has exchanged and initial situation has been restored. Start again with step 2 of the program flowchart PTB Working Group 3.54 2018-05-07 Page 13 of 31
4.4 Flowchart for purging (measurement of CO2) Start 1. Record gas pressure, humidity and temperature 2. Connect air to inlet. 3. Keep all measuring gas tubes closed 4. Open outlet 5. Check and record incoming pressure after pressure regulator (0.3 bar) 6. Purge PC1 (PC2, PC3) 7. Close incoming air and outlet 8. Measure gas concentration one by one starting at measuring point 1 (7 measurement points) 9. Note in test record if gas concentration (CO 2 ) of less than 0.25 % is reached 11. Repeat test with purging time PC2 (and PC3) 10. Have all three tests with different purging times PC1, PC2 and PC3 been performed? No Yes End Figure 6: Flowchart for purging (measurement of CO 2) PTB Working Group 3.54 2018-05-07 Page 14 of 31
Table 5: Explanations of the flowchart for purging with CO 2 Step Explanation Note 1 The recording of the temperature, humidity and pressure of the incoming gas can be helpful for further analysis of the test results. ; 2 Connection of air to the inlet. See section 3.1.1 3 To prevent unpredictable gas flow, all measuring tubes have to be See section 3.1.1 closed during purging. 4 For gas exchange during purging the outlet has to be opened. For See section 3.1.1 safety reasons it is advised to direct the outcoming gas outside. 5 The provided pressure regulator has been set to 0.3 bar at an incoming pressure of 2 bar. Please check and record the pressure in the PE test record. See section 3.1.1 6 The participants individual purging time for CO 2 (PC1, PC2, PC3) can be found in your individual Annex (Mail). Start the timer as soon as 0.3 bar have been reached. 7 Closing of incoming air and outlet after the purging time of CO 2 has elapsed. 8 Measurement of each of the seven (or ten) measuring points. Starting with measuring point 1. Please make sure to measure in the exact order (1, 2, 3, 4, 5, 6, 7, (8), (9), (10)) and start directly after purging. Make sure to not measure for a longer period than 2:00 min per measuring point. The total time period for the measurement should therefore not exceed 20:00 min. 9 The measurement for each measuring point is to be stopped when a) the gas concentration (CO 2) of 0.25% has been reached or b) the 2:00 measuring time has elapsed. Note in the PE Test Record whether the gas concentration (CO 2) of less than 0.25% is reached. See individual Annex (Mail) See section 3.1.1 10 Perform the described procedure a total of three times, each with See individual Annex (Mail) a different individual purging time (PC1, PC2, PC3) 11 Repeat test with purging times PC2 and PC3. Start again with step 2 of the program flowchart PTB Working Group 3.54 2018-05-07 Page 15 of 31
4.5 Flowchart for filling (measurement of He) Start 1. Record gas pressure, humidity and temperature 2. Connect test gas (He) to inlet. 3. Keep all measuring gas tubes closed 13. Open enclosure door to and wait for 1 min until gas has exchanged. Close door. 4. Open outlet 5. Check and record incoming pressure after pressure regulator (0.3 bar) 6. Fill for 1:30 min 7. Close incoming test gas and outlet 8. Measure gas concentration starting at measuring point 1 12. Measurement has to be repeated with 30 sec added to previous filling time 9. Is gas concentration (He) of 70% reached? No Yes 10. Switch one by one to each of the 7 measuring points. 11. Is gas concentration (He) of 70% reached at all measuring points? No Yes End Figure 7: Flowchart for filling (measurement of He) PTB Working Group 3.54 2018-05-07 Page 16 of 31
Table 6: Explanations of the flowchart for filling with He Step Explanation Note 1 The recording of the temperature, humidity and pressure of the incoming gas can be helpful for further analysis of the test results. ; 2 Connection of test gas (He) to the inlet. See section 3.1.1 3 To prevent unpredictable gas flow, all measuring tubes have to be See section 3.1.1 closed during filling. 4 For gas exchange during filling the outlet has to be opened. For See section 3.1.1 safety reasons it is advised to direct the outcoming gas outside. 5 The provided pressure regulator has been set to 0.3 bar at an incoming pressure of 2 bar. Please check and record the pressure in the PE test record. See section 3.1.1 6 The filling time for He is 1:30 min. Start the timer as soon as 0.3 bar have been reached. 7 Closing of incoming test gas and outlet after the filling time of He has elapsed. See section 3.1.1 8 Measurement of each of the seven (or ten) measuring points. Starting with measuring point 1. Please make sure to measure in the exact order (1, 2, 3, 4, 5, 6, 7, (8), (9), (10)) and start directly after filling. Make sure to not measure for a longer period than 2:00 min per measuring point. The total time period for the measurement should therefore not exceed 20:00 min. 9 The measurement for each measuring point is to be stopped when a) the gas concentration (He) of 70% has been reached or b) the 2:00 measuring time has elapsed. 10 Switch one by one to each of the seven (or ten) measuring points. Please make sure to measure in the exact order (1, 2, 3, 4, 5, 6, 7, (8), (9), (10)) and start directly after filling. 11 If the gas concentration (He) of 70% has been reached at each of the seven measuring points, the test has been completed and the filling process was successful. 12 If the 70% (He) have not been reached at each measuring point, the whole test and procedure test has to be repeated with an updated filling time of 1:30 min plus 0:30 min (=3:30 min). If the test fails again, add again 0:30 min to the last filling time (=4:00 min), and so on. Please note the final filling time (where filling was successful) in the PE Test Record. 13 Before repeating the test, open the enclosure door and wait at least for one minute until gas has exchanged and initial situation has been restored. Start again with step 2 of the program flowchart PTB Working Group 3.54 2018-05-07 Page 17 of 31
4.6 Flowchart for purging (measurement of He) Start 1. Record gas pressure, humidity and temperature 2. Connect air to inlet. 3. Keep all measuring gas tubes closed 4. Open outlet 5. Check and record incoming pressure after pressure regulator (0.3 bar) 6. Purge PH1 (PH2, PH3) 7. Close incoming air and outlet 8. Measure gas concentration one by one starting at measuring point 1 (7 measurement points) 9. Note in test record if gas concentration (He) of less than 1 % is reached 11. Repeat test with purging time PH2 (and PH3) 10. Have all three tests with different purging times PH1, PH2 and PH3 been performed? No Yes End Figure 8: Flowchart for purging (measurement of He) PTB Working Group 3.54 2018-05-07 Page 18 of 31
Table 7: Explanations of the flowchart for purging with He Step Explanation Note 1 The recording of the temperature, humidity and pressure of the incoming gas can be helpful for further analysis of the test results. ; 2 Connection of air to the inlet. See section 3.1.1 3 To prevent unpredictable gas flow, all measuring tubes have to be See section 3.1.1 closed during purging. 4 For gas exchange during purging the outlet has to be opened. For See section 3.1.1 safety reasons it is advised to direct the outcoming gas outside. 5 The provided pressure regulator has been set to 0.3 bar at an incoming pressure of 2 bar. Please check and record the pressure in the PE test record. See section 3.1.1 6 The participants individual purging time for He (PH1, PH2, PH3) can be found in your individual Annex (Mail). Start the timer as soon as 0.3 bar have been reached. 7 Closing of incoming air and outlet after the purging time of H has elapsed. 8 Measurement of each of the seven (or ten) measuring points. Starting with measuring point 1. Please make sure to measure in the exact order (1, 2, 3, 4, 5, 6, 7, (8), (9), (10)) and start directly after purging. Make sure to not measure for a longer period than 2:00 min per measuring point. The total time period for the measurement should therefore not exceed 20:00 min. 9 The measurement for each measuring point is to be stopped when a) the gas concentration (He) of 1.00% has been reached or b) the 2:00 measuring time has elapsed. Note in the PE Test Record whether the gas concentration (He) of less than 1.00% is reached. See individual Annex (Mail) See section 3.1.1 10 Perform the described procedure a total of three times, each with See individual Annex (Mail) a different individual purging time (PH1, PH2, PH3) 11 Repeat test with purging times PH2 and PH3. Start again with step 2 of the program flowchart PTB Working Group 3.54 2018-05-07 Page 19 of 31
5 Data acquisition and Transmission The templates for all data, information and documentation to be recorded are made available in an electronic form on the PTB Ex PTS website. Web address: http://www.ex-proficiency-testing.ptb.de Menu items: Programs -> Program "Pressurized Enclosure" -> Download 5.1 Records and additional documentation There are two documents which are to be completed during the tests, the PE Test Record and PE Test Setup. In the document PE Test Record the following values / parameters shall be determined: Gas temperature Gas pressure (before inlet) Gas humidity Leakage rate Gas concentration: Passed/ Not passed (gas concentration has been reached /not reached) Worst case measuring point (highest gas concentration, purging not sufficient) In the document PE Test Setup the following information shall be provided: Photos showing the total setup as well as the connections used Photos showing the used measuring system to measure the gas concentration (pressure regulators, amplifier, flowmeter, gas concentration analyzer, data acquisition device / system, etc.) Photos showing the used system to check the incoming gas pressure Photos showing the test setup and measuring system to measure the maximum leakage rate PTB Working Group 3.54 2018-05-07 Page 20 of 31
The completed templates PE Test Record and PE Test Setup are to be uploaded on the PTB Ex PTS website (http://www.ex-proficiency-testing.ptb.de) in the upload area. By this, the documents are forwarded to the coordinator. Menu items: Programs -> "Pressurized Enclosure" -> Upload 6 Additional Instructions The transmitted data must be the original data. To get a better understanding for completing the documentation, a model documentation ( PE Test Record Example, PE Test Setup Example) with fictional values is enclosed in Annex 10.1. You can also find them in an electronic form on the website in the download section. (Menu items: Programs -> Program "Pressurized Enclosure" -> Download) To facilitate the data analysis please upload your PE Test Record in the given *.xls(x) format. For decimal separation, please use dots ("."). For thousands separation, please use commas (, ). Example: 1,234,567.89 The PE Test Samples are provided for the use within the PTB Ex PT Program Pressurized Enclosure Pressure - Test Round 2017. It is not intended to use the test samples for other purposes. The PE Test Sample should be kept by the participant after the performance of the tests for future programs. Participants shall always perform the tests according to the applying standard and the Procedure Instruction for PE. In addition, participants shall perform as they would do in their daily in-house routine. 7 Data analysis and evaluation The statistical methods used to analyze and evaluate the participants results are developed and documented in accordance to ISO/IEC 17043 and ISO 13528. It is documented in the reports and describes in detail the use of descriptive statistics, methods used to determine the assigned value, interpretation of the statistical analysis and criteria for performance evaluation. 8 Reporting Reports are made available electronically in compliance with the requirements of standard ISO/IEC 17043, clause 4.8. Reports include a summary of the results for all participants of the PTB Ex Proficiency Testing Program Pressurized Enclosure - Test Round 2017 in form of tabular and graphical presentations. Furthermore, the reports include detailed information like a description of the test samples used, a description of the test samples preparation and homogeneity and stability assessment, procedures used to establish the assigned values and information about procedures used to statistically analyze the data. PTB Working Group 3.54 2018-05-07 Page 21 of 31
The reporting structure is organized in two parts, an interim report and a final report. After performance of the tests the participating laboratories receive an interim report. They can analyze their results compared with the other laboratories and are invited to repeat the tests in a second phase after improvement of their procedures and instrumentation, if they are not happy with their position regarding the difference with the assigned value. After this second phase with the new uploaded results a final report will be issued. If a participant does not want to take part in the phase II session, the participants data of phase I will be used for the final report of the program. All participants are requested to handle all information and data of the reports confidentially. PTB Working Group 3.54 2018-05-07 Page 22 of 31
9 Annex 9.1 Example of filled in templates PTB Working Group 3.54 2017-11-28 Page 23 of 31
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