Pressurised SystemPressurised System

Fast Flow psVent™ is a patented technology with unique characteristic of preventing back flow to balconies while maintaining high drainage capacity through pressure flow.

Integrated with Fast Flow psVent™, Fast Flow Pressurised Stack (psStack™) combines all the advantages of Fast Flow Siphonic System and Fast Flow Pressurised System. Fast Flow psStack™ allows a conventional gravity drainage system to be connected to a siphonic system while achieving high drainage capacity especially for high-rise buildings.

Pinnacle @ Duxton, SingaporeArchitect: ARC Studio & RSP Architects drained by Fast Flow Pressurised System

...the art of drainage

Fast Flow has been the pioneer in the application of pressure flow principles to rainwater drainage. Since the development of Fast Flow Pressurised System and its pilot launch in Singapore in 2008, approximately 50,000 psVent™ have been installed.

For many years, Fast Flow’s research and development team has continuously strived to improve and refine this technology. The result of this hard work is the Fast Flow Pressurised Technology- a unique technology that combines the strength of both pressure and gravity flow.

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Resort World Sentosa, SingaporeArchitect: Michael Graves & DP Architectsdrained by Fast Flow Pressurised System

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Introduction of Fast Flow Pressurised System

For years, drainage in buildings has not seen many innovations. To date, the conventional gravity rainwater system is still widely used to drain rainwater from the buildings’ roof. This is because it is simple and easy to implement. However, conventional gravity rainwater systems are designed on the principle of non-pressure flow (open channel flow) which is very inefficient as there is a need to maintain a lot of air in the pipes to prevent pressure fluctuation.

The invention of siphonic rainwater system in late 1960s marked a revolutionary breakthrough using full bore pressure flow and eliminating any air inside the pipe, allowing the pipe to be fully filled with water. The siphonic rainwater system cleverly made use of the height of the building to provide energy for transporting rainwater with high velocity through the system. Due to its high efficiency and range of benefits, the siphonic rainwater system has gained vast popularity in the past decades. The main difficulty in a siphonic system lies in the precise engineering and design. In order for a siphonic system to be working properly, it has to be designed and constructed as a fully enclosed system, preventing ingress of air into the system which will neutralise the pressure. Connection of gravity outlets (ie. Balcony and car park drainage) with a siphonic system is therefore commonly avoided.

Fast Flow Pressurised Technology is the result of years of continuous research with successful track records of combining siphonic and gravity drainage in projects particularly in the recent years. It utilises the principle of 2-phase flow where water flows through pipes with high velocity due to pressure flow and yet allow for connection with gravity outlets/branches.

This unique technology allows for greater design flexibility and provides economical value especially in high-rise building drainage where rainwater from the roof can be combined with water from balconies and corridors through a single pipe.

Siphonic System

Gravity System

Fast Flow Pressurised System

Flow characteristicsNon-pressure, gravity flow.

Large volume of air inside pipe work.

2-phase flow pressure flow. Mixture of air and water

inside pipe work.

Full bore pressure flow. Fully filled with water.

Flow velocity Slow High

Drainage capacity Low capacity High capacity

Pipe diameter Large pipe diameter Small to medium pipe diameter (50% of a gravity system pipe)

Small diameter with precise engineering

(30% of a gravity system pipe)

Number of pipes Many Less Minimum

Required Not requiredSlope in pipes

Water depth in gutter Very Deep Shallow and can be controlled

Pipe material Non-pressure pipe Pressure Pipe

Connection to gravity outlets (eg. Balconies) Yes Not advisable

unless specially designed for.

Outlets Gravity roof outlets, floor gratings All types; gravity outlets, gratings, siphonic outlets, pressurised outlets Siphonic outlets

With psVent™: No backflow

With T-branch: Spouting of water

WithY-branch: Spouting of water

ION Orchard, SingaporeArchitect: Benoy & RSP Architectsdrained by Fast Flow Pressurised System

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Fast Flow psVent™ - the patented invention

With increasing importance of urban areas as the engines of economic growth especially in Asia Pacific, residential and commercial buildings are growing vertically taller each day to house the growing population in the limited land area. Along with urbanisation, people are living in a faster pace of life and the concept of balcony as a private space, outside the home or office has become a selling point to many property developers.

However, as the number of floors in the building increases, the number of balconies sharing a single discharge pipe increases. This increases the amount of water discharged into the single pipe, risking water backflow in balconies especially in high-rise development and as a result increases the chance of flooding in the balcony.

Fast Flow psVent™ is a proprietary and patented technology that works to sustain the significant water increase while using a smaller rainwater downpipe. It has been proven to effectively prevent back flow. psVent™ together with the pipe system, has been tested to drain as high as 20l/s without risk of back flow.

Performance of psVent™ has been validated by TUV SUD PSB and SIRIM.

With psVent™: No backflow

With T-branch: Spouting of water

WithY-branch: Spouting of water

A common problem with gravity rainwater downpipes linked to balconies is the backflow of water through the side branch during rain. This is due to the reduced air passage in the vertical rainwater downpipes preventing proper upward movement of air within the down pipe during heavy rain. Consequently, air naturally escapes through the side branches and in the process pushes water out through the balcony outlets.

Research has shown back flow occurs in a 100 diameter vertical pipe with 50 diameter side branch at flow rate as low as 4-5 l/s. Smaller diameter rainwater downpipes will risk backflow at much lower flow rate.

Back flow problem with gravity rwdp

(Diagram showing the common cause of backflow in balconies linked to rainwater downpipes.)

Ease of CoordinationFast Flow’s Pressurised System can be engineered with precise calculations using different pipe configurations, making it easy for coordination with other services in tight spaces.

Fast Flow psRWDP™Using simple installation and application methodology, Fast Flow psRWDP™ achieves high drainage capacity. Refer to psRWDP™ brochure for further details.

Horizontal Pipe without GradientBy applying the principle of pressure flow, psStack™ (single discharge pipe connecting the psVent™) can achieve longer horizontal pipes, travelling without gradient, providing ease of coordination, design and maximising headroom.

Rainwater Harvesting SystemFast Flow psStack™ is ideal for rainwater harvesting as it can transport rainwater to any designated single location using smaller pipes that do not require gradient.

Landscape/ Green Roof SystemFast Flow psStack™ can be applied in combination with Fast Flow’s Landscape/Green Roof Drainage System.Fast Flow Pressurised System (psStack™)

Fast Flow Siphonic System

Fast Flow psRWDP™

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Flexible Connection to any Balcony OutletsFast Flow psVent™ allows the connection of any balcony outlets (siphonic, pressurised or gravity) to psStack™.

Prevent Back Flow in BalconiesFast Flow psVent™ (patented invention) are proven to achieve high capacity while preventing backflow at balconies.

Car Park/ Driveway Drainage SystemFast Flow psStack™ can be used in combination with Fast Flow Heavy Duty Siphonic Outlets to minimise size and number of pipes in multi-storey car parks.

Features of Fast Flow Pressurised SystemHigh Capacity Siphonic Roof Drainage SystemFast Flow Siphonic System provides wide range of siphonic roof drainage solutions that fits all drainage requirements (from 6 l/s to 150 l/s) and all type of constructions. Refer to Fast Flow Siphonic System Brochure for further details.

Low Water DepthFast Flow Siphonic/ Pressurised System can achieve high capacity with controlled water depth in gutter or roof top when fully engineered.

Small Pipe Diameter and Less Pipes Fast Flow psStack™ can achieve very high capacity (up to 20 l/s) with a single 75mm diameter pipe.

Fast Flow psStack™ can be linked to any

gravity floor drainage outlets from balconies,

terraces and corridors.

Arteco™-R Siphonic OutletFast Flow Arteco™-R siphonic outlet is a small

siphonic roof outlet suitable for draining small roofs (eg. roof above lift motor room, staircase

rooftop access etc.)

Arteco™-T Architectural Siphonic OutletFast Flow Arteco™-T architectural siphonic outlet

combines the high drainage capability of siphonic system with architectural aesthetics. Ideal for

drainage of roof terraces with fine architectural finishes. More design varieties are available from

the Fast Flow Arteco™ siphonic range.

Arteco™-B12 GratingArteco™-B grating is an ideal gravity balcony/floor

drain outlet where floor tiles, granites or any floor finish can be placed in the center piece. The final effect is an elegant floor drainage

outlet that matches perfectly into the architectural finishes.

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psStack™- a ‘Hybrid’ Solution...Fast Flow psStack™ is a hybrid solution, combining all the advantages of both Fast Flow Siphonic System and Fast Flow Pressurised System. One of the main features of the Fast Flow psStack™ lies in its ability to drain both the roof and multiple balconies in a single discharge pipe, saving valuable space. This is one of the distinct benefits of the Fast Flow psStack™ that a conventional system cannot do.

Fast Flow psStack™ is highly configurable and can be connected to all types of roof outlets, floor drainage outlets, including Fast Flow’s wide variety of siphonic outlets, architectural siphonic outlets, architectural gratings, and even conventional gravity floor gratings and outlets.

Primo™ Siphonic OutletFast Flow Primo™ series siphonic outlet is suitable for all types of application

and constructions from r.c. roof tops with variety of water proofing systems to metal gutters. Fast Flow Primo™ outlets come with

specially designed accessories to provide reliable and easy interface with different construction methods.

Its 3-dimensional leaf guard design is also very versatile in blockage prevention.

Arteco™-S12 GratingFast Flow Arteco™-S grating is an

elegant solution to general floor drainage. It is made from stainless steel and is both highly

efficient and durable.

Piccolo™ Siphonic Outlet

Fast Flow Piccolo™ outlets are specially designed to

achieve high drainage capacity and efficient

control of water depth in small metal gutters.

� Unattractive box-up limits opening/view, giving a crowded interior.

Conventional Gravity System

BENEFITS & ADVANTAGES OF FAST FLOW PRESSURISED SYSTEM

� Exposed box-up with limited opening/view gives a low-end feel to the building.

Conventional rwdp requires more outlets on roof top and results in deep water ponding on roof top.

Example: Flow rate of 4.0 l/s will require 150 mm of water depth for a nominal 4” gravity outlet with strainer. (Ref: BS EN 12056-3:2000)

Assuming each balcony (3.5m x 4m) has a flow rate of 0.5 l/s

8 balconies x 0.5 l/s = 4 l/s

Note: Based on 1 to 100 gradient, maximum capacity for 4” gravity rwdp is 4.0 l/s. This means every 8 balconies require one (1) number of separate 4” gravity rwdp.

Separate gravity rwdp is required to drain the rainwater on the open to sky roof terrace to avoid backflow from the balconies.

As explained above,assuming flow rate of 0.5 l/s for each balcony, one (1) number of separate 4” gravity rwdp is needed for every 8 balconies.

Larger and deeper discharge sump needed due to gradient and multiple number of gravity rwdps.

Multiple gravity rwdps need gradient and results in extensive excavation.

Multiple 4” gravity rwdp takes up valuable space.

Gravity rwdp needs gradient and takes up valuable ceiling space.

A lot of gravity rwdps are not only difficult to conceal, but take up valuable floor space.

LIMITATIONS AND DISADVANTAGES OF CONVENTIONAL GRAVITY RWDP

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Conventional Gravity System

BENEFITS & ADVANTAGES OF FAST FLOW PRESSURISED SYSTEM

� Extended view opening enhances building facade, giving a more high-end aesthetic feel to the building.

� No box-up creates extended opening/view, allowing building interior to look more spacious.

Lesser number of siphonic roof outlets required to achieve high drainage capacity with lower water depth.

Example: Flow rate of 4.0 l/s requires only 25-30mm water depth for a 2” diameter siphonic outlet. This means smaller pipe size!

Assuming each balconies (3.5m x 4.0m) has a flow rate of 0.5 l/s,

16 balconies x 0.5 l/s = 8 l/s

Total discharge capacity

Roof top: 4 l/sBalconies (16 nos): 8 l/sOpen roof terrace: 4 l/s

Total 16 l/s can all be drained by a single 3” diameter psStack™.

Smaller and shallower discharge sump required.

Small 3” or 4” underground pipe is flexible and does not require gradient.

One (1) number of 3” psStack™.

Small 3” psStack™ is easy to conceal and saves valuable space.

Small 3” horizontal pipe does NOT require gradient, is easy to conceal and saves ceiling space.

Fast Flow psVent™ connects balconies to rainwater pipe from roof and prevents backflow to balconies.

One (1) number of 3” psStack™.

2” siphonic rwdp.

Fast Flow Pressurised System

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Reflections at Keppel Bay, SingaporeArchitect: Daniel Libeskind & DCA Architects drained by Fast Flow Pressurised System

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For years, Fast Flow has always been in the forefront of developing products and systems that improve the drainage system in the building. Our research and development team are continuously at work to take up the challenges of creating workable drainage solutions to suit increasingly sophisticated architecture in buildings. We are committed to provide our clients with top services and sustainable building solutions that benefit both them and their projects.

With us, we bring innovation.

Australia / China / Hong Kong / India / Indonesia / Malaysia / Myanmar / Singapore / Thailand / Turkey / Taiwan / Vietnam

For full listing of Fast Flow offices, please refer to our website at www.fastflowgroup.com

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