External blinds
Controlling the entry of solar heat and light has considerable effects on the energy needs of a building. External blinds may be just one of the options available to specifiers, but they are highly effective.
The use of correct solar shading provides a major impact on not just the energy consumption of the building, but also on the thermal and visual comfort of the building users. The need to control overheating and thermal comfort is becoming increasingly important in all types of buildings, from residential to commercial.
Solar shading can be effective as part of a combination of passive measures to combat overheating. It can reduce the swings in temperature which can occur on sunny days.
For measuring the amount of solar radiation that reaches the interior of the building, the solar transmittance value is used. The shading coefficient can also be used; this gives the solar transmittance as a fraction of that for unshaded glazing. A low solar transmittance or shading coefficient means that the system is particularly good at reducing solar gain. External blinds have the lowest shading coefficient of any of the available shading systems. They are found to be so effective as they stop incoming solar radiation before it enters the building through the glazing.
Selecting the right solar control is important. Look at the extent to which they block incoming daylight, as this might increase the use of artificial lighting, increasing energy usage. Where view out is of a great concern, retractable blinds with an element of occupant control give most freedom. When used on roof lights external blinds can also help to reduce the noise of hail stones and rainfall. They are particularly well suited to retrofit situations, given that installation can be carried out with little disruption to the building users.
Not just for use in reducing cooling demand; external blinds can also reduce heat loss. Proper management of the system allows the blinds to be adapted to changing weather conditions. When they are closed at night, a trapped layer of air is created, reducing over night heat loss in cold weather.
More commonly used on the continent external blinds are becoming more familiar in the UK. Bere:architects used timber external blinds with automatic controls on their Camden Passivhaus and Venner Lucas Architects incorporated external roller blinds into their Sunnybank Passivhaus project.
Astralux 8000 Venetian Blinds
The adjustable slats of these blinds allows light penetration to be adjusted. The sides of the blind are guided by either an aluminium channel or a stainless steel cable. An automatic tilting device lowers and tilts the slats to a 45 degree angle.
Manufacturer: Dearnleys Ltd
Type: venetian blind
Application: commercial, education, office buildings
Material: aluminium
Operation: either manual or electric
Hardware and louvre colour: powder coating to RAL colours
Usage: externally
Maximum width: 4000mm
Maximum drop: 4000mm
Slat sizes available: 50mm, 60mm, 80mm or 88mm
Life expectancy: 10 years
Astralux 6000 Louvre Blinds
The Astralux 6000 system is well suited to awkward shapes and large sloping areas of glazing. It is designed for use in commercial environments where there is a need for low maintenance and durability.
Manufacturer: Dearnleys Ltd
Type: louvre blind
Application: commercial, museum, art galleries
Material: timber or aluminium
Operation: electric motor or gearbox
Hardware and louvre colour: powder coating to RAL colours
Usage: externally
Maximum width: 5000mm
Slat sizes available: 80mm
Life expectancy: 20 years
Roller Blind EOS 500
This modular system is suitable for both large and small scale windows. The blinds use fabrics which are fire retardant, can utilise different openness factors and colours, and do not sag or stretch.
Manufacturer: Faber
Type: roller blind
Application: commercial, office buildings
Material: PVC free fabric
Operation: chain operated crank or motorized
Fabric colour: a wide range of colours and patterns available
Hardware colour: powder coated to a range of RAL colours
Usage: externally
Maximum width: 3300mm
Maximum drop: 4000mm
Awning Blind
This blind is specifically designed for use with roof lights. Working in a similar way to a roller blind, the fabric is roller mounted, spring loaded, and fitted inside an aluminium casing which is installed at the top of the window.
Manufacturer: Fakro
Type: awning
Application: residential
Material: glass fibre fabric
Operation: manual
Fabric colour: available in 3 colours
Usage: externally
Sizes: to fit standard Fakro roof light sizes
Trojan External Venetian Blind
With the louvres of these blinds closed as little as 10 percent of the sunlight is transmitted through the glass. These blinds also have an option to of a z shaped louvre which block provide the internal lighting levels required for audio visual presentations.
Manufacturer: Hallmark Blinds
Type: venetian blind
Application: commercial, higher education, office buildings
Material: aluminium
Operation: manual or motorized
Hardware and louvre colours: available in 20 standard RAL colours
Usage: externally
Maximum width: 5000mm
Maximum drop: 5000mm
Life expectancy: 20 – 25 years
External Venetian Blind
These blinds are lowered at a pre-set tilt angle of 40º for optimal protection. This tilt angle can be regulated to keep direct sunlight out and let natural daylight in creating flexibility for the users.
Manufacturer: Hunter Douglas
Type: venetian blind
Application: residential, commercial, industrial
Material: aluminium
Operation: manual or motorized
Hardware and louvre colour: available colour coated with enamelled polyester paint in 10 standard coloursUsage: externally
Maximum width: 8000mm
Maximum drop: 4000mm
Slat sizes available: 50mm, 60mm, 80mm, 88mm
Tensioned Fabric Blinds
These blinds can be used internally or externally either on horizontal, vertical or sloping glazing. High levels of performance can be achieved by linking the operating system to sun sensors, internal temperature controls, or a time programme.
Manufacturer: Levolux
Type: tensioned fabric
Application: office buildings, commercial and residential
Material: fabric
Operation: either by a switch or automatic control
Fabric colour: a wide colour choice available
Usage: externally
Maximum width: 6000mm
Maximum drop: 6000mm
Specialist Venetian Blinds
The aluminium slats of these blinds are heat treated and double stove enamelled to provide resistance to surface abrasion created by the slats rubbing against each other. This also reduces maintenance by providing protection to peeling, corrosion, chaffing and fading.
Manufacturer: Levolux
Type: venetian blind
Application: office buildings, commercial and residential
Material: aluminium
Operation: manual, motorised, or fully automated
Hardware and louvre colour: a wide colour choice available
Usage: externally
Maximum width: 5000mm
Maximum drop: 6000mm
Slat sizes available: 50mm, 60mm, 80mm, and 100mm
Abrishade
A fabric blind designed for use on large expanses of glazed roof, making it particularly well suited for greenhouses and other industrial applications. The fabric is designed to fold into a storage box for protection when not in use.
Manufacturer: Living Shade
Type: fabric blind
Application: conservatories, atria, commercial, industrial, and greenhouses
Material: waterproof fabric
Operation: motorised or manual control
Fabric colour: white
Usage: externally or internally
Maximum width: 3000mm
VertiTex
This system can be installed either on the window frame or within the window reveal. It is controlled automatically with the both a wind and sun monitor. The fabric used has a surface which repels water and dirt minimising maintenance.
Manufacturer: Weinor
Type: roller blind
Application: residential, balconies and patios
Material: acrylic fabric
Operation: remote controlled motor
Hardware colour: 47 standard RAL colours available
Fabric colour: 9 colours available
Usage: externally
Maximum width: 6000mm
Maximum drop: 2400mm
External Roller Blinds
Used by Venner Lucas Architects on their Sunnybank Passivhaus, these blinds block up to ninety-six percent of incoming solar radiation. They can be fitted outside both windows and doors creating a unified facade.
Manufacturer: Caribbean Blinds
Type: roller blind
Application: residential
Material: fabric
Operation: motorized or manual
Fabric colour: up to 5 different fabric ranges
Hardware colour: powder coated to any specified RAL colour
Usage: externally
Maximum width: 6000m
Maximum drop: 6000m
Life expectancy: 15 – 20 years for motorized operation, and 10 – 15 years for manual operation
Venetian Blinds
These blinds are typically supplied motorised, enabling them to be connected to the buildings BMS system for greater control and flexibility. Optional cable and side guiding systems are available to meet the needs of individual projects.
Manufacturer: Faber
Type: venetian blind
Application: commercial, office buildings
Material: aluminium
Operation: motorized
Hardware and louvre colour: powder coated to a range of RAL colours
Usage: externally
Maximum width: 3000mm
Maximum drop: 4000mm
Slat sizes available: 50mm, 60mm, 80mm, 88mm, and 100mm
Architectural Blinds
These blinds control heat and glare while allowing filtered daylight into the building. They can be easily retrofitted to both masonry and curtain walls. The manufacturer claims that its use can lead to a 39 per cent reduction in the building’s energy costs.
Manufacturer: CS Solarmotion
Type: venetian or roller
Application: commercial, education and residential
Material: aluminium
Operation: motorised or automated using a solar tracker
Max width: 4,800mm
Max length: 4,600mm
Slat sizes: 60mm and 80mm
Cayman Tensioned Roof Blind
Using a range of dim-out or blackout fabrics, these exterior roof blinds control solar heat, glare, UV and sunlight. Their motorised control can be optimised through the use of a variety of different automatic sensors.
Manufacturer: Caribbean Blinds
Type: tensioned roller blind
Application: commercial, education and residential
Material: fabric with a TEXgard coating
Operation: motorised
Colour: available in any RAL colour
Max width: 5,000mm
Max drop: 6,000mm
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