In the area of drainage plumbing, “the National Building Code 2016 outlines single-stack, two-stack or three-stack systems, and the Indian Plumbing Association has provided design parameters for all these systems,” notes BSA Narayan, Managing Director, Maple Engg-Design Services (India) and National Vice-President, Indian Plumbing Association.

While the three-stack system has conventionally been used in India, nowadays a variety of propriety single-stack systems are available to connect soil and waste pipes to a single vertical stack, observes Narayan. “In the process, the flow from the upper floors will be streamlined without any obstructions and the air pressure will be maintained in the stack.”

Single-column drainage systems are catching on among developers. Narayan says this is because they help avoid a lot of fittings, vertical pipes and vent pipes, and require less space in the shaft. “However, the system has to be designed properly to ensure positive air flow in the stack. It also necessitates specially designed fittings on the vertical stack at all floor levels. Flow in the single-stack system with a vent or without a venting system is a subject of R&D globally.”

“We opt for maintenance-free plumbing systems such as patented single-stack systems available with Valsir and Geberit for customer convenience and peace of mind, says Deepak Suvarna, Chief Projects Officer, Mahindra Lifespace Developers.

“While the convention in the West is to use a single pipe for drainage, to save on piping, the conventional school of sanitary engineering recommends that venting is best done separately,” says Sunil Kumar Duggal, Director, Northern Sanitation. “We prefer to use triple-stack systems.”

Another advancement in drainage is the development of multiple inlet drain such as the Viega Advantix triple inlet drain with three movable arms, which allows the bathtub, shower area and basin to be connected to a single drain, making plumbing easier. A flange makes it leakproof, and it can be fitted with a Viega tile inlay instead of a regular grate, for a seamless bathroom floor in tile, marble or natural stone.

- CHARU BAHRI