AS 681.4-2008 pdf free download

AS 681.4-2008 pdf free download.Elastomeric seals Material requirements for pipe joint seals used in water and drainage applications.
4.2.3 Hardness
When determined by the micro-test method specified in ISO 48, the hardness shall comply with the requirement given in table 1.
NOTE: If the dimensions of a seal are appropriate, the normal test method specified in ISO 48 can be used, provided that the micro-test method is used for reference purposes.
For the same seal, the difference between the minimum and maximum hardness shall not be more than 5 IRHD. Each value shall be within the specified tolerances.
4.2.4 Tensile strength and elongation at break
The tensile strength and elongation at break shall be determined by the method specified in ISO 37. Dumb-bell shaped test pieces of types 1, 2, 3 or 4 shall be used. Type 2 is the preferred size. The test report shall state the dumb-bell type whenever type 2 is not used.
The tensile strength and the elongation at break shall comply with the requirements given in table 1.
4.2.5 Compression set in air
4.2.5.1 General
If the test piece is taken from a seal, then the measurement shall be carried out as far as possible in the direction of compression of the seal in service
4.2.5.2 Compression set at 23 °C and 70 °C
When determined by the method specified in ISO 815, at 23 °C and 70 °C, usiny the small Type B test piece, the compression set shall comply with the requirements given in table 1.
4.2.5.3 Low temperature compression set at -10°C
When determined by the method specified in ISO 815 at -10 °C using the small Type B
test piece, and the (30 ± 3) mm recovery measurement, the compression set shall comply
with the requirements given in table 1.
4.2.6 Accelerated ageing in air
Test pieces prepared for the determination of hardness (see 4.2.3) shall be aged in air by the normal oven method specified in ISO 1& for 7 days at 70 °C.
The change in hardness shall comply with the requirement given in table 1.
4.2.7 Stress relaxation in compression
The stress relaxation shall be determined at 23°C by method A of ISO 3384:1999, except that the initial measurement shall be taken at 10 mm, using the small cylindrical test piece after applying mechanical and thermal conditoning. Measurements shall then be taken after 3 h, 1, 3, 7 days for the 7 day test and after 3 h, 1,3, 7, 30, 100 days for the 100 days test. The best fit straight line shall be detemined by regression analysis using a logarithmic time scale and the correlation coefficients derived from these analyses shall not be lower than 0,93 for the 7 day test and 0,83 for the 100 day test. The 7 and 100 days requirements in table I are those derived from this straight line.
For continuous measurement using an apparatus described in the first paragraph of 5.2 of ISO 3384 the 7 days and 100 days requirements in table I are those derived from the measurements at 7 and 100 days.
The stress relaxation in compression shall comply with the requirements given in table 1.
The test temperature shall be maintained within the specified tolerance during the whole period of the test and verified by suitable recording equipment on a continuous basis.
The 100 days test shall be considered as a type approval test.
If the test piece is taken from a seal, then the measurement shall be carried out as far as possible in the direction of compression of the seal in service.AS 681.4-2008 pdf free download.