GASTEC QA Approval Requirement 197 Corrugated stainless steel piping systems for indoor gas installations

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1 September 2000 GASTEC QA Approval Requirement 197 Corrugated stainless steel piping systems for indoor gas installations

2 COMPANY PROFILE GASTEC NV, Centre of Gas Technology, is a technological support company with an international reputation in the field of gas technology. Gastec is engaged in research and development, consultancy, engineering, certification and training. Its customers include energy distribution companies, appliance and distribution equipment manufacturers, installers and contractors. Gastec also works for fellow researchers and institutions with a need for natural gas expertise. Gastec has about 350 employees in its subsidiaries in the Netherlands, Italy, the UK and Bulgaria. The services include advice about the procurement and sales of gas and the distribution of gas and heat. In addition, Gastec provides know-how about energy utilisations in general and natural gas utilisations in particular. Gastec tests and certifies gas technology products and quality management systems. Finally, it develops and organises specialist courses and seminars. GASTEC NV Centre of Gas Technology P.O. Box 137, 7300 AC Apeldoorn Wilmersdorf 50, 7327 AC Apeldoorn, The Netherlands Tel.: Fax: post@gastec.nl 2004, GASTEC NV, Apeldoorn All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or published, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of GASTEC NV.

3 CONTENTS PREFACE GENERAL Scope Pipe-fitting combinations References CONSTRUCTIONAL REQUIREMENTS Corrugated stainless steel pipe Dimensions and admissible tolerances Coating Tensile-resistant fittings Dimensions Connections MATERIAL Corrugated stainless steel pipe Fittings Copper alloys Stainless steel Rubber sealings Other sealing materials PERFORMANCE REQUIREMENTS Soundness of the connections at internal pressure Resistance to pressure load Bending resistance of the pipe without coating Bending resistance of the coated pipe Resistance to drop impact of the corrugated stainless steel pipe Resistance to drop impact of the coating Resistance to tensile load Pressure loss pipe Pressure loss system Repeated assembly Resistance to corrosion

4 5. TEST METHODS General Soundness of the connections at internal pressure Resistance to pressure load Bending resistance of the pipe without coating Bending resistance of the coated pipe Resistance to drop impact of the corrugated stainless steel pipe Resistance to drop impact of the coating Resistance to tensile load Pressure loss Repeated assembly Resistance to corrosion MARKING AND INSTRUCTIONS Pipe marking Fitting marking Instructions

5 PREFACE In the present paper no requirements are laid down for the permeability of coating materials. Further research on this field is necessary. Requirements on permeability may be added in future.

6 1. GENERAL 1.1 Scope The present approval requirements relate to plastic-coated flexible and pliable corrugated stainless steel pipes and matching tensile-resistant fittings for indoor gas installations. The nominal internal diameter of the corrugated pipes is 10 through 28 mm. The maximum admissible operating pressure is 200 mbar. The system is intended for indoor use at operating temperatures ranging from -20 C to +60 C. 1.2 Pipe-fitting combinations All combinations of pipes and fittings mentioned in the manufacturer s instructions must comply with all requirements in the present paper. 1.3 References In the present requirements reference is made to documents included in the list below. Unless otherwise stated the latest editions, including any appendices and revisions, apply. NEN 2541 Fittings and connections for gas conduits NEN 2542 Fittings and connections with outside thread for gas conduits NEN 2543 Fittings for soldering for gas conduits NEN 2544 Coupling nuts for fittings for gas and water conduits NEN 2545 Packing rings for fittings for gas conduits NEN 3084 Gasmeters with diaphragms; Type G 2.5, G 4, G 6 and G 10 EN 1982 Copper and copper alloys - Ingots and castings DIN Wrought copper alloys; copper-zinc alloys; (brass); (special brass); composition. EN 549 Rubber materials for seals and diaphragms for gas appliances and gas equipment 6

7 EN Stainless steels. Part 2: Technical delivery conditions for sheet / plate and strip for general purposes. ISO 7 Pipe threads where pressure-tight joints are made on the threads. Dimensions, tolerances and designation ISO 272 Fasteners; Widths across flats for hexagon products GASTEC QA Approval Requirement 6 Fittings, couplers and parts for soldered and screwed connections GASTEC QA Approval Requirement 35 Squeeze fittings for copper pipe GASTEC QA Approval Requirement 68 Metal clamp fittings for galvanised steel precision pipes GASTEC QA Approval Requirement 186 Clamp fittings for the connection of copper pipes to steel pipes 7

8 2. CONSTRUCTIONAL REQUIREMENTS 2.1 Corrugated stainless steel pipe The surface of the stainless steel pipe shall be smooth both internally and externally and shall not show any mill scale, loose oxide layers or acid residues. The pipe ends shall be smooth and square Dimensions and admissible tolerances No requirements are laid down for the dimensions of the coated corrugated stainless steel pipe. The dimensions and the admissible tolerances shall be in accordance with the manufacturer s specifications and shall be given on drawings. 2.2 Coating The corrugated stainless steel pipe shall have a yellow coating which protects the material against the impact of commonly used building materials such as concrete, mortar, plaster, etc. The coating material shall not have a detrimental effect on the corrugated stainless steel pipe. The manufacturer shall submit a written confirmation of the above properties. The coating shall be free from pores. 2.3 Tensile-resistant fittings The surfaces of the tensile-resistant fittings shall be smooth both internally and externally and shall show no blisters, pitting, notches or other defects. Sharp transitions that may have a notching effect shall be avoided. In fitting the tensile-resistant fitting, the stainless steel pipe and in particular the welded seam shall not tear. Fitting tools and aids shall not damage the pipe and tensile-resistant fitting. 8

9 2.3.1 Dimensions No requirements are laid down for the dimensions of the connection of the tensileresistant fitting with the corrugated stainless steel pipe. The dimensions of the tensile-resistant fittings and the admissible tolerances shall be in accordance with the manufacturer s specifications and shall be given on drawings. If the fitting features any spanner faces, these shall comply with ISO 272. Moreover, the height of the spanner face shall comply with the values given in Table 1. Spanner width (in mm) up to and and and and 50 55, 60, 65, 70 and 75 Minimum height of spanner face (in mm) Table A: Heights of spanner faces The wall thickness of the body of the fittings and nuts shall at least comply with the values given in Table 2. Pipe diameter DN (in mm) Minimum wall thickness (in mm) Castings Other up to and included >10 through >12 through >15 through >22 through Table B: Minimum wall thickness Connections It is permitted to provide one end of the tensile-resistant fitting with one of the following connections. The connection shall comply with the relevant requirements or standards. 9

10 - Gassound threads according to ISO 7 type R or Rp. The threads shall be smooth and have rounded crests and roots. - Compression fittings for copper pipe connections according to GASTEC QA Approval Requirement 35 - Metal clamp fittings for galvanised steel precision pipes according to GASTEC QA Approval Requirement 68 - Fittings, couplers and parts for soldered and screwed connections according to GASTEC QA Approval Requirement 6 - Union couplers according to NEN 2541, NEN 2542, NEN 2543, NEN 2544, NEN 2545 and NEN Press fittings according to GASTEC QA Approval Requirement 186. Other connections are permitted after consultation of the approval authority. 10

11 3. MATERIAL 3.1 Corrugated stainless steel pipe The pipe shall be made of a stainless steel grade corresponding to - grade X5 CrNi 18-10; material no. 1,4301 according to EN grade X2 CrNiMo ; material no. 1,4404 according to EN grade X6 CrNiTi 18-10; material no according to EN grade X6 CrNiMoTi ; material no according to EN The manufacturer shall submit a written confirmation of the above properties. 3.2 Fittings The component parts of joints and couplings shall be made of the materials below. Any materials used in joints and couplings shall not adversely affect each other Copper alloys Any copper alloys applied shall be selected from: - wrought brass CU-Zn 39 Pb3 according to DIN wrought brass CU-Zn 40 Pb2 according to DIN wrought brass CU-Zn 36 Pb1.5 according to DIN wrought brass G C4-Zn 35 according to DIN wrought brass G C4-Sn 5 Pb5 Zn5 according to DIN 1709 Or copper alloys of comparable quality. The manufacturer shall submit a written confirmation of the above properties. 11

12 3.2.2 Stainless steel Any stainless steel materials applied shall be selected from: - grade X5 CrNi 18-10; material no. 1,4301 according to EN grade X5 CrNiMo ; material no. 1,4401 according to EN grade X2 CrNiMo ; material no. 1,4404 according to EN grade X2 CrNiMo ; material no. 1,4435 according to EN grade X6 CrNiTi 18-10; material no according to EN grade X6 CrNiMoTi ; material no according to EN grade G-XS CrNiMoNb 18-10;material no according to EN The manufacturer shall submit a written confirmation of the above properties Rubber sealings If rubber seals are used, they shall comply with EN 549. The seals shall be minimally of temperature class A2 according to EN Other sealing materials Other sealing materials used, shall be resistant to gas. The manufacturer shall submit a written confirmation of the above property. 12

13 4. PERFORMANCE REQUIREMENTS 4.1 Soundness of the connections at internal pressure After assembly, the pipe and fitting shall be capable of withstanding an internal air pressure increasing from 0 bar to 1,5 bar at temperatures of -20 ºC and +60 ºC for a period of 25 min. without showing any leakage. The tests shall be carried out according to section Resistance to pressure load After assembly, the pipe and fitting shall be capable of withstanding an internal water pressure of 16 bar without showing any cracks or leakage. This test shall be carried out according to section Bending resistance of the pipe without coating After removal of the coating, it shall be possible to bend the corrugated stainless steel pipe 10 times through an angle of 180 and the corrugated stainless steel pipe and fittings shall show no leakage or kinks. This test shall be carried out according to section Bending resistance of the coated pipe It shall be possible to bend the coated corrugated stainless steel pipe 5 times through an angle of 180 and the coating shall show no pores. This test shall be carried out according to section

14 4.5 Resistance to drop impact of the corrugated stainless steel pipe The corrugated stainless steel pipe shall be capable of withstanding a drop impact caused by a striker falling perpendicular to the centre line of the pipe. Pipe and fitting will show no leakage. This test shall be carried out according to section Resistance to drop impact of the coating The coating of the corrugated stainless steel pipe shall be capable of withstanding a drop impact caused by a striker falling perpendicular to the centre line of the pipe. The coating shall show no pores This test shall be carried out according to section Resistance to tensile load After assembly, the pipe and fitting shall be capable of withstanding a longitudinally applied tensile load of 140 N per mm of internal diameter and an internal pressure of 300 mbar without showing any cracks or leakage. This test shall be carried out according to section Pressure loss pipe The manufacturer shall provide a curve describing the relationship between airflow and pressure loss per meter pipe. The curve shall cover pressure losses per meter pipe ranging from 0 to 1.00 mbar per meter. The airflow shall be expressed in standard cubic meters air (1013 mbar, 15 C) per hour. The pressure losses measured by the approval authority shall be smaller than or equal to the values measured by the manufacturer. The measurements by the approval authority shall be carried out according to section Pressure loss system The manufacturer shall provide a curve describing the relationship between airflow and pressure loss for a pipe system containing of a straight fitting with gassound 14

15 tread according to ISO 7 type R, one meter pipe and an elbow 90 fitting with gassound tread according to ISO 7 type R. The airflow shall be expressed in standard cubic meters air (1013 mbar, 15 C) per hour. The curve shall cover pressure losses for this system ranging from 0 to 1.00 mbar per meter. The pressure losses measured by the approval authority shall be smaller than or equal to the values measured by the manufacturer. The measurements by the approval authority shall be carried out according to section Repeated assembly If,according to the assembly instructions, the connection is fit for repeated assembly, it shall, after being assembled and disassembled 10 times, comply with the soundness requirements specified in 4.1. This test shall be carried out according to section Resistance to corrosion Tubing and fitting assemblies shall show no leakage after exposure to a corrosive environment. This test shall be carried out according to section

16 5. TEST METHODS 5.1 General The fittings shall be assembled in accordance with the manufacturer s assembly instructions. Tools used for assembling or disassembling fittings and pipes shall be provided to the testing authority. Unless otherwise stated, all measurements shall be carried out at room temperature 23 C ± 5 C. The test shall be carried out three times, unless otherwise stated, using a representative selection of the various sizes. Unless otherwise stated, all temperatures shall be measured with an uncertainty of ± 0,5 C. Unless otherwise stated, all pressure measurements shall be carried out with a measuring error of 5% Rdg. The specified dimensions shall be checked using measuring equipment that is fit for its purpose and has a measuring error not exceeding 0.1 mm and angles with a measuring error not exceeding 30'. 5.2 Soundness of the connections at internal pressure For this test, a straight tensile-resistant fitting shall be connected to both ends of a corrugated stainless steel pipe. The coating shall be removed. If the coating is needed for the soundness of the connection of the fitting to the pipe, the coating shall not be removed at the fitting. The distance between the fittings shall be at least 300 mm. If an other non-metallic sealing material is used than described in section 3.2.3, the connection shall be conditioned in water for 1000 h at 80 C. Otherwise no conditioning is needed. Immerse the test specimens horizontally to 100 ± 50 mm in a vessel containing a fluid with a temperature of -20 C ± 3 C and condition it for at least 1 h. 16

17 Expose the test specimens to an internal air pressure increasing from 0 bar to 1,5 ± 0,05 bar for a period of 25 min. The pipe and fittings are checked for leakage. Repeat the test at 60 C ± 3 C. 5.3 Resistance to pressure load For this test, a straight tensile-resistant fitting is connected to both ends of a corrugated stainless steel pipe. The coating shall be removed. If the coating is needed for the soundness of the connection of the fitting to the pipe, the coating shall not be removed at the fitting. The distance between the fittings shall be at least 300 mm. The corrugated stainless steel pipe is connected to a hydraulic system on one side and sealed off on the other side. The pipe is fully filled with water; making sure that the pipe is properly vented. A water pressure of 16.0 ± 0.5 bar is exerted to the system and maintained for 300 s. The pipe meets the requirement if no cracks or leakage are visible. After completion of this test, the pipe and fittings shall still be gastight in accordance with 4.1. In contrast to 4.1, the gastightness shall only be checked at a temperature of 23 ± 5 C. 5.4 Bending resistance of the pipe without coating For this test, a straight tensile-resistant fitting shall be connected to both ends of a corrugated stainless steel pipe. The coating shall be removed. If the coating is needed for the soundness of the connection of the fitting to the pipe, the coating shall not be removed at the fitting. The distance between the fittings shall be at least 300 ± 100 mm. One of the fittings is connected to a test apparatus in such a way that the top of fitting A is at equal height with the bottom of the arbors D as shown in figure A. In case of a longitudinal weld the orientation of the corrugated stainless steel pipe shall be such that the weld touches one of the arbors. The surface of the arbors shall be smooth. The diameter of the arbors D shall be in accordance with the table C below. Corrugated pipe internal diameter, DN in mm 10 through 12 >12 through 15 Arbor diameter in mm

18 >15 through 22 >22 through Table C: Arbor diameters The distance between the vertical centre lines of the arbors shall be such that the arbors come as close as possible to the corrugation of the pipe without clamping it. α Figure A: Principle of bending test A = fitting B = starting position at the beginning of the test C = position after one bending D = arbor Bend the pipe in the starting position depicted by the full lines and subsequently bend the free end from position B to position C via the dash-dotted circular arch. Angle α between positions B and C shall be 180 ± 10. Moving from B to C is regarded as one bending. Bend the pipe back from position C to position B. Moving from C to B is regarded as one bending as well. Each bending is carried out at a uniform speed in approximately 10 s. during each bending the pipe shall touch the arbor through The corrugated stainless steel pipe shall be bent 10 times. Only in case of a longitudinal weld, take a new sample. The orientation of the corrugated stainless steel pipe shall now be such that the weld is in the middle of the arbors. Again, the corrugated stainless steel pipe shall be bent 10 times. 18

19 After the bending the corrugated stainless steel pipe and fittings shall show no damage. The pipe and fittings shall still be gastight in accordance with 4.1. In contrast to 4.1, the gastightness shall only be checked at a temperature of 23 ± 5 C. 5.5 Bending resistance of the coated pipe For this test, a straight tensile-resistant fitting shall be connected to a coated corrugated stainless steel pipe. The free length of the corrugated pipe shall be at least 300 ± 100 mm. The fitting is connected to a test apparatus as shown in figure A. In contrast to figure 1, this time there shall be a vertical spacing of 50 mm between the fixed fitting and the arbors. The surface of the arbors shall be smooth. The diameter of the arbors D shall be in accordance with the table 3. The distance between the vertical centre lines of the arbors shall be such that the arbors come as close as possible to the coating of the corrugated pipe without clamping it. Bend the pipe in the starting position depicted in figure 1 by the full lines and subsequently bend the free end from position B to position C via the dash-dotted circular arch. Angle α between positions B and C shall be 180 ± 10. Moving from B to C is regarded as one bending. Bend the pipe back from position C to position B. Moving from C to B is regarded as one bending as well. Each bending is carried out at a uniform speed in approximately 10 s. during each bending the pipe shall touch the arbor through 90. After 5 bendings, the coating of the corrugated stainless steel pipe shall show no pores. The absence of pores shall be determined using a holiday detector. The detector shall be controllable and be able to supply such a voltage that the locally adjusted spark length corresponds to a base voltage of 5.0 ± 0.5 kv plus 5.0 ± 0.5 kv per mm of nominal layer thickness according the specification of the manufacturer. 5.6 Resistance to drop impact of the corrugated stainless steel pipe For this test, a coated corrugated stainless steel pipe is used with matching straight tensile-resistant fittings on both ends. The distance between the fittings shall be at least 300 mm. The coating shall be removed. If the coating is needed for the 19

20 soundness of the connection of the fitting to the pipe, the coating shall not be removed at the fitting. Place the stainless steel pipe stress-free on a flat horizontal plane. In case of a longitudinal weld, the orientation of the pipe shall be such that the weld is at equal height to the centreline of the pipe. For this test a falling weight testing machine incorporating the following basic components is used: main frame, with guide rails or a guiding tube fixed in the vertical position to accommodate a striker and means to release it to fall vertically and freely. When calibrated, the speed of the striker at the moment of hitting the steel block shall be not less than 95% of the theoretical speed; striker, having a flat round striking surface with a diameter of 25 ± 1 mm and a weight of 10.0 ± 0.2 kgf. The impact shall be evenly distributed over the pipe over a length of 70 mm. This length of 70 mm is realised by placing a rectangular steel block horizontally upon the pipe. The distance between the steel block and the fitting shall be 10 ± 1 mm. The dimensions of the block shall be 70.0 ± 0.1 mm x 70.0 ± 0.1 mm x 10.0 ± 0.1 mm. The two ribs of the block touching the pipe shall be rounded off with a radius of 2.0 ± 0.5 mm. The steel block shall be kept in position without significantly influencing the impact exerted on the pipe. From a height according to table 4 (calculated up to the horizontal plane), drop the striker on the steel block. Corrugated pipe inside diameter DN (mm) Falling height in mm ±5 mm 10 through >12 through >15 through > 22 through 28 1,000 Table 4 : Falling heights In case of a longitudinal weld, the other end of the pipe is tested as well. This time the orientation of the pipe shall be such that the weld is facing the steel block. The pipe meets the requirement if no cracks or failures are visible and if in addition the pipe and fitting are still gastight in accordance with 4.1 In contrast to 4.1 the gastightness shall only be checked at a temperature of 23 ± 5 C. 20

21 5.7 Resistance to drop impact of the coating For this test, a coated corrugated stainless steel pipe is used with a length of ± 500 mm. Place the coated stainless steel pipe stress-free on a support consisting of a 120 vee-block of length at least 200 mm, positioned so that the point of impact of the falling weight is in the axis of the vee-block or not more than 2,5 mm from this axis. For this test a falling weight testing machine incorporating the following basic components is used: main frame, with guide rails or a guiding tube fixed in the vertical position to accommodate a striker and means to release it to fall vertically and freely. When calibrated, the speed of the striker at the moment of hitting the steel block shall be not less than 95% of the theoretical speed; striker, having a hemispherical striking surface of 25 ± 1 mm diameter and a weight of 250 ± 5 gr. Condition the sample during 30 minutes at a temperature of 0 ± 2 C during 2 hours in air. During the testing, the sample shall not be outside the conditioning environment for longer than 10 seconds shall. After this reconditioning for a period of 10 minutes is necessary. Put the sample on the vee-block and drop the striker from a falling height of 500 ± 5 mm. Carry out 10 separate impacts on sites at least 30 mm apart. Test the impact sites within 30 seconds after impact with a high voltage holiday detector. The detector shall be controllable and be able to supply such a voltage that the locally adjusted spark length corresponds to a base voltage of 5.0 ± 0.5 kv plus 5.0 ± 0.5 kv per mm of the minimum layer thickness stated by the manufacturer. 5.8 Resistance to tensile load For this test, a corrugated stainless steel pipe is used with matching straight tensileresistant fittings on both ends. The distance between the fittings shall be at least 300 mm. The coating shall be removed. If the coating is needed for the soundness of the connection of the fitting to the pipe, the coating shall not be removed at the fitting. The pipe is exposed to a constant internal pressure of 300 ± 10 mbar. A tensile testing machine is used to exert for 300 s a tensile force corresponding to 140 ± 10 21

22 N per mm of internal pipe diameter. The tensile force shall be measured with an uncertainty of 5% Rdg. The pipe shall be horizontally immersed to 100 ± 50 mm in water during the period in which the tensile load is applied. The pipe meets the requirement if during this 300 s period in which the tensile force is applied no air bubbles are visible. 5.9 Pressure loss The pressure losses measured by the approval authority shall be smaller than or equal to the values measured by the manufacturer. The approval authority shall measure pressure losses smaller than 2.00 mbar with a maximum measuring error of 0.04 mbar. Pressure losses larger than 2.00 mbar shall be measured with a maximum measuring error of 2% Rdg. Airflow s smaller than 0.5 m 3 /hr shall be measured with a maximum measuring error of m 3 /hr. Airflow s larger than 0.5 m 3 /hr shall be measured with a maximum measuring error of 5% Rdg. The approval authority shall use the configuration in figure B for the measurement of pressure losses. 22

23 1 = inlet pressure regulator 2 = inlet pressure gauge 3 = differential pressure gauge 4 = test specimen 5 = flow meter 6 = control valve at outlet A A Figure B: Principle of pressure loss test Nominal size Internal diameter, d (mm) 1 / / / / / / / 2 41 Detail of damping tube A For measuring the pressure loss of the pipe the total length between the connections of the differential pressure gauge shall be 3.0 ± 0.1 m. The length between the connections shall be measured with a maximum measuring error of 0.01 m. Bends in the corrugated stainless steel pipe shall be avoided. The pressure loss per meter pipe is calculated by dividing the measured pressure loss by three. For measuring the pressure loss of the system the total length of the pipe between the fittings shall be 1.0 ± 0.05 m. The fittings shall have a gassound thread according to ISO 7 type R. The fittings shall be connected to the differential pressure gauges. The length between the fittings shall be measured with a maximum measuring error of 0.01 m. Bends in the corrugated stainless steel pipe shall be avoided. Air of room temperature is pumped through the pipe. The overpressure of the air at inlet, measured by the inlet pressure gauge, shall be 25.0 ± 1.0 mbar. 23

24 5.10 Repeated assembly Disassemble and assemble the test specimens 10 times according to the manufacturer instructions. Check if the requirements of 4.1 are met Resistance to corrosion For this test, two coated corrugated stainless steel pipes are used with matching straight tensile-resistant fittings on both ends. The ends shall be sealed gaslight. The total length shall be at least 300 mm. The coating shall be removed. After removal of the coating the corrugated stainless steel pipe shall be free of lime rests and grease. If the coating is needed for the soundness of the connection of the fitting to the pipe, the coating shall not be removed at the fitting. The two test assemblies shall be immersed for 2 / 3 of its length in a solution by weight of 20 percent sodium chloride, one percent sodium nitrate and 79 percent distilled water. The temperature of the solution shall be raised to 100±2 C at atmospheric pressure and maintained at that temperature for 14 hours. All boil-off vapour shall be condensed and returned to the test solution. After 14 hours in the boiling test solution, the test assemblies shall be removed from the solution and cooled to room temperature. The assemblies shall then be deformed according figure 4 from A to B. The bending shall take place at the immersed part of the pipe. One assembly shall be bend with the weld on the inside of the curve (position 1), the other assembly with the weld on the outside of the curve (position 2). After completion of this test, the pipe and fittings shall still be gastight in accordance with 4.1. In contrast to 4.1, the gastightness shall only be checked at a temperature of 23 ± 5 C. 24

25 position 2 position 1 Figure C: Bending test after corrosion 25

26 6. MARKING AND INSTRUCTIONS 6.1 Pipe marking The pipe shall be clearly and indelibly marked at intervals of not more than 5 m with: - the GASTEC QA mark; - the manufacturer s mark; - the DN of the pipe; - the year and date of production (or a code representing these data). 6.2 Fitting marking The fittings shall be clearly and indelibly marked with: - the GASTEC QA mark; - the manufacturer s mark; - the mating dimension of the corresponding pipes. 6.3 Instructions The manufacturer shall provide in clear Dutch the following data: clear assembly instructions; a confirmation stating which combination of coated corrugated stainless steel pipe and tensile resistant fitting can be used; the fitness for repeated assembly of the fitting; minimum bending radius (minimum allowable bending radius is equal to the diameter given in table 3); a statement that during installation the corrugated stainless steel pipe shall not be permanently elongated in longitudinal direction; a curve describing the relation between airflow and pressure loss per meter pipe; a curve describing the relation between airflow and pressure loss of a pipe system containing of a straight fitting, one meter pipe and an elbow 90 fitting. 26

KE 154 GASTEC QA Approval Requirements 154

KE 154 GASTEC QA Approval Requirements 154 KE 154 March 2012 GASTEC QA Approval Requirements 154 for the GASTEC QA product certificate for insulation union couplings in gas conduits up to 50 mm nominal diameter Foreword These GASTEC QA Approval