Common use of Change of Design Clause in Contracts

Change of Design. A design change is any change in the selection of structural materials or dimensional change not attributable to normal manufacturing tolerances. Minor design changes shall be permitted to be qualified through a reduced test program. Changes of design specified in table 6.7 shall require design qualification testing as specified in the table. Table 6.1. - Material design qualification test Relevant paragraph of this annex Steel Aluminium Resins Fibres Plastic liners Tensile properties 6.3.2.2. 6.3.3.4. 6.3.5. 6.3.6. Impact properties 6.3.2.3. Bending properties‌ 6.3.2.4. Weld examination 6.3.2.5. Sulfide stress cracking resistance 6.3.2.6. Sustained load crack resistance 6.3.3.3. Stress corrosion cracking 6.3.3.2. Shear strength 6.3.4.2. Glass transition temperature 6.3.4.3. Softening/Melting temperature 6.3.6. Fracture mechanics*/ 6.7. 6.7. */ Not required if flawed cylinder test approach in paragraph A.7. of Appendix A is used. /2. Strike out what does not apply 80 Cylinder diameter D, mm > 140 ≤ 140 Direction of testing transverse longitudinal Width of test piece, mm 3 - 5 > 5 - 7.5 > 7.5 - 10 3 to 5 Test temperature, °C -50 -50 Mean of 3 specimens Impact strength, J/cm² Individual specimen 30 35 40 60 Table 6.3 - Minimum actual burst values and stress ratios CNG-1 All-metal CNG-2 Hoop-wrapped CNG-3 Fully-wrapped CNG-4 All-composite Burst pressure [MPa] Stress ratio [MPa] Burst pressure [MPa] Stress ratio [MPa] Burst pressure [MPa] Stress ratio [MPa] Burst pressure [MPa] All metal 45 Glass 2.75 50 1) 3.65 70 1) 3.65 73 Aramid 2.35 47 3.10 60 1) 3.1 62 Carbon 2.35 47 2.35 47 2.35 47 Hybrid 2) 2) 2) Table 6.4 - Cylinder design qualification tests Test and annex reference Cylinder type CNG-1 CNG-2 CNG-3 CNG-4 A.12 Burst A.13 Ambient temp/cycle A.14 Acid environment test A.15 Bonfire A.16 Penetration A.17 Flaw tolerance A.18 High temp. creep A.19 Stress rupture A.20 Drop test A.21 Permeation A.24 PRD performance A.25 Boss torque test A.27 Natural gas cycling A.6 LBB assesment A.7 Extreme temperature/cycle X * X * X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X = required * = Not required for cylinders designed to ISO 9809 (ISO 9809 already provides for these tests). Table 6.5 - Batch tests Test and annex reference Cylinder type CNG-1 CNG-2 CNG-3 CNG-4

Change of Design. A design change is any change in the selection of structural materials or dimensional change not attributable to normal manufacturing tolerances. Minor design changes shall be permitted to be qualified through a reduced test program. Changes of design specified in table 6.7 shall require design qualification testing as specified in the table. Table 6.1. - Material design qualification test Relevant paragraph of this annex Steel Aluminium Resins Fibres FibresFib ers Plastic liners Tensile properties 6.3.2.2. 6.3.3.4. 6.3.5. 6.3.6. Impact properties 6.3.2.3. Bending properties‌ properties 6.3.2.4. Weld examination 6.3.2.5. Sulfide stress cracking resistance 6.3.2.6. Sustained load crack resistance 6.3.3.3. Stress corrosion cracking 6.3.3.2. Shear strength 6.3.4.2. Glass transition temperature 6.3.4.3. Softening/Melting temperature 6.3.6. Fracture mechanics*/ 6.7. 6.7. */ Not required if flawed cylinder test approach in paragraph A.7. of Appendix A is used. /2. Strike out what does not apply 80 76 Cylinder diameter D, mm > 140 ≤  140 Direction of testing transverse longitudinal Width of test piece, mm 3 - 5 > 5 - 7.5 > 7.5 - 10 3 to 5 Test temperature, °C C -50 -50 Mean of 3 specimens 30 35 40 60 Impact strength, J/cm² Individual specimen 30 35 40 60 24 28 32 48 Table 6.3 - Minimum actual burst values and stress ratios CNG-1 All-metal CNG-2 Hoop-wrapped CNG-3 Fully-wrapped CNG-4 All-composite Burst pressure [MPa] Stress ratio [MPa] Burst pressure [MPa] Stress ratio [MPa] Burst pressure [MPa] Stress ratio [MPa] Burst pressure [MPa] All metal 45 Glass 2.75 50 1) 3.65 70 1) 3.65 73 Aramid 2.35 47 3.10 60 1) 3.1 62 Carbon 2.35 47 2.35 47 2.35 47 Hybrid 2) 2) 2) Table 6.4 - Cylinder design qualification tests Test and annex reference Cylinder type CNG-1 CNG-2 CNG-3 CNG-4 A.12 Burst A.13 Ambient temp/cycle A.14 Acid environment test A.15 Bonfire A.16 Penetration A.17 Flaw tolerance A.18 High temp. creep A.19 Stress rupture A.20 Drop test A.21 Permeation A.24 PRD performance A.25 Boss torque test A.27 Natural gas cycling A.6 LBB assesment assesmentassessment A.7 Extreme temperature/cycle X * X * X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X = required * = Not required for cylinders designed to ISO 9809 (ISO 9809 already provides for these tests). Table 6.5 - Batch tests Test and annex reference Cylinder type CNG-1 CNG-2 CNG-3 CNG-4