The patented high-performance roof drainage system from CGL offering increased building protection and up to 60% reduction in outlets and downpipes. RainPulse is also the only push-fit solution in the UK.

The RainPulse outlet is specially designed to maximise the efficiency of moving rainwater from the gutter into the downpipe. This is achieved by removing the vortex action created by air entering the downpipe during heavy rainfall. Outlets offer the following features.

  • The high water flow of up to 60 liters per second, per outlet.
  • High water flow allows the system to self-clean the Gutters, Outlets, and Downpipes.
  • RainPulse helps reduce gutter size depending on the required capacity. Working with a smaller head of water than Gravity drainage. This further helps to reduce project costs.
  • The outlet Anti-Vortex plate is complete with a built-in leaf/bird guard for added protection against blockages. Smaller material will be flushed through the system while in operation.
  • Outlet has been robustly designed to withstand foot traffic with all components being manufactured from Aluminium/Stainless Steel.

The outlet’s efficiency has been tested and its capabilities are incorporated into our design software that allows CGL to design the relevant amount of drainage outlets and pipes to suit each project. The drainage outlets have been tested at the University of Sheffield to BS-EN 1253-2:2003 and comply with BS EN 12056-3:2000. RainPulse is supplied as part of a system that includes suitable pipes which are HDPE or Aluminum (Mill/PPC). Our HDPE push-fit pipes are BBA Approved. The HDPE pipes are required to accommodate the flow and pressure of water in comparison to standard UPVC rainwater pipes which do not comply with the necessary efficiencies or specifications. This is the UK’s only push-fit HDPE system that allows for quicker installation on-site with no specialist installer. We also offer aluminum downpipes which can be supplied in mill finish or a PPC finish. All pipes are specifically designed to suit the project requirements with minimum joints and are fully welded/dressed. CGL Recommends the use of Flex-Seal Adaptor Couplings for connecting drainage pipes of differing materials and outside diameters together such as ground drainage connections.


Backed by Merson Group and over 80 years of manufacturing expertise, we have the expertise and resources to deliver projects of every scale.


We have all of the necessary training and accreditations to deliver your needs in a safe, compliant and sustainable manner. With over 80 years of manufacturing excellence, we are dedicated to the achieving standards of excellence in every area of our business..


Is RainPulse just another siphonic rainwater management system?

No. RainPulse is the only high performance single stack rainwater management system available on the market which drains from the gutter outlet directly into the ground drainage. No high level (horizontal) pipes are used.

Whats the difference between a syphonic rainwater management system and a RainPulse rainwater management system?

Performance – RainPulse rainwater outlets discharge independently of each other which means if there was a blockage the remaining rainwater outlets will pulse more regularly draining the requirements. Protection – Robust built-in leaf guard. The system is self-cleaning. Outlets are not dependant on a high-level horizontal pipe transferring all the water from the roof to the ground drainage. Cost – Push-fit pipes do away with the need for a specialist contractor.

What's the difference between a Rainpulse rainwater management system and a gravity fed drainage system?

Performance – At least 50% of fewer outlets are required when compared to a gravity-fed drainage system. Protection – Robust built-in leaf guard & the system is self-cleaning. Smaller pipes – maximum pipe diameter is 110mm.

What makes the RainPulse rainwater management system outperform a gravity drainage system by at least 50%?

Gravity-fed drainage systems are restricted by the natural vortex of water that takes place and the limiting factor of the downpipe. The British Standard EN 12056 states because the vortex of water creates air, the pipe is limited to a filling capacity of 1/3 water, 2/3 air. The RainPulse rainwater outlet has been designed with an anti-vortex plate that restricts air from getting into the pipe when working at maximum capacity, allowing the pipe capacity to be maximized (3/3 water).

What does it cost?
On a comparable roof the RainPulse rainwater management system (gutter, outlet, downpipe & installation) should at least be on parity with a gravity fed drainage system and will show a significant saving when compared with a siphonic drainage system.
Has the system been tested?
Yes. Tested by The University of Sheffield. The system has been tested to UKAS calibration for flow calculations/debris effect and to BS EN 12056 for membrane clamp test, crush stability test, heat test, and also independently by UKAS Calibration for flow rig test capacity to an analytical design program.
How long has the Rainpulse rainwater management system been on the market?
The Rainpulse rainwater management system was launched in 2009 and is sold all over the world. CGL are the licence holders for the UK.
Does the system need to be installed by an approved drainage contractor?
Yes. Contact sales@rainpulse.co.uk for a suitable drainage contractors depending on location/project size.
Can standard PVC plastic pipes be used with the RainPulse rainwater management system?
No. Standard plastic PVC pipes cannot be used, only HDPE pipes or Aluminium pipes can be used.
Can two outlets be swan necked into the one downpipe?
No. Each RainPulse stack works to 100% capacity during the pulsing phase leaving no capacity in the stack for another outlet to be added.
Does the RainPulse rainwater management system require overflows?
The British Standard BS12056 part 3 states drainage overflows should not be included as part of the overall roof drainage calculations, however, good working practice would be at least to have a tell-tale overflow per run.
Does the RainPulse rainwater management system have any moving parts?
No. The RainPulse rainwater management system does not have any moving parts.
Who performs the roof drainage calculations for the RainPulse rainwater management system?
CGL will perform roof drainage calculations based on information supplied by the customer, alternatively, customers can register for our free roof drainage calculation software – GDT2. To sign up for the roof drainage calculation software click this link.
What's the smallest I can make the gutter when using the RainPulse rainwater management system?
300mm sole width x 100mm deep.
Is noise an issue with the RainPulse rainwater management system?
Running rainwater naturally makes a noise, however, RainPulse rainwater management will create no more noise than a gravity-fed drainage system.


The Honda and Hyundai car dealerships at the Cheshire Oaks Retail Park in Ellesmere Port were conceived by architecture firm Mountford Piggot. The buildings were designed to be energy efficient as well as visually appealing, a feature that was achieved by utilising the CGL Gutters’ outlet.

chesire oaks

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