The RAL-GZ 692 quality symbol is only awarded to manhole covers, tops and bridge drains. They must meet the high requirements of the quality and testing regulations for duct casting with regard to safety, durability and sustainability. In order to be awarded the quality symbol, characteristics and properties that go beyond the quality requirements of DIN EN 124 and DIN 1229 must be fulfilled and proven within the scope of test results.
In addition to high demands on the products, a quality management system according to DIN EN ISO 9001 and an environmental management system according to DIN EN 14001 are essential prerequisites. All requirements are continuously monitored by neutral, accredited testing and certification bodies.
Passavant cast iron products are tested beyond DIN EN 124 and certified with the RAL-GZ 692 quality symbol:
The GET test procedure in RAL-GZ 692 sewer casting
In summary, the four most important test procedures to ensure operational and road safety for the quality symbol beyond the DIN EN 124 standard.
The pull-out force essentially determines the safe position of the cover/grating under dynamic traffic load. The greater the pull-out force, the greater the safety against the cover/grating being ejected. There are national standards with requirements for the mass per unit area (kg/sqm) for loosely inserted covers/gratings. Lighter covers/gratings must be secured by a locking device or with a special design in accordance with the standard. However, there are no concrete requirements for this. This shortcoming is filled by the pull-out test, which requires a value 1.5 times that of the loose cover/grating. This is to ensure that a cover/grating has a high level of positional stability even when its locking device is worn and ageing.
With the cover/grating loosely inserted, it is then checked whether the mass per unit area complies with the minimum requirements of the national standards. For lighter covers/grating, the extent to which the locking device or the particular design of the cover/grating can withstand a mechanical pull-out test is checked. The locking device must not come loose during and after the test. Deformation or damage of the cover/grating and its fastening parts as well as protrusion of the cover/grating are only permissible within a defined minimum extent.
If covers/grating are inserted loosely, they can tip up if a wheel rolls over the joint and hits the edge of the cover. The opposite side of the cover/grating flips up. The more the cover/grating tilts or flips up, the more unstable its position is The risk increases that the cover/grating will rattle when driven over and be thrown out of the frame with unforeseeable consequences for road users. Consequently, the tilting characteristics are an essential factor for the operational and traffic safety of manhole covers and tops. The height of the tilting depends mainly on the design of the cover/ grating. DIN EN 124 does not include such a test. RAL-GZ 692 addresses this shortcoming.
The extent to which an increasing vertical force on the edge of the cover causes the opposite side of the cover to tilt up is measured at different measuring points for loosely inserted rectangular or round covers/gratings. The permissible values are at a minimum and are well below the risk limit for the cover/grating being thrown out of the frame. The fastenings of lighter covers/gratings that have been secured in a way that is safe for traffic must not come loose during the test.
Cushioning inserts increase positional security and minimise noise levels. Depending on thickness, hardness, elasticity and material, damping inserts in covers/gratings are compressed to a greater or lesser extent when driven over. The greater the change between the unloaded and loaded condition, the more likely a "trampoline effect" is, causing a cover/grating to be thrown out of its frame. This creates risks for both operational and road safety. The characteristics of the cushioning insert is not tested according to DIN EN 124. Consequently, no permissible limit values have been set. RAL-GZ 692 also addresses any potential safety shortcomings in this area.
The application of vertical force to the cover/grating shows the extent to which the damping insert deforms. The degree of deformation must not exceed a maximum of 3 mm to eliminate the risk of the "trampoline effect".
In practice, manhole covers and tops are exposed to a wide variety of loads and conditions, some of which are extreme, and which cannot really be simulated through isolated technical tests. Therefore, RAL-GZ 692 requires a long-term critical observation of all relevant quality and safety aspects of the product under practical conditions.
All new products are subjected to a trial phase according to the manufacturer's specifications before being launched on the market. After launching on the market, a one-year quality check is carried out in accordance with the quality regulations of RAL-GZ 692. During this period, all defects related to design and manufacturing are recorded and evaluated. If any systemic deficiencies are revealed, these must be disclosed and rectified before the quality symbol is awarded. This process is accompanied by an external supervisor. The quality mark can be awarded no earlier than after the expiry of the successful 12-month probationary period.