The answer to new challenges: The new ACO Passavant flat roof gully

ACO Building Drainage has launched the new ACO Passavant flat roof gully range -  a newly developed range of flat-roof cast iron gullies designed for use with modern gravity drainage systems.

The effects and influence of climate change and increasingly extreme weather events, mean roofs are now required to fulfil numerous functions including the retention of rainwater to protect overloaded sewer systems and the enhancement of the urban climate during dry periods. The new ACO Passavant flat roof gully has been designed specifically for use with gravity drainage in flat roof applications and fulfils the new and stricter requirements for roof drainage.

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Utilising cast iron as a material for flat roof gullies provides a number of advantages compared to other materials: Increased safety with fire protection; greater durability due to the cast iron material; flexibility in connection, and compact in design.

Cast iron is non-combustible, corresponds to building material class A1 and, as a result, does not introduce any additional fire load into the building. The ACO Passavant flat roof gully fulfils the requirements of fire protection resistance classes R30 - R120 even with a minimum flat roof thickness of 150 mm or more. The gully, in connection with the fire protection cartridge, ensures integrated fire protection. This means that, irrespective of which pipe is connected (plastic, steel or cast iron), fire protection and safety are always guaranteed. If the flat roof gully is installed in an insulated roof and fire protection is required, then a fit-in fire protection insulating body is utilised. This can be utilised without an additional heat shield.

In terms of durability, the most important factors are the coefficient of thermal expansion, UV resistance and resistance to extreme heat and cold. Differing coefficients of thermal expansion create a risk of stress cracks in components. Since cast iron and concrete indicate approximately the same coefficients, this danger is averted from the outset with the ACO Passavant flat roof gully. The same applies to UV resistance as cast iron does not require a separate coating. The material properties of cast iron remain constant for decades.

A modular product, ACO Passavant flat roof gully designs are suitable for use with a wide variety of roof structures including cold, warm or reversed roofs with a gravel fill, surface covering made from slabs or created as a greened area. Every material of the sealing membrane can be reliably pressed into the compression seal flange - the material of the gully has no effect on the choice of seal material. Gratings are available as insert-capable versions and - for utilisation in areas at risk of vandalism - screwed in versions. Subsequent adjustment of the grating height can be easily completed by using two height adjustment rings (ranges 25-40 mm and 45-60 mm). The design and construction of the components required for emergency drainage reliably prevents unattractive dripping when subject to normal amounts of rainfall.

The new ACO Passavant flat roof gullies are also more compact and lighter than previous designs - an advantage which is appreciated by fitters and which is also relevant for structural calculations for lightweight metal roofs (trapezoidal sheet metal roofs).

Designers will also benefit from the new design: The depth of the product range has been reduced and as a result, specification has been made simpler without any restriction on the range of solutions available for different types of roof structure.

Two upper parts and two grating ranges are available for a total of six gully variants (DN 70/100/125/150 with 90° and DN 70/100 with 1.5° socket inclination). The incorrect specification of drain and grating combination, and planning errors are therefore reduced to an absolute minimum.  The design and planning process is also made as easy as possible as there is only one relevant dimension for the core hole drilling (except for DN 125/150) - diameter 160 mm.

Additional information regarding the new ACO Passavant cast iron flat roof gully can be obtained from ACO Building Drainage.

ACO Building Drainage is a specialist division within the ACO Group.  It designs and manufactures drainage, separators and pumps for use in domestic and commercial buildings. As one of the leading suppliers of system solutions, ACO Building Drainage has extensive experience and capabilities in the field of building technology.  Working in partnership with its customers, ACO Building Drainage provides market-leading products, delivery and design services.