Any soil pipe vent valve shall be connected to the open end of a ventilation pipe at a point at least 150mm above the flood level of:
- Any sanitary fixture served by such a ventilated pipe.
- The highest sanitary fixture served by such ventilation pipe.
- Rated at 400 l/min.
- One-way: external and internal use.
- Two-way: external use only.
Any ventilation pipe shall not have a reduction in diameter, i.e. 110mm vent valve on a 110mm vent pipe at the head of a drain and on branch drains.
The vent valve provides for this by design, that is provided the valve is rated as a 400 l/min valve, it can be used in this situation.
This is where our Freeflo 400 ® valves are beneficial. The 50mm and 110mm valves are the same. An adaptor is simply added to increase the size to 110mm.
This means that both the 50mm and 110mm valve are rated at 400 l/min and can be selected for their size requirements and not their rating.