STUDOR expertise in drain venting systems

Since 1975, the British company has been researching and patenting solutions that have later gone into common usage, and supported institutes and laboratories in the definition of technical standards – all of which in the field of drain system venting in buildings. As well as offering an opportunity to develop our own skills, it is also an honour for Bampi to work together with the global leader in the production of positive air pressure control devices for drain systems. 

Negative and positive air pressure control in buildings over 7 stories tall

Drain systems in buildings above 6-7 stories in height may be susceptible to phenomena that are particularly detrimental to comfort in utility spaces such as bathrooms and kitchens. As effluent is transported down the vertical drain stack by gravity, negative pressure is generated along the vertical drain branches. If this negative pressure is not compensated instantaneously by admitting air with adequate ventilation, air is instead sucked from the traps of the sanitary fittings and utilities in the system, causing gurgling noises and, in the worst possible cases, the release of sewage odours in bathrooms and kitchens. Furthermore, the air trapped in the descending flow bounces off the water barrier forming temporarily near the bottom of the drain stack, generating an upward travelling transient pressure wave which may interfere with sanitary fittings and utilities on and near the bottom floor of the building, causing gurgling noises and fluctuations in the trap water levels. The solutions created by STUDOR are conceived with a very different approach from the solutions traditionally used in Italy, making them particularly advantageous not only in economic, technical and functional terms, but also in terms of style and hygiene.

P.A.P.A. – A positive air pressure attenuator for drain systems

The STUDOR system offers a simple solution for problems related to drain system ventilation, avoiding the need for complex parallel vent stacks, secondary vent lines, flow throttles and bypasses. When installed on horizontal branches, MINI-VENT vent valves and TRAP-VENT NEW vented traps allow the immediate admission of air exactly where it needed in the system, protecting the system itself against the undesirable effects of negative pressure. The P.A.P.A. (Positive Air Pressure Attenuator) device connected directly to the vertical stack completes the protection offered, protecting the system against positive pressure which may be generated in the case of simultaneous drainage from multiple utilities. This combination keeps any negative or positive pressure values below 100 Pa (10 mm water column) and balances the drain system quickly to atmospheric pressure, protecting the traps of sanitary fittings and utilities against gurgling, emptying and foaming.

How the positive pressure attenuator works

As the transient pressure wave generated at the bottom of the drain stack rises up the system, a large proportion of it enters the P.A.P.A., actuating the isoprene membrane in the device. The membrane expands extremely quickly (0.2 seconds), absorbing all the energy, and the speed of the wave is drastically reduced to a moderate 12 m/s. The remaining small volume of air is returned to the drain system, and is completely harmless to the traps of the sanitary fittings and utilities. The P.A.P.A. device has a capacity of 3.785 litres of air, may be installed either horizontally or vertically and is completely maintenance-free.