Captured rain water is much healthier for your garden than treated water from the mains. The crates are ideal for soakaways and attenuation tanks specified by planning and building control. Reduce the risk of flooding and its consequences by providing for better, more comprehensive and co-ordinated water management. Reels. Introduction: Attenuation cells, (also known as Storm Cells, Soakaway Modules, and Storm Crates) are the modern equivalent of a soakaway. More. Installation: Underground. The tool is designed to be used with a minimum of information by users who need not be drainage engineers. Delivery Info:KLARGESTER AQUAHOLD - Surface Water Storage Tanks Range. Gordon Kinchett, Ordered terram t1000. As part of our stormwater management system, we offer a range of attenuation and soakaway crates which offer aid in the storage and distribution of surface water in accordance with SUDS requirements. The soakaway crates have various load ratings that indicate their storage capacity. This product can bear up to 65 tonnes and is 1m x 0. This is placing drainage at the heart of construction projects, and with the sector kicking into gear following a challenging 2020, Mark Halsall, National Manager – Storm Water Control at ACO Water. Stormwater Attenuation Crates for Stormwater Attenuation Tank System. Rain Bloc Stormwater Attenuation/Soakaway Crate. When covered with non-woven geo-textile, it can build. Attenuation tanks Green roofs (*) SuDS Manual Page References will be included once the SuDS Manual update has been completed. Features & Benefits: Storage capacity of 290 litres. Suited to trafficked areas. Stormwater Attenuation Lagoon Also known as Detention Basins, Stormwater Lagoons are used to control the flow of. These strong, long lasting and eco-friendly crates are ideal for use in residential, commercial, industrial or retail areas including car parks. What sets this Polystorm Crate apart is its efficient interlocking mechanism. Stormwater attenuation tanks provide a storage system for rainwater and surface water. Click to download your FREE information pack. StormMaster is an innovative company specialising in underground infiltration and attenuation tanks in connection with sustainable urban drainage (SUDs) schemes. With every development in the UK needing some form of sustainable urban drainage system (SuDS), it’s important to know how an attenuation tank of this type is installed. They are versatile products that can be used under car parks, landscaped areas and heavy duty projects within residential, retail, commercial and industrial areas. Four StormCrates per 1m³; 95% void ratioHere at Drainage Superstore, we have a number of soakaway crates to choose from. 4. The honeycomb design is extremely strong allowing vehicle loading with minimal cover. The RainSmart® modular tank system is suited for subsurface infiltration, retention and detention stormwater applications. Consequently these systems can be installed under car parks and access roads as well as landscaped areas. 5L per crate. The list below also shows how many crates fit per m 3. This below ground Rain Bloc crate is a simple an effective way to form a Soakaway or attenuation tank. These include storm crates, storm attenuation tanks, storm attenuation lagoons, silt filters and flow controls. 1000 x 1000 x 400mm (0. 5 crates to provide 1. Stormwater Attenuation Tanks, also known as Modular Plastic Geo Cellular Units (egg. 0+. 1000mm x 1000mm x 400mm dimensions. Aquavoid Metro enables efficient attenuation of stormwater run off at or near its source in accordance with current best management practice. The current perception is that roof runoff is. What is a stormwater attenuation tank? Attenuation tanks are often confused with soakaway crates, and while there are some similarities between them, the way they operate is largely very different. As the crate structure fills, water begins to exfiltrate from the tank into the surrounding ground. This allows any construction site to release water at a rate that drains can adequately handle, thereby preventing a flood. Features. 4m in size and can hold 0. Features & Benefits: AquaCrate Stormwater Soakaway and Attenuation Crate 20 Tonne - 2. Comprising of. The Polystorm range of products and solutions for attenuation and soakaway applications. ABG blueroof – Blue Roof System. The system is ideally suited for the construction of underground infiltration, retention. This rainwater soakaway tank kit comprises the following: Rainbloc crates (1200x600x420mm, 95% void) (select dimensions required) Two part 300g/m² geotextile outerwrap for protection Deareation/ventilation outlet This below ground Rain Bloc crate is a simple an effective way to form an attenuation tank. Our storm attenuation systems are used to manage excess rainfall on new developments by collecting, storing and releasing stormwater in a controlled manner to local watercourses. Drainwell Crates are also used to retain stormwater for reuse. So how does it work: half of the attenuation tank takes surface water run-off and acts just as a regular attenuation tank, while. What is a stormwater attenuation tank? A stormwater attenuation tank allows for surface and rainwater storage, which can be a requirement when new housing, commercial developments or car parks are built. The system was created using stormwater attenuation crates, which offer an economical and versatile solution to stormwater management. This product can bear up to 62 tonnes and is 1m x 0. With a design that ensures that solids are. Stormwater Attenuation Lagoons. If purchasing in bulk give us a call so we can offer you the best price. It can hold 0. This water can then be re-used on-site. From £6,019. • Graf Stormwater soakaway crates: 3. Variobox attenuation systems for stormwater retention are the strongest available. 00 10,000 litre SuDS Rainwater Attenuation Tank with integrated flow regulator. Cost effective, particularly when used as a hybrid, value engineered system. The Stormwater. See the illustration. 6m x 0. Individual cells are assembled together to form an underground structure for use in commercial, industrial or residential sites. 2m x 0. In this video we take yo. Other factors to take into consideration include the expected flow rate and the type of soil in the ground. Bespoke stormwater attenuation tanks. crates are used in storm water retention, attenuation and infiltration applications. The void created by the crates can then. Go deeper with Polystorm Deep. To facilitate this, Geoline Ltd. Underground Rainwater Storage Tank Soakaway Crates Infiltration Tank Attenuation Crates Detention Tanks $26. Polystorm Crate. Features & Benefits . The drainage system and water storage-permeation and filtration system along side the roads, parking lot, water storage and drainage for the ecological shallow ridges, living community, factories. The crates are a single piece and. Torwood Glen. If specified without a geomembrane, the system can also be used as a soakaway. 4. 5m x 0. £69. 0144 m3 0. £69. If you are looking for high quality Stormwater Attenuation supplies, please visit Cotterill Civils online today & contact us on 0121 351 3230 for more info! Skip to content 0121 351 3230 I Mon - Fri 8am - 5pm. The runoff comes from car parking areas, golf courses, racecourses, as well as sports fields. Key Benefits of the PSM1A Polystorm-R Crate: Suitable for both attenuation and soakaway systems; 100% Recyclable; Only 4 StormCrates per 1m³; Load bearing strength of. Buy premium-quality soakaway crates from Build Plumb Plastics. The water is then released from the. 62’ x 1. Documentation. The full Rainbloc attenuation tank kit can be found here. We can provide you with expert advice on the different options available to you, including storm crates and bespoke stormwater attenuation tanks. The crates are a single piece and. In “hybrid” storm management systems SDS engineered water storage and treatment devices below-ground combine with, enhance the performance and extend the lifespan of vegetative SuDS materials above-ground. Joining as many crates together as required in order to achieve the specified void. The unit is available in two standard depths of 1. Car parks & roads. 5m incorporating a 150mm sump. They can be used in trafficked and non-trafficked. In some cases you may even need at least 4-5 cates per. The Surface water storage volume estimation tool provides both greenfield flow rate estimates for setting limiting discharge rates as well as surface water storage attenuation volume estimates for use in initial drainage design. Geocellular attenuation tanks or attenuation crates are also extremely space efficient, with a typical surface water holding capacity of 95% or above. These types of crates are. Dimensions: 1200mm x 600mm x 347mm. Therefore maximising an area for both land use and stormwater management is crucial in a developed city. AquaCrate 400 Rainwater Crates. Stormwater Attenuation Tank | Soakaway Crates | Infiltration Tanks | Modular. Cut outs are available for incoming pipework. £69. StormMaster is ideal for the bulk storage of stormwater in both attenuation and infiltration schemes. Crafted from 100% recycled plastic and manufactured within the UK our Rainsmart Ellipse storm and water attenuation crates are buried under earth, gravel or other permeable materials which creates a void space for the purpose of holding rain-water whilst allowing surface water to drain away. 00 Graf Infiltration Tunnel Kit for Soakaways, Attenuation and Wastewaster. Void Ratio: 95%. This capacity can meet the demands of most large projects for stormwater attenuation projects. Crate size 1200mm (L) x 600mm (W) x 420mm (D) (3. Intense periods of heavy rainfall are placing new challenges on our country's drainage infrastructure - it's reckoned that two thirds of the devastating 2007 summer floods were the result of surface water flooding - urban deluges which flooded over 44,000. It’s the fact that they’re wrapped and sealed in a completely watertight liner that they actually perform a job. Designed to suit any drainage layout with regards to connection sizes and orientation. 00 10,000 litre SuDS Rainwater Attenuation Tank with integrated flow regulator. The crates are ideal for soakaways and attenuation tanks specified by planning and building control. Attenuation Rainwater, which has been collected from impermeable surfaces, is directed to the crate structureStormwater attenuation and infiltration/soakaway crates ACO StormBrixx is a unique and patented plastic geocellular stormwater management system for attenuation and soakaway (infiltration) usage. water storage. Large net storage volume of 287 litres. Durable and long-lasting. For further information regarding Precast Concrete Tanks Please contact a member of our civil Sales Team on 028 2565 2566, Ext 3. The void created by the crates can then fill up with storm water during heavy rainfall conditions. With a design that ensures that solids are. NOT YOUR AVERAGE CRATE SYSTEM . 00 7,500 litre SuDS Rainwater Attenuation Tank with integrated flow regulator. Buried with 0. Please get in contact – 0121 351 3230. A storm pipe offers tensile strength and a low density making it a reliable transfer of water. 00 incl VAT. The Rain Bloc can withstand up to 60T with. They have an inlet that allows up to 97% of their occupied space to fill with water. Ecomerchant AquaCrate Attenuation & Soak-Away Crate 20 Tonne To 50 Tonnes Loading Capacity. Stormcell ® is a high-capacity, low-maintenance modular stormwater and surface water storage system that can be customised to suit shallow, deep or irregular sites. Easy installation, monitoring, and maintenance. Being experts in Sewage Treatment & Septic Tank Installations, we’re confident we can provide a solution that will last! Enquire Now. From £269. 83 inc VAT) KLARGESTER AQUAHOLD SM Range 14,000 - 29,000 litres. Compressive strength of 20 tonnes/m 2. The Naylor Aquavoid® range of attenuation crates provides an economic and versatile stormwater storage system for general (Traffic) and heavy duty use (Plus). Rainwater attenuation crates are used for a variety of uses. Effective stormwater attenuation relies on the ability of a product to trap and store. 5 %) Crate 9. Loading type. StormCrate55 Cellular Storm Water Crate 55 Tonne - 1200mm x 600mm x 347mm. The JFC HydroChamber is an arched chamber attenuation system designed specifically for building underground storage tanks for stormwater runoff in attenuation and soak away applications. The crates are designed to be simply and easily stacked together to create a below ground storm water holding tank or to allow the infiltration of storm water into the ground around them. Size: 2. The inlets/outlets are located in different positions and the crate structure fills when the flow rates exceeds the agreed discharge rate. Stormwater Tanks (M2017) Soakaway Crates (M2016B) Infiltration Tanks (M2016S) Harvesting Module (M2015F) Attenuation Tank (M2015H) Geocellular Units (M2014) Landscape Edging; Green Roof Trays. Designed to be installed underground, these light-weight crates are easy to assemble and connect together to enable you to create your required structure. Each crate is 0. Reviews. com. The Infiltrator ® Chamber is a pre-manufactured open underground unit that acts as a direct replacement for conventional storm water and waste water attenuation. Designed to be eco-friendly, our soakaway crates are made from recycled polypropylene and are recyclable at end of use, helping you meet sustainability targets. 4 crates and would require 750mm of cover for traffic or 500mm for non-traffic use. Alternatively, fill out our enquiry form:The attenuation tank crates/blocks are placed to the predetermined laying pattern, before holes for inlet, outlet and vent pipes are cut to size. A robust yet lightweight soak-away solution that gives the product a long life as well as making yours easier when it comes to installation. 00 7,500 litre SuDS Rainwater Attenuation Tank with. The crates are a single piece and can be easily maneuvered, stacked and placed. Stormwater crates are installed below ground and are used to control the flow of surface water when there is extreme rainfall. From £269. 62’ x 1. Get in touch today!Stormwater Management Systems. 5L per crate. Its versatile design allows the system to be used in configurations and applications across all construction environments as a standalone. Attenuation crates need to be designed to. Attenuation is where, with the use of flow controls, the water collected is slowly released back into an existing watercourse or sewer. Compare and contact a supplier serving South Africa. 64′ x 1. Graf Rain Bloc Stormwater Attenuation Crate - 3. StormCrate55 modular cellular crates are used in storm water retention, attenuation and infiltration applications. They are usually used for larger municipal or commercial applications. In some cases you may even need at least 4-5 cates per. Experts recommend that the bedrock should not be within one metre of the drainage piping, in order to maintain proper filtration levels. The compression fit units are stacked (if applicable) and sent preassembled to the construction site so there is no assembly required. Attenuation tanks are created underground using highly porous polymer crates that create a void which are sufficiently structurally stable to support the weight from overlying soils and vehicles above. Maximum installation depth of. Stormwater Attenuation Case studies. com : CORE Water | Soakaway Crates | Attenuation, Infiltration, Stormwater. Stormcell ® is a high-capacity, low-maintenance modular stormwater and surface water storage system that can be customised to suit shallow, deep or irregular sites. Looking for a Brett Martin Stormcrate Attenuation Tank? Find them a low prices from UK's #1 Drainage Wholesaler. Kingspan Klargester's Wastewater range is suitable for multiple applications, on and off-mains. Cotterill Civils have years of experience in supplying Land Drainage and Sewer Treatment solutions to clients across the UK. 3 Crates = 0. From £3,669. 75m for vehicular use, standard. Wavin AquaCell units are a tried and tested modular technique for managing excessive rainfall and can be assembled to create an underground structure as either a temporary attenuation tank or infiltration soakaway. Stormwater Attenuation & Infiltration Crates • Cellular stormwater attenuation crates • Ideal for domestic soakaways • 3. oh and don't forget we price match on most products! Storm water attenuation crates allow you to store large volumes of water which can then be slowly released into the surrounding soil. Hybrid SuDS. Our soakaway crates, attenuation tanks, attention pipes, flow control chambers and lagoons all help to prevent flooding, and slow down filtration time. Polypipe has a range of solutions for different needs, including, geocellular and large diameter pipe systems for surface water retention, attenuation and infiltration , surface water treatment products, flow control devices and rainwater re-use solutions. Stormwater management system with various applications: Rainwater infiltration, Stormwater attenuation, Rainwater harvesting, 60 tonnes/HS-20, 410 m³ (14. Integrated inlet and outlet. 00 15,000 litre SuDS Rainwater Attenuation Tank with integrated flow regulator. Polystorm: an 8 Step Guide. Most systems comprise of some sort of holding area (normally underground tanks) that fills up during a storm. Shows. These water attenuation/soakaway storage crates are lightweight and modular. The crates are designed to be easily stacked together to create a below ground storm water holding. Results for stormwater attenuation equipment from JFC, leiyuan, 2H GEOdek and other leading brands. Soakaway Crates (M2016B) Infiltration Tanks (M2016S) Harvesting Module (M2015F). 00 Graf Infiltration Tunnel Kit for Soakaways, Attenuation and Wastewaster. 125g/m. £69. Our EcoBloc stormwater attenuation crates are renowned for their modular nature, enabling them to fit into small spaces suiting different site specific constraints. Stormwater attenuation lagoons/detention. ACO. Attenuation Design. Rain Bloc Stormwater Attenuation/Soakaway Crate. The stored water inside the attenuation tank is released via a flow-control chamber and either pumped via a pumping chamber or run-off through a. Its versatile design allows the system to be used in configurations and applications across all construction environments as a standalone solution or. 7 · 276 views. We can also offer an installation service if required. 1. Soakaway Crates, also known as Attenuation Crates, Storm Cells or Storm Crates, are interlocking crate systems that allow surface water to be stored and gradually released back to the ground or sewer network slowly. Therefore maximising an area for both land use and stormwater management is crucial in a developed city. Home. Most small roof spaces will need 1m3 as specified by the building. 0 /5 · 0 reviews · Contact Supplier. We will look at the engineer’s design and optimise the tank depth to be as economical as possible for the contractor, even where there is a very shallow fall, or perhaps where we need to achieve. £69. An attenuation system can be designed to be online or offline. From £269. 5m x 0. Stormwater Management Brett Martin’s StormCrate55 modular cellular crates are used in storm water retention, attenuation and infiltration applications. Types of water management solutions. 6m for car park use, the Naylor Aquavoid-Metro can also be. Stormwater Management Brett Martin’s StormCrate55 modular cellular crates are used in storm water retention, attenuation and infiltration applications. Attenuate or infiltrate surface water and stormwater effectively even in challenging high-traffic urban environments. For more details contact our sales office. All of which are supported by our in-house Design. They have a heavy-duty lorry-bearing capacity of up to 60. 480 ft³)/Truck EcoBloc light Stormwater management system with various applications, Lorry-bearing 12 tonnes, 630 m³ (22. polypropylene soakaway crate for stormwater drainage storage. Stormwater attenuation tanks provide a storage system for rainwater & surface water. The StormMaster Heavy Duty Soak-away and Attenuation Crate is an extremely strong water permeable unit with a large storage capacity. £69. 3 crates per m 3. A stormwater attenuation tank is designed to collect and store excess surface water run-off from a large. The most common approach to creating an underground storage tank is to use; stormwater attenuation crates, impermeable geomembrane and geotextile to make a stormwater attenuation tank. With a compressive strength of 83 tonnes/m2, Polystorm Xtra is designed for various surface water solutions including, surface water rentention, surface water attenuation or surface water infiltration as a soakaway solution, for use in shallow burial depths and heavily trafficked applications such as lorry parks and industrial access roads. Variobox attenuation systems for stormwater retention are the strongest available, proven by rigorously testing for long term performance. Stormwater attenuation crates offer good flexibility as they can be stacked and most come with a void ratio of at least 90%, which helps to reduce any wastage of underground space. Cheap prices & extremely fast shipping guaranteed. Maximum installation depth of 4m. £54. These systems are required where there is a limitation to the quantity of rainwater which can be discharged. 5 m maximum installation depth; Connection DN 100 (4") on top; Pins for vertical connection already included in packaging unit; 3. Stormwater attenuation tanks provide a storage system for rainwater & surface water. By sgs. 00 Graf Infiltration Tunnel Kit for Soakaways,. Our storm attenuation systems are used to manage excess rainfall on new developments by collecting, storing and releasing stormwater in a controlled manner to local watercourses. It can be easily installed without heavy machinery one EcoBloc Inspect flex module weighs just 8 kg. Cut outs are available for incoming pipework. • Load bearing strength of 62 tonnes per m3 • 95% void ratio • 100% recyclable Hydrocell Soakaway Crate 62 Ton. Its superior design makes it suitable for building storage tanks under HGV trafficked and car park areas as well as non-trafficked areas (e. Our soakaway crates clip together to form a load-bearing underground water storage/attenuation system. £60. 2. The modular geocellular tank is made of polypropylene (PP), it is 100% recyclable at the end of its service life. The patented blue roof system utilises part of the roof build-up / depth for the attenuation of storm water, releasing it at a controlled rate in the period following the. This is provided free of charge from JDP Technical Support. Stormwater attenuation and infiltration/soakaway crates ACO StormBrixx is a unique. FREE shipping and FAST delivery. 27-29 High Street, Drayton, Abingdon, Oxfordshire OX14 4JW, England. The system counts towards 100% of attenuation volumes on-site at the same time as harvesting and re-using rainwater for a range of applications. Dimension: 1000mm x 1000mm x 400mm. SOAKAWAY CRATES FOR DRAINAGE SYSTEM. Large net storage volume of 287 litres per crate (302. Select the right Modular Cell. Applications. Attenuation crates, also known as soakaway crates, are used to control the level of surface water and reduce the risk of flooding. Geocellular attenuation or soakaway crates are also extremely versatile, which means they can be configured around site constraints. 19m3 per crate. Crafted from 100% recycled plastic and manufactured within the UK our Rainsmart Ellipse storm and water attenuation crates are buried under earth, gravel or other permeable materials which creates a void space for the purpose of holding rain-water whilst allowing surface water to drain away. The StormCrates are designed to be stacked together to create a huge. Attenuation has become an important consideration for any new build project where a SUDS strategy is required. Call us today. Leiyuan - Model M2015S - Infiltration Tank - Geocellular, for Underground Stormwater. of Stormwater Attenuation Tank - Attenuation Crates for. The installation is warrantied for 30 years as the membrane is wedge welded and the joints air tested. Soakaway Crates are quick & simple to install and a variety of size. S. Inlet to soakaway/attenuation tank 4. . 4m in size. The GRAF EcoBloc Inspect Flex Crate is a BBA Agrément-certified solution for versatile stormwater management needs. 9/m3. Domestic gardens. Using an Attenuation Tank gives you the ability to store large quantities of water from a wide. The system is comprised of base plates, crates and side. A stormwater attenuation tank is designed to collect and store surface water run-off as a result of a storm event. These include providing rainwater storage and attenuation to prevent flooding along with preventing peak flow to the main surface water drainage system. Stormwater Detention Tank Crates is also known as stormwater infiltration tank, and it also can be named as rainwater modular tank, stormwater attenuation crates, stormwater detention tank or rainwater retention tank, etc. An online attenuation system means the total volume of rainwater passes through the crate structure. Explore our wide range of durable and efficient products and make your selection today. The Polystorm geocelluar system can also be integrated with Permavoid systems. These include providing rainwater storage and attenuation to prevent flooding along with . £60. 00. Waste and water attenuation. Making use of Invisible Structure’s trademark ring-on-grid design, Rainstore3 exceeds H-20. Our extensive range of surface water drainage products are ideally suited to doing just that and include everything from unperforated (carrier drain) high-quality JFC twinwall, to geocellular soakaway and attenuation crates. A major retail and leisure complex in Northamptonshire has enhanced its sustainability credentials by using crates from ACO Water Management’s StormBrixx geocellular stormwater attenuation and soakaway (infiltration) system to promote extensive tree growth. green amenity areas). The crates are designed to be simply and easily stacked together to create a below ground storm water holding tank or to allow the infiltration of storm water into the ground around them. New – Semicircular Modular Sedum Trays; How Do Green Roofs Work? What are the benefits of a rooftop garden? How to grow plants on. Its flexible modular structure is light but strong, making it ideal for use beneath areas such as roads, car parks and industrial areas. Stormwater Solutions. FLI Precast supply award-winning Stormwater Attenuation Tanks. To facilitate this, Geoline Ltd. •DYKA Rainbox 3S soakaway crates: 3. 00 7,500 litre SuDS Rainwater Attenuation Tank with integrated flow regulator. ABG blueroof offers a new concept in the management of storm water on both flat roof and podium areas, and for new build and refurbishment projects. 5 yrs CN Supplier . 00 Product Details. As with a soakaway, an online system handles all stormwater through the storage area before being pumped into the drainage system. 00 Incl. Managing stormwater is becoming more and more of a challenge for builders and developers who need to meet the increasing regulation to control its flow. Attenuation systems are large storage facilities included in a drainage system so that rainfall from storm events can be stored onsite and slowly discharged instead of discharging the whole storm event as it happens. This enables Polypipe to supply fully integrated below ground drainage elements, which may be composed of a number of differing systems, each chosen to suit the proposed location. VAT. Step 2 – Prepare the crates. A hydro brake ensures it is released at a rate that won’t cause flooding or excess strain on the system. Max. Cut outs are available for incoming pipework. 480 ft³)/Truck The GRAF EcoBloc Maxx is the ultimate stormwater management solution designed for versatile applications including soakaway, stormwater attenuation, and rainwater. Stormwater Attenuation & Soakaway Crates. Benefits of Using. Stormwater Attenuation Tank, Geocellular Storage Crates Supplier, Stormwater Drainage Attenuation Systems. Cover depth. Our easy-to-assemble crate can be installed beneath gardens, pedestrian areas and. 5m x 0. Soakaway Crates, also known as Attenuation. Used as a soakaway, rainwater collected through pipes from a roof and/or road. • Cellular stormwater crate • 4 crates per 1m³ storage capacity • Lightweight and easy to install • High strength crate with lo ad bearing of 562kN per m² • Each crate can store up to 237. The JFC HydroChamber is an arched chamber attenuation system designed specifically for building underground storage tanks for stormwater runoff in attenuation and soak away applications. Void Ratio: 95%. The AquaCrate decreases the inconvenience of flooding during heavy rainfall, with rainwater “cleaned” by the geotextile surround. This product can bear up to 65 tonnes and is 1m x 0. Attenuation crates need to be designed to minimize. It has a 61 tonnes/m² compressive strength and is manufactured from over 90% recycled material content. Earlier this year, we assessed the carbon footprint of two different types of attenuation.