All our waterstops are manufactured in accordance with national standards and have undergone strict tests before leaving the factory to ensure high quality. However, the quality of waterstops on the market varies widely. You may use the following method to check whether PN swellable waterstops are qualified.
Flow at high temperature
Place three samples with a dimension of 20 mm × 20 mm × 4 mm on a grooved wooden frame that inclines at 75° with 2 mm thickness in the groove and 2 mm thickness outside the groove; put these samples into a drying box at 80 °C and take them out after 5 h. Observe whether these samples flow obviously. If the flow trace falls within 1 mm from the groove edge, it is considered as no flow.
Low temperature test
Put two samples with a dimension of 50 mm × 100 mm × 2 mm in a low temperature box at -20 °C for 2 h. Wind these samples around a round rod with a diameter of 10 mm after taking them out. Observe whether they are fragile.
Volume expansion rate
You may test the volume expansion rate according to the following steps.
The average value of three samples is taken as the volume expansion rate, and is calculated as follows:
When the test results are obtained, compare them with the following table. Those that meet the following technical data are considered as qualified:
|PN Swellable Waterstop
|Volume expansion rate (%, ≥)
|Flow at high temperature (80 °C, 5 h)
|Low temperature test (-20 °C , 2 h)
Only when all technical indicators are met, it can be deemed as qualified. If an indicator fails to meet the technical requirements, double samples shall be prepared for retest. If the test result is unqualified, this batch of products is considered as unqualified.
All our products are produced in strict accordance with national standards, and each batch of products will be tested before leaving the factory. Corresponding test report will be provided, you can buy these waterstops without worry.