Construction in the Asia Pacific tropics can create a plumbing nightmare for engineers due to monsoonal weather patterns.

During the Malaysian summer monsoon season, from mid-November to March, it is common for rainfall of up to 11in (28cm) to occur on several consecutive days.

The Asia Pacific region is home to about 60% of the world’s population, and atmospheric increase in carbon dioxide, methane and nitrous oxide has affected the region’s rainfall pattern.

Predictive models from the Commonwealth Scientific and Industrial Research Organization indicate an impending increase in rainfall throughout much of the region. The summer monsoon season will experience more rain, and there will be less in the winter monsoon season.

Further studies have indicated the potential for tropical cyclones that are more intense.

With the possibility of increased rainfall, many new buildings in the region are adopting Syfonic roof drainage (SRD) by Syfon Systems. SRD uses the difference in water levels between the gutter and the discharge point to initiate siphonic action. SRD also substantially reduces the number of downpipes required for projects.

Syfon Systems managing director Adam Bellgrove says increased rainfall in tropical climates due to global warming has made Syfon’s move into Malaysia in the late 1990s highly successful.

“We have completed many high-profile projects,” he says.

“Our technology allows SRD to be installed using a wide variety of materials, including stainless steel and high-density polyethylene (HDPE).

“HDPE pipe material is widely used by SRD and is becoming the material of choice compared with uPVC, as it is considered a more durable, superior and environmentally friendly material.

“Our engineers use Syfon’s proprietary software to produce a comprehensive analysis of all project drainage requirements, ensuring individual project design is addressed and customized to specific drainage needs.”

Once SRD is installed, rainwater is collected via siphonic gutter inlets and reticulated through a common pipe that is designed to run level. The main difference is that a conventional pipe runs at only one-third of its capacity, or even less.

Compared with a conventional downpipe system, SRD offers a more efficient drainage solution using reduced pipe sizes, which allows easier coordination with other services in the ceiling space.

“The system also offers environmental benefits, as it is able to cost effectively harvest clean stormwater from roofs, and separate the dirty water from car parks.

SRD has been incorporated into many Malaysian projects, among them the Putrajaya International Convention Center, the Kuala Lumpur International Airport, IKEA, the Kuala Lumpur Convention Center, and the recently completed Sunway Pyramid Extension.

The Sunway Pyramid Extension was built beside the Sunway Pyramid shopping center in Kuala Lumpur. The car park roof deck of the seven-story shopping center has a total catchment area of about 18,000 square yards (15,000m²), and project engineers had to design an efficient drainage system to handle the turbulent weather.

“The land sloped severely away from the front of the property where the entrance of the existing mall was, which resulted in many challenges for the Syfon Systems team of in-house design engineers, installers and joint contractors,” Bellgrove says.