TechTalk

Offset solution to install drainage stack correctly

It is not always possible to avoid inaccuracies during construction, but if the connection points of discharge pipes are not precisely on one axis, this often costs plumbers time and tests their patience. With the Geberit Silent-db20 Offset fitting, stacks can be connected efficiently and tension-free, even in the event of inaccuracies. This means that the stack is installed correctly, albeit at an oblique angle.

The Geberit Silent-db20 Offset fitting allows stacks to be connected simply, securely and professionally in the event of inaccuracies in the construction. A fitting is installed at the connections in the ceiling and above the expansion socket on the floor, thereby easily and efficiently compensating for an offset of up to 10 cm. Installation is the same as for other Geberit Silent-db20 fittings - quicker and easier, especially since there is no need to install an additional sliding bracket clamp.

Geberit Silent-db20 is a highly sound-insulating drainage system, making it an ideal solution for increased sound insulation requirements. In case of direction changes caused by an offset, the sound values must be corrected upwards. In a stack with the Geberit Silent-db20 Offset fitting, the water is gently diverted. Measurements show only slightly increased airborne sound values compared to a straight stack*. What’s more, a sliding bracket is no longer required, which leads to additional structure-borne sound decoupling of the drainage system from the building structure.

Stack pipe offset instllation without the Silent-db20 Offset with clamping connectors

Stack pipe offset instllation without the Silent-db20 Offset with clamping connectors

Five benefits at a glance:

  1. Tension-free installation: With the Geberit Silent-db20 Offset fittings, axis deviations of up to 10 cm can be corrected with precision. Tension during pipe installation is eliminated;
  2. Easy installation: Installation is the same as for other Geberit Silent-db20 fittings. The offset fittings are aligned by hand.
  3. Shorter installation time: The ball joint can easily adapt to any axial offset, meaning there is no need to use sliding brackets. This reduces installation time by up to one-third;
  4. Flexible solution: An offset of up to 10 cm can be corrected with the Geberit Silent-db20 Offset fitting. Instead of having various different bends of 15, 30 or 45 degrees, all that’s required is the Offset fitting; and
  5. Better sound insulation: The smoother direction changes allow water to flow more quietly*. The transmission of structure-borne sound is also reduced, since a sliding bracket is no longer required.

Planning

The Silent‑db20 Offset fitting is used to compensate an offset in the stack. The stack is secured with the Silent‑db20 expansion socket. The feed-throughs must be decoupled from the building structure with an insulation hose, insulation tape, or Isol Flex.

The Offset fitting can be used in the stack in the following case:

•Where the stack offset is a maximum of 10 cm

• Pipe length between two Silent‑db20 Offset fittings is a minimum of 1.5 m and a maximum of 3 m.

It must be noted that one Silent‑db20 Offset fitting is required in the stack for every offset.

When using Silent‑db20 expansion sockets, pipes and fittings must be connected non-positively in the entire pipe section using electrofusion or butt welding. This requirement does not only apply to the connection to the Silent‑db20 expansion socket, but also to the entire pipe section. When fastening the anchor points of Silent‑db20 expansion sockets, a larger pipe dimension must be selected for the Silent‑db20 system pipe brackets than for the pipe diameter used.

*Compared to the installation of a direction change with two 45-degree bends.

How to Install

Figure 1