© part ti stn bape th ge UDC 621.643.2-034.14 :621.643.06-034,14 1620307.6-096 742.2 DEUTSCHE NORM Polyethylene coatings for steel pipes and fittings Requirements and testing LUmhillung von Stahlrchren und -formstcken mit Polyethyien Supersedes July 1980 edition In keopirg with current practi in standerds published by the International Organization for Standardization ISO}. # comma fhas been used throughout asthe decimal marker ‘This standard has been prepared joint by DIN Deutzohee Inet fr Normung eV. end DVGW Deutscher Verein des Gas- und Wasserfaches e V. (German Gas and Water Enginests' Association), The Standard hae been adopted into the OVGW Codes of practice on gas and water, Dimensions in mm Contents ase 11 Scope and field of application 2 Concopte ... 21 Indontation hardness 22 Light ageing . 23. Minimum coating thickness 24 Continuity 26 Percentage elongation at fature 26. Bond strength 27 iempact strength 28 Costing resstty 29 Heat ageing 3 Declination . 4 Requirements... 1+. 41 Recuirements for substete 42. Recuirements for coating 42.1, Minimum thickness 422 Continuity . 423. Bood strength 424 Impact strength 1 Scope and field of application ‘This standard spaciias requirements for and motheds of testing extruded and fused polyethylene coalings applied al the works to DIN 2448 oF IN 2458 steal pipes that vl be Contact with sol of water It's Intend to be used for qual ty assurance purposes. When supplied wlth normal typo coatings (N) pipes in compliance with tis standard are su fable for continuous service temperatures af up to 50°C, ae with special type coatings (S) for temporaturee up to 70°C. For the purposes of this staidard, the term ‘sel be’ In= cludes ttings manutactured ftom such pioes 2 Concepts 2.1 Indentation hardness ‘The indentation hardness is 2 measure of the resistance of coatings tothe penetration ofa test cylinder Under speci tied eoneitions 2.2 Light ageing For the purposes of this standard, light ageing is ageing of cyatinge by expoouro to fltorod xonan arc radiation In a etas Gren Bee fs is Ne TORT ls Goa Sa OR HOT 425 426 427 Identation hardness Porcentage cloncation at failure Coating resistivity 428 Heat ageing 429 Light ageing 5 Testing 5.1 General 52_Inspectan documents 53 Procedure 581 . Coating thickness 532 Continuity 583. Bord strength 534 impact strenath 535 - Indentation hardness os 1836. Porcontage olongation at fallure 537 Coating resistivity 638. Heat ageing 839. Light ageing © Marting Standards roferred to . Soanararesnaeoannnnnd laboratory apparatus at a gWen iraciance, combine with periodic wetting 2.3 Minimum coating thickness ‘The minimum coating thickness i the requir thickness of costings et ary point 24 Continuity ‘The continuity of coatings is defined as its freedom from defects sich as cracks or pnnoles 2.5 Percentage elongation at failure ‘The percentage elongation at fallue isthe incresse in the ‘original gauge longth of a tact poss atthe momont of fai: Ure, exoressed as a percentage ofthe orginal gauge length, 2.8 Bond strength For the purposes of tis standard, the bond strength isthe force recured to peel a strp of coating from the ibe under spectied conditions. Continued on pages 2 to 7 ‘DIN 30670 Engl Price group 6Page 2 DIN 20670 2.7 Impact strength The impact strength Is defined as the impact energy coat- Ings can withstand under specitioc conditions. 28 Coating resistivity Tne coating rasstty isthe electrical resistance of costings per unit area, 2.9 Heat ageing For the purooces of thie standard, heat ageing is ageing of ‘cain by exposure to hot ar sta given tomporatute for a ‘peated per. 3 Designation ‘Costings shail be designated as being of the normal (N) or spoval (8) type (ct. subclasses 423, 4.25 and 4268) anc as being applied to-# normal (0) cr reinforced (y) thickness (et. ssubolause 421), a8 follows, Coating DIN 30670 - N-n Coating DIN 30670 - N-v Coating DIN 30670 - S-n Coating DIN 30670 - Sv 4 Requirements, 4.1 Requirements tor substrate Immediately price to appication ofthe coating, the surface ‘ofthe steel pe (substrate) shal be clean Le. ree trom di, ‘, groace, wolding boade, moisture) ard blasted to camp with standard preparation grade Sa 214 as defined. Ft DWN ssaza Part 4 42. Requirements for coating 42.1 Minimum thickness ‘The minimum coating thickness shal be as epecited In tablet ‘Table thickness Nominal size of pipe of normal (n) coating Upto ON 100, 18 ver DN 100.up to ON 250 20 (Over DN 250 to below DN S00 22 From ON 800 to bolow DN 800 25 From ON 800 30 The minimum coating thiknoss shall be 0.7 mm groater (reinforced’ (v) type) wnere coatings will be subzected to pertculery high mecnanica stress. ‘Along any 1 m length of pip, the coating thickiess may be Up to 1096 lass than the minimum tequiec, provided the ‘inner area cows not cover more than & cm! ‘The ends of pipes less than DN 500 in size shall be free from aghesive over length of 60 mm, tose of least DN'S00 in ‘zz, over a lent of 100 mm, unless otherwise specitied by the purchaser. ‘The length of uncoated pipe ends shal not exceed 150 mm unless othorwice specified by tho purchaser. 422 Continaty ‘The coating shall be continuous (le. free from pinholes). This requirement shall be deemed satisfied It n0 breakcown inte coning eoours during epark teeing (C uociause ) 42.3. Bond strength ‘When the coating is testod 38 speoited in subcizuse 5.33, not mere than 24 hours after application the mean force Fequied to It i off shal, 4) ate test temperature of (20+ 5)°C, be at east 35N per ‘om of test place width; 1 ata test temperature of (50 +5)°C, be least ISN per ‘0m of text piece wiath for type N ccetings, and 258 per com fer type $ costings. 424 impact strength ‘When tested in accordance with subclause 834, the coat ing shall withstand 39 imgacts without any oletical break own eceurting, 4.25 Indentation hardness \ihen tested in accordance with subclause 8:35, the inden- {ation Gepth of type N coatings shall ot axcoed 02 men at a temperature of (23 4 2)°C, nor 08 mm at 60-£2)°C: Inthe ‘caso of type S ccatngs, shall not exceed 05mm at ater perature of 70+ 2)°, 42.6 Percentage elongation at failure When testes in accordance with subclause 53, the per- ‘centage elongation at failure shal bo at loast 200%. 427 Costing resiativity When tested in accordance with suclause 5:17, the cost: Ing rosistivty, determines after conaitioning the tot proce in the test mechum for 160 cays, shall be not less than Wan The ratio of roditvty after 100 daye to that after 70 dey ‘hall be nt ess than 08, provided the resist is oly one [power of 10 above that specrhed fo 100 days of cantion- Ing 428 Heat ageing When tested in accordance with subclause 63, the melt ‘ow rato ahallnot Gevlte by more than 35% of the orginal value 429 Light ageing When tested in accordance wth subclause 639, the melt ow rate of the test places shal not devista by more than 366 ofthe original value